Utilisation method of wastes of hard alloys containing tungsten carbide and cobalt as binding agent

FIELD: metallurgy.

SUBSTANCE: method involves dipping of wastes into acid electrolyte, connection to a positive pole of an electric current source and performance of electrolysis with conversion of cobalt to a solution and tungsten to slurry. Electrolysis is performed using direct current. As electrolyte there used is 5-15% of sulphuric acid solution containing 2% of a reducing agent. As a result, tungsten is obtained in slurry in the form of tungsten carbide powder.

EFFECT: excluding formation of tungstic acid in slurry.

1 dwg, 1 ex

 

The invention relates to the recycling of hard materials, in particular to methods of regeneration of secondary raw materials for the production of hard alloys, containing in its composition grain carbides of tungsten, titanium and tantalum, as well as ligaments cobalt.

The most used method for processing various grades of hard alloys based on the process of fusing with nitrate [New process for reclaiming tungsten scrap / Brooker Kenneth J.A. // Int. J. Refract. Metals and Hard Mater. - 1990. - 9. N 3 - 121-122.]. The disadvantages of this method are its incompatibility with modern environmental requirements (allocation of nitrous gases), as well as the need for subsequent further processing the resulting SPECA (water leaching of tungsten, the conversion of a solution of sodium tungstate and ammonium salts, acid decomposition cake, leaching extraction of cobalt and so on), which seriously increases the cost of redistribution and degrades the quality of commercial products.

The famous "zinc" waste of hard alloys, the essence of which consists in the following. Method for processing waste lumpy solid alloys include loading of zinc and bulk waste solid alloy on the tray in a vacuum oven, melt the zinc extraction of metal-bundles of cobalt or Nickel, the Stripping of zinc and its condensation in the receiver-condenser with p what lay on the pallet leglislature SPECA, consisting of a carbide of the refractory metal powder and metal-joints and on the surface of the capacitor layer of metallic zinc, cooling and discharging the capacitor with zinc and pan, crushing the contents of the pan in a ball mill to obtain a powder mixture suitable for the production of hard alloy, and surface cleaning of the condenser from zinc for reuse. The disadvantages of this method are the low productivity, the need for careful pre-sorted recyclable materials, and ecologicall (Method of processing waste lumpy solid alloys - RF Patent №2101375).

The closest technical solution is the method of processing carbide waste of hard alloys, which consists in their selective electrochemical dissolution in acidic media with the transition of tungsten in the insoluble residue and transfer of cobalt in the solution. The electrolysis is carried out at 20-25°C using a reversible alternating current of industrial frequency. The electrolyte used is 5-6 M solution of nitric acid. Application of reverse current allows the almost complete oxidation of tungsten carbide to tungsten acid, eliminates the negative effects associated with anodic polarization and passivation of the electrodes, greatly simplified the AET constructive design of the electrolysis. The disadvantage of this method is the formation of tungstic acid, which is necessary in the future to restore to tungsten carbide at high temperatures (Method of processing carbide waste of hard alloys - RF Patent №2110590).

This disadvantage is eliminated by the invention, allows restrukturirovany hard alloys with obtaining powder of tungsten carbide in the anode sludge and transfer of cobalt in solution with subsequent restoration of his at the cathode.

A method of processing carbide waste of hard alloys is their selective electrochemical dissolution in the medium of sulfuric acid with the transition of tungsten in the form of carbide in the insoluble residue and transfer of cobalt in the solution. The electrolysis is carried out at 15-30°C using a constant electric current. The electrolyte used is 5-15% solution of sulfuric acid, and as a reductant solution of ammonium sulfate or hexamethylenetetramine (urotropine) concentration of 2%. The use of a reducing agent eliminates oxidation of the tungsten carbide in its oxide.

The scheme of installation for implementing the method shown in the drawing: 1 - capacity for electrolysis; 2 - anode; 3 - cathode; 4 - a solution containing sulfuric acid and a reducing agent.

An example of the method. In a container 1 filled with a solution containing 98% of rest the RA sulfuric acid (for example, 15%) and 2% of a reducing agent (e.g., ammonium sulfate), immersed solid alloy containing cobalt as a binder, using it as the anode 2, and an inert cathode 3. The current density of 2 to 20 A/DM2. Under the action of DC cobalt with the anode goes into solution, and the tungsten carbide is precipitated in the anode sludge.

Acidic electrolyte solution with the precipitate being filtered under vacuum to distinguish wet sediment tungsten carbide.

This method is applicable for hard alloys containing cobalt as a binder.

The disposal method of solid alloys containing tungsten carbide and cobalt as a binder, comprising immersing them in an acid electrolyte, connected to the positive pole of the source of electrical current and conducting electrolysis with translation of cobalt in the solution, and tungsten in the slurry, characterized in that the electrolysis is carried out with the use of a constant electric current in the electrolyte used is 5-15%solution of sulfuric acid containing 2% of a reducing agent to obtain a powder of tungsten carbide in the slag.



 

Same patents:

FIELD: metallurgy.

SUBSTANCE: invention refers to regeneration of secondary metal-bearing raw material, including to electrochemical processing of metal wastes of tungsten-copper alloys containing 7-50% Cu. The above method involves anodic oxidation of wastes in 10-15% of ammonia solution under action of direct current. At that, the oxidation process is performed with addition to the solution of 0.1-0.5 M NaOH or 0.1-0.5 M KOH at current density of 1000-3000 A/m2.

EFFECT: improvement of metal extraction at minimum electric power consumption and effective separation of tungsten and copper.

2 dwg, 1 tbl, 2 ex

FIELD: metallurgy.

SUBSTANCE: method includes electrochemical reprocessing of tungsten or rhenium metal junk in ammonia electrolyte, containing admixtures of ammonium compounds of tungsten or rhenium, under action of symmetric alternating-current of mains frequency. Ammonia electrolyte is preliminary kept in field of constant magnet, magnetizing force is not less than 600 eV during 24-48 hours.

EFFECT: increasing of electrical ammonia electrolyte conductance and reduction of electric power consumption in initial period of accumulative electrolysis.

5 dwg, 3 ex, 1 tbl

FIELD: regeneration processes of secondary raw material, namely electrochemical processing of metallic waste material of rhenium or molybdenum.

SUBSTANCE: method comprises steps of processing waste material of rhenium or molybdenum in ammonia electrolytes while using waste material as electrode onto which alternating electric current of commercial frequency is applied. At processing operation small plates of tantalum or niobium are used as second electrode.

EFFECT: increased electric current yield due to prevention of occurring non-desirable secondary reactions.

2 tbl, 4 ex

FIELD: extraction of valuable metals from super-alloys by electrochemical decomposition.

SUBSTANCE: super-alloy is used as both electrodes, anode and cathode. Electrochemical decomposition is realized at changing polarity of electric current with frequency 0.005 - 5 Hz while using non-organic acid as electrolyte.

EFFECT: possibility for extracting valuable metals in industrial scale, lowered cost of simplified extraction process, effective solution of part of metals, separation of metal groups.

6 cl, 2 dwg, 1 ex

FIELD: electrochemical extraction of metals from complex compounds; purification of diamond synthesis products.

SUBSTANCE: proposed method includes electrochemical treatment of synthesis product in acid electrolyte for obtaining graphite-diamond product containing 0.5-2.0% of metallic admixtures and deposition of metallic nickel and manganese on cathode. During purification of diamond synthesis products at extraction of nickel and manganese in form of metallic product, electrochemical treatment is carried out in membrane-type electrolyzer at circulation of catholyte through second electrolyzer. Process is conducted in area of temperatures of 25-30°C at cathode current density in the first electrolyzer of 2-15 A/dm2 and 15-30 A/dm2 in the second electrolyzer; catholyte pH in the presence of 100-150 g/l of (NH4)2SO4 in it is maintained at outlet from the first electrolyzer of 5-7.5 and 2.5-5 at return.

EFFECT: possibility of performing nickel and manganese extraction and purification of diamond synthesis products in one cycle.

1 tbl, 6 ex

The invention relates to hydrometallurgy of refractory metals and can be used in electrochemical recycling tungsten-containing hard alloy

FIELD: metallurgy.

SUBSTANCE: invention refers to metallurgy of precious metals, and namely to processing of slurries and concentrates containing elementary silicon, carbon and platinum. Similar slurries are formed namely at dilution of platinum-containing cast-iron in sulphuric acid. Slurries are mixed with sodium carbonate at consumption of 120-150% of the weight of silicon and carbon in initial material and sintered at the temperature of 500-650°C during 1-2 hours. Sintered material is leached in water so that insoluble residue containing precious metals and being a concentrate of precious metals is obtained.

EFFECT: simpler technology and higher quality of concentrate.

1 tbl, 1 ex

FIELD: metallurgy.

SUBSTANCE: proposed method comprises stock pelletizing and two-stage high-temperature calcination. said stock represents red mud while high-temperature calcination is divided into oxidative calcination and reducing calcination processes. Note here that oxidative calcination is carried out at 1000-1150°C in airflow. Note also that reducing calcination is performed at 1100-1200°C using coke as reducer in amount of 45-55 wt % of the weight of pellets.

EFFECT: reduced content of sulfur, phosphorus and alkaline compounds, higher strength.

2 cl, 2 dwg

FIELD: metallurgy.

SUBSTANCE: method includes charging of aluminium into a furnace after drain during remelting of secondary wastes of aluminium alloys in a rotor furnace onto the surface of hot salt slag in the furnace, cooled salt dump slag in the volume of 20-30% from rated volume of wastes in the furnace, mixing of cold and hot slag as the furnace rotates for 1-2 min and unloading of the slag into a reservoir.

EFFECT: simplified process of grinding of salt slag produced in remelting of secondary wastes of aluminium and its alloys, reduced energy costs for its grinding and improved environmental capability of the process.

FIELD: metallurgy.

SUBSTANCE: method of lead extraction from lead wastes containing one or more of Pb, PbO, PbO2 and PbSO4 includes treatment with aqueous solution of citric acid with production of lead citrate. Then lead citrate is extracted from the aqeuous solution, and the extracted lead citrate is converted into Pb and/or PbO. The method for processing of lead accumulator batteries, containing or more of Pb, PbO, PbO2 and PbSO4 includes mixing of a paste of lead plates of accumulator batteries with the aqueous solution of citric acid for production of lead citrate. Then lead citrate is extracted from the aqueous solution, and lead citrate is converted into lead and/or lead oxide. Further Pb and/or PbO are included into a plate of an accumulator battery.

EFFECT: simplified process and its improved cost-effectiveness.

17 cl, 7 dwg, 8 tbl, 1 ex

FIELD: metallurgy.

SUBSTANCE: method for processing of copper-based electronic scrap containing noble metals, consists in the fact that the electronic scrap is exposed to oxidising melting to produce an alloy with copper content of 55-85 wt %. The produced alloy is exposed to dissolution by means of electrochemical dissolution in a sulphate copper solution at voltage of 0.8-1.5 V on electrodes with production of sludge containing gold and silver, and an alloy on the cathode, containing copper and palladium. This alloy is exposed to electrochemical dissolution in the copper sulphate solution at voltage of 0.3-0.5 V on electrodes to produce copper on the cathode and sludge containing palladium. At the same time the produced sludges without mixing are leached with sulfuric acid.

EFFECT: higher extent of copper and noble metals extraction from copper-based electronic scrap.

2 ex

FIELD: chemistry.

SUBSTANCE: method involves crushing chemical cells, leaching, magnetic separation and electrolysis. The cells are crushed and leached with water in an atmosphere of carbon dioxide gas without access to oxygen. Light fractions are then removed from the scrap by floatation. Filtration is then carried out. The filtrate is treated with sorbents. After filtration, the scrap is washed with water, dried and fragments of ferrous and nonferrous metals are removed by electromagnetic separation, and then leached with sulphuric acid solution. Sulphuric acid pulp is filtered through a filter with an inert material, a filter with a coal medium and a filter with a cation-exchange medium. Ions of row d and row p metals sorbed by a cation-exchange resin are selectively desorbed with sulphuric acid solutions. Solutions containing ions of row d metals are subjected to electrolysis, and solutions containing ions of row p metals are neutralised to pH 3-4 and treated with clay mineral sorbents. The precipitate after sulphuric acid leaching is leached with nitric acid solution; the undissolved manganese dioxide precipitate is removed and the filtrate is neutralised and acidified to pH 3. The precipitate is filtered off. The filtrate containing mercury ions is subjected to cathode reduction and the precipitate containing lead and silver chlorides is dissolved in nitric acid and subjected to cathode reduction in an electrolysis cell with separate deposition of metals on electrodes.

EFFECT: environmental safety of recycling any type of spent chemical cells.

1 dwg

FIELD: metallurgy.

SUBSTANCE: proposed composition comprises 3.0-5.0 wt % of dichlorisocyanuric acid soda as halogen-bearing compound, 0.5-1.5 wt % of thiourea as complexing agent and water making the rest.

EFFECT: higher efficiency of removal mercury from soil, reduced aggressiveness of used substances relative to rooms interior, instruments and equipment.

1 tbl

FIELD: metallurgy.

SUBSTANCE: proposed method comprises anodic oxidation of melt in acid electrolyte at application of electric current. Note here that said anodic oxidation is carried out in acid electrolyte containing 150 g/l of H2SO4+50 g/l HCl. Applied direct electric current features density of 250-300 mA/cm2. Application of said current is conducted at 20-40°C.

EFFECT: notable increase in anodic oxidation rate.

3 tbl, 2 ex

FIELD: metallurgy.

SUBSTANCE: proposed method comprises thermal treatment of residues in air whereat temperature is increased to, at least 500°C at the rate of 150 °/h and curing at said temperature for, at least, two hours. Treated residues are mixed with aluminium powder resulted from grinding aluminium chips and are subjected to aluminothermy with subsequent separation of formed alloy and slag. Aluminothermy is conducted in tight reactor with continuous discharge of gaseous and sublimate reaction products. Note here that aluminium powder and thermally treated residues are taken at the ratio of 1: 6.5-7.0).

EFFECT: higher efficience of processing galvanic process copper bearing residues, method simplifying and higher ecological safety.

3 dwg, 2 tbl, 2 ex

FIELD: metallurgy.

SUBSTANCE: proposed method comprises blending the wastes with flux, smelting the blend, dividing melting products into slag and alloy containing copper and platinum metals. Sodium hydroxide is used as flux. Blending is carried out with copper at copper content of 80-30 wt %, flux content of 10-35 wt % and content of wastes of 10-35 wt %. Melting is conducted at 1100-1200°C for 10-20 min. Produced alloy is electrochemically dissolved in copper sulphate solution. Slag obtained in electrochemical dissolution contains platinum metals and is processed in sulfuric acid solution to remove impurities.

EFFECT: higher yield of platinum metals.

2 ex

FIELD: metallurgy.

SUBSTANCE: invention refers to regeneration of secondary metal-bearing raw material, including to electrochemical processing of metal wastes of tungsten-copper alloys containing 7-50% Cu. The above method involves anodic oxidation of wastes in 10-15% of ammonia solution under action of direct current. At that, the oxidation process is performed with addition to the solution of 0.1-0.5 M NaOH or 0.1-0.5 M KOH at current density of 1000-3000 A/m2.

EFFECT: improvement of metal extraction at minimum electric power consumption and effective separation of tungsten and copper.

2 dwg, 1 tbl, 2 ex

FIELD: metallurgy.

SUBSTANCE: method involves decomposition of concentrate with alkali liquor in presence of oxidiser for oxidation of ferrous iron and manganese. Then, sodium tungstate solution is obtained and processed. As oxidiser there used is nitric-acid sodium and/or potassium salt taken with excess of 20% from the theoretically required quantity for oxidation of iron and manganese. Decomposition of concentrate is performed by means of water solution of sodium hydroxide with concentration of 25-30% at temperature of 130-140°C. The reaction mass obtained during decomposition is leached with water so that solution of sodium tungstate is obtained.

EFFECT: possibility of processing both of rich and poor tungstenite concentrates with high penetration degree without specifying any special requirements for their crushing quality.

2 tbl

FIELD: process engineering.

SUBSTANCE: invention relates to production of disperse metal powders of tungsten by reduction of its compounds using gassy reducing agents. Nano-structured tungsten powder particles sized to 30 nm with specific surface of 0.34-0.40 m2/g are produced by reduction of ammonium paratungstate at 700-1000°C with subsequent treatment by hydrogen at 400-600°C. Note here that reduction of ammonium paratungstate and subsequent treatment by hydrogen are carried out continuously in the same reaction volume by varying composition of gas phase fed into reaction zone.

EFFECT: higher efficiency.

1 ex

FIELD: metallurgy.

SUBSTANCE: procedure consists in refining solution of ammonia paratangstate with sulphate of ammonia from molybdenum impurity. Further, refining is carried out with ion exchange on anionite AM-n and with thermal decomposition of ammonia paratangstate at temperature 600-800°C till production of tungsten trioxide. Tungsten trioxide is refined with zone sublimation at temperature 900-950°C in a continuous flow of oxygen. Further, trioxide of tungsten is heterogeneous reduced with hydrogen at temperature 700-750°C till production of powder of tungsten. Powder is compressed to tungsten rod which is subjected to electronic vacuum zone re-crystallisation till production of tungsten crystal. Tungsten crystals are melt in electron vacuum in a flat crystalliser with melt of flat ingot of tungsten on each side at total depth not less, than twice. A tungsten rod is treated with chlorine prior to zone re-crystallisation at rate of chlorine supply 100 ml/min and temperature 300°C during 1 hour.

EFFECT: raised purity of tungsten designed for thin film metallisation by magnetron target sputtering and improved electro-physical parametres of applied thin layers.

1 ex

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