Method for synergetic resource utilization of silver and tungsten in waste silver-tungsten carbide electric contact material

Abstract

The invention relates to a method for collaborative resource utilization of silver and tungsten in a waste silver tungsten carbide electric contact material, and belongs to the technical field of resource recycling. The method comprises the following steps: soaking the waste silver tungsten carbide electric contact material in an ethanol solution for pretreatment; the method comprises the following steps: putting a pretreated waste silver tungsten carbide electric contact material into a titanium frame as an anode, taking a stainless steel plate as a cathode, and taking a silver nitrate-nitric acid solution as an electrolyte, and carrying out direct-current electrolysis to obtain silver powder from the cathode and primary tungsten carbide from anode mud; the primary tungsten carbide is leached through a nitric acid solution, leached residues and leached liquid are obtained, the leached residues are tungsten carbide, and the leached liquid can serve as electrolyte to be returned to the electrolysis step; the method comprises the following steps: adding an additive into tungsten carbide, carrying out hydraulic cyclone classification to obtain underflow liquid and upflow liquid, carrying out solid-liquid separation on the upflow liquid to obtain particles, namely a hard alloy raw material, and carrying out solid-liquid separation on the underflow liquid to obtain a raw material for preparing tungsten oxide; and roasting the prepared tungsten oxide raw material in an oxygen-enriched atmosphere to obtain a tungsten oxide product.

Description

Technical Field

[0001] The present invention relates to a method for synergistic resource utilization of silver and tungsten in waste silver tungsten carbide electrical contact materials, belonging to the technical field of resource recycling. Background Art

[0002] Silver tungsten carbide electrical contact materials are composite functional materials that combine the advantages of high electrical conductivity and thermal conductivity of silver with the high melting point, wear resistance, and arc erosion resistance of tungsten carbide, and are widely used in high-reliability electrical systems. However, due to reasons such as electrical erosion, mechanical wear, thermal fatigue, and environmental corrosion during the use of silver tungsten carbide materials, such materials become ineffective and are discarded. Therefore, it is of great significance to recycle the high-value metals of silver and tungsten contained therein.

[0003] The patent with the publication number CN111118289A discloses a method for recycling and treating silver tungsten carbide graphite waste. In this method, the silver tungsten carbide waste is first subjected to crushing pretreatment, and the oxidation and removal of carbon are achieved through oxidative roasting. However, due to the high wear resistance of tungsten carbide, more energy and time are required during the pretreatment of a large amount of waste. In addition, since the thermodynamic tendency of metal tungsten oxidation is greater than that of tungsten carbide oxidation, tungsten in the metal is easily further oxidized to tungsten oxide during the decarbonization process, resulting in the loss of tungsten during subsequent nitric acid leaching. The patent with the publication number CN115591910A discloses a method for recycling AgWCC bulk angle materials by treating with molten caustic soda. In this method, aiming at the problem of difficult fragmentation of bulk angle materials, a method of heating and fragmenting after soaking in water is proposed. However, the soaking time of this method is as long as 24 to 48 hours, which severely restricts the improvement of production efficiency and causes the backlog of precious metals. In addition, the molten caustic soda purification process proposed in this method involves a filtration and separation step at high temperature, which is complex in operation and difficult to industrialize, and the oxidation of silver is inevitably caused during this process, which is not conducive to the subsequent electrolytic recovery of silver. The patent with the publication number CN110863107A discloses a method for recycling silver from silver tungsten skeleton in silver-containing electrical contact composite materials. The preparation process of the silver tungsten skeleton involved in this method is complex, and the recycling of tungsten carbide resources is not described. The patent with the publication number CN106191920A discloses a method for recycling and reusing silver tungsten waste. The silver tungsten alloy liquid phase sintering process is involved in this method. This process not only has a high melting temperature, but also due to the poor wettability and large melting point difference between Ag and WC, component segregation is very likely to occur during the sintering process, resulting in difficulties in the smooth progress of the electrolysis process. The patent with the publication number CN118360489A discloses a device and method for continuously separating and purifying silver tungsten alloy. The vacuum distillation device described in this method has restrictions on the raw material size (1 - 4 cm), this process has high energy consumption and high requirements for equipment, and this patent only describes silver tungsten alloy materials and does not describe silver tungsten carbide materials. In summary, the recycling methods for silver tungsten carbide electrical contact materials have problems such as low production efficiency, difficult pretreatment, high energy consumption, and poor utilization of tungsten carbide resources. Summary of the Invention

[0004] Aiming at the problem that silver and tungsten carbide resources in waste silver tungsten carbide electrical contact materials cannot be recycled synergistically, the present invention proposes a method for the synergistic resource utilization of silver and tungsten in waste silver tungsten carbide electrical contact materials. This method utilizes the differences in electrochemical and acid dissolution characteristics between silver and tungsten carbide to achieve the selective separation and enrichment of silver and tungsten carbide, and through particle size classification screening and mineral phase transformation, the directional resource utilization of tungsten carbide resources is realized. The process flow is reasonably designed, easy to operate, and has no environmental pollution risk.

[0005] A method for the synergistic resource utilization of silver and tungsten in waste silver tungsten carbide electrical contact materials, the specific steps are as follows: (1) Immerse the waste silver tungsten carbide electrical contact material in an ethanol solution for pretreatment to remove the organic matter on the material surface and avoid the obstruction of current transmission by the organic matter on the material surface during the electrolysis process, obtaining a pretreated waste silver tungsten carbide electrical contact material; (2) Place the pretreated waste silver tungsten carbide electrical contact material in a titanium frame as the anode, use a stainless steel plate as the cathode, and use a silver nitrate - nitric acid solution as the electrolyte, and perform direct current electrolysis to achieve the selective precipitation of WC in the anode mud and the selective precipitation of Ag at the cathode. Silver powder is obtained at the cathode, and primary tungsten carbide is obtained in the anode mud; (3) Add the primary tungsten carbide to a nitric acid solution for leaching to remove the Ag remaining in the anode mud, and perform solid - liquid separation to obtain a leaching residue and a leaching solution. The leaching residue is tungsten carbide, and the leaching solution is returned to step (2) as the electrolyte; (4) Add sodium dodecylbenzenesulfonate as an additive to the tungsten carbide, and perform hydrocyclone classification to obtain an underflow liquid and an overflow liquid. Solid - liquid separation of the overflow liquid gives particulate matter with a suitable particle size, and the particulate matter is the raw material for cemented carbide (WC). Solid - liquid separation of the underflow liquid gives the raw material for preparing tungsten oxide (WC products with unqualified particle size); (5) Roast the raw material for preparing tungsten oxide in an oxygen - rich atmosphere to obtain tungsten oxide products.

[0006] Preferably, in step (1), the concentration of the ethanol solution is 20 - 50 vol%, the soaking temperature is 20 - 25 °C, and the soaking time is 10 - 30 min.

[0007] Preferably, in step (2), the initial silver ion concentration in the electrolyte is 80 - 150 g / L, the nitric acid concentration is 0.16 - 0.25 mol / L, and the electrolyte temperature is 25 - 50 °C.

[0008] Preferably, in step (2), the cathode current density of the direct current electrolysis is 200 - 450 A / m 2 .

[0009] Preferably, in step (3), the concentration of the nitric acid solution is 5 - 12 mol / L, the solid - liquid ratio of the primary tungsten carbide to the nitric acid solution is g:mL = 1:1 - 5, the leaching temperature is 50 - 80 °C, and the leaching time is 20 - 60 min.

[0010] Preferably, in step (4), the addition amount of sodium dodecylbenzenesulfonate is 0.1 - 0.6 wt% of the tungsten carbide, the hydrocyclone inlet pressure is 0.2 - 1.1 MPa, the flow ratio of the underflow liquid to the overflow liquid is 1 - 3:1, the particulate matter concentration is 10 - 35 wt%, the liquid flow rate is 1 - 5 m / s, and the cyclone rotation speed is 1500 - 3500 rpm.

[0011] Preferably, the baking temperature in step (5) is 700~950 °C, and the time is 30~100 min.

[0012] Preferably, in the oxygen-rich atmosphere in step (5), the volume ratio of oxygen gas is 50~80%.

[0013] After the waste silver tungsten carbide material is treated as above, the purity of silver powder in the product is greater than 99%, the proportion of particles with a particle size of 0.5 - 1 μm in the cemented carbide raw material (WC particles) is greater than 98.8%, the WC content in the cemented carbide raw material is greater than 99%, and the WO3 content in tungsten oxide is greater than 90%.

[0014] The principle of the synergistic resource utilization of silver and tungsten in waste silver tungsten carbide electrical contact materials: Based on the significant differences in conductivity and electrochemical properties between Ag and WC in waste silver tungsten carbide electrical contact materials, the selective separation of Ag and WC is achieved through electrolysis and electroplating, and Ag is recovered in the form of silver powder; WC is enriched in the anode slime, and through the significant inertness of WC to acids, the directional purification of WC is achieved; the cyclone classification process is used to screen out WC particles that meet the particle size requirements of cemented carbide raw materials to achieve the preparation of cemented carbide raw materials; and the preparation of tungsten oxide products is achieved by utilizing the tendency of oxygen to spontaneously react with WC and W thermodynamically.

[0015] The beneficial effects of the present invention are as follows: (1) By constructing the electrochemical system of the waste silver tungsten carbide electrical contact material, the present invention can achieve the preparation of high-purity silver powder, and the silver nitrate tail liquid generated during the subsequent purification process of the anode slime is returned to the electrochemical system to achieve the full recovery and utilization of silver resources; (2) The tungsten carbide particles in the present invention are classified and screened by cyclone classification. The WC particles with appropriate particle sizes are used as the raw materials for cemented carbide, and the WC particles with unqualified particle sizes are subjected to oxygen-rich roasting to achieve mineral phase transformation, thereby realizing the directional resource utilization of tungsten carbide resources. The process flow is reasonable and meets the requirements of green production processes. Description of the Drawings

[0016] Figure 1 It is the process flow chart of the present invention. Specific Embodiments

[0017] The following further elaborates the present invention in detail in conjunction with specific embodiments, but the protection scope of the present invention is not limited to the content described.

[0018] Example 1: In this example, the main components of the waste silver tungsten carbide electrical contact material are: Ag 64 wt%, W 31 wt%, C 5 wt%; A method for the synergistic resource utilization of silver and tungsten in waste silver tungsten carbide electrical contact materials (see Figure 1 ), the specific steps are as follows: (1) Place the waste silver tungsten carbide electrical contact material in an ethanol solution with a concentration of 50 vol%, soak and pre-treat it at a temperature of 25 °C for 30 min to remove the organic matter on the material surface, and avoid the organic matter on the material surface hindering current transmission during the electrolysis process, obtaining a pre-treated waste silver tungsten carbide electrical contact material; (2) Place the pre-treated waste silver tungsten carbide electrical contact material in a titanium frame as the anode, use a stainless steel plate as the cathode, and use a silver nitrate-nitric acid solution as the electrolyte to construct an electrochemical system for direct current electrolysis to achieve the selective precipitation of WC in the anode mud and the selective precipitation of Ag at the cathode. Silver powder is obtained at the cathode, and primary tungsten carbide is obtained in the anode mud; in the electrochemical system, the initial silver ion concentration of the electrolyte is 150 g / L, the nitric acid concentration is 0.25 mol / L, the electrolyte temperature is 50 °C, and the cathode current density of the direct current electrolysis is 450 A / m 2 ; (3) Add the primary tungsten carbide to a nitric acid solution with a concentration of 12 mol / L, leach it at a temperature of 80 °C for 60 min to remove the Ag remaining in the anode mud, and perform solid-liquid separation to obtain a leached residue and a leachate. The leached residue is tungsten carbide, and the leachate is returned to step (2) as the electrolyte; the solid-liquid ratio g:mL of the primary tungsten carbide to the nitric acid solution is 1:5; (4) Add sodium dodecylbenzenesulfonate (the addition amount is 0.6 wt% of tungsten carbide) to the tungsten carbide, and perform hydrocyclone classification to obtain an underflow liquid and an overflow liquid. The overflow liquid is subjected to solid-liquid separation to obtain particulate matter (WC) with a suitable particle size. The particulate matter (WC) is used as a raw material for hard alloy, and the underflow liquid is subjected to solid-liquid separation to obtain a raw material for preparing tungsten oxide (WC products with unqualified particle size); the inlet pressure of the hydrocyclone is 1.1 MPa, the flow rate ratio of the underflow liquid to the overflow liquid is 3:1, the particulate matter concentration is 35 wt%, the liquid flow rate is 5 m / s, and the cyclone rotation speed is 3500 rpm; (5) Place the raw material for preparing tungsten oxide in a rotary kiln, and perform oxygen-enriched roasting at a temperature of 950 °C and an oxygen-enriched atmosphere (the volume ratio of oxygen is 80%) for 100 min to obtain tungsten oxide products; After the waste silver tungsten carbide material is treated as above, the purity of the silver powder in the product is 99.9%, the proportion of particles with a particle size of 0.5 - 1 μm in the raw material for hard alloy (WC particulate matter) is 99.87%, the WC content in the raw material for hard alloy is 99.96%, and the WO3 content in the tungsten oxide is 98%.

[0019] Example 2: In this example, the waste silver tungsten carbide electrical contact material is the same as that in Example 1; A method for the synergistic resource utilization of silver and tungsten in waste silver tungsten carbide electrical contact materials (see Figure 1 ), the specific steps are as follows: (1)Place the waste silver tungsten carbide electrical contact material in an ethanol solution with a concentration of 30 vol% and soak and pre-treat it at a temperature of 22 °C for 15 min to remove the organic matter on the material surface, avoiding the obstruction of current transmission by the organic matter on the material surface during the electrolysis process, and obtain the pre-treated waste silver tungsten carbide electrical contact material; (2)Place the pre-treated waste silver tungsten carbide electrical contact material in a titanium frame as the anode, use a stainless steel plate as the cathode, and use a silver nitrate-nitric acid solution as the electrolyte to construct an electrochemical system for direct current electrolysis to achieve the selective precipitation of WC in the anode mud and the selective precipitation of Ag at the cathode. Obtain silver powder at the cathode and primary tungsten carbide in the anode mud; the initial silver ion concentration in the electrolyte in the electrochemical system is 110 g / L, the nitric acid concentration is 0.2 mol / L, the electrolyte temperature is 35 °C, and the cathode current density of the direct current electrolysis is 350 A / m 2 ; (3)Add the primary tungsten carbide to a nitric acid solution with a concentration of 9 mol / L and leach it at a temperature of 65 °C for 40 min to remove the Ag remaining in the anode mud. Perform solid-liquid separation to obtain the leached residue and the leachate. The leached residue is tungsten carbide, and the leachate is returned to step (2) as the electrolyte; the solid-liquid ratio g:mL of the primary tungsten carbide to the nitric acid solution is 1:3; (4)Add sodium dodecylbenzenesulfonate (the addition amount is 0.3 wt% of tungsten carbide) as an additive to the tungsten carbide, and perform hydrocyclone classification to obtain the underflow liquid and the overflow liquid. Perform solid-liquid separation on the overflow liquid to obtain particulate matter (WC) with a suitable particle size. The particulate matter (WC) is used as a raw material for cemented carbide, and perform solid-liquid separation on the underflow liquid to obtain tungsten oxide raw materials (WC products with unqualified particle sizes); the inlet pressure of the hydrocyclone is 0.8 MPa, the flow rate ratio of the underflow liquid to the overflow liquid is 2:1, the particulate matter concentration is 20 wt%, the liquid flow rate is 3 m / s, and the cyclone rotation speed is 2000 rpm; (5)Place the prepared tungsten oxide raw materials in a rotary kiln and perform oxygen-enriched roasting at a temperature of 800 °C in an oxygen-enriched atmosphere (the volume ratio of oxygen is 65%) for 50 min to obtain tungsten oxide products; After the waste silver tungsten carbide material is treated as above, the purity of the silver powder in the product is 99.5%, the proportion of particles with a particle size of 0.5 - 1 μm in the cemented carbide raw material (WC particulate matter) is 99.21%, the WC content in the cemented carbide raw material is 99.51%, and the WO3 content in the tungsten oxide is 96%.

[0020] Example 3: In this example, the main components of the waste silver tungsten carbide electrical contact material are: Ag 68 wt%, W 28 wt%, C 4 wt%; A method for the collaborative resource utilization of silver and tungsten in waste silver tungsten carbide electrical contact materials (see Figure 1 ), the specific steps are as follows: (1)Place the waste silver tungsten carbide electrical contact material in an ethanol solution with a concentration of 20 vol% and soak and pretreat it at a temperature of 20 °C for 10 min to remove the organic matter on the material surface, avoiding the obstruction of current transmission by the organic matter on the material surface during the electrolysis process, and obtain the pretreated waste silver tungsten carbide electrical contact material; (2)Place the pretreated waste silver tungsten carbide electrical contact material in a titanium frame as the anode, use a stainless steel plate as the cathode, and use a silver nitrate - nitric acid solution as the electrolyte to construct an electrochemical system for direct current electrolysis to achieve the selective precipitation of WC in the anode mud and the selective precipitation of Ag at the cathode. Silver powder is obtained at the cathode, and primary tungsten carbide is obtained in the anode mud; in the electrochemical system, the initial silver ion concentration of the electrolyte is 80 g / L, the nitric acid concentration is 0.16 mol / L, the electrolyte temperature is 25 °C, and the cathode current density of the direct current electrolysis is 200 A / m 2 ; (3)Add the primary tungsten carbide to a nitric acid solution with a concentration of 5 mol / L and leach it at a temperature of 50 °C for 20 min to remove the Ag remaining in the anode mud. Perform solid - liquid separation to obtain the leached residue and the leachate. The leached residue is tungsten carbide, and the leachate is returned to step (2) as the electrolyte; the solid - liquid ratio g:mL of the primary tungsten carbide to the nitric acid solution is 1:1; (4)Add sodium dodecylbenzenesulfonate (the addition amount is 0.1 wt% of tungsten carbide) as an additive to the tungsten carbide, and perform hydrocyclone classification to obtain the underflow liquid and the overflow liquid. Perform solid - liquid separation on the overflow liquid to obtain particulate matter (WC) with a suitable particle size. The particulate matter (WC) is used as a raw material for cemented carbide, and perform solid - liquid separation on the underflow liquid to obtain the raw material for preparing tungsten oxide (WC products with unqualified particle size); the inlet pressure of the hydrocyclone is 0.2 MPa, the flow rate ratio of the underflow liquid to the overflow liquid is 1:1, the particulate matter concentration is 10 wt%, the liquid flow rate is 1 m / s, and the rotational speed of the cyclone is 1500 rpm; (5)Place the raw material for preparing tungsten oxide in a rotary kiln and perform oxygen - enriched roasting at a temperature of 700 °C in an oxygen - enriched atmosphere (the volume fraction of oxygen is 50%) for 30 min to obtain tungsten oxide products; After the waste silver tungsten carbide material is treated as above, the purity of the silver powder in the product is 99.2%, the proportion of particles with a particle size of 0.5 - 1 μm in the raw material for cemented carbide (WC particulate matter) is 98.93%, the WC content in the raw material for cemented carbide is 99.23%, and the WO3 content in the tungsten oxide is 93%.

[0021] Comparative Example 1: The waste silver tungsten carbide electrical contact material in this example is the same as that in Example 1; A method for the synergistic resource utilization of silver and tungsten in waste silver tungsten carbide electrical contact materials (see Figure 1 ), the specific steps are as follows: (1) Without pretreatment, the waste silver tungsten carbide electrical contact material is directly placed in a titanium frame as the anode, a stainless steel plate as the cathode, and a silver nitrate - nitric acid solution as the electrolyte to construct an electrochemical system for direct current electrolysis to achieve the selective precipitation of WC in the anode mud and the selective precipitation of Ag at the cathode. Silver powder is obtained at the cathode, and primary tungsten carbide is obtained in the anode mud. In the electrochemical system, the initial silver ion concentration of the electrolyte is 150 g / L, the nitric acid concentration is 0.25 mol / L, the electrolyte temperature is 50 °C, and the cathode current density of the direct current electrolysis is 300 A / m 2 ; (2) The primary tungsten carbide is added to a nitric acid solution with a concentration of 12 mol / L and leached at 80 °C for 60 min to remove the Ag remaining in the anode mud. Solid - liquid separation is carried out to obtain a leached residue and a leached solution. The leached residue is tungsten carbide, and the leached solution is returned to step (2) as the electrolyte. The solid - liquid ratio of the primary tungsten carbide to the nitric acid solution is g:mL = 1:5; (3) Sodium dodecyl benzene sulfonate (the addition amount is 0.6 wt% of tungsten carbide) is added to tungsten carbide, and hydrocyclone classification is carried out to obtain an underflow liquid and an overflow liquid. Solid - liquid separation of the overflow liquid gives particulate matter (WC) with a suitable particle size, and the particulate matter (WC) is used as a raw material for cemented carbide. Solid - liquid separation of the underflow liquid gives raw materials for preparing tungsten oxide (WC products with unqualified particle size); the inlet pressure of the hydrocyclone is 1.1 MPa, the flow ratio of the underflow liquid to the overflow liquid is 3:1, the particulate matter concentration is 35 wt%, the liquid flow rate is 5 m / s, and the rotational speed of the cyclone is 3500 rpm; (4) The raw materials for preparing tungsten oxide are placed in a rotary kiln and subjected to oxygen - rich roasting at 950 °C in an oxygen - rich atmosphere (the volume ratio of oxygen is 80%) for 100 min to obtain tungsten oxide products; The purity of the silver powder in the product is only 85.5%. In the cemented carbide raw material (WC particulate matter), the proportion of particles with a size of 0.5 - 1 μm is 99.32%. The WC content in the cemented carbide raw material is 95.23%, and the WO3 content in the tungsten oxide is 91%. Compared with Example 1, due to the lack of alcohol pretreatment, the electrolysis process is not smooth, and it affects the product purity of cemented carbide and tungsten oxide.

[0022] Comparative Example 2: The waste silver tungsten carbide electrical contact material in this example is the same as that in Example 1; A method for the synergistic resource utilization of silver and tungsten in waste silver tungsten carbide electrical contact materials (see Figure 1 ), the specific steps are as follows: (1) The waste silver tungsten carbide electrical contact material is placed in an ethanol solution with a concentration of 50 vol% and soaked at 25 °C for 30 min for pretreatment to remove the organic matter on the material surface and avoid the organic matter on the material surface hindering current transmission during electrolysis, obtaining pretreated waste silver tungsten carbide electrical contact materials; (2) Place the pretreated waste silver tungsten carbide electrical contact material in a titanium frame as the anode, use a stainless steel plate as the cathode, and use a silver nitrate-nitric acid solution as the electrolyte to construct an electrochemical system for direct current electrolysis to achieve the selective precipitation of WC in the anode mud and the selective precipitation of Ag at the cathode. Silver powder is obtained at the cathode, and primary tungsten carbide is obtained in the anode mud. In the electrochemical system, the initial silver ion concentration of the electrolyte is 150 g / L, the nitric acid concentration is 0.25 mol / L, the electrolyte temperature is 50 °C, and the cathode current density of the direct current electrolysis is 450 A / m 2 ; (3) Add the primary tungsten carbide to a nitric acid solution with a concentration of 12 mol / L, and leach it at 80 °C for 60 min to remove the Ag remaining in the anode mud. After solid-liquid separation, the leached residue and the leachate are obtained. The leached residue is tungsten carbide, and the leachate is returned to step (2) as the electrolyte. The solid-liquid ratio of the primary tungsten carbide to the nitric acid solution is g:mL = 1:5; (4) Without adding additives to the tungsten carbide, directly perform hydrocyclone classification to obtain the underflow liquid and the overflow liquid. The overflow liquid is subjected to solid-liquid separation to obtain particulate matter (WC) with a suitable particle size. The particulate matter (WC) is used as a raw material for hard alloys, and the underflow liquid is subjected to solid-liquid separation to obtain the raw material for preparing tungsten oxide (WC products with unqualified particle sizes). The inlet pressure of the hydrocyclone is 1.1 MPa, the flow rate ratio of the underflow liquid to the overflow liquid is 3:1, the particulate matter concentration is 35 wt%, the liquid flow rate is 5 m / s, and the cyclone rotation speed is 3500 rpm; (5) Place the raw material for preparing tungsten oxide in a rotary kiln, and perform oxygen-enriched roasting at 950 °C in an oxygen-enriched atmosphere (the volume ratio of oxygen is 80%) for 100 min to obtain tungsten oxide products; The purity of the silver powder in the product is 99.9%. In the raw material for hard alloys (WC particulate matter), the proportion of particles with a particle size of 0.5 - 1 μm is 85.21%. The WC content in the raw material for hard alloys is 99.92%. The WO3 content in the tungsten oxide is 97%. Compared with Example 1, since no additives to help disperse the particles were added during the hydrocyclone classification, the proportion of products with qualified particle sizes in the hard alloy products decreased significantly.

[0023] The specific embodiments of the present invention have been described in detail above, but the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those of ordinary skill in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A method for the collaborative resource utilization of silver and tungsten in waste silver tungsten carbide electrical contact materials, characterized in that, The specific steps are as follows: (1) Immerse the waste silver tungsten carbide electrical contact material in an ethanol solution for pretreatment to obtain a pretreated waste silver tungsten carbide electrical contact material; (2) Place the pretreated waste silver tungsten carbide electrical contact material in a titanium frame as the anode, use a stainless steel plate as the cathode, and use a silver nitrate-nitric acid solution as the electrolyte for direct current electrolysis. Silver powder is obtained at the cathode, and primary tungsten carbide is obtained in the anode mud; (3) Add the primary tungsten carbide to a nitric acid solution for leaching, perform solid-liquid separation to obtain a leaching residue and a leaching solution. The leaching residue is tungsten carbide, and the leaching solution is returned to step (2) as the electrolyte; (4) Add sodium dodecylbenzenesulfonate as an additive to the tungsten carbide, perform hydrocyclone classification to obtain an underflow liquid and an overflow liquid. Solid-liquid separation of the overflow liquid gives particulate matter, which is the raw material for cemented carbide, and solid-liquid separation of the underflow liquid gives the raw material for preparing tungsten oxide; (5) Roast the raw material for preparing tungsten oxide in an oxygen-rich atmosphere to obtain tungsten oxide products.

2. The method for synergistic resource utilization of silver and tungsten in the waste silver tungsten carbide electrical contact material according to claim 1, wherein: In step (1), the ethanol solution concentration is 20-50 vol%, the soaking temperature is 20-25 °C, and the soaking time is 10-30 min.

3. The method for synergistic resource utilization of silver and tungsten in the waste silver tungsten carbide electrical contact material according to claim 1, characterized in that: In step (2), the initial silver ion concentration in the electrolyte is 80-150 g / L, the nitric acid concentration is 0.16-0.25 mol / L, and the electrolyte temperature is 25-50 °C.

4. The method for the collaborative resource utilization of silver and tungsten in the waste silver tungsten carbide electrical contact material according to claim 1 or 3, characterized in that: The cathode current density in step (2) of direct current electrolysis is 200 - 450 A / m 2 .

5. The method for the collaborative resource utilization of silver and tungsten in the waste silver tungsten carbide electrical contact material according to claim 1, characterized in that: In step (3), the nitric acid solution concentration is 5-12 mol / L, the solid-liquid ratio of the primary tungsten carbide to the nitric acid solution is g:mL 1:1-5, the leaching temperature is 50-80 °C, and the leaching time is 20-60 min.

6. The method for the collaborative resource utilization of silver and tungsten in the waste silver tungsten carbide electrical contact material according to claim 1, characterized in that: In step (4), the addition amount of sodium dodecylbenzenesulfonate is 0.1-0.6 wt% of the tungsten carbide, the hydrocyclone inlet pressure is 0.2-1.1 MPa, the flow ratio of the underflow liquid to the overflow liquid is 1-3:1, the particulate matter concentration is 10-35 wt%, the liquid flow rate is 1-5 m / s, and the cyclone rotation speed is 1500-3500 rpm.

7. The method for the collaborative resource utilization of silver and tungsten in the waste silver tungsten carbide electrical contact material according to claim 1, characterized in that: In step (5), the volume fraction of oxygen in the oxygen-rich atmosphere is 50-80%, the roasting temperature is 700-950 °C, and the time is 30-100 min.

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