The main raw material for the production of confectionery products. Raw materials. types of raw materials. methods of enriching raw materials

Raw materials , or raw material, is any object of labor for the extraction or production of which human labor was expended. In the labor process, raw materials act as the subject of labor. But not every object of labor is a raw material. Thus, ore, coal located in the bowels of the earth, a tree in the forest, fish in a pond are objects of nature. They become objects of labor when labor is applied to them, transforming them from objects of nature into objects of labor.

According to their natural state, such objects of labor are represented by three groups. One of them includes biological, land and water resources(soil, water, forest, birds, animals, fish, etc.); the other is subsoil resources (various types of mineral raw materials and fuel); The third group includes the energy of rivers, sun, wind, underground heat sources, the force of sea tides and other types of constantly renewable energy sources.

The raw materials for fishing industry enterprises are caught fish, as well as fish grown in pond farms and received from fishing collective farms, sea animals, seafood used for the production of fish products, canned food, fats, technical and other products. The raw materials for pond fish farms are yearlings grown on the farm or obtained from outside. To produce finished products in the production process, several types of raw materials are used, which are divided into basic and auxiliary.

Main are the materials that are part of the manufactured product and are its basis. At fish processing enterprises, the main materials include raw fish, tomato paste, vegetable oil, flour, at net-knitting factories - threads, at shipbuilding and ship repair enterprises - metals, timber, etc. In planning practice, raw fish is especially highlighted.

Auxiliary These are materials that, while not being the main part of the manufactured product, participate in its formation and are also used for technical purposes. Auxiliary materials include packaging materials, ice, salt, lubricating oils, etc. From an economic point of view, fuel is also classified as an auxiliary material. However, in accounting and planning practice, based on the fact that fuel is consumed in large quantities all branches of material production, it stands out especially.

The difference between basic materials and auxiliary materials lies not in the material content of each of them, but in their participation in the manufacture of the finished product. Depending on the participation of one or another object of labor in the manufacture of the finished product, it can act either as a raw material or as an auxiliary material. For example, coal is an auxiliary material as a fuel, and in coal chemical synthesis it acts as the main material.

In the manufacturing process, the raw material that has been processed and intended to be further processed into a finished product is called semi-finished product . Fish transferred by one enterprise for processing or finishing, in contrast to fish produced in-house, is considered a semi-finished product, regardless of whether it has been subjected to any processing or delivered directly from the place of production in fresh or live form.

Depending on their origin, raw materials used in industry are divided into industrial And agricultural. Most of the raw materials that industry extracts and produces are consumed by heavy industries. With the development of science and technology, artificial raw materials (synthetic fuels, artificial and synthetic fibers, synthetic rubber, various polymers and other synthetic materials) occupy an increasing share of industrial raw materials.

Raw materials are divided into mineral and organic.

Mineral raw materials - these are all kinds of ores, coals, oil, natural gases, salts, shale, non-metallic minerals. These types of raw materials are contained in the bowels of the earth, created over many millennia by the forces of nature and cannot be reproduced by human labor. Therefore, mineral reserves can only be replenished through the discovery and development of natural deposits.

Organic - These are plant and animal raw materials. Plant and animal organisms can constantly reproduce without influence (forest, fish, wild fur-bearing animals) and through the influence of human labor on the forces of nature (agriculture, animal husbandry, forestry, fish farming, etc.).

IN modern industry are widely used as raw materials water And air. Water is used as a raw material in electrochemical, chemical and other industries to produce oxygen and hydrogen. Recently, increasing attention has been paid to the use of sea water. Like natural raw materials sea ​​water directly without processing it is used in industry, agriculture and municipal services, maritime transport, healthcare and other sectors of the national economy. It is a raw material for the production of fertilizers and other chemical products, a medium for mariculture, and a medical and health environment. Air is used as a raw material to produce nitrogen, argon, and oxygen.

In each production, as in each individual industry, people’s labor activity is determined by natural conditions. Production takes place under certain natural conditions that determine the production process itself in accordance with the objective laws of nature.

The natural environment represents a huge arsenal of objects and forces of nature. People are not able to use everything at the same time Natural resources. Natural resources provide only preliminary potential conditions and create the opportunity for development. Thus, powerful natural reserves of coal and oil as potential energy resources fully matured in the depths of the earth in the distant prehistory of social production. The use of these resources began relatively recently, at a certain level of production.

Natural resources of reservoirs cannot be considered the raw material base of the fishing industry; they are only a necessary condition, a prerequisite for the creation and development raw material base. The use of natural resources is determined by the development of productive forces and the nature of production relations.

The increasing scale and rate of use of various natural resources of the sea, including biological ones, in the national economy, have necessitated their economic classification. Biological resources hydrospheres are divided into the following interrelated categories: general fish resources of nature, potential fish resources, identified fish resources and the raw material base of fisheries - depending on the level of knowledge, accessibility and stages of development.

Fisheries raw material base - this is an economically feasible part of the identified biological resources of nature, which, without compromising their reproduction and at a given level of development of productive forces, can currently be used by society. Recognizing the determining role of the action of economic laws in the process of formation and development of the raw material base of the fishing industry and using them for its further targeted development, it is also necessary to take into account the influence on the raw material base of nature. Knowledge of the objective laws of nature provides a person with the opportunity to deeply and comprehensively use natural resources. That is why it is necessary to study the characteristics of the raw material base of the fishing industry associated with the manifestation of the action natural laws to use them skillfully to obtain the most effective results.

The objective of the course “Fundamentals of industrial technologies” is to study and select the optimal types technological processes, raw materials, energy, fuel, in determining effective directions of scientific and technological progress in industry. It is necessary that economics students must be able to analyze existing technology and understand the need to introduce new equipment and technology into the national economy.

The main determining incentives for technology development are the economic and production needs of society. Economic relations leave their mark on the development of technology.

Technology is a production method that includes a number of methods and techniques for using machines, equipment and other technological means for processing raw materials, materials and semi-finished products to obtain finished products.

Technology is the science of methods of processing or processing raw materials, semi-finished materials or products carried out in various industries, construction, etc.

Technology is artificial, purposefully created material means used by humans in production and non-production activities to facilitate and speed up labor processes.

Technology is the total number of means of human activity created to carry out production processes and service the non-production sphere. This includes the sum of all machines and mechanisms, control systems. Extraction. Storage. Substance processing. Energy and information created to produce and serve the non-material needs of society.

In the Trans-Baikal Territory, such industries as mining, engineering, and construction have received the greatest development.
Topic 1. The concept of raw materials, classification, extraction methods and enrichment
1.1. Classification of raw materials
Raw materials are materials of natural or artificial origin used in the production process to obtain semi-finished or finished products.

According to their state of aggregation, raw materials are divided into solid, liquid, and gaseous.

Based on their origin, raw materials are divided into plant, animal and mineral.

Plant and animal raw materials are processed either into food or into products for industrial or household use. The source of plant and animal raw materials is resources natural environment habitats: land, forest and water. Plant and animal raw materials are of great importance for many sectors of the national economy. A feature of many types of animal and plant raw materials is the seasonality of production associated with the growing season.

Replacing food raw materials with non-food ones is a very important task. For example, in the production of ethyl alcohol, the replacement of grain and potatoes with petrochemical raw materials.

Mineral raw materials are the most important. It is divided into ore, non-metallic and combustible. Mineral raw materials are called minerals.

There are three main groups of minerals:

1) metallic minerals - raw materials for the production of metals, which are the basis of mechanical engineering, various types of transport, electrical and defense industries;

2) non-metallic minerals that serve as raw materials for the production of non-metallic elements and their compounds (acids, salts), as well as for the production of mineral fertilizers, construction, ceramic, road and other materials;

3) combustible minerals, which in natural or processed form are used as fuel or as chemical raw materials (coal, oil).

Minerals are of great importance in the economy of every industrialized country. The scale of mining and processing of mineral resources can, to a certain extent, serve as a measure of a country’s material culture, its wealth, economic development and independence.

There is not a single sector of the national economy where minerals are not used in one form or another. They serve as the basis for the development of heavy industry. Agricultural development is also closely related to mineral resources. They are also widely used in the production of consumer goods.

Global mineral production is enormous. On average, more than 13 tons of mineral raw materials are mined per year from each square kilometer of land, and about 1 g per year per person.
1.2. Mining methods
Mineral deposits can be located in different economic, geographical and climatic zones. The depth of ore bodies varies within wide limits. Sometimes ores occur near the surface, in most cases they are located at a depth of 100-500 m, and a number of deposits can occur at depths of up to 1000 m or more (for example, deposits of copper-zinc ores).

In the mining industry that provides ore raw materials, there are three methods of extracting minerals:

Open pit;

Underground mine;

Combined.

The open method is used if the mineral is located not far from the earth's surface. First, the top fertile layer of soil is removed, then a layer of waste rock that does not contain a valuable component is removed. These operations are called stripping operations; After they are carried out, the mineral resource is directly extracted. Drilling and blasting operations can be used to soften the rock mass (to loosen it to facilitate mining). The open method has a number of significant advantages and is the most cost-effective method of development: better sanitary and hygienic working conditions, the possibility of using high-performance mining and transport equipment and, as a consequence, the ability to achieve high technical and economic indicators. With the open method, worker productivity is 4-5 times higher than with underground mining, and the cost of mined ore is 2-3 times lower. Losses of minerals in the open-pit method usually do not exceed 3-5% instead of 10-15% in underground mining. Capital costs for the construction of the entire complex of buildings and structures for underground mining are 1.5-2 times higher, construction speeds are 2-3 times longer than with the open method. Therefore, if there are several deposits of the same mineral in a region, development begins with the one that lies nearby. The open-pit mining method does not require the construction of any communications, with the exception of access roads for vehicles (no heat, power supply, water supply and drainage, etc. are required).

Deep-lying minerals are mined underground in mines. Mine is complicated engineering structure, with many communication systems, for example: providing ventilation communications, pumping groundwater.

Combined mining is used, as a rule, when the ore body is inclined, when development is initially carried out open method, and then transferred to the underground (mine) method. If the ore body is large along the dip, it is possible to simultaneously use the quarry and mine methods.

1.3. Mineral beneficiation
Only a small part of the extracted minerals is suitable for direct processing. Most of them in their natural state cannot be used, so the ores are first subjected to enrichment. The beneficiation of minerals is carried out in special structures - concentration factories.

The advantages achieved as a result of the enrichment of minerals prior to their technological processing mainly come down to the following:

1) enrichment of low-grade ores expands mineral resources, i.e., increases industrial reserves of mineral raw materials in the country;

2) enrichment of complex multicomponent ores allows for more complete use of the useful minerals contained in them;

3) in general, beneficiation increases the technical and economic efficiency of mineral processing and improves the quality of finished products;

4) removal of impurities during enrichment reduces transportation costs when transporting minerals;

5) the possibility of removing waste rock during enrichment allows the use of gross mineral extraction in the cheapest and most productive ways compared to selective deposit development systems.

The set of operations to which ore and enrichment products are subjected, and the sequence of their implementation, is called the beneficiation process flowsheet. When beneficiating minerals, qualitative-quantitative, water-sludge diagrams, and a diagram of the apparatus circuit are drawn up.

A diagram containing data on the quality characteristics of ore and enrichment products is called quality scheme. If the diagrams indicate the amount of ore and products obtained in individual operations, then it is called quantitative. Typically, qualitative and quantitative schemes are combined into a qualitative-quantitative scheme. In the water-sludge scheme, a diagram in which the devices in which this or that operation is performed is indicated, is called a device diagram.

The circuit diagram of devices is depicted as a network of branching and connecting lines, at the nodal points of which all devices, main and auxiliary, are depicted. The devices on these diagrams are given by symbols that resemble their appearance.

On water-slurry diagrams, the amounts of water in individual operations are indicated in tons or cubic meters per unit of time, and also as a ratio of the amount hard material to liquid (T:L) or moisture content as a percentage.

At processing factories, minerals are subjected to successive processing processes, which, according to their purpose in the technological cycle, are divided into preparatory, main and auxiliary.

TO preparatory processes include crushing, disintegration, grinding, screening and classification, i.e. those as a result of which the opening of minerals is achieved with the formation of a mechanical mixture of particles of different mineral composition, suitable for their subsequent separation during the enrichment process, as well as averaging operations of minerals, which can be carried out in mines, quarries, mines and concentration factories.

TO main processes include flotation, magnetic and electric separation, enrichment on concentration tables, sluices, screw separators, depositors, etc., i.e. physical and physicochemical mineral separation processes in which useful minerals are separated into concentrates and waste rock into tailings.

TO auxiliary processes include dehydration those. removal of moisture from enrichment products, cleaning Wastewater for their reuse or discharge into public water bodies and dust collection those. the process of cleaning air before releasing it into the atmosphere.

As a result of mineral enrichment, several products are obtained: concentrates, intermediate products and tailings.

Concentrate called a beneficiation product with an increased content of useful components (minerals, metals or elements) compared to the original ore. When beneficiating multicomponent minerals, two or more concentrates are usually obtained. In this case, the concentrate is named after its main component (mineral, metal or element); for example, lead, barite or sulfur concentrates.

Tails called enrichment waste containing mainly gangue minerals and a small amount of useful components.

During the enrichment process, it is not always possible to immediately obtain finished concentrate and tailings. Sometimes they get it in the first ( basic ) operation is a finished concentrate, but the remaining material still contains many useful minerals. In such cases, it is re-enriched one or more times, resulting in waste tailings and a product enriched with a useful component. Such operations, which serve to extract useful components from tailings, are called control , and the enriched products obtained as a result of these operations, poorer than the main concentrate, are called intermediate products (abbreviated as industrial products). Typically, intermediate products are subjected to additional processing to bring the content of useful minerals to the required level.

Sometimes, on the contrary, the main operation produces waste tailings and low-grade concentrates that cannot be sent to the consumer. In these cases, the concentrate is subjected to re-enrichment (one or several times), resulting in a finished concentrate and a relatively poor middling product. Such operations that serve to improve the quality of concentrates are called cleaners.

Depending on the order of operations of the same name, they are assigned numbers – first main operation, second main, first cleaning operation, second cleaning operation, etc.

The results of mineral enrichment cannot be assessed using any one indicator. For this purpose, several indicators are used that characterize the technological process as a whole. The main indicators include:

• 
  component content in feedstock and enrichment products;
• 
  yields of enrichment products;
• 
  extraction of components into enrichment products;
• 
  the degree of concentration of the useful component and the degree of reduction achieved during enrichment;
• 
  enrichment efficiency.

Contents component is the ratio of the mass of the component to the mass of the product in which it is found (in terms of dry matter). The content of components is usually determined by chemical analyzes and is expressed as percentage (%), fractions of a unit or grams per ton (g/t) (for noble metals). The contents of the components are usually denoted by letters of the Greek alphabet:

 (alpha)– component content in the original ore;

 (beta)– component content in the concentrate or enrichment products;

 (theta)– component content in tailings.

Exit enrichment product is the ratio of the mass of the resulting product to the mass of the processed feedstock. It is expressed as a percentage or fraction of a unit and is denoted by the Greek letter  (gamma). The total yield of all enrichment products corresponds to the yield of the original ore, taken as 100%. If during the enrichment process two products are obtained: a concentrate with a yield of  k and tailings with a yield of  xv, then we can write the equation for the balance of enrichment products by yield:
100 =  k +  xv,
The total mass of the valuable component in the enrichment products must correspond to its mass in the feedstock. This condition is called the balance of the valuable component:
100 =  to  +  xv .
By extraction component in the enrichment product is the ratio of the mass of the component in the product to the mass of the same component in the original mineral. Recovery is usually expressed as a percentage or fraction of a unit and is denoted by the letter  (epsilon). The extraction of a useful component into a concentrate characterizes the completeness of its transition into this product during the enrichment process.

The extraction of useful components into enrichment products is determined by the formula

;
Degree of concentration or degree of enrichment is called the ratio of the content of a useful component in the concentrate to its content in the feedstock. The degree of concentration (or degree of enrichment) shows how many times the content of the useful component in the concentrate has increased compared to its content in the original raw material. The degree of concentration is indicated by the letter K. The higher the concentration and recovery, the higher the efficiency of the enrichment process.

The degree of concentration (degree of enrichment) is determined by the formula:

K =   .
Preparatory enrichment processes have the goal of preparing the ore for enrichment. Preparation includes the operations of reducing ore pieces - crushing and grinding and the associated classification of ore on screens, classifiers and hydrocyclones. The final grinding size is determined by the dissemination size of the minerals. Of all the processes used in processing plants, the most energy-intensive and requiring significant material costs are the preparatory processes (crushing, grinding, disintegration, screening, classification). Their share, for example, in the processing of polymetallic ores accounts for about half of the total energy consumption and total processing costs, and in iron ore processing plants these costs are even higher and reach 60%. In turn, core processes account for only about a third of total costs.

By crushing called the process of reducing pieces of raw materials under the influence of external mechanical forces. In this case, the product is obtained predominantly with a particle size of more than 5 mm.

Grinding practically no different from crushing, which means grinding – this is the process of bringing mineral raw materials to the required size (from 5 mm or less). Destruction occurs predominantly along weakened sections that have cracks or other structural defects.

The degree of crushing (grinding) is the ratio of the diameter of the pieces of the source material (D) to the diameter of the pieces of the crushed (grinding) product (d):

i=D/d
Crushing and grinding of ore is usually carried out in several stages using crushers and mills various types. The degree of fragmentation achieved in each individual stage is called private, in all stages - general. The overall degree of crushing is determined by:
i=i 1 i 2 i 3

Characteristics of the crushing and grinding stages are given in the table:

Stage	Piece size, mm		i	Applicable (main units)
	nutrition	product
Coarse crushing	300-1500	100-300	3-6	Jaw, cone and impact
Medium crushing	100-300	10-50	3-8	Cone crushers
Fine crushing	10-50	3-10	3-8	Cone and roll crushers
Grinding	0,3-10	0.05 (and smaller) -2.0	20-100	Mills

The given limit values ​​of pieces of initial and crushed material for each stage, as well as the number of stages, are conditional. For example, fine grinding, in turn, can be carried out in two or more stages.

When crushing and grinding, pieces of minerals are divided into smaller parts. Depending on how the adhesion forces between mineral particles are overcome, crushing methods are distinguished, clearly shown in Fig. .

Rice. . Crushing methods:

A- crushing; b- splitting; V-hit; g-compression
In machines used for this purpose, the destruction of the mineral is usually carried out simultaneously in several ways.

The choice of crushing method depends on the physical properties of the mineral and the size of the material. For very hard materials, crushing by impact or crushing is most rational; for viscous materials, crushing or impact combined with abrasion. Brittle materials are crushed by splitting. As for the influence of the size of the original pieces, crushing and splitting are most often used for coarse crushing, while fine grinding is carried out mainly by impact and abrasion. The simplest and cheapest method of crushing is crushing, and the most expensive is abrasion, since it is associated with a high consumption of energy and materials.

Depending on the properties of the mineral and the method of its further processing, crushing and grinding are carried out using dry or wet methods.

According to their technological purpose, all machines used for the destruction of mineral raw materials and other materials are divided into two main groups: crushers and mills. They can operate in an open cycle, in which the material passes through the crusher or mill once, or in a closed cycle with a screen or classifier, the oversize (large) product of which is continuously returned to the crusher or mill for additional crushing (regrinding).

The general classification of crushing and grinding equipment is based on the principle of their operation, i.e. on the method of destruction, which is determined by the type of energy directly used to destroy the material. Destructive energy may result mechanical work crushing bodies (in crushers and mills), energy of compressed air, gas, steam or water (during explosive crushing and grinding).

Depending on the type of working (crushing) body and design features, crushers are divided into jaw, cone, roller, rotary, etc.

Crusher type	Scheme	Description of design	Varieties		Application
Cheek		1 - motionless cheek, 2 – movable cheek 3 - eccentric, 4 - eccentric shaft, 5 – mechanism for changing the width of the outlet slot, 6 - spring, 7 – vertical connecting rod, 8 – spacer plates, 9 - barbell 10 – bed, 11 - axis	A – with a simple cheek swing B – with a complex pumping of the cheeks.		For coarse and medium crushing.
conical	B is the width of the receiving hole; b o , b - minimum and maximum width of the discharge opening, respectively	1 – bed, 2 - stationary cone, 3 - crushing cone, 4 – traverse , 5 – shaft, 6 – eccentric glass, 7 - bevel gears, 8 - central vertical bearing	Cone crushers for coarse, medium and fine crushing		used for coarse, medium and fine crushing
roller		1 , 5 – rollers, 2 - fixed bearing, 3 - ore 4 - moving bearing, 6 – elastic connection, 7 – frame.	single-roll - for crushing sinter and coal; two-roll (with smooth and grooved rolls) - for crushing rocks and ores; four-roll with smooth rolls for crushing coke and limestone (at sinter plants).
hammer		1 – welded body, 2 – rotor, 3 – hammers, 4 - impact plates, 5 - grill		Hammer and rotary crushers are used for coarse, medium and fine crushing of various minerals: brittle, soft and medium hard. The advantages of these crushers are their simplicity of design, compactness, reliability and relatively high degree of crushing (10-20 or more). The main disadvantage of impact crushers is the rapid wear of hammers, beaters and grates, as a result of which the durability of the crushers is reduced. For hammer crushers Hammers of various weights (from 3 to 180 kg) and shapes are used, depending on the size and hardness of the crushed material. Hammers are made of steel with hard alloy surfacing.
rotary		1 - frame, 2 - drum, 4 - fixed plate, 6 – movable plate, 7 – beats.

Jaw crushers They are mainly used for coarse and medium crushing of hard rocks.

There are crushers with simple and complex jaw movements (Fig. 1). In crushers with a simple jaw movement (Fig. 1, a) the movable jaw 2 suspended on an axis 11 and receives movement from the eccentric shaft 4, on the eccentric of which a vertical connecting rod 7 hangs freely. Spacer plates rest against the lower part of the connecting rod on both sides through liners 8, fixed with opposite ends - one in the movable cheek, the second in the stop socket of the rear wall of the frame. To change the width of the discharge slot of the crusher, the stop is moved and secured with a screw (5-mechanism for changing the width of the discharge slot). A rod is attached to the movable cheek 9 with spring 6, pulling the cheek during the reverse stroke. When the eccentric shaft rotates, the movable cheek receives a pendulum swing, approaching and moving away from the fixed cheek 1 beds 10. Rice. . Schemes of jaw crushers with simple (a) and complex (b) jaw movements

In crushers with complex jaw movement (Fig. 1, b), the movable jaw is suspended directly on the eccentric drive shaft, and its lower part is hingedly connected to the spacer plate. The trajectories of movement of the points of the movable cheek are oval-shaped curves, with significant vertical movement, which determines not only the crushing, but also the abrasive effect of the cheek.

The most widely used are jaw crushers with a simple jaw movement. Their dimensions are determined by the width and length of the receiving opening, as well as the minimum and maximum width of the discharge opening.

Cone crushers are designed for coarse (KKD), medium (KSD) and fine (KMD) crushing.

The KKD crusher (Fig.) consists of a frame 1 with a fixed cone placed on it 2. Inside the fixed cone there is a shaft 5, on which the crushing cone is rigidly fixed 3. The upper end of the shaft is hingedly suspended on a traverse 4, a lower - loosely inserted into the eccentric glass 6.

Axis O"-O" the shaft is slightly inclined to the axis O-O symmetry crusher body (and therefore to the axis of the eccentric bowl). Thus, a certain eccentricity value is ensured e.

The eccentric cup rotates in the central vertical bearing by means of bevel gears 7 8 crusher body. When the eccentric glass rotates around its axis O-O axis shaft 5 describes a conical surface, as a result of which the movable crushing body makes circular movements inside the stationary cone, approaching or moving away every half turn to one or another (located opposite) side of the stationary cone. Crushing of the material loaded into the upper part of the crusher thus occurs in the annular working space between the fixed and movable cones, by crushing and abrasion.

Crushers KSD and KMD, in principle, differ little from crushers of the KKD type. Their main design difference is determined by the method of installing the crushing cone.

Roll crushers use the principle of crushing and splitting material located in the working space between moving smooth, grooved or serrated cylindrical surfaces.

Depending on the design features and purpose, the following types of roller crushers are used:

single-roll - for crushing sinter and coal; two-roll (with smooth and grooved rolls) - for crushing rocks and ores;

twin-roll with toothed rolls - for crushing coal and soft rocks;

four-roll with smooth rolls for crushing coke and limestone (at sinter plants).

Twin-roll crushers are the most widely used. The main working elements of a two-roll crusher (Fig.) are two rolls 1 and 5 , rotating towards each other, which are mounted on frame 7 in bearings: stationary 2 and mobile 4. The latter thanks to the elastic connection 6 can move horizontally when non-crushing objects get between the rollers. In this case, the width of the unloading slot increases and the uncrushable object or piece of ore 3 goes down. This protects the crusher from damage.

In gear crushers, each roll consists of a shaft and a polyhedron rigidly mounted on it, to which replaceable gear segments (bandages) in the form of manganese steel castings are bolted.

Hammer and rotary crushers with a rotating impact rotor are mainly divided into two types: hammer crushers with hinged hammers and rotary crushers with rigidly fixed blades (beaters).

Hammer crusher with grid (Fig. , A) consists of a welded body 1 and rotor 2. To protect against wear, the end walls of the housing are protected by lining plates. Feed material falls onto a rapidly rotating rotor with freely suspended hammers 3 and is thrown onto the impact plates 4. Crushing is carried out by hitting the material with hammers and hitting the pieces against breaker plates. The crushed material is unloaded through grate 5, and here on the grate additional crushing of large pieces takes place.

In a rotary crusher(Fig. 6) crushing is carried out rigidly mounted on the drum 2 beaters 7. Additional crushing is carried out when the material hits a stationary 4 and mobile 6 slabs

Hammer and rotary crushers are used for coarse, medium and fine crushing of various minerals: brittle, soft and medium hard. The advantages of these crushers are their simplicity of design, compactness, reliability and relatively high degree of crushing (10-20 or more). The main disadvantage of impact crushers is the rapid wear of hammers, beaters and grates, as a result of which the durability of the crushers is reduced. For hammer crushers, hammers of various weights (from 3 to 180 kg) and shapes are used, depending on the size and hardness of the crushed material. Hammers are made of steel with hard alloy surfacing.

Mills are designed to reduce the size of crushed materials to the final size determined by the subsequent technology of their use. When beneficiating minerals, the final size of the crushed products is determined by the inclusion of valuable (ore) minerals and the required completeness of their disclosure.

The grinding of minerals and other materials is in most cases carried out in drum mills: ball, rod and autogenous mills.

Drum mill(fig.) is a cylindrical (sometimes cylindrical) drum 3, supported by hollow pins 1 and 5 on bearings 2 And 4, filled to a certain level with grinding bodies 6. When the drum rotates, the ore fed into the drum, together with the grinding bodies, rises to a certain height, and then rolls or falls down, being crushed due to the forces of impact and friction in the layers of the grinding medium.

Rice. . Drum mill diagram
The process of ore grinding occurs continuously as it moves along the drum from loading through the hollow axle 1 to unloading from the axle 5.

Unloading of crushed products can be carried out due to a difference in loading and unloading levels, as well as due to the removal of the crushed product from the mill by a stream of water or air. Drum mills are distinguished by the shape of the drum, the type of grinding bodies, the grinding method used and the principle of unloading the crushed product. Metal balls, rods or large pieces of the original ore are used as grinding bodies; unloading can be carried out through a grate or by free drainage due to removal by water flow.

MSC rod mills are used in the first stage of ore grinding to a particle size of 1-5 mm. The grinding bodies in them are steel rods, the length of which is 25-50 mm less than the internal length of the mill drum.

Ball mills with an MSR grid are also used mainly in the first stage of grinding. In grate mills, balls or ore pebbles are used as grinding bodies. The crushed product passes through the grate openings, is lifted by lifters and sent to the mill's discharge axle. The mill operates in such a way that the difference in pulp levels between the loading and unloading ends of the drum remains significant, so the speed of material movement along the mill is relatively high. This predetermines the receipt of a product of relatively coarse grinding (40-60% of the class - 0.074 mm).

Ball mills with central discharge MShTs are used mainly in the II and III stages of grinding to obtain products with a particle size of 80-90% class -0.074 mm.

Autogenous mills. The essence of the ore autogenous grinding process is that the large pieces contained in the ore are crushed into smaller ones and at the same time are crushed themselves.

When self-grinding, ore with a particle size of up to 500 mm can be loaded into the mill, i.e. eliminates the need for fine, medium, and sometimes coarse crushing. In addition, it becomes possible to completely or partially abandon the use of metal grinding bodies and improve the technological performance of enrichment due to greater selectivity of grinding and less sludge of the material. The capital costs of constructing factories with autogenous mills with large drum diameters (more than 8 m) are lower than for the construction of factories with conventional crushing and grinding circuits, but operating costs may be higher.

For primary wet autogenous grinding, “Cascade” (D/L=23) and ore-pebble mills (D/L=1.52) are used; for dry autogenous grinding, “Aerofol” mills (D/L= 34) are used. ).

When operating mills, the following operating modes are used:

Grinding cycles

Grinding of minerals in mills can be carried out in open, closed or semi-closed cycles with single or multi-stage grinding schemes. In an open cycle, the crushed product is sent for enrichment or to the next grinding stage.

In closed or semi-closed cycles, the crushed product (all or some of it) is sent to a classifier, the sands of which are returned to the mill for additional grinding, and the waste is sent for further processing. Mill operation diagram 1 in a closed loop with a classifier 2 shown in Fig. .

Rice. . Scheme of operation of a mill in a closed cycle with a classifier
When the mill operates at steady state, the volume of sand returned, called the circulating load, stabilizes.

represents the ratio of the mass of sands returned to the mill to the mass of the original ore entering the mill. circulating load is calculated WITH(%) according to the formula

,

where S is the mass of sand (circulating product) per unit time; Q is the mass of the original ore entering the mill per unit time.

The technological purpose of the circulating load is to increase the speed of passage of material through the mill, which helps to increase the efficiency of the grinding bodies and reduce overgrinding of the material. Ultimately, this causes an increase in mill productivity for the finished size class. The optimal circulating load value is usually 200-400%.

IN technological schemes enrichment, sorting of solid material by size is carried out by screening or classification.

Screening is the process of separating bulk lumpy granular material into products of various sizes (classes) using sieving surfaces with calibration holes.

As a result of the screening operation, the upper (over-size) and lower (under-size) products are obtained.

According to technological purpose, there are four types of screening operations:

Auxiliary screening is used in crushing schemes for the source material, including preliminary (before the crusher), control or calibration (after the crusher) and combined (when both operations are combined into one)

Preparatory screening – to separate the material into several size classes, intended for subsequent separate processing;

Self-screening - to identify classes that represent finished products sent to the consumer. This operation is also called sorting.

Dewatering screening - to remove the bulk of water contained in the ore after washing or to separate the suspension from the final products.

Screening devices used in practice are divided into stationary (grid-iron) and movable (oscillating, vibrating, etc.) The main part of any screen is the sieves or sieves.

Fixed grate screen is a set of grate bars located parallel or with a slight widening of the gap to the discharge end of the screen. Grate screens are installed horizontally or at an angle of no more than 40-45 degrees, ensuring independent rolling of the material. The size of the gaps is usually 40-45 mm. The screening efficiency on them does not exceed 60-70%.

To increase the efficiency of sieving material, the sieving surface is given a direction of movement as a result of rocking or vibration. In swinging screens, the box with sieves undergoes forced movement due to the rigid kinematic connection between the drive and the box. The trajectory of the sieve in this case is constant. Oscillating screens may have one or more screening screens. Nowadays, swinging screens are rarely used.

The most widely used in modern processing plants are vibrating screens with inertial vibrators. These screens are characterized by a high frequency of sieve vibration and low amplitude. Typically, sieves oscillate in a direction perpendicular to their plane, which contributes to high productivity and screening efficiency.

Classification is the process of separating mineral particles based on different speed deposition in water or air. Typically, in processing plants, classification is carried out in an aquatic environment. Unlike screening, classification is used to separate relatively small material with a size of no more than 3-4 mm. In addition, classification can be used as an auxiliary operation before gravity enrichment.

The products of hydraulic classification are drainage, which contains, as a suspension in water, a fine fraction of crushed material and sand, which are precipitated large particles. All classifiers can be divided into two main types:

A – gravitational (with gravitational separation) or mechanical classifiers. (spiral classifiers)

B – centrifugal classifiers (with separation in the field of centrifugal forces. (hydrocyclones)

P
An example of mechanical classifiers is spiral classifiers. Spiral classifiers consist of an inclined trough 1, in which one or two rotating shafts 2 with spirals mounted on them are placed.
G
Hydrocyclones are a metal body shaped like a cylinder. The pulp enters the apparatus at high speed under pressure tangentially (tangentially) and under the influence of centrifugal forces, large particles are thrown towards the walls of the apparatus and removed from the apparatus. Small particles together with water, they are carried out through an internal rotating flow through a hole in the top cover.

Beneficiation of minerals is based on the use of differences in the physical and physico-chemical properties of minerals: size, shape, color, luster, specific gravity, coefficient of friction, magnetic permeability, electrical conductivity, wettability, etc.

The difference in some properties of minerals can be enhanced artificially. For example, the difference in the color and luster of minerals increases after washing them with water, as well as under special lighting. The magnetic permeability of some minerals can be increased through magnetizing firing. The wettability and electrical conductivity of minerals can be changed by treating them with special reagents.

The simplest enrichment method is manual sorting by appearance. However, this method is expensive, requires a lot of labor and therefore has limited application. Manual beneficiation is used for selecting waste rock in the extraction of many minerals, as well as for extracting useful components in the beneficiation of asbestos, mica, coal and other minerals.

Beneficiation sometimes takes advantage of the difference in size between useful minerals and gangue minerals. For example, in placers, the large part (boulders, pebbles) does not contain useful minerals. By separating this part, a significant increase in the content of valuable components in the fine fraction is achieved. Together with washing, this method is used in practice quite often. (placer enrichment).

Differences in lump shape and friction coefficients can also be used to separate useful minerals from waste rock. Thus, when moving along a stationary inclined plane of asbestos ore, flat asbestos fibers slide slowly, and rounded pieces of waste rock quickly roll down and can be collected separately from the fiber. However, friction enrichment is used very rarely.

The most widespread in industry are gravitational enrichment methods based on the use of differences in the specific gravities of minerals. As a medium in which minerals are separated according to specific gravity, water, air, heavy liquids and heavy suspensions (suspensions) can serve. Gravitational processes include:

1. 
   Jigging - separation on a sieve under the influence of a vertical stream of water or air;
2. 
   enrichment in a stream flowing along an inclined plane (enrichment on concentration tables, where separation occurs under the influence of the movement of the table and the flow of water flowing along an inclined plane; concentration on sluices, where the separation of minerals occurs due to the different speeds of movement of particles in the water flow and the trapping properties of coatings bottom of the sluice; separation in screw separators)
3. 
   enrichment in heavy environments, in which heavy minerals sink and light minerals float to the surface.

Gravity methods are widely used in the beneficiation of iron and manganese ores, as well as ores of non-ferrous and rare metals, coal and other minerals.

Essence of the process jigging consists of separating a mixture of mineral grains by density in an aqueous or air environment, oscillating (pulsating) relative to the mixture being separated in the vertical direction.

The initial product, a mixture of mineral grains of varying densities (Fig.), is fed onto a sieve, through the holes of which an ascending and descending stream of water, varying in direction and speed, passes.

R
is. . Scheme of stratification of a mixture of mineral grains of different densities in a pulsating flow of water: a - c - respectively, the initial, intermediate and final state of the system (1-3 - the grains are light, intermediate and heavy, respectively).

Gateways used for the enrichment of minerals characterized by a significant difference in the densities of the separated minerals, such as gold- or tin-bearing sands. In its simplest design, the gateway is a fixed, inclined wooden chute of rectangular cross-section.

Stencils made of various materials are placed at the bottom of the trench, the stepped or rough surface of which helps to retain settled particles of heavy minerals

The source material is continuously supplied to the gateway until the stencil cells are filled with particles of heavy trapped minerals or metal. After this, loading stops and the gateway is rinsed. First, water is supplied to remove light minerals from the top layer of the settled product, and then the water supply is reduced, the stencils are removed and the accumulated heavy product is thoroughly washed off from them. This material is moved by metal or wooden rakes up the bottom of the sluice to further remove light minerals [gang). Large pieces of rock, crushed stone and pebbles are selected by hand and removed to the dump. The concentrate remaining at the bottom of the lock is washed into a separate receiver and sent for further enrichment to finishing devices.

Screw separator(Fig.) is structurally designed in the form of a fixed helical chute 1, mounted on a stand 3. The original pulp is fed into the upper feeding part of the gutter and flows down freely under the influence of gravity. In this case, a redistribution of minerals occurs due to different trajectories of their movement: heavy minerals are concentrated at the inner side of the separator chute, and light minerals are concentrated at the outer side. Heavy fractions are unloaded through holes in the bottom of the chute, equipped with special cut-offs 2, A lungs-at-the-end free drain gutters. The screw chute, which is the main working body of the separator, consists of a number of half-turns, stamped from sheet steel or other wear-resistant metals, alloys and plastics, fastened together with flange connections. The working surface of half-turns is often lined with rubber or other wear-resistant materials. Several cut-offs are installed along the length of the gutter to collect concentrate (heavy fraction) and industrial products.

The quality of the resulting enrichment products is regulated by the solid content in the initial pulp, the productivity of the separator and the flow of wash water.

TO concentration table It is a swaying surface slightly inclined in the transverse direction - a deck with a thin layer of water flowing over it. The deck swings using a reciprocating drive. The direction of swing is horizontal, perpendicular to the direction of water movement. On the working surface of the deck there are longitudinal plates (corrugations) of various heights.

The operation diagram of the concentration table is shown in Fig. (the dotted lines show the conditional trajectories of movement of particles of different densities: 1 -heavy; 2- intermediate; 3- easy).

The separation of mineral grains on the deck of the concentration table occurs under the influence of a complex of mechanical and hydrodynamic forces. The main resulting forces that determine the looseness of the material layer and the trajectory of movement of individual particles are the forces of gravity, the hydrodynamic effect of water flow and friction against the deck surface.


Magnetic enrichment is based on the use of differences in magnetic susceptibility or magnetic permeability. Under the influence of a field, which is usually created by an electromagnet or permanent magnets, it is possible to isolate some iron-containing, manganese, tungsten and other minerals with increased magnetic permeability. This method is most often used for enrichment iron ores, less often - manganese, tungsten-tin, etc.

Electrostatic beneficiation uses the different electrical conductivities of the minerals being separated. In an electric field, different minerals, depending on their electrical conductivity and the amount of charge they receive, move along different trajectories and can therefore be obtained separately. This method can enrich some metallic and non-metallic minerals, but it does not yet have large industrial applications.

Flotation is based on the different wettabilities of minerals. In this process, finely ground mineral particles are kept suspended in water, which is saturated with air bubbles. Due to different wettability, particles of some minerals are attached to air bubbles and carried to the surface, forming foam, while others remain in the water. By removing foam from the surface of the bath, you can separate some minerals from others. Flotation is widely used in the beneficiation of a wide variety of minerals.

In addition to those listed, there are special enrichment methods that use the difference in the hardness and malleability of minerals, the ability of minerals to crack when heated (decripitation) and other properties.

In recent years, combined processes have also developed, in which metallurgical methods and various types of chemical processing are used together with enrichment. Such processes are very effective for complex and low-grade ores, the processing of which by other methods does not give satisfactory results.

The possibility of using one or another enrichment method is determined not only by the presence of a sufficient difference in the properties used, but also by the size of the mineral inclusions.

The above enrichment methods are used as independent processes or in combination with each other. Most often, flotation, gravitational and electromagnetic enrichment methods are used as independent processes. Of two methods that give equal results, choose the cheaper one. The choice of enrichment method is sometimes influenced by local conditions, such as the availability or absence of water, electricity source, climate, etc.

Helper Processes – dewatering, dust collection, and wastewater treatment.

Dehydration - removal of moisture from enrichment products. The products obtained in factories during ore enrichment are usually represented by pulps. Depending on the moisture content, products are divided into liquid (40% moisture), wet (15-20...40), wet (5-6...15-20), air-dry (several %), dry (does not contain external moisture) and calcined (chemically bound water is thermally removed). The final moisture content of the dehydrated product depends on the dehydration method, the surface properties of the minerals, their density, particle size and L:S ratio. The easiest way to remove moisture is drainage. Suitable for coarse and medium grain products. Final humidity 5-10%. Liquid pulps containing fine and fine particles are dewatered by thickening and filtration, with a moisture content of 40-60% and 10-15%, respectively. Complete removal of moisture is achieved by drying.

Dust collection- the process of cleaning air before releasing it into the atmosphere. Dust collection includes a set of engineering and technological measures and processes designed to remove dust-laden gases from sources of dust formation and subsequent separation of solid particles from the gas stream.

There are three ways to purify air:

Dry – trapping particles under the influence of gravity, centrifugal forces, inertial forces or filtration.

Wet dust collection is based on wetting dust particles with water or other liquid and depositing it in the form of a pulp.

Electric – consists of negative ionization of dust particles by a high-voltage direct current corona discharge and their deposition on the collecting electrode.

Wastewater treatment - these are cleaning processes industrial waters for reuse or discharge into public water bodies. Common wastewater treatment methods are based on three principles:

Mechanical settling of coarse suspension, sometimes with the addition of coagulants and flocculants.

Precipitation of impurities in the form of sparingly soluble salts;

Oxidation to harmless compounds.

In this regard, there are two ways to organize wastewater treatment schemes: by sequential isolation of individual impurities using reagents and by complex isolation of the majority of contaminants at once. The first provides higher wastewater treatment, but leads to a complex multi-stage scheme. The second option is simple and cheap, but for some impurities it may not be the best.

Raw materials are the most important initial element of any technological process. Its quality, compliance technological requirement and the level of processing, cost and availability largely determine the main qualitative, quantitative and cost indicators of manufactured products.
Raw materials are substances of natural and synthetic origin used as starting material in the production of industrial products and energy. Raw materials are mainly classified according to their state of aggregation, composition and origin.
According to their state of aggregation, raw materials are divided into solid (coal, peat, ores, shale, wood), liquid (water, salt brines, oil) and gaseous (air, natural and industrial gases).
Based on their composition, raw materials are divided into organic and mineral. Organic, in turn, is divided by origin into plant and animal. Mineral raw materials (from the Latin minera - ore) include minerals mined from the depths of the earth. Their feature is their non-renewability as they are mined and used. The uneven distribution of raw materials over the surface of the earth and its subsoil, the concentration of useful substances and chemical composition determine the cost of extraction and processing of raw materials.
Mineral raw materials. Mineral raw materials are the most important raw materials for industry. It includes about 2,500 different minerals, differing from each other in chemical composition, physical properties, crystalline form, application and other characteristics. The earth's crust consists mainly of 14 chemical elements (99.5%): oxygen - 49.13%, silicon - 26.00, aluminum - 7.45, iron - 4.20, calcium - 3.25, sodium - 2.40, magnesium - 2.35, potassium - 2.35, hydrogen - 1.00%, etc.
Mineral raw materials are divided into ore, non-ore and fuel.
Ore raw materials are minerals (industrial metal ores) containing one or more metals in quantity and form that allow their economically profitable extraction. Based on the amount of metals contained, ores are divided into monometallic - contain one metal, bimetallic - two metals and poly-metallic - contain more than two metals extracted during processing. Examples of monometallic ores are iron, chromium, gold and other ores, bimetallic
- lead-zinc, copper-molybdenum, etc. Polymetallic ores may contain zinc, lead, copper, silver, gold and other metals. For example, 50% of global silver production, and in Russia - 70% of all mined silver, is extracted from polymetallic ores.
Metals in ores can be in the form of oxides (iron ores), sulfides (copper ores) or more complex chemical compounds. Some metals are found in pure form or in alloys with other metals - in so-called native ores, for example, gold and platinum.
Metal ores rarely consist only of metal-containing minerals. They usually contain other minerals that do not contain metals and are called gangue.
Ore deposits are divided into bedrock - in the form of monolithic rocks, ore massifs, and loose deposits - products of decay and destruction of bedrock. Second - worse quality, more friable, small, dusty and require higher costs for extraction and processing.
Non-metallic raw materials are used in the production of non-metals (sulfur, phosphorus, etc.), various salts (potassium, soda, table salt etc.), mineral fertilizers and building materials. The most important species non-metallic raw materials are: native sulfur, apatites, phosphorites, natural salts, sand, clay, etc. Non-metallic raw materials also include rare minerals industrial value - diamonds, graphite, asbestos, etc.
For the production of building materials, rocks of various origins and compositions are used: clay, sand, gravel, sandstone, gypsum, limestone, chalk, granite, pumice, tuff, etc. Many types of raw materials for the production of building materials are mined in open pits.
Although most of non-metallic raw materials and contains metals, but in volumes and forms that are not economically feasible for their extraction, for example, phosphorites, apatites, aluminosilicates, etc.
Combustible mineral raw materials include organic fossils: oil, coal, peat and shale, which are mainly used as fuel or as raw materials for the chemical industry.
Fuel is a combustible substance, the main component of which is carbon, used to produce thermal energy when burned. Fuels are divided according to their state of aggregation and origin,
According to their state of aggregation, all fuels are divided into solid (fossil coals, peat, wood, shale), liquid (oil, petroleum products), and gaseous (natural and associated gases).
Based on their origin, fuel is divided into natural and artificial, i.e., obtained as a result of processing natural fuel or as waste from various technological processes (for example, blast furnace gas).
To evaluate fuel, the main indicator is its specific heat of combustion, i.e. the amount of heat that is released during complete combustion of a unit of mass or volume of fuel (J/kg and J/m3). Technical specifications fuel is determined by its composition. The composition of all types of fuel includes a combustible mass (organic mass + combustible inorganic substances, for example, sulfur) and a non-combustible mass (ash, moisture) - ballast. The organic mass of fuel consists mainly of carbon, hydrogen, as well as nitrogen and oxygen. The more ash and moisture in the fuel, the lower its calorific value; the higher the content of carbon and hydrogen and the less oxygen and nitrogen, the greater its calorific value.
To compare the thermal value of various types of fossil fuels, the unit of standard fuel is adopted. The heat of combustion of 1 kg of solid equivalent fuel (or 1 m3 of gaseous fuel) is 29.3 mJ or 7000 kcal. Accordingly, 1 ton of brown coal is taken as 0.4 tons, hard coal as 1.0 tons, and oil as 1.4 tons of standard fuel. To compare the economic value of fuel materials, the price of oil on the world market is taken.

Raw materials are natural materials used in the production of industrial products. Raw materials are the main element of production, on which its efficiency, choice of technology, equipment and also product quality depend. An intermediate product is a raw material that has been processed at one or more stages of production, but is not a commercial target product. The intermediate product can be the raw material for the next stage of production. A by-product is a substance that is formed during the processing of raw materials in parallel with the target product, but is not the purpose of this production. Industrial waste refers to the remains of raw materials, materials and intermediate products generated in production, which cannot be used as commercial products, having partially or completely lost their qualities.

Classification of raw materials Chemical raw materials are classified according to their origin, chemical state, resources and state of aggregation. By aggregate By chemical By type of reserve state Solid Liquid Gaseous By origin Mineral, including: Inorganic Renewable – ore, – non-ore, – combustible Vegetable Organic Non-renewable and animal Water Air

Classification of raw materials Chemical raw materials are divided into primary and secondary: primary raw materials are extracted from natural sources; secondary raw materials are intermediate and by-products industrial production and consumption. It should be noted that capital investments processing of secondary raw materials is on average four times less than for processing primary raw materials. In industrialized countries, the reuse of metals and alloys is: steel – 70; copper – 55; aluminum and tin – 45 each; zinc – 21% wt. Another principle of classification of raw materials involves their division into natural and artificial (obtained through industrial processing of natural raw materials).

General requirements for raw materials Raw materials must ensure: Ø low-stage nature production process; Ø the state of aggregation of the system, ensuring minimal energy consumption to create optimal conditions for the technological process; Ø minimal losses of supplied energy in environment; Ø minimal energy losses from process products; Ø Possibly milder process conditions (contact time, temperature, pressure) and minimal energy consumption to change the aggregate state of the reagents and implement the technological process; Ø maximum yield of the target product.

Rational use of raw materials The share of raw materials in the cost of commercial products is the main one and reaches 70%. The chemical industry uses compounds of more than 80 elements as raw materials. These elements are mainly part of the earth's crust and are distributed in it extremely unevenly both in nature, concentration, and geographical location. The fraction per element contained in the earth's crust is called clarke. Element O Si Al Fe Ca Na Mg K H t Clark, 49, 13 26, 0 7, 45 4, 20 3, 25 2, 40 2, 35 1, 00% Nine elements account for 98% of the mass of the earth's crust. The share of all other elements is only 1.87%. Of these, the clarke of carbon, which forms the basis of life, is 0.35%.

Rational use of raw materials All resources of chemical raw materials are divided into reserves, i.e. identified and studied, and potential resources. In turn, according to the degree of study and suitability for exploitation, raw material reserves are divided into three categories: Ø category A – these are reserves that have been explored in detail and prepared for development; Ø category B – these are reserves established as a result of geological exploration; Ø Category C – these are reserves determined based on the results of geophysical exploration and study of natural outcrops.

Rational use of raw materials The possibility of using raw materials for industrial production is determined by its value, availability and concentration of the useful component. The value of raw materials depends on the level of technology development and the challenges facing production, and may change over time. For example, uranium, previously a waste product during the production of radium, is now an important strategic raw material. The availability of raw materials for extraction is determined by the geography of the deposit, the depth of its occurrence, the development of industrial extraction methods, and the availability of human resources for its operation. A significant factor determining the possibility of using raw material reserves is the concentration of the target element.

Rational use of raw materials Russia accounts for the world's reserves (in mass %): gas - 40, fossil coals - 23, oil - 6 -8, wood - 30, peat and potassium salts - more than 50, various mineral raw materials - about 20, including more than 27 iron and tin, 36 nickel, 11 copper, 20 cobalt, 12 lead, 16 zinc, 40 platinum group metals. Russia ranks third in the world in terms of gold reserves. It should be added that 20% of the world's fresh water reserves are concentrated in Russia.

Preparation of mineral raw materials In the chemical industry, the efficiency of the technological process largely depends on the type of raw material, quality and its cost. Before use, mineral raw materials undergo special preparation, which includes two stages: Ø purification from impurities that negatively affect the further course of chemical transformation, this stage is the main operation in the preparation of raw materials; Ø increasing the concentration of a valuable component, so concentrated raw materials are economically and technologically more efficient.

Preparation of mineral raw materials The process of purification and separation of solid raw materials is called enrichment. For liquid and gaseous raw materials, the term concentration is used. Enrichment of mineral raw materials is based on the use of differences in the physical, physicochemical and chemical properties of the components. Enrichment methods are varied and fundamentally different for solid, liquid and gaseous raw materials. As a result of enrichment, the following components are obtained: Ø concentrate is a fraction enriched with a useful component; Ø tailings are waste rock. Enrichment methods are divided into mechanical, physical and physicochemical.

Preparation of mineral raw materials Mechanical methods of enrichment - dispersion and gravitational separation. Scattering (or screening) is the separation of solid rock based on the different strengths of the components. The crushed raw materials are passed sequentially through screens, which are metal sieves with holes of various sizes. During screening, grains of various sizes are formed, resulting in separation into fractions enriched with a specific mineral.

Preparation of mineral raw materials Mechanical methods of enrichment - dispersion and gravitational separation. Gravity enrichment is based on different falling speeds of particles of crushed material having different densities, shapes and sizes. This separation is carried out either in a liquid stream (wet gravity enrichment), or in a gas stream or under the influence of centrifugal forces.

Preparation of mineral raw materials Mechanical methods of enrichment - dispersion and gravitational separation. Schematic diagram of wet gravity enrichment

Preparation of mineral raw materials Mechanical methods of enrichment - dispersion and gravitational separation. Wet gravity enrichment devices include a hydrocyclone, the operating principle of which is based on the action of centrifugal force.

Preparation of mineral raw materials Physical methods enrichment – ​​electrostatic and electromagnetic separation, thermal method. Electromagnetic separation and electrostatic separation are based on differences in the magnetic permeability or electrical conductivity of the raw material components. Electromagnetic enrichment is used to separate magnetically susceptible particles from non-magnetic ones, and electrostatic enrichment is used to separate electrically conductive substances from dielectrics. The separation is carried out in electromagnetic or electrostatic separators, which have a similar operating principle.

Preparation of mineral raw materials Physical methods of enrichment - electrostatic and electromagnetic separation, thermal method. Electromagnetic separator diagram:

Preparation of mineral raw materials Physical methods of enrichment - electrostatic and electromagnetic separation, thermal method. Thermal enrichment of solid raw materials is based on the difference in melting temperatures of the raw material components. For example, by heating sulfur-containing rock, fusible sulfur is separated from waste rock, consisting of more refractory limestone, gypsum and other minerals.

Preparation of mineral raw materials Physico-chemical methods of enrichment - flotation and extraction. Flotation is one of the largest-scale technological processes for the enrichment and separation of solid mineral raw materials. There are foam, film and oil flotation. The basis of all types of flotation is the difference in the wettability of the liquid phase between waste rock particles and the valuable extracted material.

Preparation of mineral raw materials Physico-chemical methods of enrichment - flotation and extraction. Let's look at the basics of flotation using the example of froth flotation. The pre-crushed material is intensively mixed in water, a pulp is formed, through which air is bubbled. Typically, particles of valuable material are poorly wetted by water, are captured by air bubbles and are carried to the surface of the water in the form of foam. This foam is then mechanically removed and sent for further processing, and the well-wetted waste rock is transferred to water.

Preparation of mineral raw materials Physico-chemical methods of enrichment - flotation and extraction. Mineralized foam (foam product) is called flotation concentrate. As a rule, it is a valuable component of the enriched raw material. Particles that are well wetted and remain in the pulp form a chamber product (or tailings). As a rule, this is waste rock. The wettability of minerals is characterized by the contact angle, which is formed along the linear interface T – L – G:

Preparation of mineral raw materials Physico-chemical methods of enrichment - flotation and extraction. Most minerals in natural ores differ little in wettability from each other. To separate them, conditions of unequal water wettability of the individual components are created. To increase the efficiency of the flotation process (to increase selectivity, speed up and create stable foam), so-called flotation reagents are added to the flotator. The consumption of flotation reagents is low and can be hundreds of grams per ton of raw material. This allows the use of even relatively complex and expensive surfactants for fine control of the surface properties of the separated materials.

Preparation of mineral raw materials Physico-chemical methods of enrichment - flotation and extraction. Flotation reagents include: Ø Collectors (or collectors) – promote the formation of hydrophobic films on the surface of hydrophilic particles. Hydrophobized particles adhere to air bubbles and rise to the surface of the pulp into foam and are removed along with it in the form of a flotation concentrate. Collectors are surfactants containing a polar and nonpolar group. For example, fatty acids and their soaps (oleic acid, naphthenic acid), as well as xanthates, most often potassium xanthate.

Preparation of mineral raw materials Physico-chemical methods of enrichment - flotation and extraction. Flotation reagents include: Ø Foaming agents – provide bubble stability sufficient to deliver particles to the surface of the flotator. Mineralized foam should be moderately stable, dense and flexible. The foam layer should contain as little water as possible in order to facilitate further processing. Surfactants are used as foaming agents, forming adsorption films on the surface of air bubbles. The most effective foaming agents include pine oil, coal tar fractions, and aliphatic alcohols.

Preparation of mineral raw materials Physico-chemical methods of enrichment - flotation and extraction. Flotation reagents include: Ø Suppressors (or depressors) - used to increase the wettability of mineral impurities, they facilitate the transition of these impurities into tailings (or chamber product). Electrolytes (lime, cyanides, sulfites, zinc sulfate, sodium silicate) act as suppressants. Ø Activators – help enhance the adsorption of collectors. They are often used to separate tails and eliminate the effects of suppressors. Copper sulfate, sulfuric acid, and sodium sulfide act as activators. Environmental regulators are lime, soda, sulfuric acid and other substances.

Preparation of mineral raw materials Physico-chemical methods of enrichment - flotation and extraction. There are collective and selective flotation. Collective flotation is a process by which a concentrate containing all useful components and waste rock are obtained. The collective concentrate is then separated into its individual constituent components. This separation is accomplished by selective (or selective) flotation. In this case, in addition to collectors and foaming agents, depressants are introduced into the process. They are able to enhance the hydrophilicity of certain minerals, preventing them from floating. Subsequently, activators are added, which remove the effect of depressants and promote the floating of minerals.

Preparation of mineral raw materials Physico-chemical methods of enrichment - flotation and extraction. Extraction is the process of selectively removing one or more components from aquatic environment into liquid organic. It is assumed that the organic phase is practically insoluble in the aqueous phase. After phase separation, the extracted component is again transferred to the aqueous phase. This process is called re-extraction. In this case, the extractant is regenerated. Good extractants are carboxylic or naphthenic acids, amines, and quaternary ammonium bases, which are readily soluble in kerosene or hexane. Requirements for extractants: Ø ease of regeneration; Ø non-toxic; Ø low cost.

Preparation of gaseous raw materials Gaseous raw materials can be of natural and industrial origin. Natural raw materials are represented by hydrocarbon gases (natural gas) and air. Gases from coke production (coke oven gas), oil refining gases (associated gas), gases from metallurgical production, and gases from solid fuel processing (producer gas) are used as gaseous raw materials of industrial origin. Methods for enriching gaseous multicomponent systems (or purification and separation gas mixtures) are based on differences in the properties of the components of the mixture (for example, differences in boiling points, solubility in a solvent, sorption capacity).

Preparation of gaseous raw materials Separation of gases: Ø air is separated into nitrogen and oxygen; nitrogen is used in the production of ammonia, and oxygen is used as an oxidizing agent in the chemical industry and metallurgy. In addition, argon is released from the air; Ø ammonia is isolated from coke oven gas in the form of ammonium sulfate; hydrogen, which is then used to obtain a nitrogen-hydrogen mixture; and hydrogen sulfide, which is used to produce sulfuric acid. Gas purification: Ø natural gas used in the production of ammonia is purified from sulfur-containing compounds; Ø the converted ammonia production gas is purified from carbon dioxide; Ø before the ammonia synthesis column, the nitrogen-hydrogen mixture is purified from traces of oxygen-containing compounds.

Preparation of gaseous raw materials The main methods for separating gas mixtures: Ø the condensation method is that when the gas mixture is cooled, higher boiling components condense first and are separated in separators. In the production of synthetic ammonia, ammonia is separated from the unreacted nitrogen-hydrogen mixture by condensation. Hydrogen is released from coke oven gas by fractional cooling.

Preparation of gaseous raw materials The main methods for separating gas mixtures: Ø sorption methods are based on the different sorption abilities of the components by some absorber. In sorption processes there are: adsorption and absorption. Adsorption is the process of absorption of one or more components of a gas mixture by the solid surface of an adsorbent. The absorption process is carried out in devices called adsorbers. There are types of adsorbers: with a fixed layer of adsorbent, with a moving layer, and also with a fluidized bed. The adsorber operates in the “adsorption ↔ desorption” mode. The following adsorbents are used: activated carbon, zeolites, porous glass.

Preparation of gaseous raw materials The main methods for separating gas mixtures: Ø sorption methods are based on the different sorption abilities of the components by some absorber. In sorption processes there are: adsorption and absorption. Absorption is the selective absorption of one or more components of a gas mixture by a liquid absorbent (absorbent). Organic and inorganic solvents are usually used as absorbents. Purification and separation of the gas mixture takes place in two apparatuses. In one (absorber) absorption of any component by a cooled absorbent occurs, in the other (regenerator) desorption occurs, while the absorbed substance is released from the solution and the absorbent is regenerated.

Preparation of gaseous raw materials Basic methods for separating gas mixtures: Ø The membrane method for purifying gas mixtures is based on separation using microporous partitions (or membranes) that are permeable to molecules of one type and impermeable to molecules of another type. The membrane separation method is the most advanced, since high pressures and low temperatures. In membrane devices, air is separated into nitrogen and oxygen, methane and hydrogen, methane and helium. Gases are also purified from dust and moisture.

The industry composition of the complex is quite wide, it includes: basic chemistry (production of salts, acids and alkalis), organic synthesis and processing of polymers based on the raw materials of the mining chemical industry (apatites, phosphorites, sulfur, etc.), as well as petroleum products. The starting material for production can be of either synthetic or natural origin, and is classified according to this parameter:

1. Mineral. Includes inorganic compounds: ores of heavy and non-ferrous metals, non-metallic and combustible minerals, as well as water and air.
2. Vegetable. All types of wood, cotton, oilseeds and sugar crops, rubber and medicinal plants.
3. Animal. Fat tissue and processed bone.
4. Synthetic. Hydrocarbon products of the coal and oil and gas processing industries.

Separately, the raw materials used in the chemical industry include several irreplaceable reagents, these include: formate and sodium nitrite, which significantly increase the performance characteristics of building materials and prevent corrosion, as well as saltpeter, a metallurgical raw material.

Organic synthesis for obtaining raw materials in the chemical industry

Despite the fact that the types of raw materials of the chemical industry are quite diverse, the basis of most popular products in this industry are primary hydrocarbons contained in oil. The processing of this mineral before it can be used in the production of products and materials consists of at least three stages:

• field preparation - degassing, dehydration, desalting and stabilization;
• direct race - separation of fuel fractions: gasoline, naphtha, kerosene, diesel, fuel oil from oils and lubricants for various purposes;
• thermal and catalytic processing of petroleum distillates.

The main raw materials for the chemical industry are cracking products (alkanes and olefins). Such organic substances make it possible to obtain paraffin, ammonia fertilizers and jet fuel. Ethylene is the basis for a variety of materials from alcohol and aqueous compounds to a variety of plastics. Its compounds with other substances are used almost everywhere:

1. Ethyl alcohol is the most famous solvent and base for the production of cellophane and acetate fiber.
2. Dichloroethane makes it possible to create soft polyvinyl chloride plastics, from which linoleum, tiles and artificial leather are made, as well as latex, fiber packaging materials and coatings.
3. Isopropyl alcohol is made from propylene and is used to create acetone, phenol and plexiglass. Also, without this unsaturated carbon, it is impossible to synthesize allyl chloride, which acts as the main component of glycerol.
4. Butylene gas is converted into alcohols of the same name and is indispensable in the production of high-quality rubber.

Separately, it is worth noting ethylene-propylene rubbers with increased stability and resistance, which are indispensable for insulation needs in all industries.

Aromatic and gas hydrocarbons as raw materials for the chemical industry

Suppliers of raw materials for the chemical industry, the majority of whom work specifically with petroleum products, most often use the processing of gasoline fractions, catalytic reforming and pyrolysis of residual materials from the production of ethylene and propylene to produce organic compounds:

1. Benzene is the basis for the addition of additional substances that change its characteristics. The most commonly produced are styrene and phenol - plastic polymers, as well as aniline - a universal aromatic amine for creating wide range products. Dyes, vulcanizing agents, polyurethanes, pesticides and even medicines are made from phenylamine. In addition, it is benzene that increases octane number in fuel and is present in extracted form in most varnishes, paints and detergents.
2. Toluene - known as the basis for TNT, can also be present in paints and solvents, and is included in the list of necessary carbohydrates for the creation of saccharin.
3. Xylene (O; M; P) takes part in the polymerization of plastics, plasticizers, and coatings, and is also the basis of film mylar capacitors and nylon.

Gas, as a raw material for the chemical industry, is a much more profitable material. The selling price, manufacturability and purity of the product for such hydrocarbons are much higher than for petroleum products, and the cost, on the contrary, is lower. In addition, gas processing and transportation schemes are easily automated and are often carried out in a continuous cycle.

Methanol is a multifunctional alcohol, the basis of antifreeze, formaldehyde, resins and plastics, as well as a disinfectant, antiseptic and deodorizing agent. Raw materials for the chemical industry in Russia are mined, synthesized and processed by several hundred industries of various sizes, and this industry is today considered one of the most promising and profitable.

Examples of raw materials for the chemical industry at the exhibition

Expocentre Fairgrounds is the largest domestic organizer of exhibition events and the creator of its own successful projects aimed at stimulating the development of various industries. The “Chemistry” exposition this year will bring together domestic and foreign representatives interested in promoting and improving business in the chemical industry sector.

Expocentre is pleased to offer its guests a new, completely renovated level, designed specifically for the comfortable installation of demonstration pavilions of any complexity. The exhibition traditionally brings together representatives of the most influential companies, research institutes, government sectoral departments and a lot of journalists. One of the topics of discussion at this event is raw materials for the chemical industry and the possibilities for modernizing production and its preparation.