Process for enriching copper and nickel from secondary nickel return material

Abstract

The present application relates to the technical field of metallurgy, and discloses a process for enriching copper and nickel from secondary nickel return material, which comprises the following steps: blending the secondary nickel return material, cassiterite and a slagging agent, and then calcining in a reducing atmosphere. The main component of the cassiterite is SnO2, which is reduced to Sn in the reducing atmosphere. Sn has a low melting point and can penetrate into the intergranular space of the secondary nickel return material, thus destroying the original dense structure and forming a tin-nickel-copper low-melting-point alloy. This effectively reduces the dissolution leaching difficulty of nickel and copper in the secondary nickel return material, thereby improving the dissolution leaching efficiency. At the same time, by adding the cassiterite, the smelting temperature is reduced. Compared with the smelting temperature of about 1400-1500 DEG C in the prior art, the present application can smelt at 1000-1100 DEG C, thereby saving energy consumption and effectively recycling the tin in the cassiterite.

Description

Technical Field

[0001] This invention relates to the field of metallurgical technology, specifically to a process for enriching copper and nickel in secondary nickel return materials. Background Technology

[0002] Secondary nickel recycling typically refers to recyclable materials such as nickel-containing waste and scrap generated during nickel smelting and processing. These materials, after appropriate treatment, can be reused in production, representing an important method of nickel resource recycling. As a significant source of secondary nickel recycling, the treatment and recycling of copper smelting slag is of great importance.

[0003] In pyrometallurgical processes for nickel, nickel sulfide and other nickel-bearing ores are mostly used as raw materials. Since copper and nickel are commonly found together in natural ores, a flotation process is needed to separate these polymetallic ores to obtain nickel concentrate with a higher nickel content and copper concentrate with a higher copper content, which are then sent to the nickel pyrometallurgical system and the copper pyrometallurgical system for smelting, respectively.

[0004] During this process, a small amount of nickel remains in the separated copper concentrate. This nickel is discharged as slag during copper smelting, forming copper smelting slag. This slag mainly includes Kaldor slag and autothermal furnace slag, typically containing 35-40% copper, 14-16% nickel, and small amounts of iron and cobalt. Due to the high copper content, it cannot be directly fed into the nickel pyrometallurgical system; simultaneously, the large amount of nickel would result in severe nickel loss if fed into the copper pyrometallurgical system. This leads to the accumulation and stockpiling of large quantities of slag, causing significant resource waste. Currently, the main methods for handling this type of secondary nickel remelting include pyrometallurgical methods and hydrometallurgical methods.

[0005] Although the current pyrometallurgical process is relatively mature, it suffers from problems such as high energy consumption, serious environmental pollution, and low metal recovery rate. Therefore, it is urgent to improve the existing process to increase the metal recovery rate. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a process for enriching copper and nickel in secondary nickel reprocessing.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A process for enriching copper and nickel in secondary nickel reclaimed materials, the specific steps of which are as follows:

[0009] S1. Preparation of alloy material and slag phase

[0010] Secondary nickel scrap, cassiterite, and slag-forming agent are mixed evenly and smelted in a reducing atmosphere to obtain alloy material and slag phase.

[0011] In this step, the secondary nickel return material and cassiterite are first crushed and passed through a 40-mesh sieve, and then mixed with the slagging agent.

[0012] In this step, the mass ratio of secondary nickel regrind, cassiterite, and slag-forming agent is 50:20-30:15-25. In some embodiments of the present invention, for example, 50:20:15, 50:20:20, 50:20:25, 50:25:15, 50:25:25, 50:30:15, 50:30:20, and 50:30:25 can be selected, but it is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0013] In this step, the slag-forming agent is composed of calcium oxide, magnesium carbonate, quartz sand and starch.

[0014] In the technical solution disclosed in this invention, the mass ratio of calcium oxide, magnesium carbonate, quartz sand and starch is 20-40:10-15:10-15:10-20.

[0015] In this step, the reducing atmosphere is a mixture of CO and CO2, with a CO volume fraction of 30-40%.

[0016] In this step, the specific process of melting in a reducing atmosphere is as follows: first, heat to 600-700℃ and hold for 1-2 hours, then heat to 1000-1100℃ and hold for 1-2 hours.

[0017] In this invention, secondary nickel reclaimed material, cassiterite, and a slagging agent are blended and then calcined in a reducing atmosphere. The main component of cassiterite is SnO2, which is reduced to Sn in the reducing atmosphere. Sn has a low melting point and can penetrate into the alloy grains of the secondary nickel reclaimed material, destroying the original dense structure and forming a tin-nickel-copper low-melting-point alloy. This effectively reduces the difficulty of dissolving and leaching nickel and copper in the secondary nickel reclaimed material, thereby improving the dissolution and leaching efficiency. At the same time, by incorporating cassiterite, the smelting temperature is lowered. Compared with the smelting temperature of about 1400-1500℃ in the prior art, this invention can be smelted at 1000-1100℃, saving energy consumption and effectively recovering and utilizing the tin in the cassiterite.

[0018] The slag-forming agent provided by this invention is composed of calcium oxide, magnesium carbonate, quartz sand, and starch. Calcium oxide, as an alkaline flux, reacts with acidic oxides in the material to generate a low-melting-point silicate slag phase, promoting the stratification of the alloy material and the slag phase, and inhibiting impurities such as iron and silicon from entering the alloy phase. Magnesium carbonate decomposes into magnesium oxide and carbon dioxide at high temperatures. Magnesium oxide, as a slag phase stabilizer, can form mineral phases such as magnesium olivine (Mg2SiO4), improving the high-temperature resistance of the slag and preventing the slag phase from being too thin or too thick. The carbon dioxide gas generated during decomposition can form localized slag in the smelting system. The tiny bubbles help suspend the fine particles in the secondary nickel return material, allowing them to fully contact the reducing atmosphere, improving reduction efficiency, and thus facilitating the enrichment of copper and nickel. Quartz sand reacts with calcium oxide and magnesium oxide to form a composite silicate slag phase, giving the slag phase good fluidity for efficient separation. Starch acts as a binder during the mixing stage, enhancing the bonding strength between material particles and reducing dust loss. At the same time, it decomposes into carbon when heated in the early stage of smelting, serving as a supplementary reducing agent to strengthen the reduction of cassiterite (SnO2) to metallic tin, promoting the formation of alloys between tin and copper-nickel.

[0019] S2. Preparation of leachate

[0020] The alloy material obtained in step S1 is crushed and ground into a fine powder and then added to a sulfuric acid solution. Sodium chlorate is then added, and the mixture is heated to leach out, yielding a leachate.

[0021] In this step, the alloy material is crushed, ground, and then passed through a 40-mesh sieve.

[0022] In this step, the solid-liquid ratio of the alloy material and the sulfuric acid solution is 1g:10-20mL. In some embodiments of the present invention, for example, 1g:10mL, 1g:12mL, 1g:14mL, 1g:15mL, 1g:16mL, 1g:17mL, 1g:18mL, 1g:19mL, and 1g:20mL can be selected, but it is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0023] Specifically, the concentration of the sulfuric acid solution is 5-10 mol / L. For example, 5 mol / L, 6 mol / L, 7 mol / L, 8 mol / L, 9 mol / L, and 10 mol / L can be selected, but it is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0024] In this step, the mass ratio of the alloy material to sodium chlorate is 1:2-2.5. For example, 1:2, 1:2.1, 1:2.2, 1:2.3, 1:2.4, and 1:2.5 can be selected, but it is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0025] In this step, the heating and leaching temperature is 70-80℃, for example, 70℃, 72℃, 74℃, 75℃, 76℃, 77℃, 78℃, 79℃, or 80℃ can be selected; the heating and leaching time is 6-8 hours, for example, 6 hours, 6.5 hours, 7 hours, 7.5 hours, or 8 hours can be selected, but it is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0026] S3. Preparation of copper-nickel enriched filtrate

[0027] Adjust the pH of the leachate to 2-3, add hydrogen peroxide, and filter to obtain a filtrate enriched with copper and nickel.

[0028] In this step, hydrogen peroxide is added to remove Fe. 2+ Oxidized to Fe 3+ Fe 3+ and Sn 4+ Precipitation was carried out under conditions of pH 2-3, and the precipitate was separated by filtration, with copper and nickel enriched in the filtrate.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] (1) This invention involves blending secondary nickel reclaimed material, cassiterite, and slag-forming agent, followed by calcination in a reducing atmosphere. The main component of cassiterite is SnO2, which is reduced to Sn in the reducing atmosphere. Sn has a low melting point and can penetrate into the alloy grains of the secondary nickel reclaimed material, destroying the original dense structure and forming a tin-nickel-copper low-melting-point alloy. This effectively reduces the difficulty of dissolving and leaching nickel and copper in the secondary nickel reclaimed material, thereby improving the dissolution and leaching efficiency. At the same time, by incorporating cassiterite, the smelting temperature is lowered. Compared with the smelting temperature of about 1400-1500℃ in the prior art, this invention can be smelted at 1000-1100℃, saving energy consumption and effectively recovering and utilizing the tin in the cassiterite.

[0031] (2) The slag-forming agent provided by this invention is composed of calcium oxide, magnesium carbonate, quartz sand and starch. Calcium oxide, as an alkaline flux, reacts with acidic oxides in the material to generate a low-melting-point silicate slag phase, promoting the stratification of the alloy material and the slag phase, and inhibiting impurities such as iron and silicon from entering the alloy phase. Magnesium carbonate decomposes into magnesium oxide and carbon dioxide at high temperatures. Magnesium oxide, as a slag phase stabilizer, can form mineral phases such as magnesium olivine (Mg2SiO4), improving the high-temperature resistance of the slag and preventing the slag phase from being too thin or too thick. The carbon dioxide gas generated by decomposition can form a localized slag phase in the smelting system. The tiny bubbles in the part help to suspend the fine particles in the secondary nickel return material, allowing them to fully contact the reducing atmosphere, improving the reduction efficiency, and thus facilitating the enrichment of copper and nickel; the reaction of quartz sand with calcium oxide and magnesium oxide forms a composite silicate slag phase, giving the slag phase good fluidity for efficient separation; starch acts as a binder in the mixing stage, enhancing the bonding strength between material particles and reducing dust loss, while it decomposes into carbon when heated in the early stage of smelting, acting as a supplementary reducing agent to strengthen the reduction of cassiterite (SnO2) to metallic tin, promoting the formation of alloys between tin and copper and nickel. Detailed Implementation

[0032] The present invention will be further described in detail below through specific preferred embodiments, but the present invention is not limited to the following embodiments.

[0033] It should be noted that, unless otherwise specified, all chemical reagents involved in this invention were purchased through commercial channels.

[0034] The secondary nickel return material used in this embodiment of the invention is copper smelting slag containing copper and nickel, and its main components are: Ni 16.37%, Cu 38.23%, Fe 4.47%, Co 0.16%;

[0035] The cassiterite contains 98.5% SnO2 and 0.62% Fe.

[0036] The mesh size of calcium oxide and magnesium carbonate is 80 mesh;

[0037] The mesh size of the quartz sand is 200.

[0038] The starch is corn starch.

[0039] Example 1

[0040] A process for enriching copper and nickel in secondary nickel reclaimed materials, the specific steps of which are as follows:

[0041] S1. The secondary nickel scrap and cassiterite are pulverized separately and passed through a 40-mesh sieve. Then, 50 parts of the secondary nickel scrap, 25 parts of cassiterite, and 20 parts of slagging agent are mixed evenly. The slagging agent consists of calcium oxide, magnesium carbonate, quartz sand, and starch, with a mass ratio of 30:15:15:15. In a reducing atmosphere, the temperature is first increased to 600℃ at a heating rate of 50℃ / min and held for 2 hours. Then, the temperature is increased to 1000℃ at a heating rate of 20℃ / min and held for 1 hour. The reducing atmosphere is a mixture of CO and CO2, with a CO volume fraction of 30% and a flow rate of 10 m³ / min. 3 / h, to obtain alloy material and slag phase;

[0042] S2. After crushing and grinding the alloy material obtained in step S1, pass it through a 40-mesh sieve. Add the alloy material to an 8 mol / L sulfuric acid solution at a solid-liquid ratio of 1:15. Then add sodium chlorate. The mass ratio of the alloy material to sodium chlorate is 1:2. Heat at 70°C for 8 hours to obtain a leachate.

[0043] S3. Adjust the pH of the leachate to 2 with 1 mol / L Na2CO3 solution, add hydrogen peroxide, the volume ratio of leachate to hydrogen peroxide is 1:2, the mass fraction of hydrogen peroxide is 40%, tin and iron elements precipitate from the leachate, filter, and obtain a filtrate enriched with copper and nickel.

[0044] The nickel and copper contents in the filtrate from step S3 were determined using ICP-OES. The nickel recovery rate (%) was calculated as: (mass of nickel in the filtrate / mass of nickel in the secondary nickel return material) × 100%. The copper recovery rate (%) was calculated as: (mass of copper in the filtrate / mass of copper in the secondary nickel return material) × 100%. The nickel recovery rate was 96.6%, and the copper recovery rate was 97.2%.

[0045] Example 2

[0046] A process for enriching copper and nickel in secondary nickel reclaimed materials, the specific steps of which are as follows:

[0047] S1. The secondary nickel scrap and cassiterite are pulverized separately and passed through a 40-mesh sieve. Then, 50 parts of the secondary nickel scrap, 20 parts of cassiterite, and 15 parts of slagging agent are mixed evenly. The slagging agent consists of calcium oxide, magnesium carbonate, quartz sand, and starch, with a mass ratio of 20:10:15:20. In a reducing atmosphere, the temperature is first increased to 600℃ at a heating rate of 50℃ / min and held for 2 hours. Then, the temperature is increased to 1000℃ at a heating rate of 20℃ / min and held for 1 hour. The reducing atmosphere is a mixture of CO and CO2, with a CO volume fraction of 30% and a flow rate of 10 m³ / min. 3 / h, to obtain alloy material and slag phase;

[0048] S2. After crushing and grinding the alloy material obtained in step S1, pass it through a 40-mesh sieve. Add the alloy material to an 8 mol / L sulfuric acid solution at a solid-liquid ratio of 1:15. Then add sodium chlorate. The mass ratio of the alloy material to sodium chlorate is 1:2. Heat at 70°C for 8 hours to obtain a leachate.

[0049] S3. Adjust the pH of the leachate to 2 with 1 mol / L Na2CO3 solution, add hydrogen peroxide, the volume ratio of leachate to hydrogen peroxide is 1:2, the mass fraction of hydrogen peroxide is 40%, tin and iron elements precipitate from the leachate, filter, and obtain a filtrate enriched with copper and nickel.

[0050] The nickel and copper content in the filtrate of step S3 was determined according to the method of Example 1, and the nickel and copper recovery rates were calculated. The nickel recovery rate was 95.8%, and the copper recovery rate was 96.9%.

[0051] Example 3

[0052] A process for enriching copper and nickel in secondary nickel reclaimed materials, the specific steps of which are as follows:

[0053] S1. The secondary nickel scrap and cassiterite are pulverized separately and passed through a 40-mesh sieve. Then, 50 parts of the secondary nickel scrap, 30 parts of cassiterite, and 25 parts of slagging agent are mixed evenly. The slagging agent consists of calcium oxide, magnesium carbonate, quartz sand, and starch, with a mass ratio of 20:15:15:20. In a reducing atmosphere, the temperature is first increased to 600℃ at a heating rate of 50℃ / min and held for 2 hours. Then, the temperature is increased to 1000℃ at a heating rate of 20℃ / min and held for 1 hour. The reducing atmosphere is a mixture of CO and CO2, with a CO volume fraction of 30% and a flow rate of 10 m³ / min. 3 / h, to obtain alloy material and slag phase;

[0054] S2. After crushing and grinding the alloy material obtained in step S1, pass it through a 40-mesh sieve. Add the alloy material to an 8 mol / L sulfuric acid solution at a solid-liquid ratio of 1:15. Then add sodium chlorate. The mass ratio of the alloy material to sodium chlorate is 1:2. Heat at 70°C for 8 hours to obtain a leachate.

[0055] S3. Adjust the pH of the leachate to 2 with 1 mol / L Na2CO3 solution, add hydrogen peroxide, the volume ratio of leachate to hydrogen peroxide is 1:2, the mass fraction of hydrogen peroxide is 40%, tin and iron elements precipitate from the leachate, filter, and obtain a filtrate enriched with copper and nickel.

[0056] The nickel and copper content in the filtrate of step S3 was determined according to the method of Example 1, and the nickel and copper recovery rates were calculated; the nickel recovery rate was 97.1%, and the copper recovery rate was 97.8%.

[0057] Comparative Example 1

[0058] A process for enriching copper and nickel in secondary nickel reclaimed materials, the specific steps of which are as follows:

[0059] S1. After crushing the secondary nickel reclaimed material, pass it through a 40-mesh sieve. Then, mix 50 parts of the secondary nickel reclaimed material with 20 parts of slagging agent evenly. The slagging agent is composed of calcium oxide, magnesium carbonate, quartz sand, and starch, with a mass ratio of 30:15:15:15. In a reducing atmosphere, first heat the material to 600℃ at a heating rate of 50℃ / min and hold for 2 hours. Then, heat the material to 1000℃ at a heating rate of 20℃ / min and hold for 1 hour. The reducing atmosphere is a mixture of CO and CO2, with a CO volume fraction of 30% and a flow rate of 10 m³ / min. 3 / h, to obtain alloy material and slag phase;

[0060] S2. After crushing and grinding the alloy material obtained in step S1, pass it through a 40-mesh sieve. Add the alloy material to an 8 mol / L sulfuric acid solution at a solid-liquid ratio of 1:15. Then add sodium chlorate. The mass ratio of the alloy material to sodium chlorate is 1:2. Heat at 70°C for 8 hours to obtain a leachate.

[0061] S3. Adjust the pH of the leachate to 2 with 1 mol / L Na2CO3 solution, add hydrogen peroxide, the volume ratio of leachate to hydrogen peroxide is 1:2, the mass fraction of hydrogen peroxide is 40%, tin and iron elements precipitate from the leachate, filter, and obtain a filtrate enriched with copper and nickel.

[0062] Compared with Example 1, no cassiterite was added in Comparative Example 1. The nickel and copper content in the filtrate of step S3 was determined according to the method of Example 1, and the nickel and copper recovery rates were calculated. The nickel recovery rate was 65.1%, and the copper recovery rate was 72.3%.

[0063] Comparative Example 2

[0064] A process for enriching copper and nickel in secondary nickel reclaimed materials, the specific steps of which are as follows:

[0065] S1. The secondary nickel scrap and cassiterite are pulverized separately and passed through a 40-mesh sieve. Then, 50 parts of the secondary nickel scrap, 25 parts of cassiterite, and 20 parts of slagging agent are mixed evenly. The slagging agent consists of calcium oxide, quartz sand, and starch in a mass ratio of 30:15:15. In a reducing atmosphere, the temperature is first increased to 600℃ at a heating rate of 50℃ / min and held for 2 hours. Then, the temperature is increased to 1000℃ at a heating rate of 20℃ / min and held for 1 hour. The reducing atmosphere is a mixture of CO and CO2, with a CO volume fraction of 30% and a flow rate of 10 m³ / min. 3 / h, to obtain alloy material and slag phase;

[0066] S2. After crushing and grinding the alloy material obtained in step S1, pass it through a 40-mesh sieve. Add the alloy material to an 8 mol / L sulfuric acid solution at a solid-liquid ratio of 1:15. Then add sodium chlorate. The mass ratio of the alloy material to sodium chlorate is 1:2. Heat at 70°C for 8 hours to obtain a leachate.

[0067] S3. Adjust the pH of the leachate to 2 with 1 mol / L Na2CO3 solution, add hydrogen peroxide, the volume ratio of leachate to hydrogen peroxide is 1:2, the mass fraction of hydrogen peroxide is 40%, tin and iron elements precipitate from the leachate, filter, and obtain a filtrate enriched with copper and nickel.

[0068] Compared with Example 1, no magnesium carbonate was added to the slag-forming agent in Comparative Example 2. The nickel and copper content in the filtrate of step S3 was determined according to the method of Example 1, and the nickel and copper recovery rates were calculated. The nickel recovery rate was 82.4%, and the copper recovery rate was 90.5%.

[0069] Comparative Example 3

[0070] A process for enriching copper and nickel in secondary nickel reclaimed materials, the specific steps of which are as follows:

[0071] S1. The secondary nickel scrap and cassiterite are crushed separately and passed through a 40-mesh sieve. Then, 50 parts of the secondary nickel scrap, 25 parts of cassiterite, and 20 parts of slagging agent are mixed evenly. The slagging agent consists of calcium oxide, magnesium carbonate, and quartz sand in a mass ratio of 30:15:15. In a reducing atmosphere, the temperature is first increased to 600℃ at a heating rate of 50℃ / min and held for 2 hours. Then, the temperature is increased to 1000℃ at a heating rate of 20℃ / min and held for 1 hour. The reducing atmosphere is a mixture of CO and CO2, with a CO volume fraction of 30% and a flow rate of 10 m³ / min. 3 / h, to obtain alloy material and slag phase;

[0072] S2. After crushing and grinding the alloy material obtained in step S1, pass it through a 40-mesh sieve. Add the alloy material to an 8 mol / L sulfuric acid solution at a solid-liquid ratio of 1:15. Then add sodium chlorate. The mass ratio of the alloy material to sodium chlorate is 1:2. Heat at 70°C for 8 hours to obtain a leachate.

[0073] S3. Adjust the pH of the leachate to 2 with 1 mol / L Na2CO3 solution, add hydrogen peroxide, the volume ratio of leachate to hydrogen peroxide is 1:2, the mass fraction of hydrogen peroxide is 40%, tin and iron elements precipitate from the leachate, filter, and obtain a filtrate enriched with copper and nickel.

[0074] Compared with Example 1, no starch was added to the slag-forming agent in Comparative Example 3. The nickel and copper content in the filtrate of step S3 was determined according to the method of Example 1, and the nickel and copper recovery rates were calculated. The nickel recovery rate was 86.2%, and the copper recovery rate was 92.4%.

[0075] Comparative Example 4

[0076] A process for enriching copper and nickel in secondary nickel reclaimed materials, the specific steps of which are as follows:

[0077] S1. The secondary nickel scrap and cassiterite are pulverized separately and passed through a 40-mesh sieve. Then, 50 parts of the secondary nickel scrap, 10 parts of cassiterite, and 20 parts of slagging agent are mixed evenly. The slagging agent consists of calcium oxide, magnesium carbonate, quartz sand, and starch, with a mass ratio of 30:15:15:15. In a reducing atmosphere, the temperature is first increased to 600℃ at a heating rate of 50℃ / min and held for 2 hours. Then, the temperature is increased to 1000℃ at a heating rate of 20℃ / min and held for 1 hour. The reducing atmosphere is a mixture of CO and CO2, with a CO volume fraction of 30% and a flow rate of 10 m³ / min. 3 / h, to obtain alloy material and slag phase;

[0078] S2. After crushing and grinding the alloy material obtained in step S1, pass it through a 40-mesh sieve. Add the alloy material to an 8 mol / L sulfuric acid solution at a solid-liquid ratio of 1:15. Then add sodium chlorate. The mass ratio of the alloy material to sodium chlorate is 1:2. Heat at 70°C for 8 hours to obtain a leachate.

[0079] S3. Adjust the pH of the leachate to 2 with 1 mol / L Na2CO3 solution, add hydrogen peroxide, the volume ratio of leachate to hydrogen peroxide is 1:2, the mass fraction of hydrogen peroxide is 40%, tin and iron elements precipitate from the leachate, filter, and obtain a filtrate enriched with copper and nickel.

[0080] Compared with Example 1, the amount of cassiterite in Comparative Example 4 was replaced with 10 parts. The nickel and copper content in the filtrate of step S3 was determined according to the method of Example 1, and the nickel and copper recovery rates were calculated. The nickel recovery rate was 74.5%, and the copper recovery rate was 80.1%.

[0081] Finally, it should be noted that the above embodiments do not limit the present invention in any way. Those skilled in the art can make modifications and improvements based on the present invention. Therefore, any modifications or improvements made without departing from the spirit of the present invention are within the scope of protection claimed by the present invention.

Claims

1. A process for copper nickel enrichment from secondary nickel returns, characterized by, The specific steps are as follows: S1, the secondary nickel return material, cassiterite and slagging agent are uniformly mixed, and smelting is carried out in a reducing atmosphere to obtain an alloy material and a slag phase; S2, the alloy material obtained in step S1 is crushed and finely ground, then added to a sulfuric acid solution, and then sodium chlorate is added, and heating leaching is carried out to obtain a leaching solution; S3, the pH of the leaching solution is adjusted to 2-3, hydrogen peroxide is added, and filtration is carried out to obtain a copper and nickel enriched filtrate; In step S1, the mass ratio of the secondary nickel return material, cassiterite and slagging agent is 50:20-30:15-25; In step S1, the slagging agent is composed of calcium oxide, magnesium carbonate, quartz sand and starch, and the mass ratio of calcium oxide, magnesium carbonate, quartz sand and starch is 20-40:10-15:10-15:10-20; In step S1, the specific process of smelting in a reducing atmosphere is as follows: first, heat to 600-700℃, and keep for 1-2h, then heat to 1000-1100℃, and keep for 1-2h.

2. The process for copper nickel enrichment from secondary nickel returns according to claim 1, characterized in that, In step S1, the reducing atmosphere is a mixed atmosphere of CO and CO2, and the volume fraction of CO in the reducing atmosphere is 30-40%.

3. The process for copper nickel enrichment from secondary nickel returns according to claim 1, characterized in that, In step S2, the solid-liquid ratio of the alloy material and the sulfuric acid solution is 1g:10-20mL, and the concentration of the sulfuric acid solution is 5-10mol / L.

4. The process for copper nickel enrichment from secondary nickel returns according to claim 1, characterized in that, In step S2, the mass ratio of the alloy material and sodium chlorate is 1:2-2.

5.

5. The process for copper nickel enrichment from secondary nickel returns according to claim 1, characterized in that, In step S2, the temperature of heating leaching is 70-80℃, and the time of heating leaching is 6-8h.

6. The process for copper nickel enrichment from secondary nickel returns according to claim 1, characterized in that, In step S3, the volume ratio of the leaching solution and hydrogen peroxide is 1:2-4.