Methods of mineral processing. Methods and processes of mineral processing, their scope Mining and processing of minerals

The processes of processing minerals according to their intended purpose in the technological cycle of the factory are divided into preparatory, actually enrichment and auxiliary.

TO preparatory operations include crushing, grinding, screening and classification, as well as mineral averaging operations, which can be carried out in mines, quarries, mines and processing plants.

TO main enrichment processes include those physical and physicochemical processes of mineral separation, in which useful minerals are released into concentrates, and waste rock into waste.

TO auxiliary processes include processes for removing moisture from enrichment products. Such processes are called dehydration, which is carried out to bring the moisture content of products to established standards. Auxiliary processes include the treatment of industrial wastewater (for reuse or discharge into water bodies) and dust collection processes.

When beneficiating minerals, differences in their physical and physicochemical properties are used, of which color, shine, hardness, density, cleavage, fracture, magnetic, electrical and some other properties are essential.

Color minerals are varied. The difference in color is used during manual ore sorting or rock sampling from coals and other types of processing.

Shine minerals is determined by the nature of their surfaces. The difference in gloss can be used, as in the previous case, during manual ore sorting or rock sampling from coals or during other types of processing.

Hardness minerals that make up minerals is important when choosing methods for crushing and beneficiation of certain ores, as well as coals. Minerals with lower hardness are crushed and ground faster than minerals with higher hardness. By applying selective crushing or grinding, subsequent separation of such minerals can be carried out on a screen.

Density minerals varies widely. The difference in density between useful minerals and waste rock is widely used in the beneficiation of ores and coals.

Cleavage minerals lies in their ability to split from impacts in strictly defined directions and form smooth surfaces along the split planes. Cleavage is important for the choice of crushing and grinding methods, as well as the removal of crushed materials from beneficiation products by screening and classification.

Kink has significant practical significance in beneficiation processes, since the nature of the surface of the mineral obtained during crushing and grinding has an impact during beneficiation by electrical and other methods.

Magnetic properties minerals are used in the enrichment of minerals with different magnetic susceptibility in magnetic fields of different strengths.

Electrical The properties of minerals are used in electrical beneficiation methods associated with a different ratio of mineral particles to the action of electrical and mechanical forces when moving in an electric field.

Physico-chemical properties surfaces of mineral particles are used in flotation processes consisting of in different ways them to aquatic environment and the impact on them chemicals(reagents.

On processing plant During processing, the feedstock is subjected to a number of sequential technological operations. A graphical representation of the totality and sequence of these operations is called technological scheme of enrichment.

LECTURE COURSE

Introduction. The meaning and role of enrichment when using various PIs...6

Classification of enrichment processes……………………………………..14

Types and schemes of enrichment and their applications………………………………….21

Screening processes. Designs and principles of operation of screens…………..27

Methods and processes for crushing minerals……………………...38

Types of crushers and crushing schemes……………………………………………………….45

Grinding process. Types and principle of operation of mills…………………….58

Product classification………………………………………………………70

Design and operating principle of hydraulic classifiers. Design and principle of operation of air classifiers………………74

Gravity enrichment methods………………………………………….82

Enrichment in heavy environments…………………………………………….89

Enrichment on jigging machines……………………………………………………….....99

Enrichment on concentration tables…………………………………..110

Flotation enrichment methods. Types of flotation reagents and their use in production……………………………………………………………..118

Designs and principles of operation of flotation machines…………………….127

Magnetic enrichment methods………………………………………………………137

Electrical enrichment. Dehydration of enrichment products……..145

The use of various thickeners and the principle of their operation. Mechanical equipment for filtration……………………………………………..154

List of recommended sources……………………………………………………168

LEADING. THE SIGNIFICANCE AND ROLE OF ENRICHMENT WHEN USING VARIOUS MINERAL RESOURCES.

Goal: Students obtain initial skills in terms and names, as well as in the meaning of the subject itself and its value in practical application.

Plan:

1.
Basic terms of the subject and their meaning.

2.
General information about ores and minerals of non-ferrous and rare metals.

Divisions and grouping of ores.

3.
Characteristics of the Deposits. Concentrates, industrial products, tailings.

4.
The importance and role of processing plants in the use of minerals.

Key words: ore, mineral, monometallic ore, polymetallic, useful component, valuable component, concentrate, middling product, tailings, waste rock, oxidized ores, native, finely disseminated, sulfide, mineral processing, processing plant, significance (social, economic).

1. “The main directions of economic and social development of the Republic of Uzbekistan in modern period, it is planned to further improve the technology of extraction and processing of ores and concentrates, increase the complexity of the use of mineral raw materials, accelerate the introduction of effective technological processes, improving the quality and range of products.

The development of a country's economic stability is the development modern technologies and technology for various industries, including mineral processing.

A source of metals, many types of raw materials, fuel, as well as building materials are minerals.

Minerals Depending on the nature and purpose of valuable components, they are usually divided into: ore, non-ore and combustible.

Rudami are called minerals that contain valuable components in quantities sufficient for their extraction during current state technology and equipment was cost-effective. Ores are divided into metallic and non-metallic.

To metal include ores that are raw materials for the production of ferrous, non-ferrous, rare, precious and other metals.

To non-metallic – asbestos, barite, apatite, phosphorite, graphite, talc and others.

To nonmetallic includes raw materials for the production of building materials (sand, clay, gravel, building stone, cement raw materials and others).

To flammable include fossil solid fuels, oil and natural combustible gas.

Valuable components are the individual chemical elements or minerals that make up a mineral and are of interest for their further use.

Useful impurities name individual chemical elements or their natural compounds that are part of a mineral in not large quantities and can be isolated and used in conjunction with the main valuable component, improving its quality. For example: useful impurities in iron ores are chromium, tungsten, vanadium, manganese and others.

Related components are called valuable chemical elements and individual minerals contained in minerals in relatively small quantities, isolated during enrichment as a by-product into an independent or complex product together with the main valuable component, and subsequently extracted from it in the process of metallurgical smelting or chemical processing . For example: in some ores of non-ferrous metals, gold, silver, molybdenum and others are associated.

Harmful impurities are individual impurities and elements, or natural chemical compounds contained in minerals and which have a negative impact on the quality of extracted valuable components in minerals.

2. The composition of the ore is simple (the beneficial component is represented by one mineral) and complex (the useful component is represented by minerals with different properties).

Minerals that do not contain valuable components are called empty rock. During enrichment, they are removed into waste (tailings) together with harmful impurities.

As a result of enrichment, the main components of a mineral can be isolated in the form of independent products: concentrates (one or more) and tails. In addition, during the enrichment process, intermediate products can also be released from minerals.

Sources of extraction of non-ferrous and rare metals are deposits of ores or minerals containing one or more valuable metals (components), represented by the corresponding minerals in combination with the host rock. In very rare cases, in earth's crust Native elements (copper, gold, silver) are found in the form of grains with a crystalline or amorphous structure. The gold and silver content in the ore is very low, only a few grams per 1 ton of ore. For 1 g of gold in the earth's crust there are about 2 tons of rock.

Ore - this is a rock from which, at this stage of technological development, it is economically profitable to extract valuable components. Ore consists of individual minerals; those of them that need to be extracted are called valuable (useful), and those that are not used in this case are minerals of the host (waste) rock.

However, the concept "waste breed" conditionally. With the development of enrichment technology and methods for subsequent processing of the products obtained during enrichment, the gangue minerals contained in the ore become useful. Thus, in apatite nepheline ore, nepheline for a long time was a gangue mineral, but after the technology for producing alumina from nepheline concentrates was developed, it became a useful component.

By mineral composition ores are divided into native, sulfide, oxidized and mixed.

Ores are also divided into monometallic And polymetallic.

Monometallic ores contain only one valuable metal. Polymetallic - two or more, for example, Si, Pb, Zn, Fe, etc. In nature, polymetallic ores are found much more often than monometallic ores. Most ores contain several metals, but not all are of industrial importance. In connection with the development of enrichment technology, it becomes possible to extract those metals whose content in the ore is low, but their associated extraction is economically feasible.

There are also ores interspersed And solid. In disseminated ores, grains of valuable minerals are distributed throughout the host rock. Solid ores (pyrite) consist of 50...100% sulfides, mainly pyrite (sulfur pyrite) and small quantity host rock minerals.

According to the size of the disseminated grains of useful minerals, ores are coarsely disseminated (> 2 mm), finely disseminated (0.2...2 mm), finely disseminated (< 0,2 мм) и весьма тонковкрапленные (< 0,02 мм). Последние являются труднообогатимыми рудами.

Depending on the nature of their origin, industrial ore deposits can be: indigenous And loose. Primary deposits occur in the place of initial formation. The valuable minerals and host rock minerals in these ores are in close association with each other.

Placers are secondary deposits formed as a result of the destruction of primary bedrock deposits and the secondary deposition of material from primary ores. Placer deposits contain non-sulfide, sparingly soluble minerals in the form of rounded (rolled) grains. There are no intergrowths, which makes the process of placer enrichment easier and cheaper.

The earth's crust contains about 4 thousand different minerals, which are more or less stable natural chemical compounds. Some of them, such as quartz, feldspars, aluminosilicates, pyrite, make up the bulk of the earth's crust, others, for example, the minerals Cu, Pb, Zn, Mo, Be, Sn are found in large quantities only in certain areas - ore bodies, and others, such as germanite (germanium mineral), greenockite (cadmium mineral) are even less common, accompanying various minerals in ores.

Sulfide minerals are minerals that are compounds of metals with sulfur. For example, chalcopyrite CuP2 is the main mineral of copper, sphalerite 2n8 - zinc, molybdenite MoS2 - molybdenum.

Oxides include a significant portion of non-ferrous and rare metal minerals, for example, cuprite Cu 2 O, ilmenite FeTiO 3, rutile TiO 2, cassiterite SnO 2.

Silicates are the most large group minerals found in the earth's crust. In the upper mantle of the earth they make up up to 92%. Silicates include the bulk of the minerals of the host (waste) rock (unsuitable for industrial consumption), as well as minerals of lithium, beryllium, zircon, etc. Among the silicates, the most common is quartz SiO 2; it can be extracted into an independent product and used in the production of glass, crystal, and in the construction industry.

Aluminosilicates include spodumene LiAlSi 2 O b and beryl Be 3 Al 6 O 18, which are the main minerals in the production of 1 lithium and beryllium, as well as spars - albite NaAlSi3O 8 and microcline KAlSi 3 O 8 - the main minerals of the host rock (on average 60%).

Carbonates include minerals containing carbon dioxide: calcite CaCO3 (host rock mineral), cerussite PbCO 3 .

3. Depending on the nature of their origin, industrial ore deposits can be either bedrock or alluvial. Indigenous ores are those that occur at the site of initial formation and are located within the general massif. rocks. These ores, after being extracted from a mine or from an open pit, require crushing and grinding before beneficiation. Valuable minerals and gangue minerals in such ores are in close association with each other.

Placers are secondary deposits formed as a result of the destruction of ores of primary bedrock deposits and the secondary deposition of material from primary ores. In placers, minerals have undergone very strong changes in chemical composition and physical properties. All minerals and large pieces of ore were subject to destruction by water flows, weathering, temperature changes, exposure to chemical compounds, etc.

By river water flows or waves of the sea and ocean, pieces of ore and minerals are usually transported over long distances. As they roll, they take on a rounded shape. In this case, sulfides are destroyed and are completely absent from the deposits, and non-sulfide sparingly soluble minerals are freed from intergrowths with waste rock minerals (sand, pebbles). Therefore, ores from placer deposits are not subjected to crushing and grinding, and their enrichment processes are much simpler and cheaper.

With the help of enrichment, harmful impurities are removed from concentrates entering the metallurgical plant, which complicate the smelting processes and deteriorate the quality of the resulting metals. Removal harmful impurities allows to significantly improve the technical and economic indicators of metallurgical processes. For example, zinc is a harmful impurity in lead concentrate. Increasing its content in lead concentrate from 10 to 20% increases the loss of lead during smelting by almost 2 times. During the ore beneficiation process, concentrates (one or more), tailings and intermediate products are obtained.

Concentrates – products in which the main amount of one or another valuable component is concentrated. Concentrates, compared to beneficiated ore, are characterized by a significantly higher content of useful components and a lower content of waste rock and harmful impurities.

Industrial products – products obtained during the enrichment of mineral resources and which are a mixture of grains containing useful components with grains of waste rock. Middlings are characterized by a lower content of useful components compared to concentrates and a higher content of useful components compared to tailings.

Tails – products that contain the main amount of waste rock, harmful impurities and a small (residual) amount of a useful component.

Mineral beneficiation is a set of processes for the primary processing of mineral raw materials from the subsoil, which results in the separation of useful components (minerals) from waste rock.

Concentrates and tailings are the final products, while intermediate products are recycled products. The quality of concentrates produced by processing plants must meet the requirements determined by GOSTs or technical specifications. These requirements depend on the purpose of the concentrates and the conditions for their further processing. GOST standards indicate the lowest permissible content of a useful component and the highest permissible content of harmful impurities for concentrates of various grades.

The enrichment results are assessed by several indicators and, above all, by the completeness of extraction of valuable components and the quality of the resulting concentrates.

Recovery is the ratio of the amount of a useful component converted into concentrate to its amount in the ore, expressed as a percentage. Extraction characterizes the completeness of the transfer of a useful component from ore to concentrate and is one of the most important technological indicators of the operation of a processing plant.

The yield is the ratio of the mass of any enrichment product to the mass of processed ore, expressed as a percentage.

Ore beneficiation is a set of processes for the primary processing of mineral raw materials, with the goal of separating all useful minerals (and, if necessary, their mutual separation) from waste rock. As a result of enrichment, one or more rich concentrates and tailings are obtained. The concentrate contains tens, sometimes hundreds of times more useful mineral compared to ore. It is suitable for metallurgical processing or can serve as a raw material for other industries. Dump tailings contain mainly waste rock minerals, which under the given technical and economic conditions are impractical to extract or there is no need for these minerals.

The need for mineral processing processes is confirmed by the dependence of the technical and economic indicators of metallurgical processing on the metal content in the raw materials entering the smelting process.

An even greater economic effect is obtained when enriching poor ores containing rare and other expensive metals (molybdenum, tin, tantalum, niobium, etc.).

The importance of mineral processing is determined by the fact that:

firstly - in many cases, only after it many technological processes (metallurgical, chemical and others) become possible;

secondly, the processing of the enriched product is carried out with great economic effect than natural: the volume of processed material is reduced, the quality improves finished products, losses of valuable components with production waste and the cost of transporting raw materials are reduced, labor productivity increases, fuel and electricity costs are reduced, etc.

Mineral processing technology consists of a series of sequential operations carried out at processing plants.

Processing plants are industrial enterprises in which mineral resources are processed using beneficiation methods and one or more commercial products with a high content of valuable components and a reduced content of harmful impurities are isolated from them. A modern processing plant is a highly mechanized enterprise with a complex technological scheme for processing minerals.

Technological diagram includes information about the sequence of technological operations for processing minerals at a processing plant.

Conclusions:

The source of extraction of non-ferrous and rare metals are deposits of ores or minerals containing one or more non-ferrous or rare metals, represented by the corresponding minerals in combination with gangue minerals.

In very rare cases, native elements (copper, gold, silver and sulfur) are found in the earth's crust. They usually form various chemical compounds - minerals, which are natural products of processes occurring in the earth's crust. Native elements are found mainly in the solid state and are grains with a crystalline or amorphous structure.

Minerals are natural mineral substances that, given the level and state of technology, can be used with sufficient efficiency in national economy V natural form or after pre-treatment.

Fossils mined from the depths of the earth are solid (ore, coal, peat), liquid (oil) and gaseous (natural gases).

According to their material composition, metallic minerals are divided into ores of ferrous, non-ferrous, rare, noble and radioactive metals.

According to the mineral composition, ores are divided into native, sulfide, oxidized and mixed.

From ores of non-ferrous and rare metals, which usually contain a very small percentage of useful minerals, it is economically unprofitable and often practically impossible to smelt the metal without preliminary beneficiation. Therefore, more than 95% of mined ores are enriched.

Security questions:

1.
What groups are minerals divided into?

2.
What is ore and what ores are classified as metallic, nonmetallic, nonmetallic, or combustible?

3.
What are called valuable components, beneficial impurities, accompanying components, harmful impurities?

4.
The main importance of mineral processing and processing plants.

5. What components are ores divided into?

6. Simple and complex ores.

What are called concentrate, middlings and tailings?

What is mineral beneficiation?

How are the deposits characterized?

What are the main indicators of the economic benefits of mineral processing?

Homework :

1.
Prepare for a survey on a given lecture topic.

2.
Prepare a short thesis on the topic of the seminar assignment.

3.
Answer questions for the lecture.

CLASSIFICATION OF ENRICHMENT PROCESSES.

Goal: Knowledge of a brief description of enrichment processes for students’ initial perception of this subject.

Plan:

1.
General information on the classification of enrichment processes.

2.
Brief description main enrichment processes.

3.
Brief description of special enrichment methods.

4.
Technological indicators of enrichment

Key words: basic processes, special, screening; crushing; grinding; classification, gravitational enrichment processes; flotation methods; magnetic enrichment methods; electrical enrichment, manual and mechanized ore mining, sample mining, decripitation, radiometric enrichment methods.

Mineral beneficiation is a very important aspect in the extraction and processing of ores. It is divided into many enrichment methods, which implies the highest quality and complete process enrichment.

Preparatory processes aim to prepare the ore for beneficiation. Preparation includes, first of all, operations of reducing the size of ore pieces - crushing and grinding and the associated classification of ore on screens, classifiers and hydrocyclones. The final grinding size is determined by the size of mineral dissemination, since during grinding it is necessary to open the grains of valuable minerals as much as possible.

The beneficiation processes themselves include the processes of separating ore and other products according to physical and physical and chemical properties minerals included in their composition. These processes include gravitational enrichment, flotation, magnetic and electrical separation, etc.

Most enrichment processes are carried out in water and the resulting products contain large amounts of it. Therefore, there is a need for auxiliary processes. These include dehydration of enrichment products, including thickening, filtration and drying.

The set and sequence of operations to which ore is subjected during processing constitute enrichment schemes, which are usually depicted graphically. Depending on the purpose, the schemes can be qualitative, quantitative, or slurry. In addition to the indicated diagrams, circuit diagrams of devices are usually drawn up.

Thus, mineral beneficiation can be divided into main and auxiliary enrichment processes (methods).

The main enrichment methods include:

1.screening; 2.crushing; 3.grinding; 4.classification; 5.gravitational enrichment processes; 6.flotation methods; 7.magnetic enrichment methods; electrical enrichment.

Auxiliary methods include:

1. manual and mechanized mining and washing. Selective crushing and decripitation;

2.enrichment in friction, shape and elasticity;

3.radiometric enrichment methods;

4. chemical enrichment methods.

2Screening is the process of separating lump and granular materials into products of different sizes, called classes, using screening surfaces with calibrated holes (grids, sheet and wire sieves).

As a result of screening, the source material is divided into an oversize (upper) product, the grains (pieces) of which larger size holes of the sifting surface, and under-sieve (lower product), grains (pieces) of which are smaller than the size of the holes of the sifting surface.

Crushing and grinding – the process of destruction of minerals under the influence of external forces to a given size, the required granulometric composition or the required degree of disclosure of materials. When crushing and grinding, over-grinding of materials should not be allowed, as this impairs the process of mineral enrichment.

Classification – the process of separating a mixture of mineral grains into classes of different sizes according to the rates of their deposition in aqueous or air environments. Classification is carried out in special devices, called classifiers if the separation occurs in an aqueous environment (hydroclassification), and air separators if the separation occurs in an air environment.

Gravitational processes enrichment refers to enrichment processes in which the separation of mineral particles differing in density, size or shape is due to differences in the nature and speed of their movement in the environment under the influence of gravity and resistance forces.

Gravity processes include jigging, enrichment in heavy media, concentration on tables, enrichment in sluices, chutes, jet concentrators, cone, screw and counterflow separators, pneumatic enrichment.

Flotation enrichment methods – the process of separating finely ground minerals, carried out in an aqueous environment and based on the difference in their ability, natural or artificially created, to be wetted by water, which determines the selective adhesion of mineral particles to the interface between two phases. A major role in flotation is played by flotation reagents - substances that allow the process to proceed without any special complications and accelerate the flotation process itself, as well as the yield of the concentrate.

Magnetic enrichment methods minerals are based on the difference in the magnetic properties of the separated minerals. Division by magnetic properties carried out in magnetic fields.

During magnetic enrichment, only non-uniform magnetic fields are used. Such fields are created by the appropriate shape and arrangement of the poles of the magnetic system of the separator. Thus, magnetic enrichment is carried out in special magnetic separators.

Electric enrichment is the process of separating minerals in an electric field, based on the difference in their electrical properties. These properties are electrical conductivity, dielectric constant, triboelectric effect.

3.Manual mining and rock sampling as a method of enrichment are based on the use of differences in the external characteristics of the separated minerals - color, shine, shape of grains. From total mass of a mineral, the material that is contained in less is usually selected. In the case when a valuable component is selected from a mineral, the operation is called mining, when waste rock is called rock mining.

Decripitation is based on the ability of individual minerals to crack (destroy) when heated and subsequent rapid cooling.

Enrichment in friction, shape and elasticity is based on the use of differences in the speed of movement of separated particles along a plane under the influence of gravity. The main parameter of the movement of particles along an inclined plane is the friction coefficient, which depends mainly on the nature of the surface of the particles themselves and their shape.

Adiometric sorting , based on differences in the radioactive properties of minerals or the strength of their radiation

Radiometric enrichment methods based on the different abilities of minerals to emit, reflect, or absorb various types radiation.

To chemical enrichment methods include processes associated with the chemical transformations of minerals (or only their surface) into other chemical compounds, as a result of which their properties change, or with the transfer of minerals from one state to another.

Chemical and bacterial enrichment based on the ability of minerals, such as sulfides, to oxidize and dissolve in highly acidic solutions. In this case, the metals go into solution, from which they are extracted using various chemical and metallurgical methods. The presence of certain types of bacteria, such as thionic bacteria, in solutions significantly intensifies the process of dissolution of minerals.

In technological schemes for the enrichment of complex complex ores, two or three different enrichment methods are often used simultaneously, for example: gravity and flotation, gravity and magnetic, etc. Combined enrichment methods in combination with hydrometallurgical ones are also used.

For the successful application of one or another enrichment method, it is necessary that the minerals have sufficient differences in the properties that are used in this method.

4. The beneficiation process is characterized by the following technological indicators: metal content in the ore or beneficiation product; product yield; degree of reduction and metal recovery.

Metal content in ore or beneficiation product - this is the ratio of the mass of this metal in the ore or enrichment product to the mass of dry ore or product, expressed as a percentage. The metal content is usually denoted by the Greek letters α (in the original ore), β (in the concentrate) and θ (in the tailings). Precious metal content is usually expressed in units of mass (g/t).

Product yield - the ratio of the mass of the product obtained during enrichment to the mass of the processed original ore, expressed in fractions of a unit or percentage. The concentrate yield (γ) shows what proportion of the total ore is concentrated.

Degree of reduction - a value indicating how many times the yield of the resulting concentrate is less than the amount of processed ore. Degree of reduction (TO) expresses the number of tons; ore that needs to be processed to obtain 1 ton of concentrate, and is calculated by the formula:

K= 100/γ

Ores of non-ferrous and rare metals are characterized by a low yield of concentrate and, consequently, a high degree of reduction. The concentrate yield is determined by direct weighing or according to chemical analysis using the formula:

γ =(α - θ/β - θ)100,%.

The degree of enrichment, or degree of concentration, shows how many times the metal content in the concentrate has increased compared to the metal content in the ore. When enriching poor ores, this figure can be 1000... 10000.

Metal recoveryε - is the ratio of the mass of metal in the concentrate to the mass of metal in the original ore, expressed as a percentage

ε=γβ/α

Metal Balance Equation

εα=γβ

connects the main technological indicators of the process and allows you to calculate the degree of metal extraction into concentrate, which, in turn, shows the completeness of the transition of metal from ore to concentrate.

The yield of enrichment products can be determined from chemical analyzes of the products. If we designate: - concentrate yield; - metal content in ore; - metal content in the concentrate; - metal content in tailings, and - extraction of metal into concentrate, then it is possible to draw up a balance of metal for ore and enrichment products, i.e. the amount of metal in ore is equal to the sum of its quantities in concentrate and tailings

Here, the yield of the original ore in percent is taken as 100. Hence the concentrate output

Metal recovery into concentrate can be calculated using the formula

If the concentrate yield is unknown, then

For example, when beneficiating lead ore containing 2.5% lead, a concentrate containing 55% lead and tailings containing 0.25% lead were obtained. Substituting the results of chemical analyzes into the above formulas, we get:

concentrate yield

extraction into concentrate

tailings exit

degree of enrichment:

Qualitative and quantitative enrichment indicators characterize the technical perfection of the technological process at the factory.

The quality of the final enrichment products must meet the requirements set by consumers for their chemical composition. The quality requirements for concentrates are called standards and are regulated by GOST, technical specifications(TU) or temporary standards and are developed taking into account the technology and economics of processing of a given raw material and its properties. The standards establish the minimum or maximum permissible content of various mineral components in the final enrichment products. If the quality of the products meets the standards, then these products are called standard.

Conclusions:

The processing plant is an intermediate link between the mine (mine) and the metallurgical plant. Ore of various sizes coming from the mine is processed at the processing plant. various processes, which, according to their purpose, can be divided into preparatory, actually enrichment and auxiliary.

Preparatory processes aim to prepare the ore for beneficiation. Preparation includes, first of all, operations of reducing the size of 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 minerals, since during grinding it is necessary to open the earth as much as possible

(lecture notes)

V.B.Kuskov

SAINT PETERSBURG

INTRODUCTION 2

1. preparatory processes 8

1.1. GRANULOMETRIC COMPOSITION 8

1.2 CRUSHING 10

1.3. screening 14

1.4. GRINDING 17

1.5. HYDRAULIC CLASSIFICATION 20

2. MAIN ENRICHMENT PROCESSES 23

2.1. GRAVITY METHOD OF ENRICHMENT 23

2.3. MAGNETIC METHOD OF ENRICHMENT 35

2.4. ELECTRICAL ENRICHMENT 39

2.5. special ENRICHMENT METHODS 43

2.6. COMBINED ENRICHMENT METHODS 48

3 AUXILIARY PROCESSES 49

3.1. DEHYDRATION OF ENRICHMENT PRODUCTS 49

3.2. DUST COLLECTION 53

3.3. WASTEWATER TREATMENT 54

3.3 TESTING, CONTROL AND AUTOMATION 55

4. ENRICHMENT PLANT 55

Maintaining

Minerals- natural mineral formations of the earth's crust, chemical composition and whose physical properties make it possible to effectively use them in the field of material production. Field mineral - an accumulation of a mineral substance in the depths or on the surface of the Earth, in quantity, quality and conditions of occurrence, suitable for industrial use. (With large areas of distribution, deposits form regions, provinces and basins). There are solid, liquid and gaseous minerals.

Solid minerals (ores), in turn, are divided into combustible (peat, shale, coal) and non-combustible, which are: agronomic (apatite and phosphorite, etc.), non-metallic (quartz, barite, etc.) and metal (ores ferrous and non-ferrous metals). The efficiency of using a particular mineral depends, first of all, on the content of a valuable component and the presence of harmful impurities. Direct metallurgical or chemical processing of a mineral is advisable (technically and economically profitable) only if the content of a useful component in it is not lower than a certain limit determined by the level of development of technology and technology (and the need for this raw material) at the present time. In most cases, the direct use of the mined rock mass or its processing (metallurgical, chemical, etc.) is not economically feasible, and sometimes technically impossible, because minerals suitable for direct processing are rare in nature; in most cases they are subjected to special processing - enrichment.

Mineral beneficiation a set of processes of mechanical processing of mineral raw materials in order to extract useful (valuable) components and remove waste rock and harmful impurities. As a result of beneficiation, concentrate(s) and tailings are obtained from ore.

Concentrate- this is the product where most of the useful minerals (and a small amount of waste rock minerals) are released (concentrated). The quality of the concentrate is mainly characterized by the content of a valuable component ( it is always higher than in ore, the concentrate is richer in valuable components, hence the name - enrichment), as well as in the content of useful and harmful impurities, humidity and granulometric characteristics.

Tails- a product into which most of the waste rock minerals, harmful impurities and a small amount of useful components will be released (the content of valuable components in tailings is lower than in concentrates and ore).

In addition to concentrate and tailings, it is possible to obtain industrial products, i.e. products characterized by a lower content of useful components compared to concentrates and a higher content of useful components compared to tailings.

Useful(valuable) components are the chemical elements or natural compounds for which a given mineral is mined and processed. As a rule, the valuable component in the ore is in the form of a mineral (there are few native elements in nature: copper, gold, silver, platinum, sulfur, graphite).

Useful impurities are chemical elements or natural compounds that are part of a mineral in small quantities and improve the quality of the finished product (or are released during further processing). For example, useful impurities in iron ores are alloying additives such as chromium, tungsten, vanadium, manganese, etc.

Harmful impurities refers to individual elements and natural chemical compounds contained in minerals in small quantities and having a negative impact on the quality of the finished product. For example, harmful impurities in iron ores are sulfur, arsenic, phosphorus, in coking coals - sulfur, phosphorus, in thermal coals - sulfur, etc.

Mineral beneficiation makes it possible to increase economic efficiency of their further processing, also, in some cases, without an enrichment stage, further processing becomes completely impossible. For example, copper ores (which usually contain very little copper) cannot be directly smelted into metallic copper, since the copper turns into slag when smelted. In addition, mineral processing allows:

 increase industrial reserves of raw materials through the use of deposits of poor mineral resources with a low content of valuable components;

 increase labor productivity at mining enterprises and reduce the cost of mined ore through mechanization of mining operations and continuous mining of minerals instead of selective ones;

 comprehensive use of minerals, since preliminary enrichment makes it possible to extract not only the main useful components, but also accompanying ones contained in small quantities;

 reduce the cost of transporting richer products to consumers, rather than the entire volume of extracted minerals;

 isolate from mineral raw materials those harmful impurities that, during further processing, can pollute environment and thereby threaten human health and degrade the quality of the final product.

Enrichment methods can also be used in the processing of solid household waste (350–400 kg/year per person is generated).

Minerals at processing plants undergo a number of sequential operations, as a result of which useful components are separated from impurities. Mineral enrichment processes according to their purpose are divided into preparatory, auxiliary and main.

TO preparatory include crushing, grinding, screening and classification processes. Their task is to separate the useful mineral and waste rock (“open” the joints) and create the desired granulometric characteristics of the processed raw materials.

Task main enrichment processes - to separate useful mineral and waste rock. To separate minerals, differences in the physical properties of the minerals being separated are used. These include:

Name of enrichment method	Physical properties used for separation	Main types of minerals enriched by this method
Gravity enrichment method	Density (taking into account size and shape)	Coals (+1 mm), shales, gold-bearing, tin ores...
Flotation enrichment method	Surface wettability	Non-ferrous metal ores, apatite, phosphorite, fluorite ores...
Magnetic enrichment method	Specific magnetic susceptibility	Iron ores...
Electric enrichment method	Electrical properties (electrical conductivity, tribocharge, dielectric constant, pyrocharge)	Finishing of diamond ores, rare metals: titanium-zirconium, tantalum-niobium, tin-tungsten, rare earth (monazite-xenotime). Glass sands, electronic scrap...
Ore sorting: Ore dismantling Radiometric enrichment	External signs: color, shine, shape The ability of particles to emit, reflect and absorb various types of energy	Gemstones, mica sheets, long-fiber asbestos Ores of ferrous and non-ferrous metals, diamond-containing, fluorite and other ores
Selective crushing	Difference in strength	Phosphorite ores, coals and shale
Enrichment by form
Combined methods	In addition to traditional enrichment processes (which do not affect the chemical composition of the raw material), the scheme includes pyro- or hydrometallurgical operations that change the chemical composition of the raw material.	Uranium, gold-bearing (bedrock) ores, copper-nickel ores...

In addition to those listed, there are other enrichment methods. Also, sometimes agglomeration processes (increasing the size of materials) are classified as enrichment processes.

TO auxiliary include dewatering, dust collection, cleaning waste water, testing, control and automation. The task of these processes is to ensure the optimal flow of the main processes and to bring the separation products to the required conditions.

The set of sequential technological processing operations to which minerals are subjected at processing plants is called enrichment scheme. Depending on the nature of the information contained in the enrichment scheme, it is called technological, qualitative, quantitative, qualitative-quantitative, water-sludge and apparatus chain diagram.

Enrichment, like any other technological process, is characterized by indicators. The main technological indicators of enrichment are as follows:

 Q product mass (productivity); P – mass (performance) of the design component in the product . They are usually expressed in tons per hour, tons per day, etc.;

 the content of the calculated component in the product – ,  is the ratio of the mass of the calculated component in the product to the mass of the product; The content of various components in a mineral and in the resulting products is usually calculated as a percentage (sometimes the content in the source material is denoted , in the concentrate - , in tailings - ). The content of useful components in the extracted raw materials (ore) can range from fractions of a percent (copper, nickel, cobalt, etc.) to several percent (lead, zinc, etc.) and several tens of percent (iron, manganese, fossil coal and some other non-metallic minerals);

 product yield –  and,  to,  xv  is the ratio of the mass of the product to the mass of the original ore; the yield of any enrichment product is expressed as a percentage, less often in fractions of a unit;

 extraction of a valuable component –  i,  k,  xv  is the ratio of the mass of the calculated component in the product to the mass of the same component in the original ore; extraction is expressed as a percentage, less often as a fraction of a unit.

Exit i– th product is calculated by the formula:

 i = (Q i /Q ref)100,%

Also, in the case of separation into two products - concentrate and tailings, their yield can be determined through the content using the following formulas:

 k = 100,%;  xv =
100,%;

The sum of the concentrate and tailings yields is:

 k +  xv = 100%.

It's obvious that

Q con + Q xv = Q ref.;

R con + R xv = R ref.

 1 +  2 +…+  n = 100%.

Likewise for Q and R.

(When beneficiating minerals, as a rule, only two products are obtained - concentrate and tailings, but not always, sometimes there may be more products).

In practice, contents are usually determined by chemical analysis.

Extracting the useful component into i– product:

i = 100.%, or  i = %.

The sum of concentrate and tailings recoveries is:

 k +  xv = 100%.

This formula is valid for any number of products:

 1 +  2 +…  n = 100%.

To find the content of a mixed product, you can use the so-called balance equation (for the case of separation into two products):

 to  con +  xv  con =  out  out.

The equation is also valid for any number of products:

 1  1 +  2  2 +…+ n  n =  out  out.

It should be noted that  out = 100%.

Example. The ore is divided into two products (Fig. 1.1) – concentrate and tailings. Ore productivity Q out = 200 t/h, for concentrate – Q con = 50 t/h. Performance by calculation component R out = 45 t/h, for component in concentrate R con = 40 t/h.

Q xv = Q ref – Q con = 200 – 50 = 150 t/h;

 con = ( Q con/ Q out)100 = (50/200)100 = 25%;

 xv =  out –  k = 100 – 25 = 75%,

or  xv = ( Q xv/ Q out)100 =(150/200) . 100=75%;

it's obvious that Q xv = ( xv  Q out)/100 = (75200)/100 = 150 t/h;

=
=
= 22,5 %;

=
=
= 80 %;

R xv = R ref – R con = 45 – 40 = 5,

Then
=
=
=3,33 %.

Or, using the balance equation, we have:

 to  con +  xv  con =  out  out,

 xv =
=
= 3,33 %.

When looking at commercially valuable minerals, the question rightly arises as to how such an attractive piece of jewelry can be made from primary ore or fossil. Especially considering the fact that rock processing as such represents, if not one of the final, then at least a process of refining that precedes the final stage. The answer to the question will be enrichment, during which basic processing of the rock occurs, involving the separation of valuable minerals from empty media.

General enrichment technology

Processing of valuable minerals is carried out at special enrichment plants. The process involves performing several operations, including preparation, direct splitting and separation of rock with impurities. During enrichment, various minerals are obtained, including graphite, asbestos, tungsten, ore materials, etc. These do not necessarily have to be valuable rocks - there are many factories that process raw materials, which are later used in construction. One way or another, the basics of mineral processing are based on an analysis of the properties of minerals, which also determine the principles of separation. By the way, the need to cut off different structures arises not only for the purpose of obtaining one pure mineral. It is a common practice for several valuable breeds to be bred from one structure.

Rock crushing

At this stage, the material is crushed into individual particles. During the crushing process, mechanical forces are used to overcome the internal adhesion mechanisms.

As a result, the rock is divided into small solid particles that have a homogeneous structure. It is worth distinguishing between direct crushing and grinding techniques. In the first case, the mineral raw material undergoes a less deep separation of the structure, during which particles with a fraction of more than 5 mm are formed. In turn, grinding ensures the formation of elements with a diameter of less than 5 mm, although this indicator depends on what kind of rock you are dealing with. In both cases, the goal is to maximize grain splitting useful substance so that a pure component is released without a mix, that is, waste rock, impurities, etc.

Screening process

After completion of the crushing process, the harvested raw materials are subjected to another technological impact, which can be either sieving or weathering. Screening is essentially a method of classifying the resulting grains according to their size characteristics. Traditional way The implementation of this stage involves the use of a sieve and a sieve, provided with the ability to calibrate the cells. During the screening process, over-grid and under-grid particles are separated. In some way, the enrichment of minerals begins at this stage, since some of the impurities and mixes are separated. Small fractions less than 1 mm in size are screened out using air environment- weathering. The mass, reminiscent of fine sand, is lifted by artificial air currents and then settles.

Subsequently, particles that settle more slowly are separated from very small dust elements that linger in the air. For further collection of the derivatives of such screening, water is used.

Enrichment processes

The enrichment process aims to separate mineral particles from the feedstock. During such procedures, several groups of elements are isolated - useful concentrate, waste tailings and other products. The principle of separating these particles is based on the differences between the properties of useful minerals and waste rock. Such properties can be the following: density, wettability, magnetic susceptibility, size, electrical conductivity, shape, etc. Thus, enrichment processes that use differences in density use gravitational separation methods. This approach is used for ore and non-metallic raw materials. Enrichment based on the wettability characteristics of the components is also very common. In this case, the flotation method is used, a feature of which is the ability to separate fine grains.

Magnetic enrichment of minerals is also used, which makes it possible to separate ferrous impurities from talc and graphite media, as well as to purify tungsten, titanium, iron and other ores. This technique is based on the difference in impact magnetic field on fossil particles. The equipment used is special separators, which are also used for the recovery of magnetite suspensions.

Final stages of enrichment

The main processes of this stage include dehydration, pulp thickening and drying of the resulting particles. The selection of equipment for dehydration is based on the chemical and physical characteristics of the mineral. As a rule, this procedure performed in several sessions. However, the need for its implementation does not always arise. For example, if electrical separation was used in the enrichment process, then dewatering is not required. In addition to preparing the enrichment product for further processes processing, an appropriate infrastructure must be provided for handling mineral particles. In particular, the factory organizes appropriate production services. Intra-shop vehicles, the supply of water, heat and electricity is organized.

Enrichment equipment

At the grinding and crushing stages, special installations are used. These are mechanical units that, with the help of various driving forces, have a destructive effect on the rock. Next, in the screening process, a sieve and sieve are used, in which the possibility of calibrating the holes is provided. More complex machines called screens are also used for sifting. Direct enrichment is carried out by electric, gravitational and magnetic separators, which are used in accordance with the specific principle of structure separation. After this, drainage technologies are used for dewatering, in the implementation of which the same screens, elevators, centrifuges and filtration devices can be used. The final stage, as a rule, involves the use of funds heat treatment and drying.

Waste from the enrichment process

As a result of the enrichment process, several categories of products are formed, which can be divided into two types - useful concentrate and waste. Moreover, a valuable substance does not necessarily have to represent the same rock. It also cannot be said that waste is unnecessary material. Such products may contain valuable concentrate, but in minimal quantities. At the same time, further enrichment of minerals that are in the waste structure is often not technologically and financially justified, so secondary processes of such processing are rarely carried out.

Optimal enrichment

Depending on the enrichment conditions, the characteristics of the starting material and the method itself, the quality of the final product may vary. The higher the content of valuable components and the fewer impurities in it, the better. Ideal ore beneficiation, for example, involves complete absence waste in the product. This means that in the process of enriching the mixture obtained by crushing and screening, debris particles from waste rock were completely excluded from the total mass. However, it is not always possible to achieve such an effect.

Partial beneficiation of minerals

Partial enrichment refers to the separation of the size class of the fossil or the cutting off of an easily separated part of the impurities from the product. That is, this procedure does not aim to completely clean the product from impurities and waste, but only increases the value of the source material by increasing the concentration of useful particles. Such processing of mineral raw materials can be used, for example, to reduce the ash content of coal. During the enrichment process, a large class of elements is isolated upon further mixing of the concentrate of unenriched screenings with the fine fraction.

The problem of loss of valuable rock during enrichment

Just as unnecessary impurities remain in the mass of the useful concentrate, the valuable rock can be removed along with the waste. To account for such losses, we use special means, allowing you to calculate the permissible level of these for each of the technological processes. That is, individual standards for acceptable losses are developed for all separation methods. The acceptable percentage is taken into account in the balance of processed products in order to cover discrepancies in the calculation of the moisture coefficient and mechanical losses. Such accounting is especially important if ore beneficiation is planned, during which deep crushing is used. Accordingly, the risk of losing valuable concentrate increases. And yet, in most cases, the loss of useful rock occurs due to violations in the technological process.

Conclusion

For lately technologies for the enrichment of valuable rocks have taken a noticeable step in their development. Both individual processing processes and general separation schemes are being improved. One of the promising directions for further advancement is the use of combined processing schemes that improve the quality characteristics of concentrates. In particular, magnetic separators are combined, resulting in an optimized enrichment process. New techniques of this type include magnetohydrodynamic and magnetohydrostatic separation. At the same time, there is also a general tendency for the deterioration of ore rocks, which cannot but affect the quality of the resulting product. An increase in the level of impurities can be combated by the active use of partial enrichment, but in general, an increase in processing sessions makes the technology ineffective.