Extraction of tungsten from tailings of processing plants. Industrial production of tungsten. Draining of semi-autogenous mills with pumps

The invention relates to a method complex processing tailings from the enrichment of tungsten-containing ores. The method includes their classification into small and large fractions, screw separation of the fine fraction to obtain a tungsten product and its cleaning. In this case, re-cleaning is carried out on a screw separator to obtain a rough tungsten concentrate, which is refined on concentration tables to obtain a gravity tungsten concentrate, which is subjected to flotation to obtain a high-grade conditioned tungsten concentrate and a sulfide-containing product. The tailings of the screw separator and the concentration table are combined and subjected to thickening. In this case, the waste obtained after thickening is fed to the classification of tailings for the enrichment of tungsten-containing ores, and the thickened product is subjected to enrichment in a screw separator to obtain secondary waste tailings and a tungsten product, which is sent for cleaning. The technical result is to increase the depth of processing of tungsten-containing ore tailings. 1 salary files, 1 table, 1 ill.

The invention relates to the beneficiation of minerals and can be used in the processing of tailings from the enrichment of tungsten-containing ores.

When processing tungsten-containing ores, as well as their tailings, gravitational, flotation, magnetic, as well as electrostatic, hydrometallurgical and other methods are used (see, for example, Bert P.O., with the participation of K. Mills. Gravity enrichment technology. Translated from English. - M.: Nedra, 1990). Thus, for the preliminary concentration of useful components (mineral raw materials), photometric and lumometric sorting (for example, the Mount Carbine and King Island concentration plants), enrichment in heavy environments (for example, the Portuguese Panasquera factory and the English Hemerdan factory) are used. ), jigging (especially of poor raw materials), magnetic separation in a weak magnetic field (for example, to separate pyrite, pyrrhotite) or high-intensity magnetic separation (to separate wolframite and cassiterite).

For the processing of tungsten-containing sludge, the use of flotation is known, in particular wolframite in China and at the Canadian Mount Pleasade factory, and in some factories flotation has completely replaced gravity enrichment (for example, the Jokberg factories, Sweden and Mittersil, Austria).

It is also known to use screw separators and screw sluices for the enrichment of tungsten-containing ores, old dumps, stale tailings, and sludge.

For example, when processing old dumps of tungsten ore at the Cherdoyak factory (Kazakhstan), the initial dump material, after crushing and grinding to a size of 3 mm, was subjected to enrichment on jiggers, the under-sieve product of which was then cleaned on a concentration table. The technological scheme also included enrichment in screw separators, in which 75-77% of WO 3 was recovered with a yield of enrichment products of 25-30%. Screw separation made it possible to increase the extraction of WO 3 by 3-4% (see, for example, Anikin M.F., Ivanov V.D., Pevzner M.L. “Screw separators for ore dressing”, Moscow, Nedra publishing house ", 1970, 132 pp.).

Disadvantages technological scheme processing of old dumps is a high load at the head of the process for the jigging operation, insufficiently high WO 3 extraction and a significant yield of enrichment products.

There is a known method for the associated production of tungsten concentrate by processing molybdenite flotation tailings (Climax Molybdenum factory, Canada). Tailings containing tungsten are separated using screw separation into tungsten waste sludge (light fraction), primary wolframite - cassiterite concentrate. The latter is subjected to hydrocyclonation and the sludge discharge is sent to the waste tailings, and the sand fraction is sent to the flotation separation of pyrite concentrate containing 50% S (sulfides) and discharged into the waste tailings. The chamber product of sulfide flotation is purified using screw separation and/or cones to obtain waste pyrite-containing tailings and wolframite-cassiterite concentrate, which is processed on concentration tables. In this case, wolframite-cassiterite concentrate and waste tailings are obtained. After dehydration, the crude concentrate is cleaned sequentially by purifying it from iron using magnetic separation, removing monazite from it by flotation (phosphate flotation) and then dewatering, drying, classifying and separating using stage magnetic separation into a concentrate containing 65% WO 3 after stage I and 68% WO 3 after stage II. A non-magnetic product is also obtained - tin (cassiterite) concentrate containing ~35% tin.

This processing method has disadvantages - complexity and multi-stage nature, as well as high energy intensity.

There is a known method for additional extraction of tungsten from gravity enrichment tailings (Boulder plant, USA). Gravity enrichment tailings are further crushed and deslimed in a classifier, the sands of which are separated using hydraulic classifiers. The resulting classes are enriched separately on concentration tables. Coarse tailings are returned to the grinding cycle, and fine tailings are thickened and re-enriched on slurry tables to produce a finished concentrate, middlings sent to regrinding, and tailings sent to flotation. The main flotation concentrate is subjected to one cleaning. The original ore contains 0.3-0.5% WO 3; Tungsten recovery reaches 97%, with about 70% of tungsten recovered by flotation. However, the tungsten content in the flotation concentrate is low (about 10% WO 3) (see, Polkin S.I., Adamov E.V. Enrichment of non-ferrous metal ores. Textbook for universities. M., Nedra, 1983, 213 pp.)

The disadvantages of the technological scheme for processing tailings from gravity enrichment are the high load at the head of the process on the enrichment operation on concentration tables, multi-operation, and low quality of the resulting concentrate.

There is a known method for processing scheelite-containing tailings in order to remove hazardous materials from them and process non-hazardous and ore minerals using an improved separation process (KR 20030089109, CHAE et al., 11/21/2003). The method includes the stages of homogenizing mixing of scheelite-containing tailings, introduction of the pulp into the reactor, “filtration” of the pulp using a screen to remove various foreign materials, subsequent separation of the pulp by screw separation, thickening and dehydration of non-metallic minerals to produce a cake, drying the cake in a rotary dryer, crushing the dry cake using a hammer crusher operating in a closed cycle with a screen, separation of crushed minerals using a “micron” separator into fractions of fine and coarse grains (granules), as well as magnetic separation of the coarse-grained fraction to obtain magnetic minerals and a non-magnetic fraction containing scheelite. The disadvantage of this method is the multi-operation nature and the use of energy-intensive drying of the wet cake.

There is a known method for additional extraction of tungsten from the waste tailings of the concentrating plant of the Ingichki mine (see A.B. Ezhkov, Kh.T. Sharipov, K.L. Belkov “Involvement in the processing of stale tungsten-containing tailings of the Ingichki mine.” Abstracts of reports of the III Congress of concentrators of the CIS countries, vol.1, MISiS, M., 2001). The method includes preparing the pulp and desliming it in a hydrocyclone (removal class - 0.05 mm), subsequent separation of the deslimed pulp on a cone separator, two-stage re-cleaning of the cone separator concentrate on concentration tables to obtain a concentrate containing 20.6% WO 3 with an average recovery 29.06%. The disadvantages of this method are the low quality of the resulting concentrate and insufficiently high WO 3 extraction.

The results of research on the gravitational enrichment of tailings from the Ingichkinsky enrichment plant are described (see S.V. Rudnev, V.A. Potapov, N.V. Salikhova, A.A. Kanzel “Research on the selection of the optimal technological scheme for the gravitational enrichment of man-made formations at the Ingichkinsky enrichment plant "//Mining Bulletin of Uzbekistan, 2008, No. 3).

Closest to the patented technical solution is a method for extracting tungsten from stale tailings of the enrichment of tungsten-containing ores (Artemova O.S. Development of a technology for extracting tungsten from stale tailings of the Dzhida VMC. Abstract of the dissertation of a candidate of technical sciences, Irkutsk State Technical University, Irkutsk, 2004 - prototype).

The technology for extracting tungsten from stale tailings using this method includes the operations of obtaining rough tungsten-containing concentrate and middling product, gold-bearing product and secondary waste tailings using gravitational methods of wet enrichment - screw and centrifugal separation - and subsequent finishing of the resulting rough concentrate and middling product using gravitational (centrifugal) enrichment and magnetic separation to obtain a conditioned tungsten concentrate containing 62.7% WO 3 with a recovery of 49.9% WO 3 .

According to this method, stale tailings are subjected to primary classification with the release of 44.5% of the mass. into secondary tailings in the form of a +3 mm fraction. The tailings fraction with a particle size of -3 mm is divided into classes -0.5 and +0.5 mm, and from the latter, coarse concentrate and tailings are obtained using screw separation. The -0.5 mm fraction is divided into classes -0.1 and +0.1 mm. From the +0.1 mm class, a coarse concentrate is separated using centrifugal separation, which, like the coarse concentrate of screw separation, is subjected to centrifugal separation to obtain rough tungsten concentrate and a gold-containing product. The tailings of screw and centrifugal separation are further crushed to -0.1 mm in a closed cycle with classification and then divided into classes -0.1+0.02 and -0.02 mm. The -0.02 mm grade is removed from the process as secondary tailings. Class -0.1+0.02 mm is enriched by centrifugal separation to produce secondary tailings and tungsten middlings, sent for finishing by magnetic separation along with the centrifugal separation concentrate, ground to a size of -0.1 mm. In this case, tungsten concentrate (magnetic fraction) and middling product (non-magnetic fraction) are obtained. The latter is subjected to magnetic separation II with the release of a non-magnetic fraction into secondary tailings and tungsten concentrate (magnetic fraction), which is enriched sequentially by centrifugal, magnetic and again centrifugal separation to obtain standard tungsten concentrate containing 62.7% WO 3 with a yield of 0.14 % and recovery 49.9%. In this case, the tailings of centrifugal separations and the non-magnetic fraction are sent to secondary tailings, the total yield of which at the stage of finishing the rough tungsten concentrate is 3.28% with a content of 2.1% WO 3.

The disadvantages of this method are the multi-operational nature of the technological process, which includes 6 classification operations, 2 additional grinding operations, as well as 5 centrifugal and 3 magnetic separation operations using relatively expensive equipment. At the same time, finishing the crude tungsten concentrate to the required standard is associated with the production of secondary waste tailings with a relatively high tungsten content (2.1% WO 3).

The objective of the present invention is to improve the method of processing enrichment tailings, including stale tailings from the enrichment of tungsten-containing ores, to obtain high-grade tungsten concentrate and an associated sulfide-containing product while reducing the tungsten content in the secondary waste tailings.

The patented method for complex processing of tailings from the enrichment of tungsten-containing ores includes classification of tailings into small and large fractions, screw separation of the fine fraction to obtain a tungsten product, re-cleaning of the tungsten product, and finishing to obtain high-grade tungsten concentrate, sulfide-containing product and secondary waste tailings.

The method differs in that the resulting tungsten product is subjected to re-cleaning on a screw separator to obtain rough concentrate and tailings, the rough concentrate is subjected to finishing on concentration tables to obtain gravitational tungsten concentrate and tailings. The tailings of the concentration table and the cleaning screw separator are combined and subjected to thickening, then the thickening discharge is fed to the classification stage at the head of the technological scheme, and the thickened product is subjected to enrichment on a screw separator to obtain secondary tailings and a tungsten product, which is sent for cleaning. The gravity tungsten concentrate is subjected to flotation to obtain a high-grade tungsten concentrate (62% WO 3) and a sulfide-containing product, which is processed by known methods.

The method can be characterized by the fact that the tailings are classified into fractions, mainly with a size of +8 mm and -8 mm.

The technical result of the patented method is to increase the depth of processing while reducing the number of technological operations and the load on them due to the separation at the head of the process of the bulk of the initial tailings (more than 90%) into secondary waste tailings, using energy-saving screw separation technology that is simpler in design and operation. This makes it possible to dramatically reduce the load on subsequent enrichment operations, as well as capital and operating costs, which ensures optimization of the enrichment process.

The effectiveness of the patented method is shown using the example of complex processing of tailings from the Ingichkinsky enrichment plant (see drawing).

Processing begins with the classification of tailings into small and large fractions with the separation of secondary waste tailings in the form of a large fraction. The fine fraction of the tailings is subjected to screw separation with the separation of the bulk of the original tailings (more than 90%) at the head of the technological process into secondary dump tailings. This allows for a correspondingly dramatic reduction in downstream workload, capital costs and operating costs.

The resulting tungsten product is subjected to re-cleaning using a screw separator to obtain rough concentrate and tailings. The rough concentrate is subjected to finishing on concentration tables to obtain gravity tungsten concentrate and tailings.

The tailings of the concentration table and the cleaning screw separator are combined and subjected to thickening, for example, in a thickener, mechanical classifier, hydrocyclone and other devices. The condensation discharge is fed to the classification stage at the head of the technological scheme, and the condensed product is subjected to enrichment in a screw separator to obtain secondary tailings and a tungsten product, which is sent for cleaning.

The gravity tungsten concentrate is brought by flotation to a high-grade tungsten concentrate (62% WO 3) to obtain a sulfide-containing product.

Thus, high-grade (62% WO 3 ) conditioned tungsten concentrate is isolated from tungsten-containing tailings upon achieving a relatively high WO 3 extraction of ~49% and a relatively low tungsten content (0.04% WO 3 ) in the secondary waste tailings.

The resulting sulfide-containing product is processed in a known way, for example, is used to produce sulfuric acid and sulfur, and is also used as a corrective additive in the production of cements.

High-grade tungsten concentrate is a highly liquid commercial product.

As follows from the results of implementing the patented method using the example of stale tailings from the enrichment of tungsten-containing ores from the Ingichkinsky concentrating plant, its effectiveness is shown in comparison with the prototype method (see table). Provides additional production of sulfide-containing product, reducing the volume of fresh water consumed by creating a water cycle. It creates the possibility of processing significantly poorer tailings (0.09% WO 3), a significant reduction in the tungsten content in secondary waste tailings (up to 0.04% WO 3). In addition, the number of technological operations has been reduced and the load on most of them has been reduced due to the separation at the head of the technological process of the bulk of the initial tailings (more than 90%) into secondary waste tailings, using a simpler and less energy-intensive screw separation technology, which reduces capital costs for the purchase of equipment and operating costs.

1. A method for complex processing of tailings from the enrichment of tungsten-containing ores, including their classification into small and large fractions, screw separation of the fine fraction to produce a tungsten product, its re-cleaning and finishing to produce high-grade tungsten concentrate, sulfide-containing product and secondary waste tailings, characterized in that the resulting after screw separation, the tungsten product is subjected to re-cleaning on a screw separator to obtain rough tungsten concentrate, the resulting rough tungsten concentrate is subjected to finishing on concentration tables to obtain gravity tungsten concentrate, which is subjected to flotation to obtain high-grade conditioned tungsten concentrate and sulfide-containing product, tailings of the screw separator and concentration table are combined and subjected to thickening, the resulting waste after thickening is fed to the classification of tailings for the enrichment of tungsten-containing ores, and the thickened product is subjected to enrichment in a screw separator to obtain secondary waste tailings and a tungsten product, which is sent for cleaning.

Page 1 of 25

State budgetary professional

educational institution of the Republic of Karelia

"Kostomuksha Polytechnic College"

Deputy Director of OD ___________________ Kubar T.S.

"_____"_________________________________2019

GRADUATE QUALIFYING WORK

Subject: “Maintaining the main method of beneficiation of tungsten ores and the use of auxiliary dehydration processes in the technological scheme of Primorsky GOK”

Group student: Kuzich S.E.

4th year, group OPI-15 (41C)

Specialty 02/21/18

"Beneficiation of mineral resources"

Head of the research and development work: Volkovich O.V.

teacher special disciplines

Kostomuksha

2019

Introduction………………………………………………………………………………...…3

1. Technological part………………………………………………………6

1.1 general characteristics tungsten ores………………………………….6

1.2 Economic assessment of tungsten ores……………………………………10

1. Technological scheme for beneficiation of tungsten ores using the example of Primorsky Mining and Processing Plant………………………………………………………..……11

2. Dehydration of enrichment products…………………………………......17

2.1. The essence of dehydration processes…………………………………..….17

2.2. Centrifugation…………………………………………………..…….24

3. Organization of safe working conditions…………………………………….30

3.1. Requirements for creating safe working conditions in the workplace…………………………………………………………..…...30

3.2. Requirements for maintaining safety in the workplace…….…..32

3.3. Safety requirements for enterprise employees…………32

Conclusion………………………………………………………………………………….…..…..34

List of sources and literature used……………………....…...36

Introduction

Mineral beneficiation - This is an industry that processes solid minerals with the intention of obtaining concentrates, i.e. products whose quality is higher than the quality of the original raw materials and meets the requirements for their further use in the national economy.Minerals are the basis National economy, and there is not a single industry where minerals or their processed products are not used.

One of these minerals is tungsten, a metal with unique properties. It has the highest boiling and melting points among metals, while having the lowest coefficient of thermal expansion. In addition, it is one of the hardest, heaviest, most stable and dense metals: the density of tungsten is comparable to the density of gold and uranium and 1.7 times higher than that of lead.The main tungsten minerals are scheelite, hübnerite and wolframite. Based on the type of minerals, ores can be classified into two types; scheelite and wolframite. When processing tungsten-containing ores, gravitational, flotation, magnetic, and also electrostatic,hydrometallurgical and other methods.

IN last years Metal-ceramic hard alloys made on the basis of tungsten carbide are widely used. Such alloys are used as cutters, for the manufacture of drill bits, dies for cold wire drawing, dies, springs, parts of pneumatic tools, valves of internal combustion engines, heat-resistant parts of mechanisms operating at high temperatures. Surfacing hard alloys (stellites), consisting of tungsten (3-15%), chromium (25-35%) and cobalt (45-65%) with a small amount of carbon, are used for coating quickly wearing parts of mechanisms (turbine blades, excavator equipment and etc.). Tungsten alloys with nickel and copper are used in the manufacture of protective screens against gamma rays in medicine.

Metal tungsten is used in electrical engineering, radio engineering, X-ray engineering: for the manufacture of incandescent filaments in electric lamps, high-temperature heaters electric ovens, anticathodes and cathodes of X-ray tubes, electric vacuum equipment and much more. Tungsten compounds are used as dyes, to impart fire and water resistance to fabrics, in chemistry - as a sensitive reagent for alkaloids, nicotine, protein, and as a catalyst in the production of high-octane gasoline.

Tungsten is also widely used in the production of military and space equipment (armor plates, tank turrets, rifle and gun barrels, rocket cores, etc.).

The structure of tungsten consumption in the world is constantly changing. It is being replaced by other materials in some industries, but new areas of its application are emerging. Thus, in the first half of the 20th century, up to 90% of tungsten was spent on alloying steels. Currently, the industry is dominated by the production of tungsten carbide, and the use of tungsten metal is becoming increasingly important. IN Lately New opportunities are opening up for the use of tungsten as an environmentally friendly material. Tungsten can replace lead in the production of various ammunition, and can also be used in the manufacture of sports equipment, in particular golf clubs and balls. Developments in these areas are being carried out in the USA. In the future, tungsten should replace depleted uranium in the production of large-caliber ammunition. In the 1970s, when tungsten prices were around $170. for 1% WO content 3 per 1 ton of product, the USA, and then some NATO countries, replaced tungsten with depleted uranium in heavy ammunition, which, with the same technical characteristics, was significantly cheaper.

Tungsten, as a chemical element, belongs to the group of heavy metals and, from an environmental point of view, is classified as moderately toxic (Class II-III). The current source of tungsten pollution is environment are the processes of exploration, mining and processing (concentration and metallurgy) of tungsten-containing mineral raw materials. As a result of processing, such sources are unused solid waste, wastewater, and dusty tungsten-containing fine particles. Solid waste in the form of dumps and various tailings are formed during the enrichment of tungsten ores. Wastewater from processing plants is represented by tailings discharges, which are used as recycled water in grinding and flotation processes.

Graduation goal qualifying work : to justify the technological scheme for the enrichment of tungsten ores using the example of Primorsky GOK and the essence of dehydration processes in this technological scheme.

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Navoi Mining and Metallurgical Plant

Navoi State Mining Institute

"Chemical and Metallurgical" Faculty"

Department of Metallurgy

Explanatory note

for final qualifying work

on the topic of: “Selection, justification and calculation of tungsten-molybdenum ore processing technology”

Graduate: K. Sayfiddinov

Navoi-2014

• Introduction
• 1. General information on methods of beneficiation of tungsten ores
• 2. Enrichment of molybdenum-tungsten ores
• 2. Technological section
• 2.1 Calculation of crushing scheme with equipment selection
• 2.2 Calculation of the grinding scheme
• 2.3 Selection and calculation of semi-autogenous grinding mills
• List of used literature

Introduction

Minerals are the basis of the national economy, and there is not a single industry where minerals or their processed products are not used.

Significant mineral reserves in many deposits of Uzbekistan make it possible to build large, highly mechanized mining, processing and metallurgical enterprises that extract and process many hundreds of millions of tons of minerals with high technical and economic indicators.

The mining industry deals with solid minerals from which, with modern technology, it is advisable to extract metals or other minerals. The main conditions for the development of mineral deposits are increasing their extraction from the subsoil and complex use. This is due to:

- significant material and labor costs during exploration and industrial development of new deposits;

- the growing need of various sectors of the national economy for almost all mineral components that make up the ore;

- the need to create waste-free technology and thereby prevent environmental pollution from production waste.

For these reasons, the possibility of industrial use of a deposit is determined not only by the value and content of the mineral, its reserves, geographical location, production and transportation conditions, other economic and political factors, but also the presence effective technology processing of mined ores.

1. General information about methods of beneficiation of tungsten ores

Tungsten ores are enriched, as a rule, in two stages - primary gravity enrichment and finishing of rough concentrates using various methods, which is explained by the low tungsten content in the processed ores (0.2 - 0.8% WO3) and high requirements for the quality of standard concentrates (55 - 65% WO3), The total enrichment degree is approximately 300 - 600.

Wolframite (huebnerite and ferberite) bedrock ores and placers usually contain a number of other heavy minerals, therefore, during the primary gravity enrichment of ores, they strive to isolate collective concentrates, which can contain from 5 to 20% WO3, as well as cassiterite, tantalite-columbite, magnetite, sulfides, etc. When finishing collective concentrates, it is necessary to obtain conditioned monomineral concentrates, for which flotation or flotogravity of sulfides, magnetic separation of magnetite in a weak magnetic field, and wolframite in a stronger one can be used. It is possible to use electric separation, gravitational enrichment on tables, flotation of gangue minerals and other processes to separate minerals so that the finished concentrates meet the requirements of GOSTs and technical specifications not only for the content of the base metal, but also for the content of harmful impurities.

Considering the high density tungsten minerals(6 - 7.5 g/cm 3), during enrichment, gravitational enrichment methods can be successfully used on jigs, concentration tables, sluices, jet and screw separators, etc. When valuable minerals are finely disseminated, flotation or a combination of gravitational processes with flotation is used. Considering the possibility of wolframite sludge during gravitational enrichment, flotation is used as auxiliary process even when enriching coarsely disseminated wolframite ores for more complete extraction of tungsten from sludge.

If there are large tungsten-rich ore pieces or large pieces of waste rock in the ore, sorting of ore with a particle size of 150 + 50 mm on belt conveyors can be used to separate the rich large-lump concentrate or pieces of rock that dilute the ore supplied for enrichment.

When beneficiating scheelite ores, gravity is also used, but most often a combination of gravity methods with flotation and flotation gravity, or flotation alone.

When sorting scheelite ores, luminescent installations are used. Scheelite, when irradiated with ultraviolet rays, glows with a bright blue light, which makes it possible to separate pieces of scheelite or pieces of waste rock.

Scheelite is an easily floated mineral characterized by high sludge properties. The extraction of scheelite increases significantly with flotation enrichment compared to gravity, therefore, in the enrichment of scheelite ores in the CIS countries, flotation has now begun to be used in all factories.

During the flotation of tungsten ores, a number of difficult technological problems arise that require the right decision depending on the material composition and association of individual minerals. In the process of flotation of wolframite, hübnerite and ferberite, it is difficult to separate from them iron oxides and hydroxides, tourmaline and other minerals containing neutralize their flotation properties with tungsten minerals.

Flotation of scheelite from ores with calcium-containing minerals (calcite, fluorite, apatite, etc.) is carried out by anionic fatty acid collectors, ensuring their good flotation with calcium cations of scheelite and other calcium-containing minerals. Separation of scheelite from calcium-containing minerals is possible only with the use of such regulators as liquid glass, sodium fluorosilicone, soda, etc.

2. Enrichment of molybdenum-tungsten ores

On Tyrnyauzskaya factory are enriched with molybdenum- tungsten ores Tyrnyauz deposit, which are complex in the material composition of not only valuable minerals with very fine dissemination, but also associated waste rock minerals. Ore minerals - scheelite (tenths of a percent), molybdenite (hundredths of a percent), powellite, partially ferrimolybdite, chalcopyrite, bismuthite, pyrrhotite, pyrite, arsenopyrite. Nonmetallic minerals - skarns (50-70%), hornfels (21-48%), granite (1 - 12%), marble (0.4-2%), quartz, fluorite, calcite, apatite (3-10%) and etc.

In the upper part of the deposit, 50-60% of molybdenum is represented by powellite and ferrimolybdite, in the lower part their content decreases to 10-20%. Molybdenum is present in scheelite as an isomorphic impurity. Part of the molybdenite, oxidized from the surface, is covered with a film of powellite. Part of the molybdenum grows very finely with molybdoscheelite.

More than 50% of oxidized molybdenum is associated with scheelite in the form of powellite inclusions - a decomposition product of the Ca(W, Mo)O 4 solid solution. Such forms of tungsten and molybdenum can only be isolated into a collective concentrate with subsequent separation by hydrometallurgical methods.

Since 1978, the ore preparation scheme at the factory has been completely reconstructed. Previously, ore, after large crushing at the mine, was transported to the factory in trolleys via an overhead cableway. In the crushing department of the factory, the ore was crushed to - 12 mm, unloaded into bunkers and then crushed in one stage in ball mills operating in a closed cycle with double-spiral classifiers, up to 60% of the class - 0.074 mm.

A new ore preparation technology was developed jointly by the Mekhanobr Institute and the plant and put into operation in August 1978.

The ore preparation scheme provides for coarse crushing of the original ore up to -350 mm, screening according to the 74 mm class, separate storage of each class in bunkers in order to more accurately regulate the supply of large and small classes of ore to the autogenous grinding mill.

Self-grinding of coarse ore (-350 mm) is carried out in Cascade type mills with a diameter of 7 m (MMC-70X X23) with additional grinding of the coarse-grained fraction to 62% class -0.074 mm in MSHR-3600X5000 mills operating in a closed cycle with single-spiral classifiers 1KSN-3 and located in a new building on the mountainside at an elevation of about 2000 m above sea level between the mine and the operating factory.

Innings finished product from the autogenous vessel to flotation is carried out by hydraulic transport. The hydraulic transport route is a unique engineering structure, ensuring the transportation of pulp with a height difference of more than 600 m. It consists of two pipelines with a diameter of 630 mm, a length of 1750 m, equipped with stilling wells with a diameter of 1620 mm and a height of 5 m (126 wells for each pipeline).

The use of a hydraulic transport system made it possible to eliminate the cargo ropeway workshop, the medium and fine crushing building, and the MShR-3200X2100 mills at the processing plant. In the main building of the factory, two main flotation sections, new scheelite and molybdenum finishing departments, a liquid glass melting shop, and recycling water supply systems were built and put into operation. The thickening front for rough flotation concentrates and middlings has been significantly expanded due to the installation of thickeners with a diameter of 30 m, which reduces losses from thickening discharges.

The newly commissioned facilities are equipped with modern automated process control systems and local automation systems. Thus, in the autogenous building the automatic control system operates in direct control mode based on M-6000 computers. In the main building, a system for centralized control of the material composition of the pulp was introduced using X-ray spectral analyzers KRF-17 and KRF-18 in combination with an M-6000 computer. An automated system for sampling and delivery of samples (by pneumatic mail) to the express laboratory, controlled by the KM-2101 computer complex and issuing analyzes by teletype, has been mastered.

One of the most complex processing processes - finishing rough scheelite concentrates according to the method of N. S. Petrov - is equipped with an automatic monitoring and control system, which can work either in the “advisor” mode to the flotation operator, or in the mode of direct control of the process, regulating the flow rate of the suppressor (liquid glass), pulp level in cleaning operations and other process parameters.

The sulfide minerals flotation cycle is equipped with automatic control and dosing systems for collector (butyl xanthate) and suppressor (sodium sulfide) in the copper-molybdenum flotation cycle. The systems operate using ion-selective electrodes as sensors.

Due to the increase in production volume, the factory switched to processing new varieties of ores, characterized by a lower content of certain metals and a higher degree of oxidation. This required improvement of the reagent regime for flotation of sulfide-oxidized ores. In particular, a progressive technological solution was used in the sulfide cycle - a combination of two foaming agents of active and selective types. Reagents containing terpene alcohols are used as an active foaming agent, and a new reagent LV, developed for the enrichment of multicomponent ores, primarily Tyrnyauz ores, is used as a selective agent.

In the flotation cycle of oxidized minerals by fatty acid collectors, intensifying additives of a modifier reagent based on low molecular weight carboxylic acids are used. To improve the flotation properties of circulating industrial products pulp, regulation of their ionic composition has been introduced. Methods of chemical finishing of concentrates have found wider application.

From the autogenous grinding mill, the ore is sent to screening. Class +4 mm is further ground in a ball mill. Mill overflow and under-screen product (--4 mm) are subject to I and II classifications.

690 g/t soda and 5 g/t transformer oil are fed into the ball mill. The classifier discharge goes to the main molybdenum flotation, where 0.5 g/t xanthate and 46 g/t terpineol are fed. After I and II cleaning flotations, the molybdenum concentrate (1.2-1.5% Mo) is subjected to steaming with liquid glass (12 g/t) at 50-70°C, III cleaning flotation and further grinding to 95-98% class --0.074 mm with a supply of 3 g/t sodium cyanide and 6 g/t liquid glass.

The finished molybdenum concentrate contains about 48% Mo, 0.1% Cu and 0.5% WO 3 with a Mo recovery of 50%. The control flotation tailings of the III and IV cleaning operations are thickened and sent to copper-molybdenum flotation with a supply of 0.2 g/t xanthate and 2 g/t kerosene. The twice purified copper-molybdenum concentrate, after steaming with sodium sulfide, is sent to selective flotation, where a copper concentrate containing 8-10% Cu (with an extraction of about 45%), 0.2% Mo, 0.8% Bi is isolated.

The tailings of the control molybdenum flotation, containing up to 0 2% WO 3, are sent to scheelite flotation, which is carried out according to a very branched and complex scheme. After mixing with liquid glass (350 g/t), basic scheelite flotation is carried out with sodium oleate (40 g/t). After the first cleaning flotation and thickening to 60% solid, the scheelite concentrate is steamed with liquid glass (1600 g/t) at 80--90 °C. Next, the concentrate is cleaned twice more and again goes to steaming at 90--95 ° C with liquid glass (280 g/t) and is cleaned again three times.

2. Technological section

2.1 Calculation of crushing scheme with equipment selection

The designed concentration plant is intended for processing molybdenum-containing tungsten ores.

Medium-sized ore (f = 12 ± 14 units on Professor Protodyakonov’s scale) is characterized by a density c = 2.7 t/m 3 and is supplied to the factory with a moisture content of 1.5%. Maximum piece d=1000 mm.

In terms of productivity, the enrichment plant belongs to the category of medium productivity (Table 4/2/), according to the international classification - to group C.

To the factory ore D max. =1000 mm is supplied from open-pit mining.

1. Let's determine the productivity of the coarse crushing shop. We calculate productivity according to Razumov K.A. 1, pp. 39-40. The project adopted the delivery of ore 259 days a year, in 2 shifts of 7 hours, 5 days a week.

Ore strength factor /2/

where: Q c. etc. - daily productivity of the crushing shop, t/day

Coefficient taking into account the uneven properties of raw materials /2/

where: Q h..t. dr - hourly productivity of the crushing shop, t/h

k n - coefficient taking into account the uneven properties of raw materials,

n days - estimated number of working days per year,

n cm - number of shifts per day,

t cm - shift duration,

k" - coefficient for accounting for ore strength,

Calculation of annual working hours:

C = (n day n cm t cm) = 259 2 5 = 2590 (3)

Time utilization rate:

k in = 2590/8760 = 0.29 units = 29%

2. Calculation of crushing scheme. We carry out the calculation according to pp. 68-78 2.

According to the instructions, the moisture content of the initial ore is 1.5%, i.e. e.

Calculation procedure:

1. Determine the degree of fragmentation

2. Let us accept the degree of fragmentation.

3. Let’s determine the maximum size of products after crushing:

4. Let's determine the width of the crusher's discharge slots, taking the typical characteristics Z - coarsening of the crushed product relative to the size of the discharge slot.

5. Let’s check the compliance of the selected crushing scheme with the manufactured equipment.

The requirements that crushers must satisfy are listed in Table 1.

Table 1

In terms of the width of the receiving opening and the range of adjustment of the discharge slot, crushers of the ShchDP 12X15 brand are suitable.

Let's calculate the productivity of the crusher using the formula (109/2/):

Q cat. = m 3 / h

Q fraction. = Q cat. · with n · k f · k cr. · k ow. · k c, m 3 / h (7)

where c n is the bulk density of ore = 1.6 t/m 3,

Q cat. - passport capacity of the crusher, m 3 / h

k f . , k ow. , kcr, kc - correction factors for strength (crushingability), bulk density, ore size and moisture content.

The value of the coefficients is found from the table k f =1.6; k cr =1.05; k ow. =1%;

Q cat. = S pr. / S n · Q n = 125 / 155 · 310 ? 250 m 3 /h

Let's find the actual productivity of the crusher for the conditions defined by the project:

Q fraction. = 250 · 1.6 · 1.00 · 1.05 · 1 · 1 = 420 t/h

Based on the calculation results, we determine the number of crushers:

We accept 12 x 15 boards for installation - 1 pc.

2.2 Calculation of the grinding scheme

The grinding scheme chosen in the project is a type of VA Razumov K.A. page 86.

Calculation procedure:

1. Determining the hourly productivity of the grinding shop , which is actually the hourly productivity of the entire factory, since the grinding shop is the main ore preparation building:

where 343 is the number of working days in a year

24 - continuous work week 3 shifts of 8 hours (3x8=24 hours)

Kv - equipment utilization factor

Kn - coefficient taking into account the uneven properties of raw materials

We accept: K in =0.9 K n =1.0

The coarse ore warehouse provides a two-day supply of ore:

V= 48,127.89 / 2.7 = 2398.22

We accept the initial data

Let's ask ourselves about liquefaction in plums and sands classification:

R 10 =3 R 11 =0.28

(R 13 is based on row 2 p. 262 depending on the size of the drain)

in 1 -0.074 =10% - class content - 0.074 mm in crushed ore

in 10 -0.074 =80% - class content - 0.074 mm in the classification plum.

We accept the optimal circulation load With opt = 200%.

Calculation procedure:

Grinding stages I and II are represented by a type VA scheme, page 86 fig. 23.

The calculation of scheme B comes down to determining the weights of products 2 and 5 (the yields of products are found according to the general formula r n = Q n: Q 1)

Q 7 = Q 1 C opt = 134.9 · 2 = 269.8 t/h;

Q 4 = Q 5 = Q 3 + Q 7 = 404.7 t/h;

g 4 = g 5 = 300%;

g 3 = g 6 = 100%

The calculation is carried out according to Razumov K.A. 1 pp. 107-108.

1. Calculation of scheme A

Q 8 = Q 10 ; Q 11 = Q 12 ;

Q 9 = Q 8 + Q 12 = 134.88 + 89.26 = 224.14 t/h

g 1 = 100%; g 8 = g 10 = 99.987%;

g 11 = g 12 =Q 12: Q 1 = 89.26: 134.88 = 66.2%;

g 9 = Q 9: Q 1 = 224.14: 134.88 = 166.17%

Process flow diagramschleniyamolybdenum-tungsten ores.

CalculationByqualitative-quantitative scheme.

Initial data for calculating qualitative-quantitative schemess.

Extraction of tungsten into the final concentrate - e tungsten 17 = 68%

Extraction of tungsten into collective concentrate - e tungsten 15 =86%

Extraction of tungsten into molybdenum concentrate - e tungsten 21 = 4%

Extraction of molybdenum into the final concentrate - e Mo 21 = 77%

Extraction of molybdenum into tungsten flotation tailings - e Mo 18 =98%

Extraction of molybdenum into control flotation concentrate - eMo 19 =18%

Extraction of molybdenum into collective concentrate - e Mo 15 = 104%

Yield of collective concentrate - g 15 = 36%

Yield of tungsten concentrate - g 17 = 14%

Yield of molybdenum concentrate - g 21 = 15%

Yield of control flotation concentrate - g 19 =28%

Determining the yield of enrichment products

G 18 = g 15 - G 17 =36-14=22%

G 22 = g 18 - G 21 =22-15=7%

G 14 = g 13 + g 19 + g 22 =100+28+7=135%

G 16 = g 14 - G 15 =135-36=99%

G 20 = g 16 - G 19 =99-28=71%

Determining the masses of enrichment products

Q 13 = 127.89t/h.

Q 1 4 = Q 13 XG 14 = 127.89x1.35=172.6 t/h

Q 1 5 = Q 13 XG 15 = 127.89x0.36=46.0 t/h

Q 1 6 = Q 13 XG 16 = 127.89x0.99=126.6t/h

Q 1 7 = Q 13 XG 17 = 127.89x0.14=17.9 t/h

Q 1 8 = Q 13 XG 18 = 127.89x0.22=28.1 t/h

Q 1 9 = Q 13 XG 19 = 127.89x0.28=35.8 t/h

Q 20 = Q 13 XG 20 = 127.89x0.71=90.8 t/h

Q 21 = Q 13 XG 21 = 127.89x0.15=19.1 t/h

Q 22 = Q 13 XG 22 = 127.89x0.07=8.9 t/h

Determining the extraction of enrichment products

For tungsten

e tungsten 13 =100 %

e tungsten 18 = e tungsten 15 - e tungsten 17 =86-68=28 %

e tungsten 22 = e tungsten 18 - e tungsten 21 =28-14=14 %

e tungsten 14 = e tungsten 13 + e tungsten 22 + e tungsten 19 =100+14+10=124 %

e tungsten 16 = e tungsten 14 - e tungsten 15 =124-86=38%

e tungsten 20 = e tungsten 13 - e tungsten 17 + e tungsten 21 =100 - 68+4=28%

e tungsten 19 = e tungsten 16 - e tungsten 20 =38-28=10 %

for molybdenum

e Mo 13 =100%

e Mo 22 = e Mo 18 - e Mo 21 =98-77=11 %

e Mo 14 = e Mo 13 + e Mo 22 + e Mo 19 =100+11+18=129 %

e Mo 16 = e Mo 14 - e Mo 15 =129-94=35 %

e Mo 17 = e Mo 15 - e Mo 18 =104-98=6%

e Mo 20 = e Mo 13 - e Mo 17 + e Mo 21 =100 - 6+77=17%

e Mo 19 = e Mo 16 - e Mo 20 =35-17=18%

Determining the amount of metals in the product Oh enrichment

For tungsten

14 =124 x0.5 / 135=0.46%

15 =86x0.5 / 36=1.19%

16 =38 x0.5 / 99=0.19%

17 =68 x0.5 / 14=2.43%

18 =28 x0.5 / 22=0.64%

19 =10 x0.5 / 28=0.18%

20 =28 x0.5 / 71=0.2%

21 =14 x0.5 / 15=0.46%

22 =14 x0.5 / 7=1%

For molybdenum

14 =129 x0.04/ 135=0.04%

15 =94x0.04/ 36=0.1%

16 =35 x0.04 / 99=0.01%

17 =6 x0.04 / 14=0.017%

18 =98 x0.04 / 22=0.18%

19 =18 x0.04 / 28=0.025%

20 =17 x0.04 / 71=0.009%

21 =77 x0.04 / 15=0.2%

22 =11 x0.04 / 7=0.06%

Table 3. Table of qualitative-quantitative enrichment scheme

Operation no. cont.		Q, t/h	, %	copper , %	copper , %	zinc , %	zinc , %
I	Grinding stage I
	arrives
	crushed ore
	comes out
	crushed ore
II	Classification
	arrives
	CrushedbChennsth product IArt. grinding
	CrushedbChennsth product II st .grinding
	comes out
	drain
	sands
III	Grinding I I stage
	arrives
	Sands classification
	comes out
	Shreddedsth product
IV	Collective Wo 3 -Mo flotation
	arrives
	Drain classification
	TailsMo flotationAnd
	comes out
	concentrate
	tails
V	Control flotation
	arrives
	Tailcollective flotation
	comes out
	concentrate
	tails
VI	Tungsten flotation
	arrives
	Concentratecollective flotation
	comes out
	concentrate
	tails
	Mo flotation
	arrives
	Tails Wo 3 flotation
	comes out
	concentrate
	tails

Calculation of water-sludge scheme .

The purpose of calculating the water-sludge scheme is to: ensure optimal liquid: solid ratios in the operations of the scheme; determining the amount of water added to operations or, conversely, released from products during dehydration operations; determination of L:T ratios in the products of the scheme; determination of the total water requirement and specific water consumption per ton of processed ore.

To obtain high technological indicators of ore processing, each operation of the technological scheme must be carried out at optimal values ​​of the L:T ratio. These values ​​are established based on data from ore dressing tests and the operating practices of existing processing plants.

The relatively low specific water consumption per ton of processed ore is explained by the presence of intra-factory water circulation at the designed plant, since the thickener drains are fed into the grinding - classification cycle. Water consumption for flushing floors, washing equipment and for other purposes is 10-15% of the total consumption.

Table 3. Table of qualitative-quantitative enrichment scheme.

Opera no.walkie-talkies cont.	Name of operations and products	Q, t/h	, %	R	W
I	Grinding stage I
	arrives
	crushed ore			0 , 0 25
	comes out
	crushed ore
II	Classification
	arrives
	CrushedbChennsth product IArt. grinding
	CrushedbChennsth product II st .grinding
	comes out
	drain
	sands
III	Grinding I I stage
	arrives
	Sands classification
	comes out
	Shreddedsth product
IV	Collective Wo 3 -Mo flotation
	arrives
	Drain classification
	Control flotation concentrate
	Tails Mo flotationAnd
	comes out
	concentrate
	Tails
V	Control flotation
	arrives
	Tailcollective flotation
	comes out
	concentrate
	Tails
VI	Tungsten flotation
	Incoming
	Concentratecollective flotation
	It turns out
	Concentrate
	Tails
	Mo flotation
	Incoming
	Tails tungstenflotation
	It turns out
	concentrate
	tails

Crusher selection and calculation.

The choice of crusher type and size depends on physical properties ore, required crusher capacity, crushed product size and ore hardness.

Tungsten-molybdenum ore by strength category is an ore of medium strength.

The maximum size of a piece of ore entering the crushing operation is 1000 mm.

To crush the ore coming from the mine, I install a jaw crusher with a simple swing jaw ShchDP 12x15. *

Crusher productivity, Q is equal to:

Q =q*L*i, t/h,

where q - specific productivity of the jaw crusher per 1 cm 2 of the discharge slot area, t/(cm 2 * h);

L is the length of the discharge slot of the neck crusher, cm;

i - width of the unloading slot, see /4/

According to the practice of operating the crushing department of the processing plant, the specific productivity of the jaw crusher is 0.13 t/cm 2 * hour.

The productivity of a jaw crusher will be determined by:

Q= 0.13*150*15.5 = 302.25 t/h.

The crusher accepted for installation provides the specified ore productivity.

The maximum size of a piece in the crusher feed will be:

120*0.8 = 96 cm.

Selection and calculation of grate screen

A grate screen with a hole size of 95 cm (950 mm) is installed in front of the crusher.

The required screening area is determined by the formula:

where Q* - productivity, t/h;

a is a coefficient equal to the width of the gap between the grates, mm. /5/ According to the layout conditions, the width of the grate screen is taken to be 2.7 m, length 4.5 m.

The practice of the crushing department of the factory shows that the ore delivered from the quarry contains about 4.5% of pieces with a particle size of more than 950 mm. Pieces of this size are delivered by a front-end loader to the ore yard, where they are crushed and again fed by the loader to the grate screen.

2.3 Selection and calculation of semi-autogenous grinding mills

Recently, when processing gold ores In world and domestic practice, in the first stage of grinding, semi-autogenous grinding mills with subsequent cyanidation are becoming increasingly common. In this case, the loss of gold from iron scrap and crumbs is eliminated, the consumption of cyanide during cyanidation is reduced, and the sanitary conditions of working on quartz silicate ores are improved. Therefore, I accept a semi-autogenous grinding (SAG) mill for installation in the first stage of grinding.

1. Find the specific productivity for the newly formed class of the operating SSI mill, t/(m 3 * h):

where Q is the productivity of the operating mill, t/h;

- class content -0.074 mm in the mill discharge, %;

- class content -0.074 mm in the original product,%;

D is the diameter of the operating mill, m;

L is the length of the operating mill, m.

2. We determine the specific productivity of the designed mill according to the newly formed class:

where q 1 is the specific productivity of a working mill in the same class;

K and is a coefficient that takes into account differences in the grindability of the ore designed for processing and the ore being processed (Ki = 1);

K k - coefficient taking into account the difference in the size of the initial and final grinding products at the existing and designed factories (K k = 1);

K D is a coefficient that takes into account the difference in the diameters of the drums of the designed and operating mills:

K D = ,

where D and D 1 respectively, the nominal diameters of the drums of the mills being designed for installation and those in operation. (K D =1.1);

Kt is a coefficient that takes into account differences in the type of designed and operating mills (Kt=1).

q = 0.77*1*1*1.1*1 =0.85 t/(m 3 * h).

I accept for installation an autogenous grinding mill "Cascade" with a diameter of 7 m and a length of 2.3 m with a working volume of 81.05 m3

3. We determine the productivity of the mills for ore using the formula:

where V is the working volume of the mill. /4/

4. Determine the estimated number of mills:

n- 101/125.72 = 0.8;

then the accepted one will be equal to 1. The Cascade mill provides the specified productivity.

Screen selection and calculation II screening stage .

Draining of semi-autogenous mills using pumps...

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Tungsten is the most refractory metal, melting point 3380°C. And this determines its scope. It is also impossible to build electronics without tungsten; even the filament in a light bulb is tungsten.

And, naturally, the properties of the metal also determine the difficulties in obtaining it...

First, you need to find ore. These are just two minerals - scheelite (calcium tungstate CaWO 4) and wolframite (iron and manganese tungstate - FeWO 4 or MnWO 4). The latter has been known since the 16th century under the name "wolf's foam" - "Spuma lupi" in Latin, or "Wolf Rahm" in German. This mineral accompanies tin ores and interferes with the smelting of tin, turning it into slag. Therefore, it is possible to find it already in antiquity. Rich tungsten ores usually contain 0.2 - 2% tungsten. Tungsten was actually discovered in 1781.

However, this is the easiest thing to find in tungsten mining.
Next, the ore needs to be enriched. There are a bunch of methods and they are all quite complex. First of all, of course. Then - magnetic separation (if we have wolframite with iron tungstate). Next is gravitational separation, because the metal is very heavy and the ore can be washed, much like when mining gold. Nowadays they still use electrostatic separation, but it is unlikely that the method will be useful to the endangered person.

So, we have separated the ore from the gangue. If we have scheelite (CaWO 4), then we can skip the next step, but if we have wolframite, then we need to turn it into scheelite. To do this, tungsten is extracted soda solution under pressure and at elevated temperature (the process takes place in an autoclave), followed by neutralization and precipitation in the form of artificial scheelite, i.e. calcium tungstate.
It is also possible to sinter wolframite with an excess of soda, then we obtain tungstate not of calcium, but of sodium, which for our purposes is not so significant (4FeWO 4 + 4Na 2 CO 3 + O 2 = 4Na 2 WO 4 + 2Fe 2 O 3 + 4CO 2).

The next two stages are leaching with water CaWO 4 -> H 2 WO 4 and decomposition with hot acid.
You can take different acids - hydrochloric (Na 2 WO 4 + 2HCl = H 2 WO 4 + 2NaCl) or nitric.
As a result, tungsten acid is isolated. The latter is calcined or dissolved in an aqueous solution of NH 3, from which paratungstate is crystallized by evaporation.
As a result, it is possible to obtain the main raw material for the production of tungsten - WO 3 trioxide with good purity.

Of course, there is also a method for producing WO 3 using chlorides, when tungsten concentrate is treated with chlorine at elevated temperatures, but this method will not be simple for the outsider.

Tungsten oxides can be used in metallurgy as an alloying additive.

So, we have tungsten trioxide and there is only one step left - reduction to metal.
There are two methods here - reduction with hydrogen and reduction with carbon. In the second case, the coal and the impurities it always contains react with tungsten, forming carbides and other compounds. Therefore, tungsten comes out “dirty”, brittle, and for electronics it is pure that is very desirable, because having only 0.1% iron, tungsten becomes brittle and it is impossible to draw the thinnest wire for incandescent filaments from it.
The technical process with coal has another drawback - high temperature: 1300 - 1400°C.

However, production with hydrogen reduction is also not a gift.
The reduction process takes place in special tube furnaces, heated in such a way that as it moves through the tube, the “boat” of WO3 passes through several temperature zones. A stream of dry hydrogen comes towards it. Recovery occurs in both “cold” (450...600°C) and “hot” (750...1100°C) zones; in “cold” ones – to the lower oxide WO 2, then – to the elemental metal. Depending on the temperature and duration of the reaction in the “hot” zone, the purity and grain size of the powdered tungsten released on the walls of the “boat” change.

So, we have obtained pure tungsten metal in the form of a tiny powder.
But this is not yet an ingot of metal from which something can be made. The metal is produced by powder metallurgy. That is, it is first pressed, sintered in a hydrogen atmosphere at a temperature of 1200-1300 °C, then passed through it electricity. The metal is heated to 3000 °C, and sintering occurs into a monolithic material.

However, we rather need not ingots or even rods, but thin tungsten wire.
As you yourself understand, here again everything is not so simple.
Wire drawing is carried out at a temperature of 1000°C at the beginning of the process and 400-600°C at the end. In this case, not only the wire, but also the die is heated. Heating is carried out by a gas burner flame or an electric heater.
In this case, after drawing, the tungsten wire is coated with graphite lubricant. The surface of the wire must be cleaned. Cleaning is carried out using annealing, chemical or electrolytic etching, and electrolytic polishing.

As you can see, the task of producing a simple tungsten filament is not as simple as it seems. And only the basic methods are described here; there are probably a lot of pitfalls there.
And, of course, even now tungsten is not a cheap metal. Now one kilogram of tungsten costs more than $50, the same molybdenum is almost two times cheaper.

Actually, there are several uses for tungsten.
Of course, the main ones are radio and electrical engineering, where tungsten wire goes.

The next one is the production of alloy steels, which are distinguished by their particular hardness, elasticity and strength. Added together with chromium to iron, it produces so-called high-speed steels, which retain their hardness and sharpness even when heated. They are used to make cutters, drills, milling cutters, as well as other cutting and drilling tools (in general, drilling tools contain a lot of tungsten).
Tungsten-rhenium alloys are interesting - they are used to make high-temperature thermocouples that operate at temperatures above 2000°C, although only in an inert environment.

Well, and one more thing interesting application- These are tungsten welding electrodes for electric welding. Such electrodes are non-consumable and it is necessary to supply additional metal wire to the welding site to provide a weld pool. Tungsten electrodes are used in argon arc welding - for welding non-ferrous metals such as molybdenum, titanium, nickel, as well as high-alloy steels.

As you can see, tungsten production is not for ancient times.
And why is tungsten there?
Tungsten can only be obtained with the construction of electrical engineering - with the help of electrical engineering and for electrical engineering.
No electricity means no tungsten, but you don’t need it either.

The chemical element is tungsten.

Before describing the production of tungsten, it is necessary to take a short excursion into history. The name of this metal is translated from German as “wolf’s cream”; the origin of the term goes back to the late Middle Ages.

When obtaining tin from various ores, it was noticed that in some cases it was lost, turning into foamy slag, “like a wolf devouring its prey.”

The metaphor caught on, giving the name to the later received metal; it is currently used in many languages ​​of the world. But in English, French and some other languages, tungsten is called differently, from the metaphor “heavy stone” (tungsten in Swedish). The Swedish origin of the word is associated with the experiments of the famous Swedish chemist Scheele, who first obtained tungsten oxide from the ore later named after him (scheelite).

Swedish chemist Scheele, who discovered tungsten.

Industrial production tungsten metal can be divided into 3 stages:

• ore beneficiation and production of tungsten anhydrite;
• reduction to powder metal;
• obtaining monolithic metal.

Ore beneficiation

Tungsten does not occur in a free state in nature; it is present only in various compounds.

• wolframites
• scheelites

These ores often contain small quantities of other substances (gold, silver, tin, mercury, etc.), despite the very low content of additional minerals, sometimes their associated extraction during enrichment is economically feasible.

1. Beneficiation begins with crushing and grinding the rock. The material is then sent for further processing, the methods of which depend on the type of ore. Enrichment of wolframite ores is usually carried out using the gravitational method, the essence of which is to use the combined forces of gravity and centrifugal force; minerals are separated according to chemical and physical properties - density, particle size, wettability. This way, the waste rock is separated, and the concentrate is brought to the required purity using magnetic separation. The wolframite content in the resulting concentrate ranges from 52 to 85%.
2. Scheelite, unlike wolframite, is not magnetic mineral, therefore magnetic separation is not applied to it. For scheelite ores, the enrichment algorithm is different. The main method is flotation (the process of separating particles in an aqueous suspension) followed by the use of electrostatic separation. The concentration of scheelite at the outlet can be up to 90%. Ores can also be complex, containing wolframites and scheelites at the same time. To enrich them, methods combining gravitational and flotation schemes are used.
   
   If further purification of the concentrate to established standards is necessary, various procedures are used depending on the type of impurities. To reduce phosphorus impurities, scheelite concentrates are processed in the cold hydrochloric acid, at the same time calcite and dolomite are removed. To remove copper, arsenic, and bismuth, roasting followed by treatment with acids is used. There are other cleaning methods.

Several different methods are used to convert tungsten from a concentrate into a soluble compound.

1. For example, the concentrate is sintered with an excess of soda, thus obtaining sodium wolframite.
2. Another method can be used - leaching: tungsten is extracted with a soda solution under pressure at high temperature, followed by neutralization and precipitation.
3. Another method is to treat the concentrate with chlorine gas. This process produces tungsten chloride, which is then separated from the chlorides of other metals by sublimation. The resulting product can be converted into tungsten oxide or processed directly into elemental metal.

The main result of various enrichment methods is the production of tungsten trioxide. Further, it is he who goes into the production of metal tungsten. Tungsten carbide is also obtained from it, which is the main component of many hard alloys. There is another product of direct processing of tungsten ore concentrates - ferrotungsten. It is usually smelted for the needs of ferrous metallurgy.

Tungsten Recovery

The resulting tungsten trioxide (tungsten anhydrite) must be reduced to the metal state in the next step. Reduction is most often carried out using the widely used hydrogen method. A moving container (boat) with tungsten trioxide is fed into the furnace, the temperature rises as it moves, hydrogen is supplied towards it. As the metal is restored, the bulk density of the material increases, the container loading volume decreases by more than half, so in practice, a run in 2 stages is used, through different types ovens.

1. At the first stage, dioxide is formed from tungsten trioxide, at the second, pure tungsten powder is obtained from the dioxide.
2. Then the powder is sifted through a mesh, and large particles are additionally ground to obtain a powder with a given grain size.

Carbon is sometimes used to reduce tungsten. This method simplifies production somewhat, but requires higher temperatures. In addition, coal and the impurities it contains react with tungsten, forming various compounds that lead to contamination of the metal. There are a number of other methods used in production around the world, but in terms of all parameters, hydrogen reduction has the highest applicability.

Obtaining monolithic metal

If the first two stages of industrial production of tungsten are well known to metallurgists and have been used for a very long time, then the development of a special technology was required to obtain a monolith from powder. Most metals are obtained by simple melting and then cast into molds; with tungsten, due to its main property - refractoriness - such a procedure is impossible. The method of producing compact tungsten from powder, proposed at the beginning of the 20th century by the American Coolidge, is still used with various variations in our time. The essence of the method is that the powder turns into a monolithic metal under the influence of electric current. Instead of conventional smelting, several steps must be taken to obtain tungsten metal. At the first of them, the powder is pressed into special bars. Then these posts are subjected to a sintering procedure, and this is done in two stages:

1. 1. First, at temperatures up to 1300ºC, the rod is pre-sintered to increase its strength. The procedure is carried out in a special sealed oven with a continuous supply of hydrogen. Hydrogen is used for additional reduction; it penetrates into the porous structure of the material, and with additional exposure to high temperature, a purely metallic contact is created between the crystals of the sintered rod. After this stage, the headstock is significantly strengthened, losing up to 5% in size.
   2. Then proceed to the main stage - welding. This process is carried out at temperatures up to 3 thousandºC. The post is secured with clamping contacts, and an electric current is passed through it. Hydrogen is also used at this stage - it is needed to prevent oxidation. The current used is very high; for bars with a cross-section of 10x10 mm, a current of about 2500 A is required, and for a cross-section of 25x25 mm - about 9000 A. The voltage used is relatively small, from 10 to 20 V. For each batch of monolithic metal, a test bar is first welded, it is used to calibrate the welding mode. The duration of welding depends on the size of the post and usually ranges from 15 minutes to an hour. This stage, like the first, also leads to a reduction in the size of the stack.

The density and grain size of the resulting metal depend on the initial grain size of the rod and the maximum welding temperature. The loss of dimensions after two stages of sintering is up to 18% along the length. The final density is 17–18.5 g/cm².

To obtain highly purified tungsten, various additives are used that evaporate during the welding process, for example, silicon oxides and alkali metals. As they heat up, these additives evaporate, taking other impurities with them. This process promotes additional cleaning. When using the correct temperature regime and the absence of traces of moisture in a hydrogen atmosphere during sintering, with the help of such additives the degree of tungsten purification can be increased to 99.995%.

Production of tungsten products

Obtained from the original ore after the three production stages described, monolithic tungsten has a unique set of properties. In addition to refractoriness, it is characterized by very high stability of geometric dimensions, preservation of strength at high temperatures and the absence of internal stress. Tungsten also has good ductility and malleability. Further production most often involves drawing out wire. These are technologically relatively simple processes.

1. The blanks enter a rotary forging machine, where the material is compressed.
2. Then the drawing method produces wire of various diameters (drawing is drawing a rod using special equipment through tapering holes). This way you can obtain the thinnest tungsten wire with a total degree of deformation of 99.9995%, while its strength can reach 600 kg/mm².

Tungsten began to be used for the filaments of electric lamps even before the development of a method for producing malleable tungsten. The Russian scientist Lodygin, who had previously patented the principle of using a filament for a lamp, in the 1890s proposed using tungsten wire twisted into a spiral as such a filament. How did you get tungsten for such wires? First, a mixture of tungsten powder with some kind of plasticizer (for example, paraffin) was prepared, then a thin thread was pressed out of this mixture through a hole of a given diameter, dried and calcined in hydrogen. The result was a rather fragile wire, straight sections of which were attached to the electrodes of the lamp. There were attempts to obtain compact metal using other methods, however, in all cases, the fragility of the threads remained critically high. After the work of Coolidge and Fink, the production of tungsten wire gained a solid technological basis, and the industrial use of tungsten began to grow rapidly.

An incandescent lamp invented by the Russian scientist Lodygin.

World tungsten market

Tungsten production volumes are about 50 thousand tons per year. The leader in production, as well as in consumption, is China; this country produces approximately 41 thousand tons per year (Russia, for comparison, produces 3.5 thousand tons). An important factor currently is the processing of secondary raw materials, usually scrap tungsten carbide, shavings, sawdust and tungsten powder residues; such processing provides about 30% of global tungsten consumption.

Filaments from burnt-out incandescent lamps are practically not recycled.

The global tungsten market has recently shown a decline in demand for tungsten filaments. This is due to the development of alternative technologies in the field of lighting - fluorescent and LED bulbs aggressively replace conventional incandescent lamps both in everyday life and in industry. According to experts, the use of tungsten in this sector will decrease by 5% per year in the coming years. The demand for tungsten as a whole is not decreasing; the decline in applicability in one sector is compensated by growth in others, including innovative industries.