The technology being developed at the Ginalmazzoloto Research Institute is focused on obtaining mainly precious metals from elements and components of electronic scrap containing them. Another feature of the technology is the widespread use of separation methods in liquid media and some others typical for the enrichment of non-ferrous metal ores.

VNIIPvtortsvetmet specializes in technologies for processing certain types of scrap: printed circuit boards, electronic vacuum devices, PTC units in televisions, etc.

Based on the density, the board material is reliably divided into two fractions: a mixture of metals and non-metals (+1.25 mm) and non-metals (-1.25 mm). Such separation can be carried out on a screen. In turn, from the non-metal fraction, with additional separation on a gravity separator, the metal fraction can be separated and thereby achieve a high degree of concentration of the resulting materials.

A portion (80.26%) of the remaining +1.25 mm material can be re-crushed to a size of -1.25 mm, followed by separation of metals and non-metals.

A production complex for the extraction of precious metals has been installed and operated at the TEKON plant in St. Petersburg. Using the principles of high-speed impact crushing of initial scrap (products for microwave technology, reading devices, microelectronic circuits, printed circuits, Pd catalysts, printed circuit boards, electroplating waste) in installations (rotary knife chopper, high-speed rotary impact disintegrator, drum screen, electrostatic separator, magnetic separator) selectively disintegrated material is obtained, which is further separated by magnetic and electrical separation methods into fractions represented by non-metals, ferrous metals and non-ferrous metals enriched with platinoids, gold and silver. The precious metals are then separated through refining.

This method is intended for obtaining a polymetallic concentrate containing silver, gold, platinum, palladium, copper, and other metals, with a non-metallic fraction content of no more than 10%. The technological process allows for metal extraction, depending on the quality of scrap, by 92-98%.

Waste from electrical and radio engineering production, mainly circuit boards, consists, as a rule, of two parts: installation elements (chips) containing precious metals and a base not containing precious metals with an input part in the form of copper foil conductors glued to it. Therefore, according to the method developed by the Mekhanobr-Technogen association, each of the components undergoes a softening operation, as a result of which the laminated plastic loses its original strength characteristics. Softening is carried out in a narrow temperature range of 200-210ºС for 8-10 hours, then dried. Below 200ºС, softening does not occur; above this, the material “floats”. With subsequent mechanical crushing, the material is a mixture of laminated plastic grains with disintegrated mounting elements, conductive part and pistons. The softening operation in an aqueous environment prevents harmful emissions.

Each size class of material classified after crushing (-5.0+2.0; -2.0+0.5 and -0.5+0 mm) is subjected to electrostatic separation in a corona discharge field, resulting in the formation of fractions: conductive metal elements of the boards and non-conductive - fraction of laminated plastic of the appropriate size. Then solder and precious metal concentrates are obtained from the metal fraction. The non-conductive fraction after processing is used either as a filler and pigment in the production of varnishes, paints, enamels, or reused in the production of plastics. Thus, the essential distinguishing features are: softening of electrical waste (boards) before crushing in an aqueous environment at a temperature of 200-210ºС, and classification into certain fractions, each of which is then processed for further use in industry.

The technology is characterized by high efficiency: the conductive fraction contains 98.9% of metal with its extraction of 95.02%; the non-conductive fraction contains 99.3% of modified fiberglass with its recovery being 99.85%.

There is another known method for extracting noble metals (patent Russian Federation RU2276196). It includes disintegration of radio-electronic scrap, vibration processing with separation of the heavy fraction containing noble metals, separation and separation of metals. In this case, the resulting radio-electronic scrap is sorted and metal parts are separated, the remaining part of the scrap is subjected to vibration processing with separation of the heavy fraction and separation. The heavy fraction after separation is mixed with pre-separated metal parts and the mixture is subjected to oxidative melting by supplying an air blast in the range of 0.15-0.25 nm3 per 1 kg of the mixture, after which the resulting alloy is electrorefined in a copper sulfate solution and noble metals are separated from the resulting sludge metals. Thanks to the method, high extraction of precious metals is ensured,%: gold - 98.2; silver - 96.9; palladium - 98.2; platinum - 98.5.

Directly, there are practically no programs for the systematic collection and recycling of used electronic and electrical equipment in Russia.

In 2007, on the territory of Moscow and the Moscow region, in accordance with the order of the Moscow government "On the creation of a city system for the collection, processing and disposal of electronic and electrical waste" they were going to choose land for the development of the production capacity of the Ecocenter MGUP "Industrial Waste" for the collection and industrial processing of waste with the allocation of zones for recycling scrap electronic and electrical products within the areas planned for sanitary cleaning facilities.

As of 10/30/2008, the project had not yet been implemented, and in order to optimize Moscow city budget expenditures for 2009-2010 and the planning period 2011-2012, Moscow Mayor Yuri Luzhkov, in difficult financial and economic conditions, ordered the suspension of earlier decisions made on the construction and operation of a number of waste processing enterprises and factories in Moscow.

Including the suspended orders:

• "On the procedure for attracting investments to complete the construction and operation of a waste transfer complex in the Yuzhnoye Butovo industrial zone of Moscow";
• "On organizational support for the construction and operation of a waste recycling plant at the address: Ostapovsky proezd, 6 and 6a (South-Eastern administrative district of Moscow)";
• "On the implementation of an automated system for controlling the circulation of production and consumption waste in the city of Moscow";
• "On the design of an integrated sanitary cleaning enterprise of the State Unitary Enterprise "Ekotekhprom" at the address: Vostryakovsky proezd, no. 10 (Southern administrative district of Moscow)."

The deadlines for implementing the orders have been postponed to 2011:

• Order No. 2553-RP "On organizing the construction of a production and warehouse technological complex with elements of sorting and pre-processing of bulky waste in the Kuryanovo industrial zone";
• Order No. 2693-RP "On the creation of a waste processing complex."

The order “On the creation of a city system for the collection, processing and disposal of electronic and electrical waste” was also declared invalid.

A similar situation is observed in many cities of the Russian Federation, and it is aggravated during the economic crisis.

Now in Russia there is a law that regulates the management of consumer waste, which includes used household appliances, for violation of which a fine is provided: for citizens - 4-5 thousand rubles; for officials – 30-50 thousand rubles; For legal entities– 300-500 thousand rubles. But at the same time, throwing away an old refrigerator, radio or any part of the car is still the easiest way to get rid of old equipment. Moreover, you can only be fined if you decide to simply leave trash on the street, in a place not intended for this purpose.

M.Sh. BARKAN, Ph.D. tech. Sciences, Associate Professor, Department of Geoecology, [email protected]
M.I. CHINENKOVA, Master's student, Department of Geoecology
St. Petersburg State Mining University

LITERATURE

1. Secondary metallurgy of silver. Moscow State Institute of Steel and Alloys. - Moscow. – 2007.
2. Getmanov V.V., Kablukov V.I. Electrolytic waste recycling
computer equipment containing precious metals // MSTU " Ecological problems modernity." – 2009.
3. Patent of the Russian Federation RU 2014135
4. Patent of the Russian Federation RU2276196
5. A set of equipment for processing and sorting electronic and electrical scrap and cable. [Electronic resource]
6. Recycling of office equipment, electronics, and household appliances. [Electronic resource]

Owners of patent RU 2553320:

The invention relates to the metallurgy of precious metals and can be used at secondary metallurgy enterprises for processing radio-electronic scrap and for the extraction of gold or silver from radio-electronic industry waste. The method involves melting radio-electronic waste in a reducing atmosphere in the presence of silicon dioxide to produce a copper-nickel anode containing from 2.5 to 5% silicon. The resulting electrode, containing lead impurities from 1.3 to 2.4%, is subjected to electrolytic dissolution using nickel sulfate electrolyte to obtain sludge with noble metals. The technical result is a reduction in losses of precious metals in the sludge, an increase in the dissolution rate due to a decrease in anode passivation and a reduction in energy consumption. 1 table, 3 etc.

The invention relates to the metallurgy of precious metals and can be used at secondary metallurgy enterprises for processing radio-electronic scrap and for the extraction of gold or silver from waste from the electronic and electrochemical industries.

There is a known method for extracting gold and silver from concentrates, secondary raw materials and other dispersed materials (RF application No. 94005910, published on October 20, 1995), which relates to the hydrometallurgy of precious metals, in particular to methods for extracting gold and silver from concentrates, electronic waste and jewelry industry. A method in which the recovery of gold and silver involves treatment with solutions of complexing salts and passing electric current with a density of 0.5-10 A/dm 2, solutions containing thiocyanate ions, ferric ions are used as solutions, and the pH of the solution is 0.5-4.0. The separation of gold and silver is carried out at the cathode, separated from the anode space by a filter membrane.

Disadvantages this method are increased losses precious metals in the sludge. The method requires additional treatment of concentrates with complexing salts.

There is a known method for extracting gold and/or silver from waste (RF patent No. 2194801, published on December 20, 2002), including the electrochemical dissolution of gold and silver in an aqueous solution at a temperature of 10-70°C in the presence of a complexing agent. Sodium ethylenediaminetetraacetate is used as a complexing agent. Concentration of ethylenediaminetetraacetic acid Na 5-150 g/l. Dissolution is carried out at pH 7-14. Current density 0.2-10 A/dm2. The use of the invention makes it possible to increase the rate of dissolution of gold and silver; reduce the copper content in the sludge to 1.5-3.0%.

There is a known method for extracting gold from gold-containing polymetallic materials (RF application No. 2000105358/02, published on February 10, 2002), including the production, regeneration or refining of metals by electrolytic method. The material being processed, previously melted and cast into a mold, is used as an anode and electrochemical dissolution and deposition of impurity metals on the cathode are carried out and gold is released in the form of anode sludge. In this case, the gold content in the anode material is ensured within the range of 5-50 wt.% and the electrolysis process is carried out in an aqueous solution of acid and/or salt with anion NO 3 or SO 4 in a concentration of 100-250 g-ion/l at an anodic current density of 1200 -2500 A/m 2 and bath voltage 5-12 V.

The disadvantage of this method is that electrolysis is carried out at a high anodic current density.

There is a known method for extracting gold from waste (RF patent No. 2095478, published on November 10, 1997) by electrochemical dissolution of gold in the processes of its extraction from waste of galvanic production and gold ores in the presence of protein complexing agents. Essence: in the method, the processing of raw materials is carried out with anodic polarization of gold-containing raw materials (waste from galvanic production, gold ores and waste) at potentials of 1.2-1.4 V (n.e.) in the presence of a protein complexing agent - enzymatic hydrolyzate of protein substances from microbial biomass having a degree of hydrolysis of at least 0.65, with an amine nitrogen content in the solution of 0.02-0.04 g/l and a 0.1 M sodium chloride solution (pH 4-6).

The disadvantage of this method is that the dissolution rate is not high enough.

There is a known method for refining copper and nickel from copper-nickel alloys, adopted as a prototype (Baymakov Yu.V., Zhurin A.I. Electrolysis in hydrometallurgy. - M.: Metallurgizdat, 1963, pp. 213, 214). The method involves electrolytic dissolution of copper-nickel alloy anodes, copper deposition to produce a nickel solution and slurry. The alloy is refined at a current density of 100-150 A/m 2 and a temperature of 50-65°C. The current density is limited by diffusion kinetics and depends on the concentration of salts of other metals in the solution. The alloy contains about 70% copper, 30% nickel and up to 0.5% other metals, in particular gold.

The disadvantages of this method are high energy consumption and loss of precious metals, in particular gold, contained in the alloy.

The technical result is a reduction in losses of precious metals in sludge, an increase in the dissolution rate, and a reduction in energy consumption.

The technical result is achieved by the fact that the melting of electronic scrap is carried out in a reducing atmosphere in the presence of silicon from 2.5 to 5%, and the electrolytic dissolution of anodes containing lead impurities from 1.3 to 2.4% is carried out using nickel sulfate electrolyte.

Table 1 shows the composition of the anode (in %) that was used when melting radio-electronic scrap.

The method is implemented as follows.

Nickel sulfate electrolyte is poured into an electrolytic bath to dissolve a copper-nickel anode with a silicon content of 2 to 5%. The process of anode dissolution is carried out at a current density of 250 to 300 A/m 2, a temperature of 40 to 70°C and a voltage of 6 V. Under the influence of electric current and the oxidative effect of silicon, the dissolution of the anode is significantly accelerated and the content of noble metals in the sludge and the anode potential increase is 430 mV. As a result, favorable conditions are created for electrolytic and chemical action to dissolve the copper-nickel anode.

This method is proven by the following examples:

When melting radio-electronic scrap as a flux

SiO 2 was used, i.e. melting was carried out in a reducing atmosphere, due to which silicon was restored to an elemental state, which was proven by microanalysis carried out on a microscope.

When carrying out electrolytic dissolution of this anode using a nickel electrolyte and a current density of 250-300 A/m 2, the anode potential is leveled at 430 mV.

When carrying out the electrolytic dissolution of an anode that does not contain silicon, in elemental form, under the same conditions, the process is stable and occurs at a potential of 730 mV. As the anode potential increases, the current in the circuit decreases, which leads to the need to increase the voltage across the bath. This leads, on the one hand, to an increase in the temperature of the electrolyte and its evaporation, and on the other hand, at a critical current value, to the release of hydrogen at the cathode.

Thanks to the proposed method, the following effects are achieved:

increase in the content of noble metals in sludge; significant increase in the rate of anode dissolution; the possibility of conducting the process in a nickel electrolyte; lack of passivation of the dissolution process of Cu-Ni anodes; reducing energy costs by at least two times; fairly low electrolyte temperatures (70°C), ensuring low evaporation of the electrolyte; low current densities, allowing the process to be carried out without hydrogen evolution at the cathode.

A method for extracting noble metals from radio-electronic industry waste, including melting radio-electronic scrap to produce copper-nickel anodes and their electrolytic anodic dissolution to produce noble metals in sludge, characterized in that the melting of radio-electronic scrap is carried out in a reducing atmosphere in the presence of silicon dioxide to produce anodes, containing from 2.5 to 5% silicon, while the resulting anodes are subjected to electrolytic anodic dissolution with a lead impurity content of 1.3 to 2.4% and using nickel sulfate electrolyte.

Similar patents:

The invention relates to the metallurgy of precious metals, in particular to the refining of gold. A method for processing an alloy of alloyed gold containing no more than 13% silver and no less than 85% gold includes electrolysis with soluble anodes from the original alloy using a hydrochloric acid solution of chloroauric acid (HAuCl4) with excess acidity in HCl 70-150 g/l as an electrolyte .

A method for extracting noble metals from refractory raw materials includes the stage of electrical treatment of a pulp of crushed raw materials in a chloride solution and the subsequent stage of extraction of commercial metals, in which both stages are carried out in a reactor using at least one diaphragm-less electrolyzer.

The invention relates to the metallurgy of precious metals and can be used for the production of non-ferrous, precious metals and their alloys obtained from the recycling of electronic devices and parts, as well as for the recycling of defective products.

The invention relates to the hydrometallurgy of precious metals, in particular to a method for the electrochemical extraction of silver from silver-containing conductive waste, and can be used in processing various types polymetallic raw materials (scrap electronic and computer equipment, waste from the electronic, electrochemical and jewelry industries, technological processing concentrates).

The invention relates to a colloidal solution of nanosilver and a method for its preparation and can be used in medicine, veterinary medicine, the food industry, cosmetology, household chemicals and agrochemicals.

The invention relates to pyrometallurgy of precious metals. A method for extracting platinum group metals from catalysts on a refractory aluminum oxide substrate containing platinum group metals includes grinding the refractory substrate, preparing a charge, melting it in a furnace and holding the metal melt with periodic draining of slag.

The invention relates to the field of metallurgy of non-ferrous and precious metals, in particular to the processing of sludge from electrolytic refining of copper. The method for processing copper-electrolyte sludge includes depuration, enrichment and leaching of selenium from decontaminated sludge or its enrichment products in an alkaline solution.

The invention relates to metallurgy. The method includes dosing zinc-containing waste from metallurgical production, solid fuel, binder and fluxing additives, mixing and pelletizing the resulting charge, drying and heat treatment of the pellets.

The invention relates to a method for acid processing of red mud obtained during the production of alumina, and can be used in technologies for recycling waste from sludge fields of alumina refineries.

The invention relates to a method for melting a solid charge of aluminum scrap in a furnace with combustion of fuel under distributed combustion conditions. The method involves melting a solid charge by burning fuel under distributed combustion conditions due to the deflection of the flame towards the solid charge during the melting phase by means of an acting oxidizer jet that redirects the flame in the direction opposite to the charge, and a stepwise change in the distribution of the oxidizer input between the primary and secondary portions in continuation of the distributed combustion phase. Method for isolating ultrafine and colloid-ionic noble inclusions from mineral raw materials and man-made products and installation for its implementation // 2541248

The invention relates to the isolation of ultrafine and colloidal ionic noble inclusions from mineral raw materials and man-made products. The method involves supplying raw materials to a substrate and processing them with laser radiation with an intensity sufficient for their high-speed heating.

The invention relates to the metallurgy of precious metals and can be used at secondary metallurgy enterprises for processing radio-electronic scrap and for the extraction of gold or silver from radio-electronic industry waste. The method involves melting radio-electronic waste in a reducing atmosphere in the presence of silicon dioxide to produce a copper-nickel anode containing from 2.5 to 5 silicon. The resulting electrode, containing lead impurities from 1.3 to 2.4, is subjected to electrolytic dissolution using a nickel sulfate electrolyte to obtain a slurry containing noble metals. The technical result is a reduction in losses of precious metals in the sludge, an increase in the dissolution rate due to a decrease in anode passivation and a reduction in energy consumption. 1 table, 3 etc.

480 rub. | 150 UAH | $7.5 ", MOUSEOFF, FGCOLOR, "#FFFFCC",BGCOLOR, "#393939");" onMouseOut="return nd();"> Dissertation - 480 RUR, delivery 10 minutes, around the clock, seven days a week and holidays

Telyakov Alexey Nailievich. Development of an effective technology for the extraction of non-ferrous and precious metals from waste of the radio engineering industry: dissertation... Candidate of Technical Sciences: 05.16.02 St. Petersburg, 2007 177 pp., Bibliography: p. 104-112 RSL OD, 61:07-5/4493

Introduction

Chapter 1. Literature Review 7

Chapter 2. Study of the material composition of radio-electronic scrap 18

Chapter 3. Development of technology for averaging radio-electronic scrap 27

3.1. Burning radio-electronic scrap 27

3.1.1. Information about plastics 27

3.1.2. Technological calculations for the utilization of roasting gases 29

3.1.3. Roasting radio-electronic scrap in a lack of air 32

3.1.4. Firing radio-electronic scrap in a tube furnace 34

3.2 Physical methods recycling electronic scrap 35

3.2.1. Description of processing area 36

3.2.2. Technological diagram of enrichment section 42

3.2.3. Development of enrichment technology on industrial units 43

3.2.4. Determination of the productivity of units of the enrichment site when processing radio-electronic scrap 50

3.3. Industrial tests of enrichment of radio-electronic scrap 54

3.4. Conclusions to Chapter 3 65

Chapter 4. Development of technology for processing radio-electronic scrap concentrates . 67

4.1. Research on the processing of REL concentrates in acid solutions... 67

4.2. Testing the technology for producing concentrated gold and silver 68

4.2.1. Testing the technology for producing concentrated gold 68

4.2.2. Testing the technology for producing concentrated silver... 68

4.3. Laboratory studies on the extraction of gold and silver REL by smelting and electrolysis 69

4.4. Development of technology for extracting palladium from sulfuric acid solutions. 70

4.5. Conclusions to Chapter 4 74

Chapter 5. Pilot tests on smelting and electrolysis of radio-electronic scrap concentrates 75

5.1. Smelting of metal concentrates REL 75

5.2. Electrolysis of smelting products REL 76

5.3. Conclusions to Chapter 5 81

Chapter 6. Study of oxidation of impurities during melting of radio-electronic scrap 83

6.1. Thermodynamic calculations of impurity oxidation REL 83

6.2. Study of the oxidation of impurities in REL 88 concentrates

6.2. Study of the oxidation of impurities in REL 89 concentrates

6.3. Pilot tests on oxidative smelting and electrolysis of REL 97 concentrates

6.4. Chapter 102 Conclusions

Conclusions on work 103

Literature 104

Introduction to the work

Relevance of the work

Modern technology requires more and more precious metals. Currently, the extraction of the latter has sharply decreased and does not meet the demand, so it is necessary to use all opportunities to mobilize the resources of these metals, and, consequently, the role of secondary metallurgy of precious metals is increasing. In addition, the extraction of Au, Ag, Pt and Pd contained in waste is more profitable than from ores.

Changes in the economic mechanism of the country, including the military-industrial complex and the armed forces, have necessitated the creation in certain regions of the country of complexes for processing radio-electronic industry scrap containing precious metals. In this case, it is mandatory to maximize the extraction of precious metals from poor raw materials and reduce the mass of tailings. It is also important that, along with the extraction of precious metals, it is possible to additionally obtain non-ferrous metals, for example, copper, nickel, aluminum and others.

The purpose of the work is the development of technology for the extraction of gold, silver, platinum, palladium and non-ferrous metals from scrap electronics industry and technological waste from enterprises.

Main provisions submitted for defense

Preliminary sorting of REL with subsequent mechanical enrichment ensures the production of metal alloys with increased extraction of precious metals.

Physico-chemical analysis of radio-electronic scrap parts showed that the parts contain up to 32 chemical element, while the ratio of copper to the sum of the remaining elements is 50-r60: 50-O.

The low dissolution potential of copper-nickel anodes obtained by melting electronic scrap makes it possible to obtain

5 precious metal sludge suitable for processing using standard technology.

Research methods. Laboratory, enlarged laboratory, industrial tests; analysis of enrichment, smelting, and electrolysis products was carried out using chemical methods. For the study, the method of X-ray spectral microanalysis (XMA) and X-ray phase analysis (XRF) was used using the DRON-06 installation.

Validity and reliability of scientific statements, conclusions and recommendations are due to the use of modern and reliable research methods and are confirmed by the good convergence of the results of complex studies performed in laboratory, large-scale laboratory and industrial conditions.

Scientific novelty

The main qualitative and quantitative characteristics of radioelements containing non-ferrous and precious metals have been determined, making it possible to predict the possibility of chemical and metallurgical processing of radio-electronic scrap.

The passivating effect of lead oxide films during the electrolysis of copper-nickel anodes made from radioelectronic scrap has been established. The composition of the films was revealed and the technological conditions for the preparation of anodes were determined, ensuring the absence of a passivation effect.

The possibility of oxidation of iron, zinc, nickel, cobalt, lead, tin from copper-nickel anodes made from radio-electronic scrap was theoretically calculated and confirmed as a result of fire experiments at 75" noble metals.

Practical significance of the work

A technological line for testing radio-electronic scrap has been developed, including departments for disassembly, sorting, mechanical

enrichment of smelting and analysis of noble and non-ferrous metals;

A technology has been developed for melting radio-electronic scrap in induction
oven, combined with the effect on the melt of oxidative radial
but-axial jets, providing intense mass and heat transfer in the zone
metal melting;

Developed and tested on a pilot scale
logical scheme for processing radio-electronic scrap and technological materials
progress of enterprises, providing individual processing and settlement with
each REL supplier.

Approbation of work. The materials of the dissertation work were presented: at International conference“Metallurgical technologies and equipment”, April 2003, St. Petersburg; All-Russian scientific and practical conference “New technologies in metallurgy, chemistry, enrichment and ecology”, October 2004, St. Petersburg; annual scientific conference young scientists “Russian mineral resources and their development” March 9 - April 10, 2004, St. Petersburg; annual scientific conference of young scientists "Russian mineral resources and their development" March 13-29, 2006, St. Petersburg.

Publications. The main provisions of the dissertation were published in 7 published works, including 3 patents for inventions.

The materials of this work present the results of laboratory studies and industrial processing of waste containing precious metals at the stages of disassembly, sorting and enrichment of radio-electronic scrap, smelting and electrolysis, carried out in the industrial conditions of the SKIF-3 enterprise at the sites of the Russian Scientific Center "Applied Chemistry" and a mechanical plant them. Karl Liebknecht.

Study of the material composition of radio-electronic scrap

Currently, there is no domestic technology for processing poor radio-electronic scrap. Purchasing a license from Western companies is impractical due to the dissimilarity of laws on precious metals. Western companies can buy electronic scrap from suppliers, store and accumulate the volume of scrap to a value that corresponds to the scale of the production line. The resulting precious metals are the property of the manufacturer.

In our country, according to the terms of monetary settlements with scrap suppliers, each batch of waste from each deliverer, regardless of its size, must undergo a full technological testing cycle, including opening of parcels, checking net and gross masses, averaging of raw materials by composition (mechanical, pyrometallurgical, chemical) and selection of head samples , sampling from by-products of averaging (slag, insoluble sediments, wash waters, etc.), encryption, analysis, decoding of samples and certification of analysis results, calculation of the amount of precious metals in a batch, their acceptance on the balance sheet of the enterprise and registration of all accounting and settlement documentation.

After receiving semi-products concentrated in precious metals (for example, Dore metal), the concentrates are delivered to a state refinery, where, after refining, the metals are sent to Gokhran, and payment for their cost is sent through the reverse financial chain up to the supplier. It becomes obvious that for processing enterprises to operate successfully, each batch from a supplier must go through the entire technological cycle separately from materials from other suppliers.

Analysis of the literature showed that one of possible ways averaging of radio-electronic scrap is its firing at a temperature that ensures the combustion of plastics included in the REL, after which it is possible to melt the sinter, obtain an anode, followed by electrolysis.

Synthetic resins are used to make plastics. Synthetic resins, depending on the reaction of their formation, are divided into polymerized and condensed. There are also thermoplastic and thermosetting resins.

Thermoplastic resins can melt repeatedly when reheated without losing plastic properties, these include: polyvinylacetate, polystyrene, polyvinyl chloride, condensation products of glycol with dibasic carboxylic acids, etc.

Thermosetting resins - when heated, they form infusible products, these include phenol-aldehyde and urea-formaldehyde resins, condensation products of glycerol with polybasic acids, etc.

Many plastics consist only of polymer, these include: polyethylenes, polystyrenes, polyamide resins, etc. Most plastics (phenoplasts, amioplastics, wood plastics, etc.) in addition to the polymer (binder) may contain: fillers, plasticizers, binding hardening and coloring agents, stabilizers and other additives. The following plastics are used in electrical engineering and electronics: 1. Phenolic plastics - plastics based on phenolic resins. Phenoplasts include: a) cast phenoplasts - hardened resins of the resol type, for example bakelite, carbolite, neoleukorite, etc.; b) layered phenolics - for example, a pressed product made of fabric and resol resin, called textolite. Phenol-aldehyde resins are obtained by condensation of phenol, cresol, xylene, alkylphenol with formaldehyde, furfural. In the presence of basic catalysts, resol (thermosetting) resins are obtained, in the presence of acidic catalysts, novolac (thermoplastic resins) are obtained.

Technological calculations for the utilization of roasting gases

All plastics mainly consist of carbon, hydrogen and oxygen, with valency being replaced by additives of chlorine, nitrogen, and fluorine. Consider, as an example, the burning of textolite. Textolite is a highly flammable material and is one of the components of electronic scrap. It consists of pressed cotton fabric impregnated with artificial resole (formaldehyde) resins. Morphological composition of radio-technical textolite: - cotton fabric - 40-60% (average - 50%) - resol resin - 60-40% (average -50%) Gross formula of cotton cellulose [SbN702(OH)z]z, and resol resin - (Cg H702)-m, where m is the coefficient corresponding to the products of the degree of polymerization. According to literature data, with an ash content of textolite of 8%, the humidity will be 5%. Chemical composition textolite in terms of working mass will be, %: Cp-55.4; Hp-5.8; OP-24.0; Sp-0.l; Np-I.7; Fp-8.0; Wp-5, 0.

When 1 t/hour of textolite is burned, 0.05 t/hour of moisture evaporation and 0.08 t/hour of ash are formed. At the same time, it is supplied for combustion, t/hour: C - 0.554; N - 0.058; 0-0.24; S-0.001, N-0.017. Composition of textolite ash grades A, B, R according to literature data,%: CaO -40.0; Na, K20 - 23.0; Mg O - 14.0; РпО10 - 9.0; Si02 - 8.0; Al 203 - 3.0; Fe203 -2.7; SO3 -0.3. To carry out the experiments, firing was chosen in a sealed chamber without air access; for this purpose, a box measuring 100x150x70 mm with a flange fastening of the lid was made of stainless steel 3 mm thick. The lid was attached to the box through an asbestos gasket with bolted connections. Fitting holes were made in the end surfaces of the box, through which the contents of the retort were purged with inert gas (N2) and gas products of the process were removed. The following samples were used as test samples: 1. Boards cleared of radioelements, sawn to dimensions of 20x20 mm. 2. Black microcircuits from boards (full size 6x12 mm) 3. Connectors made of textolite (sawed to sizes 20x20 mm) 4. Connectors made of thermosetting plastic (cut to sizes 20x20 mm) The experiment was carried out as follows: 100 g of the test sample was loaded into the retort , was closed with a lid and placed in a muffle. The contents were purged with nitrogen for 10 minutes at a flow rate of 0.05 l/min. Throughout the experiment, nitrogen flow was maintained at 20-30 cm3/min. The exhaust gases were neutralized with an alkaline solution. The muffle shaft was closed with brick and asbestos. The temperature rise was regulated within 10-15C per minute. Upon reaching 600C, an hour-long exposure was carried out, after which the furnace was turned off and the retort was removed. During cooling, the nitrogen flow rate increased to 0.2 l/min. The observation results are presented in Table 3.2.

The main negative factor of the process is a very strong, pungent, unpleasant odor, released both from the cinder itself and from the equipment, which was “saturated” with this odor after the first experiment.

For the study, a continuous tubular rotary kiln with indirect electric heating was used with a charge capacity of 0.5-3.0 kg/hour. The furnace consists of a metal casing (length 1040 mm, diameter 400 mm), lined with refractory bricks. The heaters are 6 silit rods with a working part length of 600 mm, powered by two RNO-250 voltage variators. The reactor (total length 1560 mm) is a stainless steel pipe with an outer diameter of 89 mm lined with a porcelain pipe with an inner diameter of 73 mm. The reactor rests on 4 rollers and is equipped with a drive consisting of an electric motor, gearbox and belt drive.

To control the temperature in the reaction zone, a thermocouple complete with a portable potentiometer installed inside the reactor is used. Previously, its readings were adjusted based on direct measurements of the temperature inside the reactor.

Radio-electronic scrap was manually loaded into the oven at the ratio: boards cleared of radio elements: black microcircuits: PCB connectors: thermoplastic resin connectors = 60:10:15:15.

This experiment was carried out on the assumption that the plastic would burn before it melted, which would release the metal contacts. This turned out to be unattainable, since the problem of a strong odor remains, and as soon as the connectors reached the temperature zone of 300C, the thermoplastic plastic connectors stuck to the inner surface of the rotary kiln and blocked the passage of the entire mass of electronic scrap. Forced air supply into the furnace and an increase in temperature in the sticking zone did not lead to the possibility of firing.

Thermosetting plastic is also characterized by high viscosity and strength. A characteristic of these properties is that when cooled in liquid nitrogen for 15 minutes, thermoset plastic connectors were broken on an anvil using a ten-kilogram hammer, and no destruction of the connectors occurred. Considering that the number of parts made from such plastics is small and they can be easily cut using a mechanical tool, it is advisable to disassemble them manually. For example, cutting or cutting connectors along the central axis results in the release of the metal contacts from the plastic base.

The range of electronic industry scrap supplied for processing covers all parts and assemblies of various units and devices in the manufacture of which precious metals are used.

The base of a product containing precious metals, and accordingly their scrap, can be made of plastic, ceramics, fiberglass, multilayer material (BaTiO3) and metal.

Raw materials arriving from supplying enterprises are sent for preliminary disassembly. At this stage, components containing precious metals are removed from electronic computers and other electronic equipment. They make up about 10-15% of the total mass of computers. Materials that do not contain precious metals are used for the extraction of non-ferrous and ferrous metals. Waste material containing precious metals (printed circuit boards, connectors, wires, etc.) is sorted to remove gold and silver wires, gold-plated PCB side connector pins, and other parts with a high precious metal content. Selected parts go directly to the precious metals refining site.

Testing the technology for producing concentrated gold and silver

A sample of gold sponge weighing 10.10 g was dissolved in aqua regia, the nitric acid was removed by evaporation with hydrochloric acid, and metallic gold was precipitated with a saturated solution of iron (I) sulfate prepared from carbonyl iron dissolved in sulfuric acid. The precipitate was washed repeatedly by boiling with distilled HC1 (1:1) and water, and gold powder was dissolved in aqua regia, prepared from acids distilled in a quartz vessel. The precipitation and washing operation was repeated and a sample was taken for emission analysis, which showed a gold content of 99.99%.

To carry out a material balance, the remains of samples selected for analysis (1.39 g Au) and gold from burnt filters and electrodes (0.48 g) were combined and weighed; irrecoverable losses amounted to 0.15 g, or 1.5% of the processed material . Such high percent losses are explained by the small amount of gold involved in processing and the latter’s costs of debugging analytical operations.

Ingots of silver isolated from the contacts were dissolved by heating in concentrated nitric acid, the solution was evaporated, cooled and drained from the precipitated salt crystals. The resulting nitrate precipitate was washed with distilled nitric acid, dissolved in water and the metal was precipitated in the form of chloride with hydrochloric acid. The decanted mother liquor was used to develop the technology for refining silver by electrolysis.

The silver chloride precipitate that had settled for 24 hours was washed with nitrogenous acid and water, dissolved in excess aqueous ammonia and filtered. The filtrate was treated with excess hydrochloric acid until the formation of precipitate ceased. The latter was washed with cooled water and alkaline melting, metallic silver was isolated, which was etched with boiling HC1, washed with water and melted with boric acid. The resulting ingot was washed with hot HCI (1:1), water, dissolved in hot nitric acid, and the entire cycle of silver separation through chloride was repeated. After melting with flux and washing with hydrochloric acid, the ingot was remelted twice in a pyrographite crucible with intermediate operations to clean the surface with hot hydrochloric acid. After this, the ingot was rolled into a plate, its surface was etched with hot HC1 (1:1) and a flat cathode was made for purifying silver by electrolysis.

Metallic silver was dissolved in nitric acid, the acidity of the solution was adjusted to 1.3% in HNO3, and electrolysis of this solution was carried out with a silver cathode. The operation was repeated, and the resulting metal was fused in a pyrographite crucible into an ingot weighing 10.60 g. Analysis in three independent organizations showed that the mass fraction of silver in the ingot was at least 99.99%.

From large quantity work on the extraction of noble metals from intermediate products, we chose for testing the method of electrolysis in a solution of copper sulfate.

62 g of metal contacts from the connectors were alloyed with borax and a flat ingot weighing 58.53 g was cast. The mass fraction of gold and silver is 3.25% and 3.1%, respectively. A portion of the ingot (52.42 g) was electrolyzed as an anode in a solution of copper sulfate acidified with sulfuric acid, resulting in 49.72 g of anode material dissolving. The resulting sludge was separated from the electrolyte and after fractional dissolution in nitric acid and aqua regia, 1.50 g of gold and 1.52 g of silver were isolated. After burning the filters, 0.11 g of gold was obtained. The losses of this metal amounted to 0.6%; irreversible loss of silver - 1.2%. The phenomenon of the appearance of palladium in the solution (up to 120 mg/l) has been established.

During the electrolysis of copper anodes, the precious metals contained therein are concentrated in sludge, which falls to the bottom of the electrolysis bath. However, a significant (up to 50%) transition of palladium into the electrolyte solution is observed. To cover the beginning of palladium losses, this work was performed.

The difficulty of extracting palladium from electrolytes is due to their complex composition. There are known works on sorption-extraction processing of solutions. The goal of the work is to obtain pure palladium sulfates and return the purified electrolyte to the process. To solve this problem, we used the process of sorption of metals on synthetic ion-exchange fiber AMPAN H/SO4. Two solutions were used as initial solutions: No. 1 - containing (g/l): 0.755 palladium and 200 sulfuric acid; No. 2 - containing (g/l): palladium 0.4, copper 38.5, iron - 1.9 and 200 sulfuric acid. To prepare the sorption column, 1 gram of AMPAN fiber was weighed, placed in a column with a diameter of 10 mm, and the fiber was soaked in water for 24 hours.

Development of technology for extracting palladium from sulfuric acid solutions

The solution was supplied from below using a dosing pump. During the experiments, the volume of the passed solution was recorded. Samples taken at regular intervals were analyzed by the atomic adsorption method for palladium content.

The experimental results showed that palladium sorbed on the fiber is desorbed by a solution of sulfuric acid (200 g/l).

Based on the results obtained when studying the processes of sorption-desorption of palladium on solution No. 1, an experiment was carried out to study the behavior of copper and iron in quantities close to their content in the electrolyte during the sorption of palladium on the fiber. The experiments were carried out according to the scheme presented in Fig. 4.2 (Table 4.1-4.3), which includes the process of sorption of palladium from solution No. 2 on the fiber, washing of palladium from copper and iron with a solution of 0.5 M sulfuric acid, desorption of palladium with a solution of 200 g/ l sulfuric acid and washing the fiber with water (Fig. 4.3).

The beneficiation products obtained at the beneficiation site of the SKIF-3 enterprise were taken as the initial raw material for the melts. The melting was carried out in the Tammana furnace at a temperature of 1250-1450C in graphite-fireclay crucibles with a volume of 200 g (for copper). Table 5.1 presents the results of laboratory melts of various concentrates and their mixtures. The concentrates, the compositions of which are presented in Tables 3.14 and 3.16, melted without complications. Concentrates, the composition of which is presented in Table 3.15, require a temperature in the range of 1400-1450C for melting. mixtures of these materials L-4 and L-8 require a temperature of about 1300-1350C for melting.

Industrial smelting P-1, P-2, P-6, carried out in an induction furnace with a crucible with a volume of 75 kg for copper, confirmed the possibility of melting concentrates when the bulk composition of enriched concentrates was fed to the smelting.

During the research, it turned out that part of the electronic scrap is melted with large losses of platinum and palladium (concentrates from REL capacitors, Table 3.14). The loss mechanism was determined by adding contacts to the surface of a copper molten bath with surface sputtering of silver and palladium on them (palladium content in contacts 8.0-8.5%). In this case, the copper and silver were melted, leaving a palladium shell of the contacts on the surface of the bath. An attempt to mix palladium into the bath resulted in the destruction of the shell. Some of the palladium flew off the surface of the crucible before it had time to dissolve in the copper bath. Therefore, all subsequent melts were carried out with a synthetic cover slag (50% S1O2 + 50% soda).

Kozyrev, Vladimir Vasilievich

Field of activity (technology) to which the described invention relates

The invention relates to the field of hydrometallurgy and can be used for the extraction of precious metals from waste of the electronic and electrical industry (electronic scrap), mainly from electronic boards modern microelectronics.

DETAILED DESCRIPTION OF THE INVENTION

Modern methods recycling of scrap electronic and electronic equipment is based on the mechanical enrichment of raw materials, including the operation of manual disassembly, if the materials, due to their characteristics and composition, cannot be transferred to a homogeneous state. After grinding, the scrap components are separated using magnetic and electrostatic separation methods, followed by hydrometallurgical or pyrometallurgical extraction of useful components.

The disadvantages of the method are associated with the impossibility of isolating in this way unpackaged elements from the printed circuit boards of modern computers, which contain the bulk of precious metals. Due to the miniaturization of products and minimization of the content of precious metals in them, their quantity is evenly distributed throughout the entire mass of raw materials after grinding, which makes further processing ineffective - low degrees of extraction at the stage of hydropyrometallurgical processing.

There is a known hydrometallurgical method for leaching precious metals from scrap electronic devices with nitric acid. According to this method, scrap is leached with 30-60% nitric acid with stirring for a duration sufficient to achieve a copper concentration in the solution of 150 g/l. After this, plastic particles are separated from the resulting pulp, the pulp is treated with sulfuric acid, bringing its concentration to 40%, nitrogen oxides are distilled off, absorbing and neutralizing them in a special column. In this case, copper sulfates crystallize and gold and tin acid precipitate. Then, the solution is separated from the resulting pulp and silver and platinoids are isolated from it by cementing them with copper, and the washed sediment is subjected to smelting, as a result of which gold beads are obtained (GDR, patent 253948 dated 10/01/86. VEB Bergbau und Huffen Kombinat "Albert Funk" ). The disadvantages of this method are:

• an excessively large mass of crushed scrap subjected to nitrate treatment due to its two to threefold increase due to additional grinding of the plastic substrate on which the electronic parts are attached, since their manual separation requires large labor costs;
• very high consumption of chemicals associated with the need to treat an increased mass of crushed scrap with acids and dissolve all ballast metals;
• low content of gold and silver with high contents of associated impurities in sediments subjected to refining;
• release of toxins into the air and contamination of the air with them due to the release of toxins during the chemical destruction of plastic with strong acid solutions at elevated temperatures.

The closest to the proposed invention is a method for extracting gold and silver from waste from the electronic and electrical industry using nitric acid with separation of electronic parts. Therefore, in this method, the scrap is treated with 30% nitric acid at 50-70°C until the “attached” parts of electronic circuits are separated, which are then crushed and treated with nitric acid solutions, additionally strengthened after processing the source material to the initial concentration and processed at a temperature of 90°C for two hours, and then at the boiling point of the solution until it is completely denitrated to obtain a solution containing noble metals (RF Patent 2066698, class C22B 7/00, C22B 11/00, published -1996).

The disadvantages of this method are: high consumption of reagents for dissolving ballast metals; irretrievable losses of gold along with tin and lead; high energy costs for evaporation and denitration operations; irretrievable losses of palladium, platinum;

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At the first stage of the process, extremely poorly filtered precipitates of metatinic acid containing gold are formed. Clarification of the product solution for subsequent use in technological scheme isolating precious metals requires a very large amount of time, which makes it impossible to implement the process in technological practice.

The technical result of the proposed invention is to eliminate the above disadvantages.

These disadvantages are eliminated by the fact that in order to separate the mounted and unframed parts of electronic circuits of printed circuit boards from the plastic “carrying” plates, the tin solder is dissolved with a 5-20% solution of methanesulfonic acid with oxidizing additives at a temperature of 70-90°C for two hours , and the introduction of the oxidizing agent at the stage of dissolving the solder with methane sulfonic acid is carried out in portions until the oxidation-reduction potential (ORP) of the medium is reached at a level of no more than 250 mV, then the plastic (“bearing” plates) is removed, washed and transferred for further disposal, separated on a grid mounted and unframed parts, microcircuits, they are washed from a solution of methanesulfonic acid, dried, crushed to a size of 0.5 mm, separated on a magnetic separator into two fractions - magnetic and non-magnetic - and processed using fractional hydrometallurgical methods, and the magnetic fraction is processed with iodine -iodide method, and the non-magnetic one - “regia vodka”, and the remaining suspension of metatinic acid in a solution of methanesulfonic acid with impurities of gold and lead is coagulated by boiling for 30-40 minutes, filtered, the filtered precipitate is washed with hot water, dried and calcined until gold-containing tin dioxide with subsequent extraction of gold from it by the iodine-iodide method, and from the filtrate containing lead, lead sulfate is precipitated, the resulting suspension is filtered, the methanesulfonic acid filtrate, after adjustment, is reused at the solder dissolution stage, when the methanesulfonic acid content is less than 5%, it is significantly reduced the rate of solder dissolution, with a content of more than 20%, intensive decomposition of the oxidizing agent is observed, the redox potential is maintained at a level of no more than 250 mV, since, at values ​​above 250 mV, copper dissolves intensively, and below, the dissolution process of tin solder slows down, the oxidizing agent is introduced at a temperature of 70-90°C, since at temperatures above 90°C there is intense decomposition of nitric acid, at temperatures below 70°C it is not possible to completely dissolve the solder.

Example. 100 kg of electronic printed circuit boards are sent for recycling personal computers Pentium generation (motherboards). In a 200 liter bath equipped with a heating jacket, 25 kg of printed circuit boards are loaded in a mesh basket with a 50x50 mm cell and 150 liters of 20% methanesulfonic acid are added. The process is carried out by shaking the basket at a temperature of 70°C for two hours with a portional introduction (200 ml) of an oxidizing agent to maintain the ORP of the solution at a level of 250 mV. As a result, the solder that holds the electronic parts, which fall to the bottom of the bath, is completely dissolved. The boards processed in this way are removed in a basket, washed in a washing bath, unloaded, dried and transferred for testing and further disposal. On processed boards weighing 88 kg, precious metals with a concentration of no more than: gold - 2.5 g/t, platinum and palladium - 2.1 g/t, silver - 4.0 g/t can remain. A suspension of metatinic acid in a solution of methanesulfonic acid, together with attached parts, is coagulated by introducing a weighed portion of a surfactant, followed by boiling for 30 minutes. After cooling, the solution is decanted from the settled metatin acid and attached parts into a settling tank. Then the attached parts are separated from the metatinic acid suspension on a mesh with a mesh size of 0.2 mm. After separation, the parts are washed with water, the washing water is combined with the decantation in a settling tank, and the combined material is left to settle for 12 hours. The metatinic acid settled in the settling tank is filtered off on a vacuum filter, washed with water, dried and calcined at a temperature of 800°C. The yield of tin oxide obtained after calcination is 6575 grams. From the filtrate containing methanesulfonic acid, lead sulfate is precipitated with sulfuric acid. After filtration, washing and drying, 230 g of lead sulfate was obtained. The resulting filtrate is adjusted for the content of methanesulfonic acid and reused to dissolve solder from the next portion of boards. To do this, a new portion of boards in the amount of 25 kg is loaded into the basket and the dissolution process cycle is repeated. Thus, all 100 kg of raw materials are processed. To extract precious metals, separated mounted and open-frame parts of electronic circuits of printed circuit boards are dried, homogenized to a particle size of 0.5 mm and subjected to magnetic separation. The yield of the magnetic fraction is 3430 g, the yield of the non-magnetic fraction is 3520 g.

Gold is extracted from the magnetic fraction using iodine-iodide technology. From the non-magnetic fraction, gold, silver, platinum and palladium are extracted using the “aqua regia” technology. Gold is extracted from calcined tin oxide using iodine-iodide technology. In total, from 100 kg of electronic printed circuit boards of personal computers of the Pentium generation (motherboards), grams of: gold - 15.15; silver - 3.08; platinum - 0.62; palladium - 7.38. In addition to precious metals, the following was obtained: tin oxide - 6575 g with a tin content of 65%, lead sulfate - 230 g with a lead content of 67%.

Claim

1. A method for processing waste from the electronic and electrical industry, including the separation of mounted and open-frame parts from plastic carrier plates of printed circuit boards, followed by hydrometallurgical extraction of precious metals, tin and lead salts from them, characterized in that before separating the plates, tin solder is dissolved 5-20 % solution of methanesulfonic acid with the addition of an oxidizing agent at a temperature of 70-90°C for two hours, and the oxidizing agent is supplied in portions until the redox potential of the medium reaches no more than 250 mV, then the plastic is removed, washed, tested and sent for further processing, The separation of mounted and unframed parts of microcircuits is carried out on a mesh, they are washed from the captured suspension, dried, crushed to a particle size of 0.5 mm, separated on a magnetic separator into two fractions - magnetic and non-magnetic, and processed fractionally by hydrometallurgical methods, and the remaining suspension of metatinic acid in a solution of methanesulfonic acid with impurities of gold and lead, coagulate by boiling for 30-40 minutes, filter, the filtered precipitate is washed with hot water, dried and calcined to obtain gold-containing tin dioxide, followed by extraction of gold from it, and lead sulfate is precipitated from the filtrate, forming the suspension is filtered, the methanesulfonic acid filtrate, after adjustment, is reused at the stage of dissolving the tin solder.

2. The method according to claim 1, characterized in that the processing of the magnetic fraction after magnetic separation of homogenized attached parts of electronic circuits of printed circuit boards is carried out using the iodine-iodide method.

3. The method according to claim 1, characterized in that the processing of the non-magnetic fraction after magnetic separation of homogenized attached parts of electronic circuits of printed circuit boards is carried out using aqua regia.

4. The method according to claim 1, characterized in that the calcined tin dioxide is made using an iodine-iodide solution, followed by the reduction of tin dioxide with coal to obtain metal rough tin.

5. The method according to claim 1, characterized in that nitric acid, hydrogen peroxide and peroxo compounds in the form of ammonium perborate, potassium, sodium percarbonate are used as an oxidizing agent.

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6. The method according to claim 1, characterized in that the coagulation of metatinic acid from a solution of methanesulfonic acid is carried out using polyacrylamide with a concentration of 0.5 g/l.

Inventor's name: Erisov Alexander Gennadievich (RU), Bochkarev Valery Mikhailovich (RU), Sysoev Yuri Mitrofanovich (RU), Buchikhin Evgeniy Petrovich (RU)
Patent owner's name: Limited Liability Company "Company "ORIA"
Postal address for correspondence: 109391, Moscow, PO Box 42, ORIA Company LLC
Patent start date: 22.05.2012