Method for decomposing tungsten-containing nickel diamond wire

Abstract

The application discloses a method for decomposing a tungsten-containing nickel diamond wire, which comprises the following steps: mixing phosphoric acid, nitric acid and citric acid to form a mixed acid solution, passing the tungsten-containing nickel diamond wire through the mixed acid solution to obtain a diamond precipitate and a first solution, and filtering the first solution to obtain a nickel hydroxide precipitate and a tungsten salt solution after the first solution is treated by an alkaline solution. The concentration of the phosphoric acid is 0.15-0.4 mol / L, the concentration of the nitric acid is 0.1-0.6 mol / L, and the concentration of the citric acid is 0.05-0.1 mol / L. The method provided by the application has the advantages of simple process, short time, low cost, high product utilization rate, and the like. The diamond precipitate, the nickel hydroxide precipitate and the tungsten salt solution obtained after separation can be reused in industrial production, the mixed acid solution has a small amount, has a small environmental protection pressure, and is extremely easy to popularize and apply in the market.

Description

Technical Field

[0001] This invention relates to the field of decomposition and utilization of tungsten-nickel diamond wire, and more specifically to a method for decomposing tungsten-nickel diamond wire. Background Technology

[0002] Diamond wire is a product made by bonding diamond microparticles to high-strength steel wire. It is mainly used for cutting hard and brittle materials, such as photovoltaic silicon wafers and sapphire. Diamond wire is primarily used in photovoltaic silicon wafer cutting, making it an upstream product in the photovoltaic industry. Under the backdrop of "dual carbon" (carbonization and dicarbonization), the photovoltaic industry has become a key national development sector. With the rapid growth of photovoltaic installations, the demand for diamond wire continues to increase. Diamond wire is a diamond cutting wire or diamond wire with tungsten-doped wire as the main wire / substrate. It consists of tungsten-doped wire, a pre-plated nickel layer, an outer nickel layer, and a fixed nickel layer. The diamond wire industry is facing both challenges and opportunities in technological upgrades and iterations, such as increasing efficiency and reducing costs. Tungsten wire has the characteristics of high tensile strength, good toughness, high breaking force, fatigue resistance, and corrosion resistance. Decomposing tungsten-nickel diamond wire can promote the reuse of tungsten and nickel resources. Chinese patent application number 202211128838.X discloses a method for decomposing and recovering tungsten-containing materials using a phosphorus-nitro acid mixture. Although the method utilizes a phosphorus-nitro acid mixture, the process is too complicated and dangerous, requiring high temperature and high pressure conditions to complete. Moreover, this application cannot completely dissolve the tungsten and nickel components in diamond wire.

[0003] Traditional methods for treating nickel-containing sludge mainly include landfilling and resource recovery. Landfilling requires excavation and construction of large-scale anti-corrosion and anti-seepage ponds, resulting in large land area requirements, high leakage risks, and resource waste. Resource recovery methods mainly include pyrometallurgical processes, smelting processes, hydrometallurgical extraction processes, and pyrometallurgical roasting-hydrometallurgical extraction processes. Chinese patent application number 202211558488.0 discloses a method for treating nickel-containing sludge from diamond wire and its application, including dissolving it in sulfuric acid followed by electrolytic recovery of nickel. This patent requires the use of large amounts of sulfuric acid for diamond wire treatment; 1 kg of nickel-containing sludge from diamond wire requires 4-6 L of sulfuric acid solution. This acidic wastewater easily leads to resource waste and environmental pollution, and it cannot simultaneously achieve the goal of separating and utilizing tungsten and nickel elements in the diamond wire. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a method for decomposing tungsten-nickel diamond wire, which has advantages such as a short process flow, short time, low acid consumption, and high product utilization rate.

[0005] To achieve the above objectives, this application adopts the following technical solution:

[0006] A method for decomposing tungsten-nickel diamond wire involves using a mixed solution of phosphoric acid, nitric acid, and citric acid to decompose the tungsten-nickel diamond wire, yielding solid diamond and a first solution. The first solution includes nickel salt and phosphotungstic acid. An alkaline solution is added to the first solution for alkaline treatment, resulting in nickel hydroxide precipitate and a second solution. The second solution is then filtered to obtain a tungstate solution.

[0007] The chemical reaction principle of mixed acid decomposition is that tungsten reacts with acid to form a soluble heteropolyacid, namely phosphotungstic acid. After the nickel in the diamond wire reacts with the acid, a water-soluble salt is formed. The ionic reaction is: W + HNO3 + H3PO4 → H3PW 12 O 40 Ni + 2H + →Ni 2+ Citric acid can assist nitrophosphate in complexing tungsten, making the complexation more complete and ensuring that the tungsten ions generated in the acid solution in a short time do not turn into tungstic acid.

[0008] Alkaline treatment involves the reaction of nickel salts in an alkaline solution to form nickel hydroxide precipitate. The reaction of phosphotungstic acid with sodium hydroxide produces water-soluble sodium tungstate and other products. The ionic reaction results in Ni... 2+ +2OH - =Ni(OH)2↓, H3PW 12 O 40 +27OH - =PO4 3- +12WO4 2- +15H2O.

[0009] Furthermore, the concentration of the phosphoric acid solution is 0.15-0.4 mol / L, the concentration of the nitric acid solution is 0.1-0.6 mol / L, and the concentration of the citric acid solution is 0.05-0.1 mol / L.

[0010] Furthermore, the concentration of the phosphoric acid solution is 0.162 mol / L, the concentration of the nitric acid solution is 0.440 mol / L, and the concentration of the citric acid solution is 0.076 mol / L.

[0011] Furthermore, the concentration of nitric acid is 0.377 mol / L, the concentration of phosphoric acid is 0.139 mol / L, and the concentration of citric acid is 0.076 mol / L.

[0012] Furthermore, the temperature for the decomposition of the mixed acid is maintained at 80-95℃, and the decomposition reaction time is 1-2 hours.

[0013] Furthermore, the alkaline solution is a sodium hydroxide solution.

[0014] Phosphotungstic acid reacts with sodium hydroxide to produce sodium tungstate and other products that are easily soluble in water. Filtration can remove impurities such as nickel hydroxide precipitate. The chemical reaction formula is:

[0015] H3PW 12 O 40 +27NaOH=Na3PO4+12Na2WO4+15H2O

[0016] Furthermore, the reaction temperature for the alkali treatment is maintained at 80-95℃, the concentration is 1.73-2.5mol / L, and the reaction time is 1-2h.

[0017] Furthermore, the tungsten-nickel diamond wire is a diced tungsten-nickel diamond wire for photovoltaic applications, with a diameter of 0.030-0.038 mm.

[0018] Compared with the prior art, the beneficial effects of the present invention are:

[0019] (1) The mixed acid ratio used in this invention can effectively dissolve the tungsten and nickel components in tungsten-nickel diamond wire into a solution, and the amount of mixed acid used in the decomposition of tungsten-nickel diamond wire is small. Chinese Patent Application No. 202211558488.0 discloses a method for treating nickel-containing sludge from diamond wire and its application, requiring 4-6 L of sulfuric acid solution per kg of nickel-containing sludge from diamond wire; Chinese Patent Application No. 202211128838.X discloses a method for decomposing and recovering tungsten-containing materials using a phosphorus-nitric acid mixture, where the molar concentration of nitric acid is generally 6-15 mol / L and the molar concentration of phosphoric acid is 2-5.5 mol / L. In this application, the concentration of phosphoric acid solution is 0.15-0.4 mol / L, the concentration of nitric acid solution is 0.1-0.6 mol / L, and the concentration of citric acid solution is 0.05-0.1 mol / L, resulting in a small amount of mixed acid used, thus reducing environmental and cost pressures.

[0020] (2) The method provided by the present invention is simple and quick. It can be directly used to react under normal pressure without the need to purchase high pressure equipment. It can quickly solve the problem of producing high-strength and high-toughness tungsten-nickel diamond wire, and is very easy to carry out industrial production and promotion.

[0021] Tungsten-nickel diamond wire comprises tungsten, nickel, and diamond particles. During mixed acid decomposition, a mixed solution of phosphoric acid, nitric acid, and citric acid is used. In this process, the diamond wire reacts chemically with phosphoric acid and nitric acid under the influence of citric acid to form phosphotungstic acid. Phosphotungstic acid dissolves in the first solution, allowing the tungsten to exist in solution. Simultaneously, the nickel alloy exists in the mixed acid solution as soluble salts such as nickel nitrate or nickel phosphate. Only the diamond exists in solid form in the first solution, which can be separated through filtration or other processes.

[0022] Citric acid helps nitric acid and phosphate complex tungsten, preventing the formation of tungsten acid in the mixed acid solution. Tungsten acid is insoluble in acid and remains solid in the solution, which can be trapped in the diamond filter material during filtration, making it difficult to distinguish later. Adding citric acid to the mixed acid ensures that the tungsten and nickel in the diamond wire exist in solution, while the diamond remains solid, facilitating the separation of diamond from tungsten-nickel diamond wire.

[0023] During the alkaline treatment process, nickel salts such as nickel nitrate and nickel phosphate can react with alkaline solutions to form nickel hydroxide precipitate, and phosphotungstic acid reacts with sodium hydroxide to produce products such as sodium tungstate, which are easily soluble in water. Through operations such as filtration, the nickel hydroxide precipitate and tungsten salts can be separated into solid and liquid components, thus achieving the separation of tungsten and nickel in tungsten-nickel diamond wire.

[0024] (3) This application not only enables the rapid separation of diamond, nickel, and tungsten from tungsten-nickel diamond wire, but also ensures that the separated products can be recycled, generating high economic value. The final separated products of this application include diamond, nickel hydroxide, nickel salts, and tungsten salts, which can be recycled again. Diamond can be directly recycled and used in various fields such as abrasive manufacturing, diamond processing, and electronics manufacturing. Nickel hydroxide is an inorganic compound with a wide range of applications. It can be used as a catalyst for various chemical reactions, as a battery material, for the preparation of energy storage devices, for the preparation of high-temperature and gas sensors, catalyst carriers, and in the fields of pharmaceuticals, cosmetics, and glass. The sodium tungstate solution obtained in this application can be directly used for evaporation crystallization to obtain sodium tungstate products. The application scope of sodium tungstate covers many aspects from the metallurgical industry to the medical field. It can be used to manufacture metallic tungsten, tungstic acid, tungstate salts, as a coating corrosion inhibitor, for the preparation of some antioxidants, and for the preparation of some drugs beneficial to the nervous system. Ammonium tungstate solution can also be obtained through ion exchange or extraction processes. The ammonium tungstate solution is then evaporated and crystallized to obtain APT (ammonium paratungstate). Ammonium paratungstate can be used directly as a raw material for the production of metallic tungsten. It can also be used as a precursor for the synthesis of various tungsten compounds such as tungsten carbide, tungsten oxide, and tungsten oxide. In the aerospace industry, it is used to produce tungsten-based alloys and coatings, and in the chemical industry, it is used to produce tungsten-based catalysts. For example, ammonium paratungstate can also be used to produce tungsten oxide products through an ammonia process. Tungsten oxide can be directly reduced to tungsten powder, and the tungsten powder can be carbonized to obtain tungsten carbide products, achieving efficient and thorough recycling of tungsten. Detailed Implementation

[0025] The following embodiments are used to illustrate the present invention, but are not intended to limit the scope of the invention. Modifications or substitutions made to the methods, steps, or conditions of the present invention without departing from the spirit and essence of the invention are all within the scope of protection of the present invention. Unless otherwise specified, the experimental materials, reagents, instruments, etc., used in the embodiments of the present invention are all commercially available; unless specifically specified, all technical means in the embodiments of the present invention are conventional means well known to those skilled in the art.

[0026] This application provides a method for decomposing tungsten-nickel diamond wire, comprising:

[0027] S1: The tungsten-nickel diamond wire is decomposed using a mixed acid solution of phosphoric acid, nitric acid, and citric acid to obtain solid diamond and a first solution, which includes nickel salt and phosphotungstic acid. The solid diamond, nickel salt, and tungsten salt are then separated through filtration and other operations.

[0028] The tungsten-nickel diamond wire comprises diamond microparticles, a tungsten wire conductor, and a nickel plating layer. The diameter of the tungsten-nickel diamond wire is 0.030-0.038 mm.

[0029] The concentration of the phosphoric acid solution is 0.15-0.4 mol / L, the concentration of the nitric acid solution is 0.1-0.6 mol / L, and the concentration of the citric acid solution is 0.05-0.1 mol / L.

[0030] Preferably, the concentration of the phosphoric acid solution is 0.162 mol / L, the concentration of the nitric acid solution is 0.440 mol / L, and the concentration of the citric acid solution is 0.076 mol / L.

[0031] Preferably, the concentration of nitric acid is 0.377 mol / L, the concentration of phosphoric acid is 0.139 mol / L, and the concentration of citric acid is 0.076 mol / L.

[0032] The temperature for the decomposition of the mixed acid is maintained at 80-95℃, and the decomposition reaction time is 1-2 hours.

[0033] Specific process and chemical formula:

[0034] The chemical principle of the mixed acid decomposition reaction is that tungsten reacts with the acid to form a soluble heteropolyacid, namely phosphotungstic acid. The nickel in the diamond wire reacts with the acid to form a water-soluble salt. The ionic reaction is: W + HNO3 + H3PO4 → H3PW 12 O 40 Ni + 2H + →Ni 2+Citric acid assists in the complexation of tungsten with nitrophosphate, ensuring a more complete complexation and preventing the tungsten ions generated in the acid solution for a short period from becoming tungstic acid. Tungstic acid is insoluble in the acid solution and remains in solid form, which can be trapped in the diamond filter material during subsequent filtration, making it difficult to distinguish later. The mixed acid with added citric acid allows the tungsten and nickel alloys to exist in solution form, while the diamond remains in solid form, facilitating the separation of diamond from tungsten-nickel diamond wire.

[0035] S2: Add an alkaline solution to the first dissolving solution for alkaline treatment to obtain nickel hydroxide precipitate and a second dissolving solution, which is a tungsten salt solution.

[0036] The alkaline solution is a sodium hydroxide solution.

[0037] The reaction temperature for the alkali treatment is maintained at 80-95℃, the concentration of the alkaline solution is 1.73-2.5mol / L, and the reaction time is 1-2h.

[0038] Specific process and chemical formula:

[0039] Alkaline treatment involves the reaction of nickel salts in an alkaline solution to form nickel hydroxide precipitate. The reaction of phosphotungstic acid with sodium hydroxide produces water-soluble sodium tungstate and other products. The ionic reaction is: Ni... 2+ +2OH - =Ni(OH)2↓, H3PW 12 O 40 +27OH - =PO4 3- +12WO4 2- +15H2O.

[0040] The reaction of phosphotungstic acid with sodium hydroxide produces sodium tungstate and other products that are easily soluble in water. Filtration removes impurities such as nickel hydroxide precipitate. The resulting sodium tungstate solution can be directly crystallized by evaporation to obtain sodium tungstate product, or an ammonium tungstate solution can be obtained using ion exchange or extraction processes. The ammonium tungstate solution is then crystallized by evaporation to obtain APT product (ammonium paratungstate). The chemical reaction formula is: H₃PW 12 O 40 +27NaOH=Na3PO4+12Na2WO4+15H2O.

[0041] This application uses sodium hydroxide as the alkaline treatment solution, so that tungsten exists in the form of sodium tungstate. Sodium tungstate can be easily converted into ammonium paratungstate, which helps to efficiently recycle and utilize tungsten.

[0042] S3: Filter to obtain tungsten salt solution.

[0043] The precipitate after alkali treatment is nickel hydroxide, which can be filtered to obtain a tungsten salt solution.

[0044] S4: Diamond, nickel hydroxide and tungsten salts are recycled.

[0045] The products obtained after each reaction step in this application can be recycled, resulting in high product utilization. Diamond can be directly recycled and reused in various fields such as abrasive manufacturing, diamond processing, and electronics manufacturing. Nickel hydroxide is an inorganic compound with a wide range of applications. It can be used as a catalyst for various chemical reactions, as a battery material, in the preparation of energy storage devices, in the manufacture of high-temperature and gas sensors, as a catalyst support, and in pharmaceuticals, cosmetics, and glass. The sodium tungstate solution obtained in this application can be directly used to obtain sodium tungstate products through evaporation and crystallization. Sodium tungstate has applications spanning from the metallurgical industry to the medical field, including the manufacture of metallic tungsten, tungstic acid, tungstates, as a coating corrosion inhibitor, in the preparation of antioxidants, and in the preparation of drugs beneficial to the nervous system. Ammonium tungstate solution can also be obtained through ion exchange or extraction processes. The ammonium tungstate solution is then evaporated and crystallized to obtain APT (ammonium paratungstate). Ammonium paratungstate can be used as a raw material for the production of metallic tungsten and as a precursor for the synthesis of various tungsten compounds such as tungsten carbide, tungsten oxide, and tungsten oxide. In the aerospace industry, it is used to produce tungsten-based alloys and coatings, and in the chemical industry, it is used to produce tungsten-based catalysts. For example, ammonium paratungstate can also be used to produce tungsten oxide products through an ammonia process. Tungsten oxide can be directly reduced to tungsten powder, and the tungsten powder can be carbonized to obtain tungsten carbide products, achieving efficient and thorough recycling of tungsten.

[0046] The method provided in this application is simple, quick, low-cost, and environmentally friendly. It can quickly solve the problem of producing high-strength and high-toughness tungsten-nickel diamond wire and can achieve efficient recycling and reuse of the decomposition products (diamond, nickel hydroxide, and tungsten salts) of tungsten-nickel diamond. It has good market prospects and application value.

[0047] Example 1: Main component composition of tungsten-nickel diamond wire: W / %: 84.82%, Ni 13.72%

[0048] A method for decomposing tungsten-nickel diamond wire includes:

[0049] S0: Weigh 20g of tungsten-nickel diamond wire;

[0050] S1: Prepare a mixed acid solution with a concentration of 0.377 mol / L nitric acid, 0.139 mol / L phosphoric acid, and 0.076 mol / L citric acid. Heat the solution in a water bath to 90°C for 2 hours to decompose the mixture. After the reaction, no filamentous residue remains in the solution, yielding a green first solution and diamond solid. Filter to remove the diamond solid, leaving a mixture of nickel salt and tungsten salt in the first solution.

[0051] Tungsten reacts with acids to form a soluble heteropolyacid, phosphotungstic acid. Nickel in the diamond wire reacts with acids to form a water-soluble salt. The ionic reaction is: W + HNO3 + H3PO4 → H3PW 12 O 40 Ni + 2H + →Ni 2+ Citric acid assists in the complexation of tungsten with nitrophosphate, ensuring a more complete complexation and preventing the tungsten ions generated in the acid solution for a short period from transforming into tungstic acid. Tungstic acid is insoluble in the acid solution and remains in solid form, which can be trapped in the diamond filter material during subsequent filtration, making it difficult to distinguish later. The mixed acid mixture with added citric acid ensures that the tungsten and nickel in the diamond wire exist in solution, while the diamond remains in solid form, facilitating the separation of diamond from tungsten-nickel diamond wire.

[0052] S2: Sodium hydroxide solution is added to the first solution for alkali treatment to obtain nickel hydroxide precipitate and a second solution; specifically, the first solution is added to a 2.5 mol / L sodium hydroxide solution for reaction, and the reaction is carried out in a water bath at 90°C for 2 hours. After alkalization and decomposition, a large amount of precipitate is produced in the green first solution, which is nickel hydroxide precipitate. After filtration, a slightly yellow and clear second solution is obtained.

[0053] The reaction process is as follows: nickel salts react in alkaline solution to form nickel hydroxide precipitate; phosphotungstic acid reacts with sodium hydroxide to produce sodium tungstate and other products that are easily soluble in water. The ionic reaction is: Ni... 2+ +2OH - =Ni(OH)2↓, H3PW 12 O 40 +27OH - =PO4 3- +12WO4 2- +15H2O.

[0054] S3: Sodium tungstate product is obtained by evaporation and crystallization of the second solution.

[0055] S4: The diamond obtained after filtering the first solution is used to manufacture abrasives; the nickel hydroxide obtained after filtering the second solution is used to manufacture nickel-metal hydride batteries and nickel-cadmium batteries; sodium tungstate is used to manufacture metallic tungsten and antioxidants.

[0056] Example 2: Main component composition of tungsten-nickel diamond wire: W / %: 92.56%, Ni 5.48%

[0057] S0: Weigh 40g of tungsten-nickel diamond wire;

[0058] S1: Prepare a mixed acid solution with a concentration of 0.440 mol / L nitric acid, 0.162 mol / L phosphoric acid, and 0.076 mol / L citric acid. Heat the solution in a water bath to 90°C for 2 hours to decompose the mixture. After the reaction, there are no residual filaments in the solution. The solution is green and contains diamond solid. Filter the solution to remove the diamond solid. The remaining solution is a mixture of nickel salt and tungsten salt.

[0059] S2: Sodium hydroxide solution is added to the first solution for alkali treatment to obtain nickel hydroxide precipitate and a second solution. Specifically, the first solution is added to a 2.5 mol / L sodium hydroxide solution for reaction, and the reaction is carried out in a water bath at 90°C for 2 hours. After alkalization and decomposition, a large amount of precipitate is produced in the green first solution, which is nickel hydroxide precipitate. After filtration, a slightly yellow and clear second solution is obtained.

[0060] S3: An extraction process is used to obtain an ammonium tungstate solution from the second solution. The ammonium tungstate solution is then evaporated and crystallized to obtain the APT product (ammonium paratungstate).

[0061] S4: The diamond obtained after filtering the first solution is used for brick and stone processing, and the nickel hydroxide obtained after filtering the second solution is used as a catalyst for chemical reactions; APT products (ammonium paratungstate) can be produced by ammonia process to obtain tungsten oxide products. Tungsten oxide can be directly reduced to obtain tungsten powder, and tungsten powder can be carbonized to obtain tungsten carbide products, realizing the efficient recycling of tungsten.

[0062] Example 3: Main component composition of tungsten-nickel diamond wire: W / %: 92.76%, Ni 5.39%

[0063] S0: Weigh 40g of tungsten-nickel diamond wire;

[0064] S1: Prepare a mixed acid solution with a concentration of 0.377 mol / L nitric acid, 0.139 mol / L phosphoric acid, and 0.076 mol / L citric acid. Heat the solution in a water bath to 90°C for 2 hours to decompose the mixture. After the reaction, there are no residual filaments in the solution. The solution is green and contains diamond solid. Filter the solution to remove the diamond solid. The remaining solution is a mixture of nickel salt and tungsten salt.

[0065] S2: Sodium hydroxide solution is added to the first solution for alkali treatment to obtain nickel hydroxide precipitate and a second solution. Specifically, the first solution is added to a 2.5 mol / L sodium hydroxide solution for reaction, and the reaction is carried out in a water bath at 90°C for 2 hours. After alkalization and decomposition, a large amount of precipitate is produced in the green first solution, which is nickel hydroxide precipitate. After filtration, a slightly yellow and clear second solution is obtained.

[0066] S3: An extraction process is used to obtain an ammonium tungstate solution from the second solution, and the ammonium tungstate solution is then evaporated and crystallized to obtain the APT product.

[0067] Example 4: Main component composition of tungsten-nickel diamond wire: W / %: 80.06%, Ni 16.80%

[0068] S0: Weigh 30g of tungsten-nickel diamond wire;

[0069] S1: Prepare a mixed acid solution with a concentration of 0.377 mol / L nitric acid, 0.139 mol / L phosphoric acid, and 0.076 mol / L citric acid. Heat the solution in a water bath to 90°C for 2 hours to decompose the mixture. After the reaction, there are no residual filaments in the solution. The solution is green and contains diamond solid. Filter the solution to remove the diamond solid. The remaining solution is a mixture of nickel salt and tungsten salt.

[0070] S2: Sodium hydroxide solution is added to the first solution for alkali treatment to obtain nickel hydroxide precipitate and a second solution. Specifically, the first solution is added to a 2.5 mol / L sodium hydroxide solution for reaction, and the reaction is carried out in a water bath at 90°C for 2 hours. After alkalization and decomposition, a large amount of precipitate is produced in the green first solution, which is nickel hydroxide precipitate. After filtration, a slightly yellow and clear second solution is obtained.

[0071] S3: An ammonium tungstate solution is obtained by ion exchange process on the second solution, and the ammonium tungstate solution is then crystallized by evaporation to obtain the APT product.

[0072] Example 5: Main component composition of tungsten-nickel diamond wire: W / %: 84.82%, Ni 13.72%

[0073] S0: Weigh 40g of tungsten-nickel diamond wire;

[0074] S1: Prepare a mixed acid with a concentration of 0.60 mol / L nitric acid, 0.15 mol / L phosphoric acid, and 0.1 mol / L citric acid. Heat the mixture in a water bath to 90°C for 2 hours to decompose it. After the reaction, there are no residual filaments in the solution. The first solution, which is green, and diamond solid are obtained. Filter to remove the diamond solid. The remaining first solution is a mixture of nickel salt and tungsten salt.

[0075] S2: Sodium hydroxide solution is added to the first solution for alkali treatment to obtain nickel hydroxide precipitate and a second solution. Specifically, the first solution is added to a 1.73 mol / L sodium hydroxide solution for reaction, and the reaction is carried out in a water bath at 90°C for 2 hours. After alkalization and decomposition, a large amount of precipitate is produced in the green first solution, which is nickel hydroxide precipitate. After filtration, a slightly yellow and clear second solution is obtained.

[0076] S3: An extraction process is used to obtain an ammonium tungstate solution from the second solution, and the ammonium tungstate solution is then evaporated and crystallized to obtain the APT product.

[0077] Example 6: Main component composition of tungsten-nickel diamond wire: W / %: 84.82%, Ni 13.72%

[0078] S0: Weigh 40g of tungsten-nickel diamond wire;

[0079] S1: Prepare a mixed acid with a concentration of 0.10 mol / L nitric acid, 0.4 mol / L phosphoric acid, and 0.05 mol / L citric acid. Heat the mixture in a water bath to 90°C for 2 hours to decompose it. After the reaction, there are no residual filaments in the solution. The first solution, which is green, and diamond solid are obtained. Filter to remove the diamond solid. The remaining first solution is a mixture of nickel salt and tungsten salt.

[0080] S2: Sodium hydroxide solution is added to the first solution for alkali treatment to obtain nickel hydroxide precipitate and a second solution. Specifically, the first solution is added to a 2.0 mol / L sodium hydroxide solution for reaction, and the reaction is carried out in a water bath at 90°C for 2 hours. After alkalization and decomposition, a large amount of precipitate is produced in the green first solution, which is nickel hydroxide precipitate. After filtration, a slightly yellow and clear second solution is obtained.

[0081] S3: An extraction process is used to obtain an ammonium tungstate solution from the second solution, and the ammonium tungstate solution is then evaporated and crystallized to obtain the APT product.

[0082] The main components of the tungsten-nickel diamond wire in Comparative Example 1 are: W / %: 84.82%, Ni 13.72%. The difference between this comparative example and Example 1 is that nitric acid is replaced with hydrochloric acid. The other steps are the same as in Example 1. As a result, the tungsten-nickel diamond wire is basically insoluble.

[0083] The main components of the tungsten-nickel diamond wire in Comparative Example 2 are: W / %: 84.82%, Ni 13.72%. The difference between this comparative example and Example 1 is that nitric acid is replaced with sulfuric acid, and the other steps are the same as in Example 1. As a result, the tungsten-nickel diamond wire is basically insoluble.

[0084] The main components of the tungsten-nickel diamond wire in Comparative Example 3 are: W / %: 84.82%, Ni 13.72%. The difference between this comparative example and Example 1 is that citric acid is not added to the mixed acid, while the other steps are the same as in Example 1. As a result, the tungsten-nickel diamond wire was not fully dissolved.

[0085] As can be seen from the comparative examples and embodiments, the beneficial effects of the present invention are as follows:

[0086] (1) The mixed acid ratio used in this invention can effectively dissolve the tungsten and nickel components in tungsten-nickel diamond wire into a solution, and the amount of mixed acid used in the decomposition of tungsten-nickel diamond wire is small. Chinese Patent Application No. 202211558488.0 discloses a method for treating nickel-containing sludge from diamond wire and its application, requiring 4-6 L of sulfuric acid solution per kg of nickel-containing sludge from diamond wire; Chinese Patent Application No. 202211128838.X discloses a method for decomposing and recovering tungsten-containing materials using a phosphorus-nitric acid mixture, where the molar concentration of nitric acid is generally 6-15 mol / L and the molar concentration of phosphoric acid is 2-5.5 mol / L. In this application, the concentration of phosphoric acid solution is 0.15-0.4 mol / L, the concentration of nitric acid solution is 0.1-0.6 mol / L, and the concentration of citric acid solution is 0.05-0.1 mol / L, resulting in a small amount of mixed acid used, thus reducing environmental and cost pressures.

[0087] (2) The method provided by the present invention is simple and quick. It can be directly used to react under normal pressure without the need to purchase high pressure equipment. It can quickly solve the problem of producing high-strength and high-toughness tungsten-nickel diamond wire, and is very easy to carry out industrial production and promotion.

[0088] Tungsten-nickel diamond wire comprises tungsten, nickel, and diamond particles. During mixed acid decomposition, a mixed solution of phosphoric acid, nitric acid, and citric acid is used. In this process, the diamond wire reacts chemically with phosphoric acid and nitric acid under the influence of citric acid to form phosphotungstic acid. Phosphotungstic acid dissolves in the first solution, allowing the tungsten to exist in solution. Simultaneously, the nickel alloy exists in the mixed acid solution as soluble salts such as nickel nitrate or nickel phosphate. Only the diamond exists in solid form in the first solution, which can be separated through filtration or other processes.

[0089] Citric acid helps nitric acid and phosphate complex tungsten, preventing the formation of tungsten acid in the mixed acid solution. Tungsten acid is insoluble in acid and remains solid in the solution, which can be trapped in the diamond filter material during filtration, making it difficult to distinguish later. Adding citric acid to the mixed acid ensures that the tungsten and nickel in the diamond wire exist in solution, while the diamond remains solid, facilitating the separation of diamond from tungsten-nickel diamond wire.

[0090] During the alkaline treatment process, nickel salts such as nickel nitrate and nickel phosphate can react with alkaline solutions to form nickel hydroxide precipitate, and phosphotungstic acid reacts with sodium hydroxide to produce products such as sodium tungstate, which are easily soluble in water. Through operations such as filtration, the nickel hydroxide precipitate and tungsten salts can be separated into solid and liquid components, thus achieving the separation of tungsten and nickel in tungsten-nickel diamond wire.

[0091] (3) This application not only enables the rapid separation of diamond, nickel, and tungsten from tungsten-nickel diamond wire, but also ensures that the separated products can be recycled, generating high economic value. The final separated products of this application include diamond, nickel hydroxide, nickel salts, and tungsten salts, which can be recycled again. Diamond can be directly recycled and used in various fields such as abrasive manufacturing, diamond processing, and electronics manufacturing. Nickel hydroxide is an inorganic compound with a wide range of applications. It can be used as a catalyst for various chemical reactions, as a battery material, for the preparation of energy storage devices, for the preparation of gas sensors, catalyst carriers, and in the fields of pharmaceuticals, cosmetics, and glass. The sodium tungstate solution obtained in this application can be directly used to obtain sodium tungstate products through evaporation and crystallization. The application scope of sodium tungstate covers many aspects from the metallurgical industry to the medical field. It can be used to manufacture metallic tungsten, tungstic acid, tungstate salts, as a coating corrosion inhibitor, for the preparation of some antioxidants, and for the preparation of some drugs beneficial to the nervous system. Ammonium tungstate solution can also be obtained through ion exchange or extraction processes. The ammonium tungstate solution is then evaporated and crystallized to obtain APT (ammonium paratungstate). Ammonium paratungstate can be used as a raw material for the production of metallic tungsten and as a precursor for the synthesis of various tungsten compounds such as tungsten carbide, tungsten oxide, and tungsten oxide. In the aerospace industry, it is used to produce tungsten-based alloys and coatings, and in the chemical industry, it is used to produce tungsten-based catalysts. For example, ammonium paratungstate can also be used to produce tungsten oxide products through an ammonia process. Tungsten oxide can be directly reduced to tungsten powder, and the tungsten powder can be carbonized to obtain tungsten carbide products, achieving efficient and thorough recycling of tungsten.

[0092] The above embodiments only illustrate preferred embodiments of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can freely combine the above technical features without departing from the concept of the present invention, and can also make several modifications and improvements, all of which fall within the protection scope of the present invention. Therefore, all equivalent transformations and modifications made with respect to the scope of the claims of the present invention should fall within the scope of the claims of the present invention.

Claims

1. A method for decomposing tungsten-nickel diamond wire, characterized in that, include: A mixed acid decomposition method is used to decompose tungsten-nickel diamond wire using a mixed solution of phosphoric acid, nitric acid, and citric acid to obtain solid diamond and a first solution. The first solution includes nickel salt and phosphotungstic acid. The concentration of phosphoric acid is 0.15-0.4 mol / L, the concentration of nitric acid is 0.1-0.6 mol / L, and the concentration of citric acid is 0.05-0.1 mol / L. An alkaline solution was added to the first solution for alkaline treatment to obtain nickel hydroxide precipitate and a second solution. The second solution was filtered to obtain a tungsten salt solution; Diamond, nickel hydroxide, and tungsten salts are recycled.

2. The method for decomposing tungsten-nickel diamond wire as described in claim 1, characterized in that: The concentration of phosphoric acid is 0.162 mol / L, the concentration of nitric acid is 0.440 mol / L, and the concentration of citric acid is 0.076 mol / L.

3. The method for decomposing tungsten-nickel diamond wire as described in claim 1, characterized in that: The concentrations of the nitric acid, phosphoric acid, and citric acid are 0.377 mol / L, 0.139 mol / L, and 0.076 mol / L, respectively.

4. The method for decomposing tungsten-nickel diamond wire as described in claim 1, characterized in that: The temperature for the decomposition of the mixed acid is maintained at 80-95℃, and the decomposition reaction time is 1-2 h.

5. The method for decomposing tungsten-nickel diamond wire as described in claim 1, characterized in that: The alkaline solution is a sodium hydroxide solution.

6. The method for decomposing tungsten-nickel diamond wire as described in claim 1, characterized in that: The reaction temperature for the alkali treatment is maintained at 80-95℃, the concentration of the alkaline solution is 1.73-2.5 mol / L, and the reaction time is 1-2 h.

7. The method according to any one of claims 1-6, characterized in that, The diameter of the tungsten-nickel diamond wire is 0.030-0.038 mm.