Samara City District Administration
AMOU VPO Samara Academy of State and Municipal Administration
Faculty of Economics
Department of Cadastre and Geoinformation Technologies
Test
by discipline: "Materials Science"
on the topic: "Raw materials for the production of ceramic building materials"
Samara, 2013
Content
Introduction ……………………………………………… .. …… ……….… .. …….… .3
I. General information and raw materials for the production of ceramic building materials …………………………………………………………………………… ..4
II. Formation of clay materials and their chemical and mineralogical compositions ………………………………………………………………………………………………………………………………………………………………………………………………… .6
2.1 Main mineral components of clays ………………………………. 7
2.2 Impurities …………………………………………………………………… ..8
2.3 Chemical composition clay …………………… ……………………………… ... 9
3.1 Granulometric composition of clays ………………………………………… .12
3.2 Technological properties of clays …………………………………………… 13
3.3 Classification of clay raw materials for ceramic products ……… 20
Bibliography………………………………………….…. 24
Appendices …………………………………………………………………… .... 25
Introduction
In this test, on the topic: "Ceramic building materials" we will consider:
-
general information and raw materials for the production of ceramic building materials;
formation of clay materials and their chemical and mineralogical compositions;
technological properties of clay materials.
Ceramic production originated in prehistoric times after people learned to receive and use fire. The man saw that with the help of heat it is possible to preserve the shape of objects molded from clay and make them impervious to water. It was soon noticed that all clays have different properties and that different clays should be used to make certain products.
Ceramic building materials fully meet the requirements of durability and have high architectural and artistic qualities. They are resistant to aggressive environments, weather-resistant and frost-resistant.
Ceramic products are widely used in many sectors of the national economy and in everyday life. They are used as building materials - bricks, roof tiles, wall and floor tiles, sewer pipes, various sanitary products. Porcelain and earthenware crockery remains the most widespread and widely used dish to this day.
I. General information and raw materials for the production of ceramic building materials
Ceramic is called artificial stone materials obtained by firing raw material molded from clay rocks. Ceramic materials used since ancient times have many advantages: raw materials for them are widespread in nature; raw can be given any shape; fired products are strong and durable. The disadvantages of ceramic materials include: the ability to manufacture products of only relatively small sizes; high fuel consumption for firing; the difficulty of mechanizing work in the construction of structures made of ceramic materials.
Depending on the porosity, ceramic materials are divided into porous with a water absorption of more than 5% and dense with a water absorption of less than 5%. Both dense and porous materials can refer to coarse ceramics, characterized by a colored shard, or fine ceramics, characterized by a white and uniform shard at fracture. In construction, coarse ceramics are used more widely. Regardless of the porosity and color of the shard, ceramic materials can be unglazed and glazed. Glaze is a glassy layer applied to the surface of a material and fixed to it during firing. The glaze has a high density and chemical resistance.
Depending on the field of application in construction, ceramic materials are divided into the following groups:
wall - ordinary clay brick, hollow and porous-hollow plastic molding, solid and hollow semi-dry pressing, hollow plastic molding stones;
hollow stones for frequently ribbed ceilings, for reinforced ceramic beams, roll stones;
for facing the facades of buildings - facing bricks and stones, carpet ceramics, small-sized facade tiles, facade slabs and window-sills;
for interior cladding of buildings - wall cladding tiles, embedded parts, floor tiles;
roofing - ordinary clay tiles, ridge, end-grooved and special;
ceramic pipes - sewer and drainage;
special-purpose materials - bricks, curved stones for sewage facilities, sanitary and highly porous heat-insulating ceramics, acid-resistant products (bricks, tiles, shaped parts and pipes), refractory products (bricks, shaped tiles and parts).
According to the established tradition, porous products of a coarse-grained structure from clay masses are called coarse ceramics, and products of dense, fine-grained structure, CA sintered shard, waterproof, such as floor tiles are called thin building ceramics.
In the production of building ceramics, mainly methods of plastic formation and semi-dry pressing are used, and much less often casting into plaster molds (sanitary-technical products).
Many scientists believe that the main strength of sintered ceramic materials is provided by mullite. Mullite 3Al 2 O 3? 2SiO 2 forms needle-shaped, prismatic or fibrous crystals with clearly distinguishable perfect cleavage.
The composition of mullite has long been the subject of discussions, as a result of which researchers came to the conclusion that the composition of mullite ranges from 2Al 2 O 3? SiO 2 to 3Al 2 O 3? 2SiO 2.
The mineral can produce intergrowths and accumulations (Appendix A). Impurities of Fe 2 O 3 and TiO 2 cause the appearance of pleochrism in yellowish and bluish tones. The density of mullite is 3.03 g / cm 3. The size of mullite crystals is varied: from 2 to 5 × 10 -6 m, in chamotte - up to 10 mm in length in mullite objects. Also included in porcelain.
II. Formation of clay materials and their chemical and mineralogical compositions
Clay is a finely dispersed product of decomposition and weathering of a wide variety of rocks (the predominant particle size is less than 0.01 mm) - it is capable of forming a plastic mass with water, which retains the shape given to it, and after drying and firing it acquires stone-like properties.
Depending on the geological conditions, the formation of clays is divided into residual or primary (eluvial), formed directly at the place of occurrence of the parent rock, and sedimentary or secondary, formed by transfer and redeposition by water, wind or glaciers to a new place. As a rule, eluvial clays are of poor quality, they retain parent rocks, they are often clogged with iron hydroxides and usually have low plasticity.
Secondary clays are divided into deluvial, carried by rain or snow waters, glacial and loess, carried by glaciers and wind, respectively. Deluvial clays are characterized by layered strata, great heterogeneity of composition and contamination with various impurities. Glacial clays are usually overlain by lenses and are heavily clogged with foreign inclusions (from large boulders to fine gravel). The most homogeneous are loess clays. They are characterized by high dispersion and porous structure.
Clay rocks (clays, loams, mudstones, siltstones, shales and others) used as raw materials for the production of ceramic bricks and stones must comply with the requirements of OST 21-78-88 (valid until 01.01.96), and the classification of raw materials is given in GOST 9169-75 *.
The suitability of clay for bricks is determined based on the mineral and petrographic characteristics, chemical composition, indicators of technological properties and rational characteristics.
2.1 The main mineral constituents of clays: kaolinite, montmorillonite, hydromica (illite).
Kaolinite (Al 2 O 3? 2SiO 2? 2H 2 O) - has a relatively dense structure of the crystal lattice with a relatively small interplanar distance of 7.2 A. Therefore, kaolinite is not able to attach and firmly hold a large amount of water, and when drying clay with a high kaolinite give off attached water relatively freely and quickly. The particle size of kaolinite is 0.003 - 0.001 mm. The main varieties of the kaolinite group are kaolinite, dikkit, nakrit. Kaolinite is the most common. Kaolinite is not very sensitive to drying and firing, weakly swells in water and has a low adsorption capacity and plasticity.
Montmorillonite - (Al 2 O 3? 2SiO 2? 2H 2 O? NH 2 O) (Appendix B) - has a weak connection between the packets, since the distance between them is relatively large - 9.6-21.4 A, and it can grow under the influence of intervening water molecules. In other words, the crystal lattice of montmorillonite is mobile (swelling). Therefore, montmorillonite clays are capable of intensively absorbing a large amount of water, holding it firmly and difficult to release during drying, as well as swelling strongly when moistened with an increase in volume up to 16 times. The particle size of montmorillonite is much less than 1 micron (<0,001мм). Эти глины
имеют наиболее высокую дисперсность
среди всех глинистых минералов, наибольшую
набухаемость, пластичность, связность
и высокую чувствительность к сушке
и обжигу.
The main representatives of the montmorillonite group are: montmorillonite, nontronite, beidelite.
Halloysite - Al 2 O 3? 2SiO 2? 4H 2 O - includes halloysite, ferrigalloysite and metagalloisite, is a frequent companion in kaolinite and kaolinite clays. Halloysite, in comparison with kaolinite, has a greater dispersion, plasticity and adsorption capacity.
Hydromica - (illite, hydromuscovite, glauconite, etc.) are a product of varying degrees of hydration of micas. They are found in significant quantities in low-melting clays and in small quantities in refractory and refractory clays.
Illite (hydromica) - K 2 O? MgO? 4Al 2 O 3? 7SiO 2? 2H 2 O - is a product of long-term hydration of micas, and its crystal lattice is similar to montmorillonite. In terms of the intensity of their bond with water, hydromica occupy an intermediate position between kaolinite and montmorillonite. The particle size of hydromica is of the order of 1 micron (~ 0.001mm).
2.2 Impurities.
In addition to clay components, clayey rocks include various impurities, which are divided into quartz, carbonate, ferruginous, organic and alkaline oxides.
Quartz impurities are found in clay in the form of quartz sand and dust. They thin the clay and impair its plasticity and formability, although coarse quartz sand improves the drying properties of clays, and fine quartz degrades them. At the same time, quartz impurities worsen the firing properties, lowering the fracture toughness of fired products when they are cooled, and reduce strength and frost resistance.
Carbonate impurities are found in clays in 3 structural forms: in the form of finely dispersed uniformly distributed dusty particles, loose and powdery smears, and in the form of dense stony particles.
Finely dispersed carbonate impurities, decomposing during firing according to the reaction CaCO 3 = CaO + CO 2, contribute to the formation of a porous shard and a decrease in its strength. These small inclusions are not harmful to wall ceramics. Loose smears and accumulations during mechanical processing of clay are easily destroyed into smaller ones and do not significantly reduce the quality of products.
The most harmful and dangerous are stony carbonate inclusions larger than 1 mm, since after firing the ceramics, these inclusions remain in the shard in the form of burnt lime, which subsequently, when moisture is added from the atmosphere or, for example, when the fired products are moistened, transforms into calcium hydroxide according to the scheme
CaO + H 2 O = Ca (OH) 2 + Q (heat).
Considering that the volume of hydroxide in comparison with CaO increases more than four times, significant internal stresses arise in the shard, causing the formation of cracks. If there are many of these inclusions, complete destruction of the ceramic product is possible.
Ferrous impurities color ceramics in different colors: from light brown to dark red and even black. Organic impurities burn out during firing, they significantly affect the drying of the product, as they cause large shrinkage, which leads to the formation of cracks.
2.3 The chemical composition of clays.
The content of the main chemical constituents in the clay rock is estimated by the quantitative content of silicon dioxide, including free quartz, the amount of oxides of aluminum and titanium, iron, calcium and magnesium, potassium and sodium, the amount of sulfur compounds (in terms of SO 3), including sulfide.
Usually the chemical composition of low-melting clays is,%: SiO 2 - 60 ... 85; Al 2 O 3 together with TiO 2 - not less than 7; Fe 2 O 3 together with FeO- no more than 14; CaO + MgO - no more than 20; R 2 O (K 2 O + Na 2 O) - no more than 7.
Comparative characteristics of the chemical composition of various clays are given in table. 1.
Table 1. Chemical composition of clays
Silica (SiO 2) is in clays in bound and free states. The first is a part of clay-forming minerals, and the second is represented by siliceous impurities. With an increase in SiO 2 content, the plasticity of clays decreases, porosity increases, and the strength of fired products decreases. Limiting content of SiO 2 - no more than 85%, including free quartz - no more than 60%.
Alumina (Al 2 O 3) is found in clay-forming minerals and micaceous impurities. With an increase in the Al 2 O 3 content, the plasticity and refractoriness of clays increases. Usually, the alumina content is indirectly judged on the relative size of the clay fraction in the clay rock. Alumina contains from 10-15% in brick and up to 32-35% in refractory clays.
Alkaline earth metal oxides (CaO and MgO) are present in small amounts in some clay minerals. At high temperatures, CaO reacts with Al 2 O 3 and SiO 2 and, forming eutectic melts in the form of aluminum-calcium-silicate glasses, sharply lower the melting point of clays.
Alkaline earth metal oxides (Na 2 O and K 2 O) are part of some clay-forming minerals, but in most cases they are involved in impurities in the form of soluble salts and in feldspar sands. They lower the melting point of the clay and weaken the coloring effect of Fe 2 O 3 and TiO 2. Alkali metal oxides are strong fluxes, contribute to an increase in shrinkage, compaction of a shard and an increase in its strength.
As the limiting value of sulfur compounds in terms of SO 3, no more than 2% is taken, including sulphide - no more than 0.8%. In the presence of SO 3 more than 0.5%, including sulphide not more than 0.3%, in the process of testing clay rock, methods of eliminating efflorescence and efflorescence on unbaked products by converting soluble salts into insoluble ones should be determined.
III. Technological properties of clay materials
3.1 The particle size distribution of clays is the distribution of grains in a clayey rock according to their size. Typically, the grain size composition of various clays is characterized by the data shown in Table 2.
Table 2 . Grain composition of clays
Comparing the data of the tables of chemical (Table 1) and granulometric (Table 2) compositions, we can conclude that their fluctuations are significant for various clays, which does not allow us to accurately establish the relationship with the properties of raw materials. However, there are certain general patterns. An insignificant content of alumina (Al 2 O 3) with a high content of silica (SiO 2) indicates a high content of free silica, which is mainly found in the coarsely dispersed component of clays and is a natural leaning additive.
Low-melting clays are characterized by the highest content of SiO 2 and fluids (R 2 O, RO, Fe 2 O 3) and the lowest content of Al 2 O 3. Here, alumina is almost completely included in the composition of clay-forming minerals, as indicated by the data in Table 2, where the content of particles less than 0.001 mm in fusible clays is the smallest in comparison with refractory and refractory clays.
The increased content of Al 2 O 3 in clays indicates a large amount of clay matter, its greater dispersion, and, consequently, a greater plasticity and cohesion of the material. A high content of fluids and especially R 2 O (Na 2 O and K 2 O) with a low content of Al 2 O 3 indicates a low refractoriness of the clay. The less the clay contains smoother, the more refractory and sintered at higher temperatures. However, the simultaneous presence in clay of a significant amount of alkali oxides (mainly K 2 O) with a simultaneous high content of Al 2 O 3 and a low content of other fluxes can cause high refractoriness of clays and the ability to sinter at low temperatures, which makes it possible to manufacture a wide range of porous and sintered products. Thus, on the basis of knowledge of the chemical-mineralogical and grain composition of raw materials, one can approximately estimate its properties.
3.2 The technological properties of clays characterize the material at different stages of its processing in the process of making products from it. The technological properties of clay rocks are studied in laboratory conditions, and the results of the study are, as a rule, verified in semi-industrial conditions. For bentonite, refractory clays and ceramic raw materials, laboratory test results are verified under industrial conditions. With the planned use of clayey rocks for purposes for which there is no experience in processing in industrial conditions, as well as when studying the possibility of using raw materials that do not meet the requirements of standards and technical conditions, technological studies are carried out according to a special program agreed with the interested organizations.
The most important technological properties of clay rocks that determine their use in industry are plasticity, refractoriness, sintering, swelling, as well as swelling, shrinkage, shrinkage, adsorption capacity, binding capacity, hiding power, color, the ability to form stable suspensions with excess water, relative chemical inertness. ... These properties are determined by the processes occurring in the material when it is mixed with water, molded, dried, and fired.
If dry clay powder is moistened with water, its temperature will rise. This is due to the fact that water molecules are firmly bound to clay-forming minerals and are arranged on them in a certain order.
Moisture capacity characterizes the ability of clay to hold a certain amount of water and retain it. With an increase in the dispersion of clay, its moisture capacity increases. Montmorillonite clays have the highest moisture capacity, kaolinite ones - the least.
Swelling is the ability of clay to increase its volume by absorbing moisture from the air or by direct contact with water. The swelling process dies out over time. Loose clays swell faster than dense clays. The sandiness of the clays reduces the degree of their swelling. Montmorillonite clays swell more than kaolinite clays.
Dilution is the disintegration of large clay aggregates in water into smaller or more elementary particles. The first stage of the disintegration of a clay aggregate occurs when it swells, when water molecules, being drawn into the gaps between clay grains, wedge them. As the thickness of the water shell increases, the bond between individual clay grains is weakened, and they begin to move freely in the water, being in suspension in it - the clay is completely soaked. To speed up the soaking process, the clay is stirred, mechanically breaking its pieces, or the water is heated.
Clay in water gets wet. Dense clays are very difficult to soak. Pre-crushing and mixing while soaking speeds up this process. When wet, water, penetrating into the pores between clay particles, wedges them. Aggregated particles break down into smaller grains or elementary particles of clay minerals with the formation of a polydisperse system. At the same time, clay particles begin to absorb water, which is absorbed between the layers of groups of atoms ("pack") of the crystal lattice of clay particles. In this case, the particles swell and increase in volume.
Water in clay always contains a certain amount of dissolved salts, the molecules of which are dissociated into ions. The cations of these salts, being carriers of positive charges, are also surrounded by their “own” water shell and together with it can be either in a diffuse layer or on the surface of a grain of a clay-forming mineral, creating a so-called sorbed complex.
Processes involving an exchange complex of ions sharply affect the stability (resistance to settling) of clay slurries of slips, water filtration in clay-containing masses during dehydration (filter pressing) of masses or during drying. They affect the mechanical properties of plastic clay masses and dry semi-finished product.
Thixotropic hardening is the property of a wet clay mass to spontaneously restore damaged structure and strength. So, if a freshly prepared slip (clay mass of liquid consistency) is left alone for a while, it will thicken and harden, and after mixing its fluidity will be restored. This can be repeated many times. Self-strengthening of clay occurs due to the process of reorientation of clay particles and water molecules, which increases the strength of their cohesion. In this case, part of the free water passes into bound water. The thixotropy of clays is of great importance in the preparation of slips, plastic dough and molding products.
The phenomenon of thixotropic hardening of clay slip in the ceramic industry is called thickening. The amount of thickening depends on the nature of the clays, electrolyte content and moisture content.
Liquefaction is the property of clays and kaolins to form mobile stable suspensions when water is added. The amount of water required for liquefaction is determined by the mineralogical composition of the clays and is regulated by the addition of electrolytes. Optimum liquefaction, i.e. a combination of sufficient fluidity and the lowest hearth content, is achieved with the correct choice of electrolyte and its concentration. As electrolytes, usually 5% or 10% solutions of soda, water glass, sodium pyrophosphate, etc. are used.
Plasticity is the ability of clay to form a dough when mixed with water, which, under the influence of external mechanical forces, can take any shape without breaking the continuity and retain this shape after the action of the forces ceases. The plasticity of clays depends on the grain and mineralogical composition, as well as the sandiness of the clays. With an increase in the dispersion of clays, their plasticity increases, montmorillonite clays have the greatest plasticity, kaolinite clays have the least.
Binding ability - the property of clays to bind particles of inelastic materials (sand, chamotte), while maintaining the ability of the mass to be molded and to give a sufficiently strong product after drying. The binding capacity depends on the grain size and mineralogical composition of the clay.
Changes that occur in the clay mass during drying are expressed in properties such as air shrinkage, the sensitivity of the clay to drying, and the moisture-conducting ability.
Air shrinkage is the reduction in the linear dimensions and volume of a clay sample when it is dried. The amount of air shrinkage depends on the quantitative and qualitative composition of the clay matter and the moisture capacity of the clay and ranges from 2 to 10%. Montmorillonite clays have the highest shrinkage, kaolinite clays - minimum. Sandiness of clays reduces air shrinkage.
For the same clay, the amount of air shrinkage depends on the initial moisture content of the sample. In the first period of drying, the volumetric shrinkage is equal to the volume of moisture evaporated from the product. In this case, first of all, capillary water evaporates from the clay, which has a less strong bond with clay particles. Then the water from the hydration shells begins to move into the capillaries, the thickness of the shells decreases, and the clay particles begin to approach. Then there comes a moment when the particles come into contact, and the shrinkage gradually stops. The grains of non-plastic materials can also converge due to the convergence of clay particles, however, other grains prevent the complete convergence of clay particles, i.e., the presence of non-plastic materials in the mass reduces air shrinkage.
The sensitivity of clays to drying affects the drying time - the more sensitive the clay is to drying, the more time it takes to dry to get a product without cracks. With an increase in the content of clay matter, especially montmorillonite, the sensitivity of clays to drying increases.
The moisture-conducting ability characterizes the intensity of moisture movement inside the drying product. The process of drying a clay product includes three phases: movement of moisture inside the material, vaporization and movement of water vapor from the surface of the product into the environment. The diffusion coefficient is a quantitative measure that indirectly characterizes the intensity of moisture movement inside the drying product. It depends on the size of capillaries, temperature, moisture content, type of clay mineral (in montmorillonite clays it is 10-15 times less than in kaolinite ones), sandiness of clays.
In the process of heating clays, their thermal properties are manifested. The most important of them are refractoriness, sinterability and fire shrinkage.
Refractoriness - the ability of clays to resist, not melting at high temperatures. The refractoriness of clays depends on their chemical composition. Alumina increases the refractoriness of clays, finely dispersed silica decreases, and coarse silica increases. Salts of alkali metals (sodium, potassium) sharply reduce the refractoriness of clays and serve as the strongest fluxes, oxides of alkaline earth metals also reduce the refractoriness of clays, but their effect is manifested at higher temperatures. According to the refractoriness index (° C), clay raw materials are divided into three groups: 1st - refractory (1580 and above), 2nd - refractory (less than 1580 - up to 1350), 3rd - low-melting (less than 1350).
Refractory varieties of clayey rocks are mainly kaolinite, hydromica and halloysite composition or consist of a mixture of these minerals with an admixture of quartz and carbonates. The chemical composition of refractory clay rocks is dominated by SiO2 and A12O3, which in the best varieties of refractory clays are in amounts close to their content in kaolinite (SiO2 - 46.5%, Al2O3 - 39.5%). In some varieties of refractory clays, the content of А12О3 decreases to 15–20%. Iron oxides and sulfides are found in subordinate amounts. Harmful impurities are calcite, gypsum, siderite, Mn and Ti compounds.
Refractory clay rocks are not consistent in mineral composition: they contain kaolinite, halloysite, hydromica and, in the form of impurities, quartz, mica, feldspar and other minerals. Alumina is contained in them in the range of 18-24%, sometimes up to 30-32%; silica - 50-60%, iron oxides - up to 4-6%, less often 7-12%.
Low-melting clayey rocks are usually polymineral. They usually contain montmorillonite, beidellite, hydromica and admixtures of quartz, micas, carbonates and other minerals. The content of alumina in these rocks does not exceed 15–18%, silica - 80%, and the content of iron oxides is increased to 8–12%. They are also characterized by a high content of fluids - finely dispersed admixtures of ferruginous, calcium, magnesium and alkaline minerals.
Sintering capacity - the ability of clays to compact during firing with the formation of a hard stone-like shard. It is characterized by the degree and range of sintering.
The degree of sintering is controlled by the amount of water absorption and density of the ceramic shard. Depending on the degree of sintering, clay raw materials are divided into highly sintered (a shard is obtained without signs of burnout with water absorption of less than 2%), medium-sintered (a shard with water absorption of 2-5%) and non-sintered (a shard with water absorption of 5% or less is not obtained without signs of burnout) ... Signs of burnout are deformation of the sample, visible swelling or a decrease in its total density by more than 0.05 * 10 g / cm3. The indicated values of water absorption must be maintained at least at two temperature points with an interval of 50 "C. For example, if during the firing of clay at a temperature of 1150 ° C the crock has a water absorption of 0.5%, and at 1100 - 2%, the glnya is highly caked, and if the same clay at a temperature of 1100:; "C forms a shard with a water absorption of 4%, it is referred to as mid-sintering.
Clays can be sintered at different temperatures.
etc.................
Ministry of Science and Education of Ukraine
Kiev National University of Civil Engineering and Architecture
Department of Building Materials Science
Abstract on the topic: "The use of secondary products in the manufacture of building materials"
1. The problem of industrial waste and the main directions of its solution
a) Industrial development and waste accumulation
b) Classification of industrial waste
2. Experience in the use of waste from metallurgy, fuel industry and energy
a) Binder materials based on slags and ash
b) Aggregates from ash waste
c) Fused and artificial stone materials based on slag and ash
d) Ashes and slags in road-building and insulating materials
e) Materials based on sludge from metallurgical industries
f) The use of burnt rocks, waste of coal preparation, mining and processing of ores
3. Experience in the use of wastes from chemical-technological production and wood processing
a) Application of slags from electrothermal phosphorus production
b) Materials based on gypsum and ferrous waste
c) Materials from wood chemistry and wood processing waste
d) Disposal of own waste in the production of building materials
4. References
1. The problem of industrial waste and the main directions of its solution.
a) Industrial development and waste accumulation
A characteristic feature of the scientific and technical process is an increase in the volume of social production. The rapid development of the productive forces causes the rapid involvement of more and more natural resources in the economic circulation. The degree of their rational use remains, however, on the whole very low. Every year, mankind uses about 10 billion tons of mineral and almost the same amount of organic raw materials. Most of the world's most important minerals are being developed faster than their proven reserves are growing. Around 70% of industrial costs are spent on raw materials, supplies, fuel and energy. At the same time, 10 ... 99% of raw materials are converted into waste, discharged into the atmosphere and water bodies that pollute the earth. In the coal industry, for example, about 1.3 billion tons of overburden and mine rocks and about 80 million tons of waste from coal preparation are generated annually. Annually the output of ferrous metallurgy slags is about 80 million tons, non-ferrous 2.5, ash and slag from thermal power plants 60 ... 70 million tons, wood waste is about 40 million m³.
Industrial waste actively affects environmental factors, i.e. have a significant impact on living organisms. This primarily refers to the composition of atmospheric air. Gaseous and solid wastes enter the atmosphere as a result of fuel combustion and various technological processes. Industrial waste actively affects not only the atmosphere, but also the hydrosphere, i.e. aquatic environment. Under the influence of industrial waste, concentrated in dumps, slag accumulators, tailing dumps, etc., the surface runoff in the area of industrial enterprises is polluted. The discharge of industrial waste ultimately leads to pollution of the waters of the World Ocean, which leads to a sharp decrease in its biological productivity and negatively affects the climate of the planet. Waste generation as a result of industrial activities negatively affects the quality of the soil. Excessive amounts of compounds harmful to living organisms, including carcinogenic substances, accumulate in the soil. In the contaminated "sick" soil, degradation processes take place, the vital activity of soil organisms is disrupted.
A rational solution to the problem of industrial waste depends on a number of factors: the material composition of the waste, its state of aggregation, quantity, technological features, etc. The most effective solution to the problem of industrial waste is the introduction of waste-free technology. The creation of waste-free production is carried out due to a fundamental change in technological processes, the development of closed-cycle systems that ensure the repeated use of raw materials. With the complex use of raw materials, industrial waste from some industries is the initial raw material of others. The importance of the integrated use of raw materials can be seen from several aspects. Firstly, waste disposal allows solving the problems of environmental protection, freeing up valuable land occupied by dumps and sludge storage, and eliminating harmful emissions into the environment. Secondly, waste to a large extent covers the needs of a number of processing industries for raw materials. Thirdly, with the complex use of raw materials, specific capital costs per unit of output are reduced and their payback period is reduced.
Of the industries that consume industrial waste, the construction materials industry is the most capacious. It has been established that the use of industrial waste can cover up to 40% of the construction needs in raw materials. The use of industrial waste allows to reduce the costs of manufacturing building materials by 10 ... 30% in comparison with their production from natural raw materials, saving capital investments reaches 35..50%.
b) Classification of industrial waste
To date, there is no comprehensive classification of industrial waste. This is due to the extreme diversity of their chemical composition, properties, technological features, and conditions of formation.
All industrial waste can be divided into two large groups: mineral (inorganic) and organic. Mineral waste is of the greatest importance for the production of building materials. They account for the overwhelming share of all waste generated by mining and processing industries. These wastes are more studied than organic ones.
Bazhenov P.I. it is proposed to classify industrial waste at the time of their separation from the main technological process into three classes: A; B; V.
Class A products (quarry residues and residues after beneficiation for mineral resources) have the chemical and mineralogical composition and properties of the corresponding rocks. The scope of their application is due to the state of aggregation, fractional and chemical composition, physical and mechanical properties.
Class B products are artificial substances. They are obtained as by-products as a result of physicochemical processes occurring at normal or, more often, high temperatures. The range of possible uses for this industrial waste is wider than that of Class A products.
Class B products are formed as a result of physical and chemical processes taking place in dumps. Such processes can be spontaneous combustion, decomposition of slags and the formation of powder. Burnt rocks are typical representatives of this class of waste.
2. Experience of using waste from metallurgy, fuel industry and energy
a) Binder materials based on slags and ash
The bulk of waste in the production of metals and the combustion of solid fuels is formed in the form of slags and ash. In addition to slags and ash, in the production of metal in large quantities, waste is formed in the form of aqueous suspensions of dispersed particles-slimes.
A valuable and very common mineral raw material for the production of building materials is burnt rocks and waste of coal preparation, as well as overburden and waste of ore dressing.
The production of binders is one of the most effective slag applications. Slag binders can be divided into the following main groups: slag Portland cements, sulfate-slag, lime-slag, slag-alkaline binders.
Slag and ash can be considered as a largely prepared raw material. In their composition, calcium oxide (CaO) is bound in various chemical compounds, including in the form of dicalcium silicate, one of the minerals of cement clinker. The high level of preparation of the raw mixture with the use of slags and ashes provides an increase in furnace productivity and fuel economy. Replacing clay with blast-furnace slag allows to reduce the content of the lime component by 20%, to reduce the specific consumption of raw materials and fuel by 10 ... 15% during dry production of clinker, and also to increase the productivity of furnaces by 15%.
White cements are obtained in electric furnaces by the use of low-iron slags - blast furnace and ferrochromic ones - and the creation of reducing conditions for melting. On the basis of ferrochromium slags by oxidation of metallic chromium in the melt, clinkers can be obtained, when using which cements with an even and persistent color.
Sulphate slag cements are hydraulic binders obtained by joint fine grinding of granular blast furnace slags and a sulphate hardening agent - gypsum or anhydride with a small addition of an alkaline activator: lime, Portland cement or burnt dolomite. Gypsum-slag cement containing 75 ... 85% slag, 10 ... 15% gypsum dihydrate or anhydride, up to 2% calcium oxide or 5% Portland cement clinker is the most widely used from the group of sulfate-slag cement. High activation is ensured when using anhydrite, calcined at a temperature of about 700 ° C, and high-alumina basic slags. The activity of sulphate-slag cement significantly depends on the fineness of grinding. A high specific surface area (4000 ... 5000 cm² / g) of the binder is achieved by wet grinding. With a sufficiently high fineness of grinding in a rational composition, the strength of sulfate-slag cement is not inferior to the strength of Portland cement. Like other slag binders, sulfate-slag cement has a low heat of hydration - up to 7 days, which makes it possible to use it in the construction of massive hydraulic structures. This is also facilitated by its high resistance to soft sulphate waters. The chemical resistance of sulphate-slag cement is higher than that of slag Portland cement, which makes its use especially expedient in various aggressive conditions.
Lime-slag and lime-ash cements are hydraulic binders obtained by joint grinding of granulated blast furnace slag or fly ash from thermal power plants and lime. They are used for the preparation of mortars of grades no more than M 200. To regulate the setting time and improve other properties of these binders, up to 5% of gypsum is introduced during their manufacture. The lime content is 10% ... 30%.
Lime-slag and ash cements are inferior in strength to sulfate-slag cements. Their brands are: 50, 100, 150 and 200. The beginning of setting should occur no earlier than 25 minutes, and the end - no later than 24 hours after the start of mixing. With a decrease in temperature, especially after 10 ° C, the increase in strength slows down sharply and, conversely, an increase in temperature with sufficient humidity of the environment promotes intensive hardening. Air hardening is possible only after sufficient long-term hardening (15 ... 30 days) in humid conditions. These cements are characterized by low frost resistance, high resistance in aggressive waters and low exotherm.
Slag-alkali binders consist of finely ground granular slag (specific surface ≥ 3000 cm² / g) and an alkaline component - sodium or potassium alkali metal compounds.
To obtain a slag-alkali binder, granular slags with a different mineralogical composition are acceptable. The decisive condition for their activity is the content of the vitreous phase capable of interacting with alkalis.
The properties of the slag-alkaline binder depend on the type, mineralogical composition of the slag, the fineness of its grinding, the type and concentration of its alkaline component solution. With a specific slag surface of 3000 ... 3500 cm² / g, the amount of water for the formation of a dough of normal density is 20 ... 30% of the mass of the binder. The strength of the slag-alkaline binder when testing samples from a test of normal density is 30 ... 150 MPa. They are characterized by an intense increase in strength both during the first month and in the subsequent periods of hardening. So, if the strength of Portland cement after 3 months. hardening in optimal conditions exceeds the branded one by about 1.2 times, then the slag-alkali binder by 1.5 times. With heat and moisture treatment, the hardening process is also accelerated more intensively than with hardening of Portland cement. Under normal steaming modes, adopted in precast concrete technology, within 28 days. 90 ... 120% of the brand strength is achieved.
The alkaline components that make up the binder play the role of an antifreeze additive, therefore slag-alkaline binders harden quite intensively at low temperatures.
b) Aggregates from ash waste
Slag and ash waste represent the richest raw material base for the production of both heavy and light porous concrete aggregates. The main types of aggregates based on metallurgical slags are crushed slag and slag pumice.
From fuel slag and ash, porous aggregates are made, including aggloporite, ash gravel, alumina expanded clay.
Cast crushed slag belongs to effective types of heavy concrete aggregates, which are not inferior in physical and mechanical properties of the product of crushing dense natural stone materials. During the production of this material, cast fiery liquid slag from slag ladles is poured in layers 200 ... 500 mm thick onto special casting sites or into tarpezoid pits-trenches. When held for 2 ... 3 hours in the open air, the temperature of the melt in the layer decreases to 800 ° C, and the slag crystallizes. Then it is cooled by water, which leads to the development of numerous cracks in the slag layer. Slag masses at foundry sites or in trenches are mined by excavators followed by crushing.
Cast slag crushed stone is characterized by high frost and heat resistance, as well as abrasion resistance. Its cost is 3 ... 4 times lower than crushed stone from natural stone.
Slag pumice (inhibits) is one of the most effective types of artificial porous aggregates. It is obtained by porous slag melts as a result of their rapid cooling with water, air or steam, as well as the effect of mineral gas formers. Of the technological methods for producing slag pumice, the most often used are basin, jet and hydroscreen methods.
Fuel slag and ash are the best raw materials for the production of artificial porous filler - aggloporite. This is due, firstly, to the ability of ash and slag raw materials, as well as clay rocks and other aluminosilicate materials, to sinter on the gratings of sintering machines, and secondly, the content of fuel residues in it, sufficient for the sintering process. Using conventional technology, agloporite is obtained in the form of crushed stone from sand. From the ashes of thermal power plants, it is possible to obtain aggloporite gravel, which has high technical and economic indicators.
The main feature of the aggloporite gravel technology is that, as a result of the agglomeration of raw materials, not a caked cake is formed, but fired granules. The essence of the technology for the production of agglomerated gravel consists in obtaining raw ash granules with a size of 10 ... 20 mm, placing them on the grates of a belt sintering machine with a layer thickness of 200 ... 300 mm and heat treatment.
The production of agglopite in comparison with the usual production of aggloporite is characterized by a 20 ... 30% decrease in the consumption of process fuel, a lower air rarefaction in vacuum chambers and an increase in specific productivity by 1.5 ... 3 times. Agloporite gravel has a dense surface shell and therefore, with an almost equal bulk density with crushed stone, it differs from it in higher strength and lower water absorption. Calculations that replacing 1 million m³ of imported natural crushed stone with agdoport gravel from TPP ash only by reducing transport costs for transportation over a distance of 500 ... 1000 km will save 2 million rubles. The use of aggloporite based on ash and slag from TPPs makes it possible to obtain lightweight concretes of grades 50 ... 4000 with a bulk density of 900 to 1800 kg / m³ at a cement consumption of 200 to 400 kg / m³.
Ash gravel is obtained by granulating a prepared ash-and-slag mixture or fly ash from TPPs with subsequent sintering and swelling in a rotary kiln at a temperature of 1150 ... 1250 ° С. In the production of fly ash, only swelling ash from TPPs with a fuel residue content of no more than 10% is effective.
Alumina expanded clay is a product of swelling and sintering in a rotary kiln of granules formed from a mixture of clays and ash and slag waste from thermal power plants. Ash can make up from 30 to 80% of the total mass of raw materials. The introduction of the clay component improves the molding properties of the charge, promotes the burning of coal residues in the ash, which makes it possible to use ash with a high content of unburned fuel.
The bulk mass of alumina expanded clay is 400..6000 kg / m³, and the compressive strength in a steel cylinder is 3.4 ... 5 MPa. The main advantages of alumina expanded clay production in comparison with aggloporite and ash gravel are the possibility of using TPP ash from dumps in a wet state without using drying and grinding units and an easier way to form granules.
c) Fused and artificial stone materials based on slags and ash
The main areas of processing of metallurgical and fuel slags, as well as ash, along with the production of binders, aggregates and concretes based on them, include the production of slag wool, cast materials and slag sandals, ash ceramics and silicate bricks.
Slag wool is a type of mineral wool, which occupies a leading place among heat-insulating materials, both in terms of production volume and in terms of construction and technical properties. In the production of mineral wool, blast-furnace slags have found the greatest application. The use of slag here instead of natural raw materials gives savings of up to UAH 150. per 1 ton. To obtain mineral wool, along with blast furnaces, cupola, open-hearth slags and slags of non-ferrous metallurgy are also used.
The required ratio of acidic and basic oxides in the charge is ensured by the use of acidic slags. In addition, acidic slags are more resistant to degradation, which is unacceptable in mineral wool. An increase in the silica content expands the temperature range of viscosity, i.e. temperature difference within which fiberization is possible. The acidity modulus of the slags is adjusted by introducing acidic or basic additives into the charge.
A variety of products are cast from the melt of metallurgical and fuel slags: stones for paving roads and floors of industrial buildings, tubing, curb stones, anti-corrosion tiles, pipes. The manufacture of slag casting began simultaneously with the introduction of the blast furnace process into metallurgy. Cast products from molten slag are economically more profitable in comparison with stone casting, approaching it in mechanical properties. The bulk density of dense cast slag products reaches 3000 kg / m³, the ultimate compressive strength is 500 MPa.
Slagositalls are a kind of glass-crystalline materials obtained by directional crystallization of glasses. Unlike other sitalls, the raw materials for them are slags of ferrous and nonferrous metallurgy, as well as ash from coal combustion. Slagositalls were developed for the first time in the USSR. They are widely used in construction as structural and finishing materials with high strength. The production of slag glass consists in the melting of slag glasses, the formation of products from them and their subsequent crystallization. The charge for glass production consists of slag, sand, alkali-containing and other additives. The most efficient use of fiery-liquid metallurgical slag, which saves up to 30 ... 40% of the total heat spent on cooking.
Slagositalls are increasingly used in construction. Plates of sheet slagossitall are used for revetting the basements and facades of buildings, decorating internal walls and partitions, and making balconies and roof fences from them. Slagostiall is an effective material for steps, window sills and other structural elements of buildings. High wear resistance and chemical resistance make it possible to successfully use Slagositalls for the protection of building structures and equipment in the chemical, mining and other industries.
Ash and slag waste from thermal power plants can serve as lean fuel-containing additives in the production of ceramic products based on clay rocks, as well as the main raw material for the manufacture of ash ceramics. The most widely used fuel ash and slag as additives in the production of ceramic wall products. For the manufacture of solid and hollow bricks and ceramic stones, first of all, it is recommended to use low-melting ash with a softening temperature of up to 1200 ° C. Ash and slags containing up to 10% of fuel are used as lean ones, and 10% or more as fuel-containing additives. In the latter case, it is possible to significantly reduce or eliminate the introduction of process fuel into the charge.
A number of technological methods for producing ash ceramics have been developed, where ash and slag waste from TPPs is no longer an additional material, but the main raw component. So, with the usual equipment of brick factories, an ash brick can be made from a mass including ash, slag and sodium water glass in an amount of 3% by volume. The latter plays the role of a plasticizer, ensuring the production of products with a minimum moisture content, which eliminates the need to dry the raw material.
Ash ceramics are produced in the form of pressed products from a mass containing 60 ... 80% fly ash, 10 ... 20% clay and other additives. Products go to drying and firing. Ash ceramics can serve not only as a wall material with stable strength and high frost resistance. It is characterized by high acid resistance and low abrasion, which makes it possible to manufacture paving slabs and paving slabs and products with high durability from it.
In the production of silicate bricks, TPP ash is used as a component of a binder or aggregate. In the first case, its consumption reaches 500 kg., In the second - 1.5 ... 3.5 tons per 1 thousand pieces. bricks. With the introduction of coal ash, lime consumption is reduced by 10 ... 50%, and shale ash with CaO + MgO content up to 40 ... 50% can completely replace lime in the silicate mass. Ash in a lime-ash binder is not only an active silica additive, but also contributes to the plasticization of the mixture and an increase of 1.3 ... 1.5 times the strength of the raw material, which is especially important for ensuring the normal operation of automatic stackers.
d) Ashes and slags in road-building and insulating materials
A large-scale consumer of fuel ash and slag is road construction, where ashes and ash-and-slag mixtures are used for the installation of underlying and lower layers of bases, partial replacement of binders during soil stabilization with cement and lime, as a mineral powder in asphalt concrete and mortars, as additives in road cement concrete.
Ashes obtained from burning coal and oil shale are used as fillers for roofing and waterproofing mastics. Ash and slag mixtures in road construction are used unreinforced and hardened. Unreinforced ash and slag mixtures are used mainly as a material for the construction of the underlying and lower layers of the bases of regional and local roads. With a content of no more than 16% of dusty ash, they are used to improve ground coatings subjected to surface treatment with bitumen or tar emulsion. Structural layers of roads can be made of ash and slag mixtures with an ash content of no more than 25 ... 30%. In gravel and crushed stone bases, it is advisable to use an ash-and-slag mixture with a pulverized ash content of up to 50% as a compacting additive. The content of unburned coal in fuel waste of TPPs used for road construction should not exceed 10%.
As well as natural stone materials of relatively high strength, ash and slag waste from TPPs are used for the manufacture of bitumen-mineral mixtures used to create structural layers of roads of 3-5 categories. Black crushed stone is obtained from fuel slag treated with bitumen or tar (up to 2% by weight). By mixing ash heated to 170 ... 200 ° C with 0.3 ... 2% bitumen solution in green oil, a hydrophobic powder with a bulk density of 450 ... 6000 kg / m³ is obtained. The hydrophobic powder can simultaneously function as a hydro- and heat-insulating material. The use of ashes as a filler for mastics is widespread.
e) Materials based on sludge from metallurgical industries
For the production of building materials, nepheline, bauxite, sulfate, white and multi-calcium sludge is of industrial importance. The volume of nepheline sludge alone, suitable for use, is more than 7 million tons annually.
The main area of application of sludge waste from the metallurgical industry is the production of clinker-free binders, materials based on them, the production of Portland cement and mixed cements. In industry, nepheline (belite) sludge obtained from the extraction of alumina from nepheline rocks is especially widely used.
Under the leadership of P.I. Bazhenov developed a technology for the manufacture of nepheline cement and materials based on it. Nepheline cement is a product of joint grinding or thorough mixing of preliminary crushed nepheline sludge (80 ... 85%), lime or other activator, such as Portland cement (15 ... 20%) and gypsum (4 ... 7%). The beginning of the setting of nepheline cement should occur no earlier than 45 minutes, the end - no later than 6 hours. after its closure, His stamps are 100, 150, 200 and 250.
Nepheline cement is effective for masonry and plaster mortars, as well as for normal and especially autoclaved concretes. In terms of plasticity and setting time, solutions on nepheline cement are close to lime-gypsum solutions. In concretes of normal hardening, nepheline cement ensures the production of grades 100 ... 200, in autoclave - grades 300 ... 500 at a consumption of 250 ... 300 kg / m³. The specific features of concretes based on nepheline cement are low exometrics, which is important to take into account in the construction of massive hydraulic structures, high adhesion to steel reinforcement after autoclaving, and increased resistance in saline waters.
Binders based on bauxite, sulphate and other sludge from metallurgical industries are similar in composition to nepheline cement. If a significant part of these minerals is hydrated, for the manifestation of the binding properties of the slimes, they must be dried in the range of 300 ... 700 ° C. To activate these binders, it is advisable to introduce additives of lime and gypsum.
Slurry binders are classified as local materials. It is most rational to use them for the manufacture of autoclave hardened products. However, they can also be used in building solutions, in finishing works, in the manufacture of materials with organic fillers, such as fiberboard. The chemical composition of a number of metallurgical slimes allows them to be used as the main raw material component of Portland cement clinker, as well as an active additive in the production of Portland cement and mixed cements.
f) The use of burnt rocks, waste of coal preparation, mining and processing of ores
The bulk of burnt rocks is the product of burning waste rocks associated with coal deposits. The varieties of burnt rocks are glezhi - clayey and clay-sandy rocks burnt in the bowels of the earth during underground fires in coal seams, and dump, burnt out mine rocks.
The possibilities of using burnt rocks and waste of coal preparation in the production of building materials are very diverse. Burnt rocks, like other fired clay materials, are active towards lime and are used as hydraulic additives in lime-pozzolanic binders, Portland cement, pozzolanic Portland cement and autoclave materials. High adsorption activity and adhesion to organic binders allow their use in asphalt and polymer compositions. Naturally, burnt rocks burnt in the bowels of the earth or in the waste heaps of coal mines - mudstones, siltstones and sandstones - are of a ceramic nature and can be used in the production of refractory concrete and porous aggregates. Some burnt rocks are light non-metallic materials, which makes them suitable for use as aggregates for light mortars and concretes.
Waste from coal preparation is a valuable type of mineralogical raw material, mainly used in the production of wall ceramic materials and porous aggregates. In terms of chemical composition, coal preparation wastes are close to traditional clay raw materials. The role of a harmful impurity in them is the sulfur contained in sulfate II and sulfide compounds. Their calorific value varies widely - from 3360 to 12600 kJkg and more.
in the production of wall ceramic products, coal preparation wastes are used as a depleted or burn-out fuel-containing additive. Lump waste is crushed before being introduced into the ceramic batch. Pre-crushing is not required for sludge with a particle size of less than 1mm. The sludge is pre-dried to a moisture content of 5 ... 6%. The addition of waste when receiving bricks by the plastic method should be 10 ... 30%. The introduction of the optimal amount of fuel containing additives as a result of a more uniform roasting significantly improves the strength characteristics of products (up to 30 ... 40%), saves fuel (up to 30%), eliminates the need to introduce coal into the charge, and increases the productivity of furnaces.
It is possible to use coal preparation sludge with a relatively high calorific value (18900 ... 21000 kJ / kg) as a process fuel. It does not require additional crushing, it is well distributed over the charge when filling through the fuel holes, which contributes to uniform firing of products, and most importantly, it is much cheaper than coal.
Some types of waste coal enrichment can be used to produce not only aggloporite, but also expanded clay. A valuable source of nonmetallic materials is the incidentally mined rocks of the mining industries. The main direction of utilization of this group of waste is the production, first of all, of aggregates for concrete and mortars, road building materials, rubble stone.
Construction crushed stone is obtained from associated rocks during the extraction of iron and other ores. High-quality raw materials for the production of crushed stone are barren ferruginous quartzites: hornfelses, quartzite and crystalline schists. Crushed stone from associated rocks during the extraction of iron ore is obtained in crushing and screening plants, as well as dry magnetic separation.
3. Experience in the use of wastes from chemical-technological production and wood processing
a) Application of slags from electrothermal phosphorus production
Agricultural waste of plant origin is also an important source of construction materials. The annual output, for example, of waste stems of cotton is about 5 million tons per year, and flax fire is more than 1 million tons.
Wood waste is generated at all stages of harvesting and processing. These include branches, twigs, tops, picks, canopies, sawdust, stumps, roots, bark and brushwood, which together make up about 21% of the total mass of wood. When processing wood for sawn timber, the yield reaches 65%, the rest forms waste in the form of slabs (14%), sawdust (12%), cuttings and fines (9%). In the manufacture of construction parts, furniture and other products from sawn timber, waste occurs in the form of shavings, sawdust and individual pieces of wood - cuttings that make up up to 40% of the mass of processed sawn timber.
The most important for the production of building materials and products are sawdust, shavings and lumpy waste. The latter are used both directly for the manufacture of glued construction products and for processing into technological chips, and then shavings, crushed pieces, and fibrous mass. A technology has been developed for obtaining building materials from bark and oak - a waste from the production of tanning extracts.
Phosphorus slag is a by-product of the thermal production of phosphorus in electric furnaces. At a temperature of 1300 ... 1500 ° C, calcium phosphate interacts with coke carbon and silica, resulting in the formation of phosphorus and slag melt. Slag is discharged from the furnaces in a fiery liquid state and granulated in a wet way. For 1 ton of phosphorus there are 10 ... 12 tons of slag. Large chemical plants produce up to two million tons of slag per year. The chemical composition of phosphorus slags is close to that of blast furnace slags.
Slag pumice, cotton wool and cast products can be obtained from phosphorus-slag melts. Slag pumice is obtained by conventional technology without changing the composition of phosphorus slags. It has a bulk density of 600 ... 800 kg / m³ and a glassy fine-pored structure. Phosphoric slag wool is characterized by long thin fibers and a bulk density of 80 ... 200 kg / m³. Phosphorus-slag melts can be processed into cast crushed stone using trench technology used at metallurgical enterprises.
b) Materials based on gypsum and ferrous waste
The demand of the building materials industry for gypsum stone currently exceeds 40 million tons. At the same time, the need for gypsum raw materials can be mainly satisfied by gypsum-containing wastes from the chemical, food, and wood-chemical industries. In 1980, in our country, the yield of waste and by-products containing calcium sulfates reached about 20 million tons per year, including phosphogypsum - 15.6 million tons.
Phosphogypsum is a waste of sulfuric acid processing of apatites or phosphorites into phosphoric acid or concentrated phosphoric fertilizers. It contains 92 ... 95% of gypsum dihydrate with mechanical impurity 1 ... 1.5% of phosphorus pentoxide and a certain amount of other impurities. Phosphogypsum has the form of a sludge with a moisture content of 20 ... 30% with a high content of soluble impurities. The solid phase of the sludge is finely dispersed and more than 50% consists of particles less than 10 microns in size. The cost of transportation and storage of phosphogypsum in dumps is up to 30% of the total cost of facilities and operation of the main production.
In the production of phosphoric acid by the method of extraction according to the hemihydrate scheme, the waste is calcium sulfate phosphohydrate containing 92 ... 95% - the main component of high-strength gypsum. However, the presence of passivating films on the surface of the hemihydrate crystals noticeably inhibits the manifestation of the binding properties of this product without its special technological processing.
With conventional technology, gypsum binders based on phosphogypsum are of low quality, which is explained by the high water demand of phosphogypsum, due to the high porosity of the hemihydrate as a result of the presence of large crystals in the feedstock. If the water demand of ordinary stucco is 50 ... 70%, then to obtain a dough of normal density from a phosphogypsum binder without additional treatment, 120 ... 130% of water is required. Negatively affect the building properties of phosphogypsum and impurities contained in it. This influence is somewhat reduced when phosphogypsum is finished and products are formed by vibro-laying. In this case, the quality of phosphogypsum binder increases, although it remains lower than that of stucco from natural raw materials.
At IISI, on the basis of phosphogypsum, a composite binder of increased water resistance was obtained, containing 70 ... 90% of α-hemihydrate, 5 ... 20% of Portland cement and 3 ... 10% of pozzolanic additives. With a specific surface area of 3000 ... 4500 cm² / g, the water demand of the binder is 35 ... 45%, setting begins after 20 ... 30 minutes, ends after 30 ... 60 minutes, the compressive strength is 30 ... 35 MPa, the softening coefficient is 0.6 ... 0 , 7. a water-resistant binder is obtained by hydrothermal treatment in an autoclave of a mixture of phosphogypsum, Portland cement and additives containing active silica.
In the cement industry Phosphogypsum is used as a mineralizer for clinker burning and instead of natural gypsum as an additive to regulate the setting of cement. The addition of 3 ... 4% to the slurry makes it possible to increase the saturation coefficient of clinker from 0.89 ... 0.9 to 0.94 ... 0.96 without reducing the furnace productivity, to increase the lining resistance in the sintering zone due to the uniform formation of a stable coating and to obtain an easily grindable clinker. It has been established that phosphogypsum is suitable for replacing gypsum when grinding cement clinker.
The widespread use of phosphogypsum as an additive in the production of cement is possible only when it is dried and granulated. The moisture content of granulated phosphogypsum should not exceed 10 ... 12%. The essence of the main scheme of phosphogypsum granulation is to dehydrate a part of the original phosphogypsum sludge at a temperature of 220 ... 250 ° C to a state of soluble anhydride, followed by mixing it with the rest of the phosphogypsum. When phosphoanhydride is mixed with phosphogypsum in a rotating drum, the dewatered product is hydrated due to the free moisture of the starting material, and as a result, solid granules of phosphogypsum dihydrate are formed. Another method of granulation of phosphogypsum is possible - with a hardening addition of pyrite cinders.
In addition to the production of binders and products based on them, other ways of utilizing gypsum-containing waste are known. Experiments have shown that the addition of up to 5% phosphogypsum to the charge in the production of bricks intensifies the drying process and improves the quality of products. This is explained by the improvement of the ceramic-technological properties of clay raw materials due to the presence of the main component of phosphogypsum - calcium sulfate dihydrate.
Of the ferrous waste, pyrite cinders are the most widely used. In particular, in the production of Portland cement clinker, they are used as a corrective additive. However, cinders consumed in the cement industry make up only a small part of their total output at sulfuric acid plants that consume pyrite as the main feedstock.
A technology for the production of high-iron cements has been developed. The initial components for the production of such cements are chalk (60%) and pyrite cinders (40%). The raw mixture is fired at a temperature of 1220 ... 1250 ° C. High-iron cements are characterized by normal setting times when up to 3% gypsum is added to the raw mixture. Their compressive strength under conditions of water and air-wet hardening for 28 days. corresponds to grades 150 and 200, and when steamed in an autoclave, it increases by 2 ... 2.5 times. High iron cements are non-shrinkable.
Pyrite cinders in the production of artificial concrete aggregates can serve as both an additive and the main raw material. The addition of pyrite cinders in the amount of 2 ... 4% of the total mass is introduced to increase the gas-generating capacity of clays when obtaining expanded clay. This is facilitated by the decomposition of pyrite residues in cinders at 700 ... 800 ° C with the formation of sulfur dioxide and the reduction of iron oxides under the influence of organic impurities present in the clay raw material, with the release of gases. Ferrous compounds, especially in the acidic form, act as melts, causing the melt to dilute and reduce the temperature range of changes in its viscosity.
Iron-containing additives are used in the production of ceramic wall materials to reduce the firing temperature, improve quality and improve color characteristics. Positive results are obtained by preliminary calcination of cinders for the decomposition of sulfide and sulfate impurities, which form gaseous products during calcination, the presence of which reduces the mechanical strength of products. It is effective to introduce 5 ... 10% cinders into the charge, especially in raw materials with a low amount of flux and insufficient sintering capacity.
In the production of facade tiles by semi-dry and slip methods, calcined cinders can be added to the batch in an amount of 5 to 50% by weight. The use of cinders allows the production of colored ceramic facade tiles without additional introduction of chamotte into the clay. At the same time, the firing temperature of tiles made of refractory and refractory clays is reduced by 50 ... 100 ° C.
c) Materials from wood chemistry and wood processing waste
For the production of building materials, the most valuable raw materials from the waste of the chemical industry are slags from the electrothermal production of phosphorus, gypsum-containing and lime waste.
Waste of winter-technological production includes worn-out rubber and secondary polymer raw materials, as well as a number of by-products of building materials enterprises: cement dust, precipitation in water treatment devices of asbestos-cement enterprises, broken glass and ceramics. Waste accounts for up to 50% of the total mass of processed wood, most of which is currently burned or dumped.
Building materials enterprises located near hydrolysis plants can successfully utilize lignin, one of the most capacious wood chemistry wastes. The experience of a number of brick factories allows lignin to be considered an effective burnout additive. It mixes well with other components of the charge, does not impair its forming properties and does not complicate the cutting of the timber. The greatest effect of its application takes place with a relatively low career clay moisture. Lignin pressed into the raw material does not burn during drying. The combustible part of lignin completely evaporates at a temperature of 350 ... 400 ° С, its ash content is 4 ... 7%. To ensure the conditioned mechanical strength of ordinary clay brick, lignin should be introduced into the forming charge in an amount of up to 20 ... 25% of its volume.
In the production of cement, lignin can be used as a plasticizer of raw sludge and an intensifier for grinding the raw mixture and cement. The dosage of lignin in this case is 0.2 ... 0.3%. The liquefying effect of hydrolytic lignin is explained by the presence of phenolic substances in it, which well reduce the viscosity of limestone-clay suspensions. The action of lignin during grinding is mainly to reduce the adhesion of fine material fractions and their adhesion to the grinding media.
Wood waste without preliminary processing (sawdust, shavings) or after grinding (wood chips, shredded chips, wood wool) can serve as fillers in building materials based on mineral and organic binders, these materials are characterized by low bulk density and thermal conductivity, as well as good workability. Impregnation of wood fillers with mineralizers and subsequent mixing with mineral binders ensures the biostability and fire resistance of materials based on them. Common disadvantages of wood-based materials are high water absorption and relatively low water resistance. According to their purpose, these materials are divided into heat-insulating and structural-heat-insulating materials.
The main representatives of the group of materials based on wood aggregates and mineral binders are arbolite, fiberboard and sawdust concrete.
Arbolit - lightweight concrete based on aggregates of plant origin, pre-treated with a solution of a mineralizer. It is used in industrial, civil and agricultural construction in the form of panels and blocks for the construction of walls and partitions, floor slabs and building coatings, thermal insulation and sound insulation boards. The cost of wood concrete buildings is 20 ... 30% lower than that of bricks. Arbolite structures can be operated at a relative humidity of no more than 75%. At high humidity, a vapor barrier layer is required.
Fibrolite, in contrast to wood concrete as a filler and at the same time a reinforcing component, includes wood wool - shavings from 200 to 500 mm long, 4 ... 7 mm wide. and with a thickness of 0.25 ... 0.5 mm. Wood wool is obtained from non-commercial coniferous wood, less often deciduous wood. Fiberboard is characterized by high sound absorption, easy workability, nailing properties, good adhesion to the plaster layer and concrete. Fiberboard production technology includes the preparation of wood wool, processing it with a mineralizer, mixing with cement, pressing the boards and their heat treatment.
Sawdust concrete is a material based on mineral binders and sawdust. These include xylolite, xyloconcrete and some other materials that are close to them in composition and technology.
Xylolite is an artificial building material obtained by hardening a mixture of magnesia binder and sawdust, mixed with a solution of magnesium chloride or sulfate. Xylolite is mainly used for the installation of monolithic or prefabricated floor coverings. The advantages of xylolite floors are a relatively low coefficient of heat absorption, hygiene, sufficient hardness, low abrasion, the possibility of various colors.
Xyloconcrete is a kind of lightweight concrete, the filler of which is sawdust, and the binder is cement or lime and gypsum, xyloconcrete with a bulk density of 300 ... 700 kg / m³ and a compressive strength of 0.4 ... 3 MPa is used as thermal insulation, and with a bulk density of 700 ... 1200 kg / m³ and compressive strength up to 10 MPA - as a structural and thermal insulation material.
Glued timber is one of the most efficient building materials. It can be laminated or obtained from veneer (plywood, laminated plastics); massive lump waste from sawmilling and woodworking (panels, sheets, beams, boards) and combined (joinery boards). Advantages of glued timber - low bulk density, water resistance, the ability to obtain from small-sized material products of complex shape, large structural elements. In glued structures, the influence of the anisotropy of wood and its defects is weakened, they are characterized by increased clay resistance and low flammability, are not subject to shrinkage and warping. Glued wooden structures often compete successfully with steel and reinforced concrete structures in terms of time and labor costs during the construction of buildings, resistance during the construction of an aggressive air environment. Their use is effective in the construction of agricultural and industrial enterprises, exhibition and trade pavilions, sports complexes, buildings and structures of collapsible type.
Chipboard is a material obtained by hot pressing of chopped wood mixed with binders - synthetic polymers. The advantages of this material are the homogeneity of physical and mechanical properties in various directions, relatively small linear changes at variable humidity, the possibility of high mechanization and automation of production.
Building materials based on some wood waste can be produced without the use of special binders. Wood particles in such materials are bound as a result of the convergence and interlacing of fibers, their cohesive ability and physicochemical bonds that arise during the processing of the press mass at high pressures and temperatures.
Fiber boards are obtained without the use of special binders.
Fiberboard is a material formed from pulp with subsequent heat treatment. Approximately 90% of all fibreboard is made from wood. The raw materials are non-commercial wood and waste from sawmills and woodworking industries. Plates can be obtained from bast fibers and from other fibrous raw materials that have sufficient strength and flexibility.
The group of wood plastics includes: Wood-laminated plastics - a material made of veneer sheets impregnated with a synthetic resin of the resole type and glued as a result of thermal pressure treatment, lignocarbohydrate and piezo-thermoplastics, produced from sawdust by high-temperature processing of press mass without the introduction of special binders. The technology of ligno-carbohydrate plastics consists of preparation, drying and dosing of wood particles, carpet shaping, cold pre-pressing, hot pressing and cooling without relieving pressure. The area of application of ligno-carbohydrate plastics is the same as for fibreboard and chipboard.
Piezothermoplastics can be made from sawdust in two ways - without pretreatment and with hydrothermal treatment of the feedstock. According to the second method, conditioned sawdust is processed in autoclaves with steam at a temperature of 170 ... 180 ° C and a pressure of 0.8 ... 1 MPa for 2 hours. The hydrolyzed press mass is partially dried and at a certain humidity is successively subjected to cold and hot pressing.
Piezo thermoplastics are used to produce floor tiles with a thickness of 12 mm. The raw material can be sawdust or shredded wood of coniferous and deciduous species, flax or hemp of a fire, reeds, hydrolytic lignin, and oodubin.
d) Disposal of own waste in the production of building materials
The experience of the enterprises of the Crimean Autonomous Republic, developing limestone-shell rock to obtain wall piece stone, shows the effectiveness of manufacturing shell-concrete blocks from stone sawing waste. Blocks are formed in horizontal metal molds with drop sides. The bottom of the mold is covered with a shell rock solution 12..15 mm thick to create an inner textured layer. The form is filled with coarse or fine-grained shell concrete. The texture of the outer surface of the blocks can be created with a special solution. Shell-concrete blocks are used for laying foundations and walls in the construction of industrial and residential buildings.
In the production of cement, as a result of the processing of finely dispersed mineral materials, a significant amount of dust is generated. The total amount of dust captured in cement plants can be up to 30% of the total volume of production. Up to 80% of the total amount of dust is emitted with the gases of clinker kilns. The dust carried out from the furnaces is a polydisperse powder containing 40 ... 70 in the wet production process, and up to 80% of fractions less than 20 microns in size in the dry process. Mineralogical studies have established that the dust contains up to 20% of clinker minerals, 2 ... 14% of free calcium oxide and from 1 to 8% of alkalis. The bulk of the dust consists of a mixture of baked clay and undecomposed limestone. The composition of the dust depends significantly on the type of furnaces, the type and properties of the raw materials used, and the collection method.
The main direction of dust utilization at cement plants is its use in the process of cement production itself. Dust from the dust collection chambers returns to the rotary kiln together with the sludge. The main amount of free calcium oxide, alkalis and sulfuric anhydride. The addition of 5 ... 15% of such dust to the raw sludge causes its coagulation and a decrease in fluidity. With an increased content of alkali oxides in the dust, the quality of the clinker also decreases.
Asbestos-cement waste contains a large amount of hydrated cement minerals and asbestos. When fired, as a result of dehydration of the hydrated components of cement and asbestos, they acquire astringent properties. The optimum firing temperature is in the range of 600 ... 700 ° C. In this temperature range, the dehydration of hydrosilicates is completed, asbestos decomposes and a number of minerals are formed that are capable of hydraulic hardening. Binders with pronounced activity can be obtained by mixing thermally treated asbestos-cement waste with metallurgical slag and gypsum. Facing tiles and floor tiles are made from asbestos-cement waste.
An effective type of binder in asbestos-cement waste compositions is water glass. Facing slabs from a mixture of dried and powdered asbestos-cement waste and a liquid glass solution with a density of 1.1 ... 1.15 kg / cm³ are obtained at a specific pressing pressure of 40 ... 50 MPa. In a dry state, these slabs have a bulk density of 1380 ... 1410 kg / m³, ultimate bending strength 6.5 ... 7 MPa, compressive strength 12 ... 16 MPa.
Heat-insulating materials can be made from asbestos-cement waste. Products in the form of plates, segments and shells are obtained from burnt and crushed waste with the addition of lime, sand and blowing agents. Aerated concrete based on binders from asbestos-cement waste has a compressive strength of 1.9 ... 2.4 MPa and a bulk density of 370 ... 420 kg / m³. Waste from the asbestos-cement industry can serve as fillers for warm plasters, asphalt mastics and asphalt concrete, as well as aggregates for concrete with high impact strength.
Glass waste is generated both in the production of glass and in the use of glass products at construction sites and in everyday life. The return of cullet to the main technological process of glass production is the main direction of its disposal.
One of the most effective heat-insulating materials - foam glass - is obtained from the powder of glass breakage with gas generators by sintering at 800 ... 900 ° C. Plates and blocks of foam glass have a bulk density of 100 ... 300 kg / m³, a thermal conductivity of 0.09 ... 0.1 W and a compressive strength of 0.5 ... 3 MPa.
In a mixture with plastic clays, glass breakage can serve as the main component of ceramic masses. Products from such masses are made using semi-dry technology, they are distinguished by high mechanical strength. The introduction of broken glass into the ceramic mass reduces the firing temperature and increases the productivity of the furnaces. Glass-ceramic tiles are produced from a batch containing from 10 to 70% of broken glass crushed in a ball mill. The mass is moistened up to 5 ... 7%. The tiles are pressed, dried and fired at 750 ... 1000 ° C. Water absorption of the tiles is no more than 6%. frost resistance more than 50 cycles.
Broken glass is also used as a decorative material in colored plasters, ground glass waste can be used as a powder for oil paint, an abrasive can be used to make sandpaper and as a component of glaze.
In ceramic production, waste occurs at various stages of the technological process. Drying waste after the required grinding serves as an additive to reduce the moisture content of the initial charge. The broken clay brick is used after crushing as crushed stone in general construction works and in the manufacture of concrete. Crushed brick has a bulk bulk density of 800 ... 900 kg / m³, it can be used to produce concrete with a bulk density of 1800 ... 2000 kg / m³, i.e. 20% lighter than conventional heavy aggregates. The use of crushed brick is effective for the manufacture of coarsely porous concrete blocks with a bulk density of up to 1400 kg / m³. The number of brick breakage has dropped dramatically due to containerization and complex mechanization of brick loading and unloading.
4. References:
Bozhenov P.I. Complex use of mineral raw materials for the production of building materials. - L.-M .: Stroyizdat, 1963.
Gladkikh K.V. Slags are not waste, but valuable raw materials. - M .: Stroyizdat, 1966.
Popov L.N. Construction materials from industrial waste. - M .: Knowledge, 1978.
Bazhenov Yu.M., Shubenkin P.F., Dvorkin L.I. The use of industrial waste in the production of building materials. - M .: Stroyizdat, 1986.
Dvorkin L.I., Pashkov I.A. Construction materials from industrial waste. - K .: Vyscha school, 1989.
Ministry of Science and Education of Ukraine Kiev National University of Construction and Architecture Department of Building Materials Science Abstract on the topic: "The use of secondary products in the manufacture of construction materialsIn Belarus, this type of mineral raw material is represented by numerous and varied deposits of sands and sand and gravel mixtures, clays, carbonate rocks, gypsum, as well as natural building stone. Despite the relative cheapness of this type of raw material, its importance in the modern economy of the country can hardly be overestimated.
Sands are widespread in Belarus. Deposits of sands are confined to the Quaternary strata, less often to deposits of the Paleogene and Neogene. They are, as a rule, of water-glacial and lacustrine-alluvial origin; in the south of the country there are also sands of aeolian genesis. Sands are used both in their natural state and after beneficiation for the production of concrete, mortar, in the glass industry and foundry.
The raw material base of construction and silicate sands includes about 80 deposits (total reserves of about 350 million m3) located throughout the country. Sands occur on the surface or close to it in the form of lenticular or sheet-like deposits of various sizes. The thickness of individual deposits reaches 15 m. Deposits of building sands are confined to lakes, outwash plains, and river terraces. More than 35 fields are being developed. Annual production is 7-8 million m3.
Deposits of molding sands were found in the Zhlobin (Chetvernya deposit) and Dobrush (Lenino) districts of the Gomel region. The Chetvernya deposit is operated by the Zhlobin quarry department and the Lenino-Gomel mining and processing plant. About 0.6 million m3 of molding sand is mined annually.
Deposits of glass sands have been explored in the Gomel (Loevskoye) and Brest (Gorodnoye) regions. Their total reserves are 15 million m3. Glass sands are suitable for producing window and container glass.
Sand-gravel mixtures are associated with moraine, less often alluvial deposits. Deposits of sand and gravel material are widespread in the northern and central parts of Belarus. They are usually small in size (up to 50 hectares). The thickness of the productive strata is from 1-3 to 10-20 m. The particle size distribution is variable. The content of the main components varies as follows: pebbles - from 0 to 55%, gravel - from 5-10 to 75, sand - from 5-10 to 75, clay particles - up to 5-7%. 136 fields have been explored with total reserves of over 700 million m3; 82 deposits are in operation. About 3 million m3 of sand and gravel materials are mined annually. They are mainly used for the preparation of concretes and mortars.
Clays are a raw material base for the production of coarse ceramics, lightweight aggregates, and are also used as an essential component in the manufacture of various types of cement. Deposits of fusible clays are mainly associated with Quaternary deposits, refractory - with Oligocene and Pliocene formations, common in the south of Belarus.
More than 210 deposits of low-melting clays have been explored with total reserves of about 200 million m3. More than software for deposits is being developed, 2.5-3.5 million m3 of raw materials are produced annually. There are also 9 explored deposits for the production of aggloporite and expanded clay with total reserves of about 60 million m3. 6 of them are in operation (production 0.6 million m3). The reserves of clay rocks for cement production are over 110 million m3.
The raw material base of refractory clays includes 6 deposits with total reserves in categories A + B + Cj over 50 million m3. The deposits are represented by layer-like deposits with a thickness of 1.5 to 15 m. The depth of their occurrence does not exceed 7-8 m. The annual production of refractory clays is 0.4-1 million m3.
The group of industrially valuable clay rocks of Belarus also includes kaolins found within the Mikashevichsko-Zhitkovichi uplift of the crystalline basement. They are products of weathering of granite gneisses and gneisses. Kaolins are usually light gray and white, micaceous, with an admixture of hydromica and montmorillonite. 4 deposits have been identified. The deposits are cape-like, their average thickness is 10 m, the depth varies from 13 to 35 m. The predicted resources are estimated at almost 27 million tons. Kaolins contain increased amounts of coloring iron oxides. They are suitable for the production of porcelain and earthenware products that do not require high whiteness, as well as for the manufacture of fireclay products.
Carbonate rocks, used mainly for the production of cement and lime, are represented by writing chalk and marls, occurring in the Late Cretaceous strata. They are found both in bedding and in glacial rejects. On the areas of their shallow occurrence, mainly in the Krichevsky, Klimovichsky, Kostyukovichsky and Cherikovsky districts of the Mogilev region, the Volkovysk and Grodno districts of the Grodno region, a number of deposits have been explored. Some of them (for example, Krichevskoe) are represented by writing chalk, others (Kommunarskoe) by marl, and still others (Kamenka) by marl and writing chalk. The thickness of the productive strata in the fields varies from 10-20 to 50 m with a roof depth of 1 to 25 m. The CaCO3 content ranges from 65% in marls to 98% in writing chalk.
The raw material base of the cement industry includes 15 fields with total reserves of carbonate rocks in categories A + B + Cj 720 million tons. 8 fields are being developed, on the basis of which RUE Volkovyskcementoshyfer and Krichevcementoshyfer operate, as well as the Belorussky cement plant, which is developing the reserves of Kommunarsky marls. Place of Birth. The cement industry of Belarus is provided with carbonate raw materials for the long term.
The raw material base for lime production is based on the use of writing chalk. There are 33 deposits of this mineral in the country with total reserves in categories A + B + Cj of about 210 million tons. 6 deposits are in operation.
Gypsum in a platform case has been known on the territory of Belarus for a long time; it occurs in the form of strata, layers, interlayers, veins and nests in the Middle, Upper Devonian and Lower Permian deposits. Relatively shallow (167-460 m) thick layers of gypsum are found among the deposits of the Famennian stage of the Upper Devonian in the west of the Pripyat trough. They are confined to the raised block of the crystalline basement and form the Brinevskoe gypsum deposit. Up to 14 layers of gypsum are installed here, which are combined into four horizons. The thickness of the gypsum horizons ranges from 1-3 to 46 m. In the section of the lower one, thick lenses of gypsum-anhydrite and anhydrite rocks are observed. The content of gypsum in productive formations varies from 37 to 95%. The reserves of gypsum in the Cj + C2 categories are 340 million tons, anhydrite - 140 million tons. It is possible to organize the extraction of 1 million tons of gypsum per year.
Natural building stone on the territory of Belarus is represented by various rocks of the crystalline basement (granites, granodiorites, diorites, migmatites, etc.). In the Brest region, two deposits of building stone were explored (Mikashevichi and Sitnitsa), in the Gomel region - a deposit of building stone (Glushkevichi, the Krestyanskaya Niva site) and a deposit of facing materials (Nadezhdy's Quarry). The largest of them is the Mikashevichi field. The building stone here lies at a depth of 8 to 41 m. The mineral is represented by diorites, granodiorites and granites. The original stone reserves in the A + B + Cj categories were 168 million m3. The deposit is being exploited by an open pit; the depth of the quarry is about 120 m. The Glushkevichi deposit is also being developed. At the Mikashevichi deposit, the annual production of stone is about 3.5 million m3, the production of crushed stone - 5.5 million m3, at the Glushkevichi deposit - 0.1 million m3 and 0.2 million m3, respectively.
At the Nadezhda Quarry facing stone deposit, the productive stratum is represented by gray and dark gray migmatites with good decorative properties. The depth of the mineral resource is from several tens of centimeters to 7 m; stocks of raw materials here are 3, 3 million m3.
There are prospects in the country to increase the production of building stone through the construction of a second enterprise based on the Mikashevichi deposit, as well as expanding the production of facing materials at the Nadezhdy Quarry deposit. Certain types of natural building stone can be used for stone casting and the production of mineral fibers. In this respect, the metadiabases of the Mikashevichskoye deposit are especially interesting.
In Belarus, this type of mineral raw material is represented by numerous and varied deposits of sands and sand and gravel mixtures, clays, carbonate rocks, gypsum, as well as natural building stone. Despite the relative cheapness of this type of raw material, its importance in the modern economy of the country can hardly be overestimated.
Sands are widespread in Belarus. Deposits of sands are confined to the Quaternary strata, less often to deposits of the Paleogene and Neogene. They are, as a rule, of water-glacial and lacustrine-alluvial origin; in the south of the country there are also sands of aeolian genesis. Sands are used both in their natural state and after beneficiation for the production of concrete, mortar, in the glass industry and foundry.
The raw material base of construction and silicate sands includes about 80 deposits (total reserves of about 350 million m 3), located throughout the country. Sands occur on the surface or close to it in the form of lenticular or sheet-like deposits of various sizes. The thickness of individual deposits reaches 15 m. Deposits of building sands are confined to lakes, outwash plains, and river terraces. More than 35 fields are being developed. Annual production is 7-8 million m 3.
Deposits of molding sands were found in the Zhlobin (Chetvernya deposit) and Dobrush (Lenino) districts of the Gomel region. The Chetvernya deposit is operated by the Zhlobin quarry department, and Lenino by the Gomel mining and processing plant. About 0.6 million m 3 of molding sands are mined annually.
Deposits of glass sands have been explored in the Gomel (Loevskoye) and Brest (Gorodnoye) regions. Their total reserves are 15 million m 3. Glass sands are suitable for producing window and container glass.
Sand-gravel mixtures are associated with moraine, less often alluvial deposits. Deposits of sand and gravel material are widespread in the northern and central parts of Belarus. They are usually small in size (up to 50 hectares). The thickness of the productive strata is from 1-3 to 10-20 m. The particle size distribution is variable. The content of the main components varies as follows: pebbles - from 0 to 55%, gravel - from 5-10 to 75, sand - from 5-10 to 75, clay particles - up to 5-7%. 136 fields have been explored with total reserves of over 700 million m 3; 82 deposits are in operation. About 3 million m 3 of sand and gravel materials are mined annually. They are mainly used for the preparation of concretes and mortars.
Clays are a raw material base for the production of coarse ceramics, lightweight aggregates, and are also used as an essential component in the manufacture of various types of cement. Deposits of fusible clays are mainly associated with Quaternary deposits, refractory - with Oligocene and Pliocene formations, common in the south of Belarus.
More than 210 deposits of low-melting clays with total reserves of about 200 million m 3 have been explored. More than 110 deposits are being developed, 2.5-3.5 million m 3 of raw materials are produced annually. There are also 9 explored deposits for the production of aggloporite and expanded clay with total reserves of about 60 million m 3. Of these, 6 fields are being exploited (production 0.6 million m 3). Reserves of clay rocks for cement production - more than 110 million m 3.
The raw material base of refractory clays includes 6 deposits with total reserves in categories A + B + Cj over 50 million m 3. Deposits are represented by sheet-like deposits with a thickness of 1.5 to 15 m. The depth of their occurrence does not exceed 7-8 m. The annual production of refractory clays is 0.4-1 million m 3.
The group of industrially valuable clayey rocks of Belarus also includes kaolins found within the Mikashevichsko-Zhitkovichi uplift of the crystalline basement. They are products of weathering of granite gneisses and gneisses. Kaolins are usually light gray and white, micaceous, with an admixture of hydromica and montmorillonite. 4 deposits have been identified. The deposits are cape-like, their average thickness is 10 m, the depth varies from 13 to 35 m. The predicted resources are estimated at almost 27 million tons. Kaolins contain increased amounts of coloring iron oxides. They are suitable for the production of porcelain and earthenware products that do not require high whiteness, as well as for the manufacture of fireclay products.
Carbonate rocks, used mainly for the production of cement and lime, are represented by writing chalk and marls, occurring in the Late Cretaceous strata. They are found both in bedding and in glacial rejects. On the areas of their shallow occurrence, mainly in the Krichevsky, Klimovichsky, Kostyukovichsky and Cherikovsky districts of the Mogilev region, Volkovysk and Grodno districts of the Grodno region, a number of deposits have been explored. Some of them (for example, Krichevskoe) are represented by writing chalk, others (Kommunarskoe) by marl, and still others (Kamenka) by marl and writing chalk. The thickness of the productive strata in the fields varies from 10-20 to 50 m with a roof depth of 1 to 25 m. The CaCO 3 content ranges from 65% in marls to 98% in writing chalk.
The raw material base of the cement industry includes 15 fields with total reserves of carbonate rocks in categories A + B + Cj 720 million tons. 8 fields are being developed, on the basis of which the RUE Volkovyskcementoshyfer and Krichevcementoshifer operate, as well as the Belorussky cement plant, which is developing the reserves of Kommunarsky marls. Place of Birth. The cement industry of Belarus is provided with carbonate raw materials for the long term.
The raw material base for lime production is based on the use of writing chalk. There are 33 deposits of this mineral in the country with total reserves in categories A + B + C j of about 210 million tons. 6 deposits are in operation.
Gypsum in a platform case has been known on the territory of Belarus for a long time; it occurs in the form of strata, layers, interlayers, veins and nests in the Middle, Upper Devonian and Lower Permian deposits. Relatively shallow (167-460 m) thick layers of gypsum are found among the deposits of the Famennian stage of the Upper Devonian in the west of the Pripyat trough. They are confined to the raised block of the crystalline basement and form the Brinevskoe gypsum deposit. Up to 14 layers of gypsum are installed here, which are combined into four horizons. The thickness of the gypsum horizons ranges from 1-3 to 46 m. In the section of the lower one, thick lenses of gypsum-anhydrite and anhydrite rocks are observed. The content of gypsum in productive formations varies from 37 to 95%. The reserves of gypsum in the ^ + C 2 categories are 340 million tons, anhydrite - 140 million tons. It is possible to organize the extraction of 1 million tons of gypsum per year.
Natural building stone on the territory of Belarus is represented by various rocks of the crystalline basement (granites, granodiorites, diorites, migmatites, etc.). In the Brest region, two deposits of building stone have been explored (Mikashevichi and Sitnitsa), in Gomel - a deposit of building stone (Glushkevichi, the Krestyanskaya Niva site) and a deposit of facing materials (Nadezhdy's Quarry). The largest of them is the Mikashevichi field. The building stone lies here at a depth of 8 to 41 m. The mineral is represented by diorite, granodiorite and granite. The initial reserves of stone in categories A + B + C j amounted to 168 million m 3. The field is being exploited by an open pit; the depth of the quarry is about 120 m. The Glushkevichi deposit is also being developed. At the Mikashevichi deposit, the annual production of stone is about 3.5 million cubic meters, the production of crushed stone is 5.5 million cubic meters, at the Glushkevichi deposit - 0.1 million cubic meters and 0.2 million cubic meters, respectively.
At the Nadezhda Quarry facing stone deposit, the productive stratum is represented by gray and dark gray migmatites with good decorative properties. The depth of the mineral resource is from several tens of centimeters to 7 m; stocks of raw materials here are 3.3 million m 3.
There are prospects in the country to increase the production of building stone through the construction of a second enterprise based on the Mikashevichi deposit, as well as expanding the production of facing materials at the Nadezhdy Quarry deposit. Certain types of natural building stone can be used for stone casting and the production of mineral fibers. In this respect, the metadiabases of the Mikashevichskoye field are especially interesting.
End of work -
This topic belongs to the section:
INTRODUCTION TO THE GEOLOGY OF BELARUS
A.A. Makhnach ... INTRODUCTION TO THE GEOLOGY OF BELARUS ... MINSK Makhnach A.A.
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I. HISTORY OF GEOLOGICAL STUDY
In the history of geological exploration of the territory of Belarus, three main stages can be distinguished: (1) the beginning of the XIX - beginning of the XX century; (2) early XX century. - 1941; (3) from 1945 to the present.
MAIN FEATURES OF THE GEOLOGICAL STRUCTURE
The territory of Belarus is located in the west of the ancient East European platform. The geological structure of such platforms is two-tiered. Here on a crystalline basement, folded metamorphically
I. GRANULITE COMPLEX
Formations of the granulite complex are distributed over at least 50% of the area of Belarus. Its constituent rocks are metamorphic under conditions of granulite facies (t = 700-780 ° C, P = 6-9 kbar) and are considered
AMPHIBOLITE-Gneiss complex
The formations of the complex include strata of moderate felsic and intermediate gneisses with amphibolite horizons widespread on the territory of Belarus. Areas of development of amphibolite-gneiss
AMPHIBOLITE-Gneiso-Shale Complex
The complex has a local distribution in the central part of Belarus. Here, numerous boreholes have uncovered plagiogneisses, microgneisses, shales, amphibolites and
SHALE COMPLEX
This complex is sparsely distributed within the Mikashevichsko-Zhitkovichi uplift of the crystalline basement in the central part of the Osnitsko-Mikashevichy volcanoplutonic belt. Will distinguish
I. ENDERBIT-CHARNOKITE COMPLEX
The rocks of the complex are widespread in the western part of Belarus, where they are closely associated with the main metamorphic rocks (crystalline shales) of the Shchuchin Group and Rudmyanskaya strata, forming in
BLASTOMILONITE COMPLEX
In the crystalline basement of Belarus, blastomylonites are quite widespread - gneiss-like rocks formed as a result of sheathing, mylonitization and simultaneous recrystallization of m
S.2. COMPLEXES OF BASIC ROCKS
The Berezovsky complex lies in the central part of the Byelorussian-Baltic granulite belt among the main crystalline schists of the Shchuchin series. It is represented by medium-grained metamorphoses
S.3. COMPLEXES OF ROCKS OF MEDIUM COMPOSITION
The Mikashevichi complex is developed in the southern part of Belarus and is represented by large (up to 120 km across) massifs, located close to each other. Arrays are stacked in an almost continuous series
S.4. COMPLEXES OF ROCKS OF ACIDIC COMPOSITION
The Osmolovskii complex includes coarse-grained biotite, amphibole, and sometimes hypersthene-bearing plagioclase-orthoclase granites and monzodiorites, which occur within the Belorussian-Baltic region.
I. LOWER RIPHEAN, MIDDLE RIPHEAN AND UPPER RIPHEAN ERATHEMES
In the Riphean of Belarus (Fig. 5), formations of all three erathems were established (Table 2). The formations of the Lower Riphean erathema on the territory of Belarus are of limited distribution. In their
VENISH SYSTEM
Deposits of the Vendian system are represented by sedimentary (marine, continental, glacial), volcanic and volcanic-sedimentary rocks. Vendian formations are widespread in
PALEOZOIC ERATHEM 7.I. CAMBRIAN SYSTEM
Cambrian deposits occupy the extreme northwestern (slopes of the Belorussian anteclise and Baltic syneclise) and southwestern (Podlasko-Brest depression) parts of the territory of Belarus (Fig. 6) and
ORDOVIK SYSTEM
Ordovician deposits, like Cambrian ones, are widespread in the extreme northwestern and southwestern parts of Belarus (Fig. 7). In the north-west of the country (the slopes of the Belarusian anteclise and the Baltic
SILURIAN SYSTEM
The deposits of the Silurian, like the Ordovician, have an extremely limited areal distribution in the territory of Belarus - in the southwest and northwest (Fig. 9). The most complete and powerful incisions of the Silurian mouth
DEVON SYSTEM
Devonian formations are widespread in Belarus - in the Orsha depression, the Pripyat trough (and in the Pripyat graben, and on the North Pripyat shoulder), in the Latvian, Zhlobin and B
S. CHARCOAL SYSTEM (CARBON)
Deposits of the Carboniferous system are much less developed on the territory of Belarus than the Devonian ones. They occur in two distant regions of the country - in the southeast (Pr
PERM SYSTEM
Permian deposits are distributed in three isolated areas of the territory of Belarus: in the southeast (Pripyat trough and Bragin-Loev saddle), in the southwest (Podlyassko-Brest depression)
MESOSOIC ERATHEM 8.I. TRIASS SYSTEM
Triassic deposits are widespread in the south-east of Belarus (Pripyat trough and Bragin-Loev saddle) and in its south-west (Podlyassko-Brest depression) (Fig. 17). In the southeast
YURSKY SYSTEM
Deposits of the Jurassic system are distributed in (a) southeastern, eastern and (b) southwestern, western regions of Belarus (Fig. 19). They occur in the Pripyat trough, on the Braginsko-Loevskaya and Zhlobins
CHALK SYSTEM
Deposits of the Cretaceous system are distributed over the entire southern half of the territory of Belarus (Fig. 21). They occur transgressively on rocks of different ages - from Upper Jurassic to Archean, overlap
Cainozoic era 9.I. PALEOGEN SYSTEM
Paleogene deposits are widespread within the southern half of Belarus (Fig. 23). They lie under the formations of the Quarter, and in places of the Neogene, in the southeast along the valleys of the Dnieper and N
NEOGENIC SYSTEM
The Neogene deposits of Belarus lie in numerous patches mainly to the south of the Grodno - Novogrudok - Minsk - Bykhov line (Fig. 25). These are mainly terrigenous formations that have accumulated
QUATERNARY SYSTEM (KBAPTEP, ANTHROPOGEN)
Deposits of the Quaternary system on the territory of Belarus cover the formations of more ancient geological systems (see Fig. 3). The thickness of the deposits ranges from a few to 300 m
EARTH CRUST AND UPPER MANTLE
Information about the deep structure of the earth's crust and upper mantle of the territory of Belarus was obtained on the basis of mainly geophysical (gravimetric, magnetometric, seismic) data.
STRUCTURE OF THE CRYSTALLINE FOUNDATION
Three large structural-material megacomplexes have been identified in the crystalline basement of Belarus, each of which corresponds to a certain stage in the development of the region's crust. This is Charnockite
STRUCTURE OF THE PLATFORM COVER 12.1. STRUCTURAL COMPLEXES AND FLOORS
As part of the platform cover of the territory of Belarus, there are several vertical, successively replacing each other in the context of structural complexes, each of which has its own space.
MAIN MODERN STRUCTURES
The most important structural surface, the position of which determines the modern tectonics of the cover of the territory of Belarus, is the border of the cover and the basement. Analysis of the nature of structural surfaces, le
EARLY ARCHEAN, LATE ARCHEAN AND EARLY PROTEROSOIC EON
The history of the geological development of the territory of Belarus during the Early Archean, Late Archean and Early Proterozoic eons is the history of the formation of the crystalline basement. In connection with
LATE PROTEROSOIC EON
In the Late Proterozoic, the platform cover began to form. The first formations of the cover, confined to individual depressions in the basement, date back to the Early Riphean. These are volcanic rocks and are highly variable
IS. PALEOZOIC ERA 15.1. CAMBRIAN PERIOD
In the “pre-trilobite” (Baltic) time of the Early Cambrian epoch, the geographic position of the sedimentation area changed little in comparison with the Valdai time of the Late Vendian. Sedimentation was
ORDOVIAN PERIOD
At the beginning of the Ordovician, after a long hiatus, the sea again entered the territory of Belarus. As in the Cambrian period, it came in two languages from the west, which were probably periodically combined
SILURIAN
During this period, the conditions of sedimentation on the territory of Belarus were close to those in the Ordovician. Shallow marine carbonate sedimentation continued in the extreme western regions of the country. Together
DEVONIAN
Devon is the most studied of all periods of the Paleozoic era on the territory of Belarus. This is due to the great practical value of the formations accumulated at that time (potassium and rock salts, not
STONE-COAL PERIOD
Starting from the Early Carboniferous, the territory of the Pripyat Trough entered the stage of post-rift syneclise. The sinking rates of the territory in the Carboniferous period (0-27 m / million years) became much
PERM PERIOD
The Early Permian era on the territory of Belarus began with a marine transgression from the Dnieper-Donets depression. In the Asselian age, the sea at times reached the central part of the Pripyat trough. Precipitation
MESOZOIC ERA 16.1. TRIASSIC
In the Early Triassic epoch, subsidence and sedimentation took place in the south-east of Belarus (Pripyat depression and Bragin-Loev saddle) and in its south-west (Podlyassko-Brest depression). Pain
JURASSIC PERIOD
Throughout the early Jurassic era, the territory of Belarus was dry land and was subject to erosion. In the Middle Jurassic, sedimentation resumed. It was due to the formation of the largest
THE CRETAL PERIOD
In the Valanginian Age of the Early Cretaceous, the sea penetrated the territory of Belarus from the east. It captured a very small area in the eastern part of the Pripyat trough, on the Bragin-Loyev saddle and
THE CENOZOIC ERA 17.1. PALEOGENIC PERIOD
The Paleocene epoch on the territory of Belarus began with a long hiatus in sedimentation. Erosion and karsting of the Upper Cretaceous carbonate deposits took place with the formation of a weathering crust (t
NEOGEN PERIOD
Sedimentation during the Neogene period took place in the southern half of the territory of Belarus. Here at the beginning of the Miocene epoch there was a low-lying alluvial plain with periodically swampy
QUATERNUM PERIOD
The history of the development of the territory of Belarus in the Quaternary period is divided into three stages: preglacial, glacial and postglacial. The first two correspond to the Pleistocene epoch, the last one to the Holocene
COMBUSTIBLE MINERAL FOSSILS
64 oil fields have been discovered in the Pripyat trough. Their search and exploration have been carried out since 1952, development - since 1965. There are 185 oil deposits in these fields, of which 183 are in the Devonian deposits
Svetlogorsk
Rechmtsa U1 Kamenets
CHEMICAL AND AGROCHEMICAL RAW MATERIALS
An important place in the mineral resource base of the country is occupied by minerals, which are raw materials for use in the chemical industry and in the production of agricultural fertilizers.
METAL MINERALS
In Belarus, ore occurrences and deposits of ferrous, non-ferrous, rare and noble metals are known, mainly confined to the crystalline basement. So, it revealed a deposit
AMBER AND OTHER CANDY STONES
Findings of amber on the territory of Belarus have been known for a long time. The overwhelming majority of them are confined to the south-west of the country, mainly to the territory of Brest Polesie. Two levels of amber-bearing were revealed: lower
FRESH, MINERAL AND THERMAL UNDERGROUND WATER
Belarus possesses significant resources of fresh and mineral groundwater. Fresh groundwater is associated with intermoraine sediments of the Anthropogenic strata, Paleogene, Upper Cretaceous
CONCLUSION
This book ends with a chapter on minerals. This reflects the main ultimate goal of subsoil study - prospecting and exploration of mineral deposits. This goal is still relevant today.
In Belarus, this type of mineral raw material is represented by numerous and varied deposits of sands and sand and gravel mixtures, clays, carbonate rocks, gypsum, as well as natural building stone. Despite the relative cheapness of this type of raw material, its importance in the modern economy of the country can hardly be overestimated.
Sands are widespread in Belarus. Deposits of sands are confined to the Quaternary strata, less often to deposits of the Paleogene and Neogene. They are, as a rule, of water-glacial and lacustrine-alluvial origin; in the south of the country there are also sands of aeolian genesis. Sands are used both in their natural state and after beneficiation for the production of concrete, mortar, in the glass industry and foundry.
The raw material base of construction and silicate sands includes about 80 deposits (total reserves of about 350 million m3) located throughout the country. Sands occur on the surface or close to it in the form of lenticular or sheet-like deposits of various sizes. The thickness of individual deposits reaches 15 m. Deposits of building sands are confined to lakes, outwash plains, and river terraces. More than 35 fields are being developed. Annual production is 7-8 million m3.
Deposits of molding sands were found in the Zhlobin (Chetvernya deposit) and Dobrush (Lenino) districts of the Gomel region. The Chetvernya deposit is operated by the Zhlobin quarry department and the Lenino-Gomel mining and processing plant. About 0.6 million m3 of molding sand is mined annually.
Deposits of glass sands have been explored in the Gomel (Loevskoye) and Brest (Gorodnoye) regions. Their total reserves are 15 million m3. Glass sands are suitable for producing window and container glass.
Sand-gravel mixtures are associated with moraine, less often alluvial deposits. Deposits of sand and gravel material are widespread in the northern and central parts of Belarus. They are usually small in size (up to 50 hectares). The thickness of the productive strata is from 1-3 to 10-20 m. The particle size distribution is variable. The content of the main components varies as follows: pebbles - from 0 to 55%, gravel - from 5-10 to 75, sand - from 5-10 to 75, clay particles - up to 5-7%. 136 fields have been explored with total reserves of over 700 million m3; 82 deposits are in operation. About 3 million m3 of sand and gravel materials are mined annually. They are mainly used for the preparation of concretes and mortars.
Clays are a raw material base for the production of coarse ceramics, lightweight aggregates, and are also used as an essential component in the manufacture of various types of cement. Deposits of fusible clays are mainly associated with Quaternary deposits, refractory - with Oligocene and Pliocene formations, common in the south of Belarus.
More than 210 deposits of low-melting clays have been explored with total reserves of about 200 million m3. More than software for deposits is being developed, 2.5-3.5 million m3 of raw materials are produced annually. There are also 9 explored deposits for the production of aggloporite and expanded clay with total reserves of about 60 million m3. 6 of them are in operation (production 0.6 million m3). The reserves of clay rocks for cement production are over 110 million m3.
The raw material base of refractory clays includes 6 deposits with total reserves in categories A + B + Cj over 50 million m3. The deposits are represented by layer-like deposits with a thickness of 1.5 to 15 m. The depth of their occurrence does not exceed 7-8 m. The annual production of refractory clays is 0.4-1 million m3.
The group of industrially valuable clay rocks of Belarus also includes kaolins found within the Mikashevichsko-Zhitkovichi uplift of the crystalline basement. They are products of weathering of granite gneisses and gneisses. Kaolins are usually light gray and white, micaceous, with an admixture of hydromica and montmorillonite. 4 deposits have been identified. The deposits are cape-like, their average thickness is 10 m, the depth varies from 13 to 35 m. The predicted resources are estimated at almost 27 million tons. Kaolins contain increased amounts of coloring iron oxides. They are suitable for the production of porcelain and earthenware products that do not require high whiteness, as well as for the manufacture of fireclay products.
Carbonate rocks, used mainly for the production of cement and lime, are represented by writing chalk and marls, occurring in the Late Cretaceous strata. They are found both in bedding and in glacial rejects. On the areas of their shallow occurrence, mainly in the Krichevsky, Klimovichsky, Kostyukovichsky and Cherikovsky districts of the Mogilev region, the Volkovysk and Grodno districts of the Grodno region, a number of deposits have been explored. Some of them (for example, Krichevskoe) are represented by writing chalk, others (Kommunarskoe) by marl, and still others (Kamenka) by marl and writing chalk. The thickness of the productive strata in the fields varies from 10-20 to 50 m with a roof depth of 1 to 25 m. The CaCO3 content ranges from 65% in marls to 98% in writing chalk.
The raw material base of the cement industry includes 15 fields with total reserves of carbonate rocks in categories A + B + Cj 720 million tons. 8 fields are being developed, on the basis of which RUE Volkovyskcementoshyfer and Krichevcementoshyfer operate, as well as the Belorussky cement plant, which is developing the reserves of Kommunarsky marls. Place of Birth. The cement industry of Belarus is provided with carbonate raw materials for the long term.
The raw material base for lime production is based on the use of writing chalk. There are 33 deposits of this mineral in the country with total reserves in categories A + B + Cj of about 210 million tons. 6 deposits are in operation.
Gypsum in a platform case has been known on the territory of Belarus for a long time; it occurs in the form of strata, layers, interlayers, veins and nests in the Middle, Upper Devonian and Lower Permian deposits. Relatively shallow (167-460 m) thick layers of gypsum are found among the deposits of the Famennian stage of the Upper Devonian in the west of the Pripyat trough. They are confined to the raised block of the crystalline basement and form the Brinevskoe gypsum deposit. Up to 14 layers of gypsum are installed here, which are combined into four horizons. The thickness of the gypsum horizons ranges from 1-3 to 46 m. In the section of the lower one, thick lenses of gypsum-anhydrite and anhydrite rocks are observed. The content of gypsum in productive formations varies from 37 to 95%. The reserves of gypsum in the Cj + C2 categories are 340 million tons, anhydrite - 140 million tons. It is possible to organize the extraction of 1 million tons of gypsum per year.
Natural building stone on the territory of Belarus is represented by various rocks of the crystalline basement (granites, granodiorites, diorites, migmatites, etc.). In the Brest region, two deposits of building stone were explored (Mikashevichi and Sitnitsa), in the Gomel region - a deposit of building stone (Glushkevichi, the Krestyanskaya Niva site) and a deposit of facing materials (Nadezhdy's Quarry). The largest of them is the Mikashevichi field. The building stone here lies at a depth of 8 to 41 m. The mineral is represented by diorites, granodiorites and granites. The original stone reserves in the A + B + Cj categories were 168 million m3. The deposit is being exploited by an open pit; the depth of the quarry is about 120 m. The Glushkevichi deposit is also being developed. At the Mikashevichi deposit, the annual production of stone is about 3.5 million m3, the production of crushed stone - 5.5 million m3, at the Glushkevichi deposit - 0.1 million m3 and 0.2 million m3, respectively.
At the Nadezhda Quarry facing stone deposit, the productive stratum is represented by gray and dark gray migmatites with good decorative properties. The depth of the mineral resource is from several tens of centimeters to 7 m; stocks of raw materials here are 3, 3 million m3.
