A method for synergistic resource utilization of silver and tungsten in waste silver tungsten carbide electrical contact materials

Abstract

The present invention relates to a method for the coordinated resource utilization of silver and tungsten in waste silver tungsten carbide electrical contact materials, belonging to the technical field of resource recycling. The present invention pre-treats the waste silver tungsten carbide electrical contact materials by soaking them in an ethanol solution; the pre-treated waste silver tungsten carbide electrical contact materials are placed in a titanium frame as an anode, a stainless steel plate is used as a cathode, and a silver nitrate-nitric acid solution is used as an electrolyte to perform direct current electrolysis, wherein silver powder is obtained at the cathode and primary tungsten carbide is obtained in the anode mud; the primary tungsten carbide is leached with a nitric acid solution to obtain a leached residue and a leached liquid, wherein the leached residue is tungsten carbide and the leached liquid can be returned to the electrolysis step as an electrolyte; an additive is added to the tungsten carbide, and hydrocyclone classification is performed to obtain an underflow liquid and an upper flow liquid, wherein the upper flow liquid is subjected to solid-liquid separation to obtain particulate matter, which is a cemented carbide raw material, and the underflow liquid is subjected to solid-liquid separation to obtain a raw material for preparing tungsten oxide; the prepared tungsten oxide raw material is placed in an oxygen-rich atmosphere for roasting to obtain a tungsten oxide product.

Description

Technical Field

[0001] The invention relates to a method for collaborative 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 materials that combine the advantages of silver's high electrical and thermal conductivity with tungsten carbide's high melting point, wear resistance, and arc erosion resistance. They are widely used in high-reliability electrical systems. However, during use, silver-tungsten carbide materials fail and become obsolete due to electrical erosion, mechanical wear, thermal fatigue, and environmental corrosion. Therefore, recycling the high-value-added silver and tungsten metals they contain is of great significance.

[0003] Patent 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 crushed and pre-treated, and carbon is oxidized and removed by oxidative roasting. However, due to the high wear resistance of tungsten carbide, this method consumes more energy and time during the pretreatment of large amounts of waste. In addition, since the thermodynamic tendency of metallic tungsten oxidation is greater than that of tungsten carbide, this method is very likely to further oxidize metallic tungsten to tungsten oxide during the oxidative decarburization process, resulting in the loss of tungsten in subsequent nitric acid leaching. Patent publication number CN115591910A discloses a method for recovering AgWCC block scraps by molten caustic soda treatment. In this method, the problem of the block scraps being difficult to crush is addressed by using a method of water soaking followed by heating and crushing. However, the soaking time of this method is as long as 24 to 48 hours, which seriously restricts the improvement of production efficiency and causes a 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 complicated to operate and difficult to industrialize. In addition, the oxidation of silver is inevitable in this process, which is not conducive to the subsequent electrolytic recovery of silver. Patent publication number CN110863107A discloses a method for recovering silver from silver-containing electrical contact composite materials using a silver-tungsten skeleton. The method involves a complex preparation process of the silver-tungsten skeleton and does not elaborate on the recovery of tungsten carbide resources. Patent publication number CN106191920A discloses a method for recycling and reusing silver-tungsten waste, which involves a liquid-phase sintering process of a silver-tungsten alloy. This process not only has a high smelting temperature, but also because of the poor wettability of Ag and WC and the large difference in melting points, component segregation is very likely to occur during the sintering process, making the electrolytic process difficult to proceed smoothly. Publication No. CN118360489A discloses an apparatus and method for the continuous separation and purification of silver-tungsten alloy. The vacuum distillation equipment described in this method has limitations on the size of the raw materials (1-4 cm). The process is energy-intensive and requires high equipment requirements. Furthermore, the patent only addresses silver-tungsten alloy materials, not silver tungsten carbide. In summary, the recovery method for silver-tungsten carbide electrical contact materials suffers from low production efficiency, difficult pretreatment, high energy consumption, and poor utilization of tungsten carbide resources. Summary of the Invention

[0004] To address the problem of the inability to synergistically recycle silver and tungsten carbide in discarded silver-tungsten carbide electrical contact materials, this paper proposes a method for the synergistic resource utilization of silver and tungsten in discarded silver-tungsten carbide electrical contact materials. This method leverages the differences in electrochemical and acid-solubility properties of silver and tungsten carbide to selectively separate and enrich silver and tungsten carbide. Furthermore, through particle size classification and mineral phase transformation, targeted resource utilization of tungsten carbide is achieved. This process is rationally designed, simple to operate, and poses no environmental pollution risk.

[0005] A method for the coordinated resource utilization of silver and tungsten in waste silver tungsten carbide electrical contact materials, comprising the following steps:

[0006] (1) Pre-treating the discarded silver tungsten carbide electrical contact material by soaking it in an ethanol solution to remove organic matter on the surface of the material, thereby preventing the organic matter on the surface of the material from hindering current transmission during the electrolysis process, and obtaining pre-treated discarded silver tungsten carbide electrical contact material;

[0007] (2) Pre-treated waste silver tungsten carbide electrical contact material is placed in a titanium frame as the anode, a stainless steel plate is used as the cathode, and a silver nitrate-nitric acid solution is used as the electrolyte. DC electrolysis is performed to achieve the selective precipitation of WC in the anode mud and the selective precipitation of Ag at the cathode, and silver powder is obtained at the cathode and primary tungsten carbide is obtained in the anode mud;

[0008] (3) The primary tungsten carbide is added to a nitric acid solution for leaching to remove the Ag remaining in the anode mud. The solid-liquid separation is performed to obtain a leaching residue and a leaching liquid. The leaching residue is tungsten carbide, and the leaching liquid is returned to step (2) as an electrolyte.

[0009] (4) Sodium dodecylbenzene sulfonate is added to tungsten carbide, and hydrocyclone classification is performed to obtain underflow liquid and upper flow liquid. The upper flow liquid is separated into solid and liquid to obtain particles of appropriate particle size. The particles are the cemented carbide raw material (WC). The underflow liquid is separated into solid and liquid to obtain the raw material for preparing tungsten oxide (WC product with unqualified particle size).

[0010] (5) The raw materials for preparing tungsten oxide are placed in an oxygen-rich atmosphere and roasted to obtain tungsten oxide products.

[0011] Preferably, the concentration of the ethanol solution in step (1) is 20-50 vol%, the soaking temperature is 20-25° C., and the soaking time is 10-30 min.

[0012] 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.

[0013] Preferably, the cathode current density of the DC electrolysis in step (2) is 200-450 A / m 2 .

[0014] Preferably, the concentration of the nitric acid solution in step (3) is 5-12 mol / L, the solid-liquid ratio (g:mL) of the primary tungsten carbide to the nitric acid solution is 1:1-5, the leaching temperature is 50-80°C, and the leaching time is 20-60 min.

[0015] Preferably, the amount of sodium dodecylbenzenesulfonate added in step (4) is 0.1-0.6 wt % of tungsten carbide, the hydrocyclone inlet pressure is 0.2-1.1 MPa, the flow ratio of the bottom flow liquid to the top flow liquid is 1-3:1, the particle concentration is 10-35 wt %, the liquid flow rate is 1-5 m / s, and the cyclone speed is 1500-3500 rpm.

[0016] Preferably, the calcination temperature in step (5) is 700-950° C. and the calcination time is 30-100 min.

[0017] Preferably, the volume proportion of oxygen in the oxygen-enriched atmosphere in step (5) is 50-80%.

[0018] After the above treatment, the purity of silver powder in the waste silver tungsten carbide material is greater than 99%, the proportion of particles with a diameter of 0.5-1μm 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%.

[0019] The principle of 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, selective separation of Ag and WC is achieved through electrolysis and electrodeposition, and Ag is recovered in the form of silver powder; WC is enriched in the anode mud, and the directionally purified WC is achieved through the significant inertness of WC to acid; the cyclone classification process is used to screen out WC particles that meet the particle size requirements of cemented carbide raw materials to realize the preparation of cemented carbide raw materials; and the tendency of oxygen to react spontaneously with WC and W in thermodynamics is used to realize the preparation of tungsten oxide products.

[0020] The beneficial effects of the present invention are:

[0021] (1) The present invention can realize the preparation of high-purity silver powder by constructing an electrochemical system for waste silver tungsten carbide electrical contact materials, and the silver nitrate tail liquid generated in the subsequent anode mud purification process is returned to the electrochemical system to achieve full recycling of silver resources;

[0022] (2) The tungsten carbide particles of the present invention are screened by cyclone classification to achieve particle size classification. WC particles with suitable particle size are used as cemented carbide raw materials, and WC particles with unqualified particle size are roasted in oxygen-enriched water to achieve mineral phase transformation, thereby realizing the targeted resource utilization of tungsten carbide resources. The process flow is reasonable and meets the requirements of green production process. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0024] The present invention will be further described in detail below in conjunction with specific embodiments, but the protection scope of the present invention is not limited to the contents described above.

[0025] Example 1: The main components of the waste silver tungsten carbide electrical contact material in this example are: Ag 64wt%, W 31wt%, C 5wt%;

[0026] A method for the coordinated resource utilization of silver and tungsten in waste silver tungsten carbide electrical contact materials (see Figure 1 ), the specific steps are as follows:

[0027] (1) The waste silver tungsten carbide electrical contact material is placed in a 50 vol% ethanol solution and soaked for 30 min at a temperature of 25°C to remove organic matter on the surface of the material, thereby preventing the organic matter on the surface of the material from hindering current transmission during the electrolysis process, thereby obtaining the pretreated waste silver tungsten carbide electrical contact material;

[0028] (2) The pretreated waste silver tungsten carbide electrical contact material is placed in a titanium frame as an anode, a stainless steel plate is used as a cathode, and a silver nitrate-nitric acid solution is used as an 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, and 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 ;

[0029] (3) The primary tungsten carbide is added to a nitric acid solution with a concentration of 12 mol / L and leached at a temperature of 80°C for 60 min to remove the Ag remaining in the anode mud. The solid-liquid separation is performed to obtain a leaching residue and a leaching liquid. The leaching residue is tungsten carbide, and the leaching liquid is returned to step (2) as an electrolyte. The solid-liquid ratio of the primary tungsten carbide to the nitric acid solution is g:mL 1:5.

[0030] (4) Sodium dodecylbenzene sulfonate (0.6 wt% of tungsten carbide) was added to tungsten carbide, and hydrocyclone classification was performed to obtain bottom flow liquid and top flow liquid. The top flow liquid was separated into solid-liquid to obtain particles (WC) of suitable particle size. The particles (WC) were used as cemented carbide raw materials. The bottom flow liquid was separated into solid-liquid to obtain raw materials for preparing tungsten oxide (WC products with unqualified particle size). The hydrocyclone inlet pressure was 1.1 MPa, the flow ratio of bottom flow liquid to top flow liquid was 3:1, the particle concentration was 35 wt%, the liquid flow rate was 5 m / s, and the cyclone speed was 3500 rpm.

[0031] (5) The tungsten oxide raw material is placed in a rotary kiln and calcined at 950°C in an oxygen-rich atmosphere (oxygen volume percentage is 80%) for 100 minutes to obtain a tungsten oxide product;

[0032] After the above treatment, the purity of silver powder in the waste silver tungsten carbide material is 99.9%, the particle size of 0.5-1μm in the cemented carbide raw material (WC particles) accounts for 99.87%, the WC content in the cemented carbide raw material is 99.96%, and the WO3 content in tungsten oxide is 98%.

[0033] Example 2: The discarded silver tungsten carbide electrical contact material in this example is the same as that in Example 1;

[0034] A method for the coordinated resource utilization of silver and tungsten in waste silver tungsten carbide electrical contact materials (see Figure 1 ), the specific steps are as follows:

[0035] (1) The waste silver tungsten carbide electrical contact material was placed in a 30 vol% ethanol solution and soaked for 15 min at a temperature of 22°C to remove organic matter on the surface of the material, thereby preventing the organic matter on the surface of the material from hindering current transmission during the electrolysis process, thereby obtaining the pretreated waste silver tungsten carbide electrical contact material;

[0036] (2) The pretreated waste silver tungsten carbide electrical contact material is placed in a titanium frame as an anode, a stainless steel plate is used as a cathode, and a silver nitrate-nitric acid solution is used as an 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, thereby obtaining silver powder at the cathode and primary tungsten carbide in the anode mud; in the electrochemical system, the initial silver ion concentration of the electrolyte 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 ;

[0037] (3) The primary tungsten carbide is added to a nitric acid solution with a concentration of 9 mol / L and leached at a temperature of 65°C for 40 min to remove the Ag remaining in the anode mud. The solid-liquid separation is performed to obtain a leaching residue and a leaching liquid. The leaching residue is tungsten carbide, and the leaching liquid is returned to step (2) as an electrolyte. The solid-liquid ratio of the primary tungsten carbide to the nitric acid solution is g:mL 1:3.

[0038] (4) Sodium dodecylbenzene sulfonate (0.3 wt% of tungsten carbide) was added to tungsten carbide, and hydrocyclone classification was performed to obtain bottom flow liquid and top flow liquid. The top flow liquid was separated into particles (WC) of suitable particle size. The particles (WC) were used as cemented carbide raw materials. The bottom flow liquid was separated into tungsten oxide raw materials (WC products with unqualified particle size). The hydrocyclone inlet pressure was 0.8 MPa, the flow ratio of bottom flow liquid to top flow liquid was 2:1, the particle concentration was 20 wt%, the liquid flow rate was 3 m / s, and the cyclone speed was 2000 rpm.

[0039] (5) The tungsten oxide raw material is placed in a rotary kiln and calcined at 800°C in an oxygen-rich atmosphere (oxygen volume percentage is 65%) for 50 minutes to obtain a tungsten oxide product;

[0040] After the above treatment, the purity of silver powder in the waste silver tungsten carbide material is 99.5%, the particle size of 0.5-1μm in the cemented carbide raw material (WC particles) accounts for 99.21%, the WC content in the cemented carbide raw material is 99.51%, and the WO3 content in tungsten oxide is 96%.

[0041] Example 3: The main components of the waste silver tungsten carbide electrical contact material in this example are: Ag 68wt%, W 28wt%, C 4wt%;

[0042] A method for the coordinated resource utilization of silver and tungsten in waste silver tungsten carbide electrical contact materials (see Figure 1 ), the specific steps are as follows:

[0043] (1) The waste silver tungsten carbide electrical contact material is placed in a 20 vol% ethanol solution and soaked for 10 min at a temperature of 20°C to remove organic matter on the surface of the material, thereby preventing the organic matter on the surface of the material from hindering current transmission during the electrolysis process, thereby obtaining the pretreated waste silver tungsten carbide electrical contact material;

[0044] (2) The pretreated waste silver tungsten carbide electrical contact material is placed in a titanium frame as an anode, a stainless steel plate is used as a cathode, and a silver nitrate-nitric acid solution is used as an electrolyte. An electrochemical system is constructed for direct current electrolysis to achieve the selective precipitation of WC in the anode mud and the selective precipitation of Ag at the cathode, and 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 ;

[0045] (3) The primary tungsten carbide is added to a nitric acid solution with a concentration of 5 mol / L and leached at a temperature of 50°C for 20 minutes to remove the Ag remaining in the anode mud. The solid-liquid separation is performed to obtain a leaching residue and a leaching liquid. The leaching residue is tungsten carbide, and the leaching liquid is returned to step (2) as an electrolyte. The solid-liquid ratio of the primary tungsten carbide to the nitric acid solution is 1:1 in g:mL.

[0046] (4) Sodium dodecylbenzene sulfonate (0.1 wt% of tungsten carbide) was added as an additive to tungsten carbide, and hydrocyclone classification was performed to obtain an underflow liquid and an upstream liquid. The upstream liquid was subjected to solid-liquid separation to obtain particles (WC) of suitable particle size. The particles (WC) were used as cemented carbide raw materials. The underflow liquid was separated into a raw material for preparing tungsten oxide (WC product with unqualified particle size). The hydrocyclone inlet pressure was 0.2 MPa, the flow ratio of the underflow liquid to the upstream liquid was 1:1, the particle concentration was 10 wt%, the liquid flow rate was 1 m / s, and the cyclone speed was 1500 rpm.

[0047] (5) The tungsten oxide raw material is placed in a rotary kiln and calcined at 700°C in an oxygen-rich atmosphere (oxygen volume percentage is 50%) for 30 minutes to obtain a tungsten oxide product;

[0048] After the above treatment, the purity of silver powder in the waste silver tungsten carbide material is 99.2%, the particle size of 0.5-1μm in the cemented carbide raw material (WC particles) accounts for 98.93%, the WC content in the cemented carbide raw material is 99.23%, and the WO3 content in tungsten oxide is 93%.

[0049] Comparative Example 1: The discarded silver tungsten carbide electrical contact material in this embodiment is the same as that in Example 1;

[0050] A method for the coordinated resource utilization of silver and tungsten in waste silver tungsten carbide electrical contact materials (see Figure 1 ), the specific steps are as follows:

[0051] (1) The discarded silver tungsten carbide electrical contact material is placed directly in a titanium frame as an anode without pretreatment, a stainless steel plate is used as a cathode, and a silver nitrate-nitric acid solution is used as an electrolyte. An electrochemical system is constructed for direct current electrolysis to achieve selective precipitation of WC in the anode mud and selective precipitation of Ag at the cathode, thereby obtaining silver powder at the cathode and primary tungsten carbide 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 ;

[0052] (2) The primary tungsten carbide is added to a nitric acid solution with a concentration of 12 mol / L and leached at a temperature of 80°C for 60 min to remove the Ag remaining in the anode mud. The solid-liquid separation is performed to obtain a leaching residue and a leaching liquid. The leaching residue is tungsten carbide, and the leaching liquid is returned to step (2) as an electrolyte. The solid-liquid ratio of the primary tungsten carbide to the nitric acid solution is 1:5 in g:mL.

[0053] (3) Sodium dodecylbenzene sulfonate (0.6 wt% of tungsten carbide) was added to tungsten carbide, and hydrocyclone classification was performed to obtain bottom flow liquid and top flow liquid. The top flow liquid was separated into solid-liquid to obtain particles (WC) of suitable particle size. The particles (WC) were used as cemented carbide raw materials. The bottom flow liquid was separated into solid-liquid to obtain raw materials for preparing tungsten oxide (WC products with unqualified particle size). The hydrocyclone inlet pressure was 1.1 MPa, the flow ratio of bottom flow liquid to top flow liquid was 3:1, the particle concentration was 35 wt%, the liquid flow rate was 5 m / s, and the cyclone speed was 3500 rpm.

[0054] (4) The tungsten oxide raw material is placed in a rotary kiln and calcined at 950°C in an oxygen-rich atmosphere (oxygen volume percentage is 80%) for 100 minutes to obtain a tungsten oxide product;

[0055] The purity of silver powder in the product is only 85.5%, the proportion of particle size 0.5-1 μm in the cemented carbide raw material (WC particles) is 99.32%, the WC content in the cemented carbide raw material is 95.23%, and the WO3 content in tungsten oxide is 91%; compared with Example 1, due to the lack of alcohol pretreatment, the electrolysis process does not proceed smoothly, and affects the product purity of cemented carbide and tungsten oxide.

[0056] Comparative Example 2: The discarded silver tungsten carbide electrical contact material in this example is the same as that in Example 1;

[0057] A method for the coordinated resource utilization of silver and tungsten in waste silver tungsten carbide electrical contact materials (see Figure 1 ), the specific steps are as follows:

[0058] (1) The waste silver tungsten carbide electrical contact material is placed in a 50 vol% ethanol solution and soaked for 30 min at a temperature of 25°C to remove organic matter on the surface of the material, thereby preventing the organic matter on the surface of the material from hindering current transmission during the electrolysis process, thereby obtaining the pretreated waste silver tungsten carbide electrical contact material;

[0059] (2) The pretreated waste silver tungsten carbide electrical contact material is placed in a titanium frame as an anode, a stainless steel plate is used as a cathode, and a silver nitrate-nitric acid solution is used as an 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, and 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 ;

[0060] (3) The primary tungsten carbide is added to a nitric acid solution with a concentration of 12 mol / L and leached at a temperature of 80°C for 60 min to remove the Ag remaining in the anode mud. The solid-liquid separation is performed to obtain a leaching residue and a leaching liquid. The leaching residue is tungsten carbide, and the leaching liquid is returned to step (2) as an electrolyte. The solid-liquid ratio of the primary tungsten carbide to the nitric acid solution is g:mL 1:5.

[0061] (4) Without adding additives to tungsten carbide, hydrocyclone classification is directly performed to obtain underflow liquid and upstream liquid, and the upstream liquid is subjected to solid-liquid separation to obtain particles (WC) of suitable particle size. The particles (WC) are used as cemented carbide raw materials, and the underflow liquid is separated into solid-liquid to obtain raw materials for preparing tungsten oxide (WC products with unqualified particle size); the hydrocyclone inlet pressure is 1.1 MPa, the flow ratio of underflow liquid to upstream liquid is 3:1, the particle concentration is 35wt%, the liquid flow rate is 5m / s, and the cyclone speed is 3500rpm;

[0062] (5) The tungsten oxide raw material is placed in a rotary kiln and calcined at 950°C in an oxygen-rich atmosphere (oxygen volume percentage is 80%) for 100 minutes to obtain a tungsten oxide product;

[0063] The purity of silver powder in the product is 99.9%, the proportion of particle size of 0.5-1 μm in the cemented carbide raw material (WC particles) is 85.21%, the WC content in the cemented carbide raw material is 99.92%, and the WO3 content in tungsten oxide is 97%. Compared with Example 1, since no additives that help particle dispersion are added in the cyclone classification, the qualified particle size products in the cemented carbide products are greatly reduced.

[0064] The above describes the specific embodiments of the present invention in detail, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in this field without departing from the scope of the present invention.

Claims

1. A method for the coordinated resource utilization of silver and tungsten in waste silver tungsten carbide electrical contact materials, characterized in that: The specific steps are as follows: (1) Pre-treating the discarded silver tungsten carbide electrical contact material by immersing it in an ethanol solution to obtain a pre-treated discarded silver tungsten carbide electrical contact material; (2) The pretreated discarded silver tungsten carbide electrical contact material is 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, and DC electrolysis is performed to obtain silver powder at the cathode and primary tungsten carbide in the anode mud; (3) Primary tungsten carbide is added to a nitric acid solution for leaching, and solid-liquid separation is performed to obtain leaching residue and leaching liquid, wherein the leaching residue is tungsten carbide, and the leaching liquid is returned to step (2) as an electrolyte; the concentration of the nitric acid solution is 5-12 mol / L; (4) adding sodium dodecylbenzene sulfonate as an additive to tungsten carbide, performing hydrocyclone classification to obtain underflow liquid and upstream liquid, separating the upstream liquid into particulate matter, which is the raw material for cemented carbide, and separating the underflow liquid into a raw material for preparing tungsten oxide; the amount of sodium dodecylbenzene sulfonate added is 0.1-0.6 wt% of tungsten carbide, the hydrocyclone inlet pressure is 0.2-1.1 MPa, the flow ratio of underflow liquid to upstream 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 speed is 1500-3500 rpm; (5) The raw materials for preparing tungsten oxide are placed in an oxygen-rich atmosphere and roasted to obtain tungsten oxide products.

2. The method for synergistic resource utilization of silver and tungsten in waste silver tungsten carbide electrical contact materials according to claim 1, characterized in that: 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.

3. The method for synergistic resource utilization of silver and tungsten in waste silver tungsten carbide electrical contact materials 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 synergistic resource utilization of silver and tungsten in waste silver tungsten carbide electrical contact materials according to claim 1 or 3, characterized in that: The cathode current density of step (2) DC electrolysis is 200~450A / m 2 .

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

6. The method for synergistic resource utilization of silver and tungsten in waste silver tungsten carbide electrical contact materials according to claim 1, characterized in that: In step (5), the volume proportion 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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