A method for resource processing and comprehensive utilization of low-nickel high-impurity material

Abstract

The application discloses a kind of low nickel high impurity element material's resource processing and comprehensive utilization method.The low nickel high impurity element material can be cobalt-nickel hydrometallurgy intermediate slag, various recovery nickel-containing catalysts after calcination and removal of organic matter, nickel-containing electroplating sludge and the like.Its main process includes the following steps: pretreatment-oxidation acid leaching-neutralization and precipitation of leaching solution-after partial neutralization and precipitation slag is removed by sulfuric acid curing-silicon-copper extraction agent LIX984 removes copper-nickel specific extraction agent HBL110 enriches nickel-sodium carbonate aqueous solution neutralization and precipitation slag is overalkalized to remove aluminum-sodium carbonate aqueous solution neutralization and precipitation slag removes chromium.The application achieves good economic benefits and environmental benefits.

Description

Technical Field

[0001] This invention relates to the field of hydrometallurgical smelting, and more specifically to a method for the resource-based treatment and comprehensive utilization of low-nickel, high-impurity element materials. Technical Background

[0002] Nickel is an important strategic material, widely used in defense, aerospace, transportation, petrochemicals, energy materials and other fields. It is an important raw material for the production of stainless steel, alloy steel, special alloys, energy storage materials, magnetic materials and so on.

[0003] The metallurgical industry is the dominant consumer of nickel, accounting for over 80% of total consumption. The global nickel consumption structure is as follows: stainless steel 60%, alloys 25%, electroplating 3%, batteries 5%, and others 7%.

[0004] Primary nickel sulfide deposits are mainly concentrated in Canada, Russia, and Australia. Primary laterite nickel deposits are mainly distributed within the Tropic of Cancer and Tropic of Capricorn: New Caledonia, eastern Australia, Papua New Guinea, the Philippines, Indonesia, and the Caribbean region of Central America.

[0005] Low-nickel, high-impurity element materials are mostly hazardous solid wastes. Their resource-based treatment and comprehensive utilization can reduce the import of non-renewable primary nickel resources and avoid environmental pollution, which has high economic value and social significance. Summary of the Invention

[0006] The purpose of this invention is to address the shortcomings of existing technologies and, in light of increasingly stringent national environmental protection policies and higher standards, to provide a more specific and environmentally friendly method for the resource-based treatment and comprehensive utilization of low-nickel, high-impurity element materials.

[0007] To solve the above technical problems, the present invention provides the following technical solution:

[0008] A method for the resource-based treatment and comprehensive utilization of low-nickel, high-impurity element materials includes the following steps:

[0009] a) Pretreatment: The low-nickel, high-impurity material is pulped in a pulping tank using desalinated water or washing water (liquid-solid mass ratio 5-6:1) to obtain slurry. The slurry is then overflowed and filtered into an oxidation acid leaching tank through an overflow pipe with a screen (preferably 100 mesh) on the side above the pulping tank.

[0010] A small amount of large particles will accumulate at the bottom of the slurry tank. The large particles at the bottom of the slurry tank will be periodically extracted, finely ground in a ball mill until the particle size is <100 mesh, and then returned to the slurry tank.

[0011] b) Oxidative acid leaching: In an oxidative acid leaching tank, concentrated sulfuric acid (preferably with a concentration greater than or equal to 98%) and hydrogen peroxide (preferably with a concentration of 3%-8%) are added to the slurry obtained in step a) for oxidative acid leaching to obtain qualified leaching slurry;

[0012] The amount of concentrated sulfuric acid used is approximately 1.8-2.0 times the mass of nickel in the low-nickel, high-impurity material, while the amount of hydrogen peroxide used is approximately 3.0-4.0 times the mass of nickel. The oxidative acid leaching reaction temperature is 70℃-80℃, with stirring for 4-5 hours. The optimal pH value at the reaction endpoint is 1.6-1.8. Hydrogen peroxide, chosen as the oxidant, possesses both oxidizing and reducing properties, and also functions to oxidize and decompose organic matter and disinfect. Sulfuric acid is used as the acid, allowing most of the calcium to be effectively treated in the form of gypsum through the leaching residue.

[0013] c) Filtration and demineralized water multi-stage countercurrent washing: The qualified leachate obtained in step b) is filtered to obtain leachate residue and leachate;

[0014] The leaching residue is washed with desalinated water in a multi-stage countercurrent process until it becomes neutral. The leaching residue is mainly composed of iron, silicon, and calcium. According to the hazardous waste identification standards, the leaching toxicity and toxic substance content are identified, and all of them meet the standards for identification as general industrial solid waste, which facilitates outsourcing of disposal.

[0015] d) Neutralization and precipitation of leachate: Neutralize the leachate obtained in step c) (preferably using primary alkali precipitate residue for neutralization) at a temperature of 70℃-80℃, stir for 1-2 hours, and neutralize and precipitate to a pH value of 2.0-2.5 to obtain neutralized precipitate slurry.

[0016] e) Filtration, without washing: The neutralized precipitate obtained in step d) is filtered to obtain neutralized residue (pH 2.0-2.5) and neutralized liquid (pH 2.0-2.5).

[0017] f) Sulfuric acid aging to remove silicon: After the neutralized residue (pH 2.0-2.5) obtained in step e) is aged with sulfuric acid to remove silicon, it is returned to step b) oxidative acid leaching;

[0018] Basic principle: Under high acid (sulfuric acid concentration ≥40%-50%) and high temperature (>100℃) conditions, silicic acid will coagulate and dehydrate, existing in the form of silicon dioxide granules. This form of silicon is insoluble in acid of any concentration, thus enabling the separation of valuable components from silicon in acid solutions. This process mainly includes two steps. The first step is to put the neutralized residue (pH value 2.0-2.5) filter cake into the reaction vessel, slowly add a certain amount of concentrated sulfuric acid of 98% or higher (the amount of sulfuric acid is 0.7-0.8 times the mass of the filter cake), stir evenly, and let it stand and mature at high temperature (e.g., temperature 100-140℃, maturation time is 3-4 hours). The second step is to return to step b) oxidative acid immersion tank for stirring and dissolution.

[0019] g) Copper removal using copper extractant LIX984: The neutralized solution (pH 2.0-2.5) obtained in step e) is treated with copper extractant to remove copper until the raffinate Cu ≤ 0.1 g / L; wherein, a small amount of antioxidant additives, such as ascorbic acid and glucose, are added during the extraction process, and the amount added is 0.1‰-0.2‰ of the extractant.

[0020] The copper-loaded extractant is back-extracted with 1.8-2 mol / L dilute sulfuric acid (preferably, organic phase: aqueous phase = 3-4:1) to obtain a copper sulfate solution;

[0021] The copper extractant after back-extraction can be directly reused; after oil removal, the resulting copper sulfate solution can be sold to copper refineries as raw material.

[0022] h) Nickel enrichment using HBL110 nickel-specific extractant: The copper-removed liquid obtained in step g) is enriched with nickel using HBL110 nickel-specific extractant until the raffinate Ni ≤ 0.1 g / L; wherein, a small amount of antioxidant additives, such as ascorbic acid and glucose, are added during the extraction process, and the amount added is 0.1‰-0.2‰ of the extractant;

[0023] The nickel-loaded special extractant HBL110 was back-extracted with 0.7-0.75 mol / L dilute sulfuric acid (preferably, organic phase: aqueous phase = 3.5-4.5:1) to obtain a nickel sulfate solution;

[0024] After back-extraction, the nickel-specific extractant HBL110 is saponified using 1.4-1.5 mol / L liquid alkali (preferably, organic phase: aqueous phase = 8-10:1), with a preferred saponification rate of 50%, and then reused.

[0025] i) Alkali precipitation (pH 8.5-9.0): After removing the oil from the nickel sulfate solution obtained by back-extraction of nickel special extractant HBL110 in step h), it is precipitated with a soda ash aqueous solution to a pH of 8.5-9.0, and then filtered to obtain the alkali precipitation mother liquor and nickel carbonate.

[0026] The mother liquor from the alkaline precipitation is mainly sodium sulfate solution, which is outsourced to an industrial park wastewater treatment company for recycling as a byproduct of sodium sulfate. Nickel carbonate is washed with deionized water in multiple countercurrent stages until neutral, and the resulting high-nickel, low-impurity nickel carbonate is used as concentrate and sold to cobalt and nickel refineries as raw material.

[0027] j) Primary alkaline precipitation (pH 3.5-4.0): After removing oil from the raffinate of nickel-specific extractant HBL110 in step h), the raffinate is subjected to alkaline precipitation with soda ash aqueous solution until the pH value is 3.5-4.0. The raffinate residue (pH 3.5-4.0) and the primary alkaline precipitation mother liquor (pH 3.5-4.0) are obtained by filtration.

[0028] k) Aluminum removal from primary alkali precipitate: The primary alkali precipitate obtained in step j) is directly reused in the leachate of step d) for neutralization and precipitation; or the primary alkali precipitate is periodically extracted, and sodium hydroxide aqueous solution or calcium hydroxide aqueous solution is added to overalkalize to pH 12.0-13.5 to remove aluminum, and the overalkalized mother liquor (pH 12.0-13.5) and overalkalized precipitate are obtained by filtration.

[0029] The over-alkalization mother liquor contains a small amount of alkali solution, which can be outsourced to an industrial park wastewater company for treatment as a low-concentration alkaline solution, or calcined at high temperature to produce alumina for sale. The over-alkalization precipitate residue is not washed and can be reused in step d) to neutralize the precipitate (pH value 2.0-2.5).

[0030] l) Secondary alkaline precipitation (pH 5.2-5.4): Filter the mother liquor obtained from the primary alkaline precipitation in step j) to obtain secondary alkaline precipitation mother liquor (pH 5.2-5.4) and secondary alkaline precipitation residue (pH 5.2-5.4);

[0031] The secondary alkali precipitation mother liquor is mainly composed of sodium sulfate, magnesium sulfate, and calcium sulfate solution. It can be outsourced to an industrial park wastewater treatment company to recover byproducts such as gypsum, basic magnesium carbonate, and sodium sulfate. The secondary alkali precipitation residue can be washed with deionized water in multiple countercurrent stages until neutral. The resulting multi-metal hydroxides, after calcination (dry basis: Ni: 10-14%, Cr: 2-3%), can be sold to pyrometallurgical stainless steel plants as raw materials.

[0032] In this invention, the low-nickel, high-impurity element materials refer to intermediate slag from cobalt-nickel hydrometallurgical processes, various recovered nickel-containing catalysts that have been calcined and deorganized, nickel-containing electroplating sludge, etc.

[0033] The beneficial effects of this invention are as follows:

[0034] 1. Through process design, the resource-based treatment and comprehensive utilization of low-nickel, high-impurity element materials were realized;

[0035] 2. In the preferred embodiment, by adding a small amount of antioxidant additive, the extractant loss rate is only about 20% of that of a conventional extraction clarification tank, achieving better economic and environmental benefits (TOC of wastewater at the boundary of the production unit is reduced by about 80%, which is environmentally friendly). Detailed Implementation

[0036] The technical solution and its effects of the present invention will be further illustrated below through specific embodiments.

[0037] Example 1: A method for resource-based treatment and comprehensive utilization of intermediate slag from cobalt-nickel hydrometallurgical processes.

[0038] a) Pretreatment: Weigh 200g of intermediate slag from cobalt-nickel hydrometallurgical process with a moisture content of 55.6%, add 1.0L of demineralized water for pulping, and filter it through the overflow pipe with a 100-mesh screen above the side of the pulping tank to the oxidation acid leaching tank.

[0039] b) Oxidative acid leaching: Add 40g of concentrated sulfuric acid (98%) and 75g of hydrogen peroxide (8%) to the slurry obtained in step a) for oxidative acid leaching at 70℃ and stirring for 4 hours. The final pH value of the reaction is 1.6. Then filter.

[0040] c) Filtration and demineralized water multi-stage countercurrent washing: The qualified leachate obtained in step b) is filtered to obtain leach residue and leachate; the measured dry basis (XRF) values ​​of the leach residue are: Fe: 1.14%, SiO2: 24.55%, CaSO4: 67.95%, Ni: 0.036%, which are outsourced for processing.

[0041] d) Neutralization and precipitation of leachate: The leachate obtained in step c) is neutralized and precipitated to pH 2.2 using a primary alkali precipitate residue at 70°C and stirred for 1 hour to obtain a neutralized and precipitated leachate slurry.

[0042] e) Filtration, without washing: Neutralize the leachate obtained in step d) with the precipitated slurry, and then filter to obtain neutralized residue and neutralized liquid.

[0043] f) Sulfuric acid aging for silicon removal: Place 100g of the wet-based neutralized residue obtained in step e) into a polytetrafluoroethylene reactor, slowly add 80g of 98% sulfuric acid, stir evenly, and let it stand for aging at 120℃ for 3 hours. 99.87% of the silicon element is in the leaching residue, and the silicon removal effect is obvious.

[0044] g) Copper removal using LIX984 copper extractant: Ascorbic acid is added during the extraction process at a concentration of 0.1‰ of the extractant. The extraction equipment uses a pulse extraction tower (0.1 MPa nitrogen protection), and the oil removal equipment uses a coalescing oil separator (flow rate, 2 BV).

[0045] The neutralized solution obtained in step e) was subjected to copper extraction using a copper extractant. A three-stage cross-flow extraction process was used. The Cu concentration in the solution before extraction was 0.33 g / L, and the Cu concentration in the solution after extraction was 0.0021 g / L, resulting in a copper extraction rate of 99.36%. The copper-loaded extractant was back-extracted using 1.8 mol / L dilute sulfuric acid (organic phase: aqueous phase = 4:1) to obtain a copper sulfate solution (sold externally). The copper extractant after back-extraction was directly reused.

[0046] h) Nickel enrichment using HBL110 nickel-specific extractant: Ascorbic acid is added during the extraction process at a concentration of 0.1‰ of the extractant. The extraction equipment uses a pulse extraction tower (0.1MPa nitrogen protection), and the oil removal equipment uses a coalescing oil separator (flow rate, 2 BV).

[0047] The copper-removed solution obtained in step g) is enriched with nickel using the nickel-specific extractant HBL110. After three-stage cross-flow extraction, the nickel-specific extractant HBL110 is back-extracted with 0.7 mol / L dilute sulfuric acid (organic phase: aqueous phase = 4.0:1) to obtain a nickel sulfate solution (nickel-enriched back-extraction solution). After back-extraction, the nickel-specific extractant HBL110 is saponified with 1.4 mol / L liquid alkali (organic phase: aqueous phase = 10:1) and then reused.

[0048] The nickel extraction solution before extraction contained Ni: 5.21 g / L, Cr: 1.13 g / L, and Al: 2.46%.

[0049] The nickel extraction solution contained Ni: 0.035 g / L, Cr: 0.72 g / L, Al: 2.29%, and TOC: 17 ppm.

[0050] Results: In conventional processes, the average TOC in the aqueous phase is 85 ppm (80-90 ppm), while in this case, the TOC in the aqueous phase is 17 ppm, which is only 20.0% of the TOC (extractant) loss rate in the aqueous phase of conventional processes.

[0051] i) Alkali precipitation: After removing oil from the nickel sulfate solution obtained by back-extraction with the nickel-specific extractant HBL110 in step h), the solution is subjected to alkali precipitation with 20% sodium carbonate aqueous solution until the pH value is 8.5. The solution is then filtered to obtain alkali precipitation mother liquor (in which Ni: 0.016 g / L) and nickel carbonate (in which, on a dry basis, Ni: 46.21%).

[0052] j) Primary alkaline precipitation: After removing oil from the nickel-specific extractant HBL110 raffinate (nickel extraction residue) from step h), the residue is subjected to alkaline precipitation with 20% sodium carbonate solution until the pH value reaches 3.5. The residue is then filtered to obtain primary alkaline precipitation residue and primary alkaline precipitation mother liquor.

[0053] k) Aluminum removal from primary alkali precipitate residue: The primary alkali precipitate residue obtained in step j) is directly reused in the leachate of step d) for neutralization and precipitation;

[0054] l) Secondary alkaline precipitation (pH 5.2-5.4): Filter the mother liquor obtained from the primary alkaline precipitation in step j) to obtain the secondary alkaline precipitation mother liquor and the secondary alkaline precipitation residue.

[0055] Example 2: A method for the resource-based treatment and comprehensive utilization of recovered nickel-containing catalysts after calcination and removal of organic matter.

[0056] a) Pretreatment: Weigh 200g of nickel-containing catalyst with a moisture content of 45.2%, add it to 1.0L of demineralized water for slurrying, and filter it through the overflow pipe with a 100-mesh screen above the side of the slurrying tank to the oxidation acid leaching tank.

[0057] b) Oxidative acid leaching: Add 47g of concentrated sulfuric acid (98%) and 90g of hydrogen peroxide (8%) to the slurry obtained in step a) for oxidative acid leaching at 70℃ and stirring for 5 hours. The final pH value of the reaction is 1.7. Then filter.

[0058] c) Filtration and demineralized water multi-stage countercurrent washing: The qualified leachate obtained in step b) is filtered to obtain leach residue and leachate; the measured dry basis (XRF) values ​​of the leach residue are: Fe: 3.25%, SiO2: 42.35%, CaSO4: 48.58%, Ni: 0.023%, which are outsourced for processing.

[0059] d) Neutralization and precipitation of leachate: The leachate obtained in step c) is neutralized and precipitated to pH 2.3 using a primary alkali precipitate residue at 75°C and stirred for 2 hours to obtain a neutralized and precipitated leachate slurry.

[0060] e) Filtration, without washing: Neutralize the leachate obtained in step d) with the precipitated slurry, and then filter to obtain neutralized residue and neutralized liquid.

[0061] f) Sulfuric acid aging for silicon removal: Place 100g of the wet-based neutralized residue obtained in step e) into a polytetrafluoroethylene reactor, slowly add 75g of 98% sulfuric acid, stir evenly, and let it stand for aging at 130℃ for 4 hours. 99.96% of the silicon element is in the leaching residue, and the silicon removal effect is obvious.

[0062] g) Copper removal using copper extractant LIX984:

[0063] Glucose was added during the extraction process at a concentration of 0.1‰ of the extractant. The extraction equipment used a pulse extraction tower (0.1 MPa nitrogen protection), and the oil removal equipment used a coalescing oil separator (flow rate, 2 BV).

[0064] The neutralized solution obtained in step e) was subjected to copper extraction using a copper extractant. A three-stage cross-flow extraction process was used. The Cu concentration in the solution before extraction was 0.42 g / L, and the Cu concentration in the solution after extraction was 0.0018 g / L, resulting in a copper extraction rate of 99.57%. The copper-loaded extractant was back-extracted with 2.0 mol / L dilute sulfuric acid (organic phase: aqueous phase = 3.5:1) to obtain a copper sulfate solution (sold externally). The copper extractant after back-extraction was directly reused.

[0065] h) Nickel enrichment using the nickel-specific extractant HBL110:

[0066] A small amount of glucose, 0.1‰ of the extractant, is added during the extraction process. The extraction equipment uses a pulse extraction tower (0.1 MPa nitrogen protection), and the oil removal equipment uses a coalescing oil separator (flow rate, 2 BV).

[0067] The copper-removed solution obtained in step g) is enriched with nickel using the nickel-specific extractant HBL110. After three-stage cross-flow extraction, the nickel-specific extractant HBL110 is back-extracted with 0.72 mol / L dilute sulfuric acid (organic phase: aqueous phase = 3.6:1) to obtain a nickel sulfate solution (nickel-enriched back-extraction solution). After back-extraction, the nickel-specific extractant HBL110 is saponified with 1.5 mol / L liquid alkali (organic phase: aqueous phase = 9:1) and then reused.

[0068] The nickel extraction solution before extraction contained Ni: 4.98 g / L, Cr: 1.25 g / L, and Al: 5.45%.

[0069] The nickel extraction solution contained Ni: 0.033 g / L, Cr: 0.98 g / L, Al: 4.98%, and TOC: 16 ppm.

[0070] Results: The average TOC in the aqueous phase of the conventional process is 85 ppm (80-90 ppm), while the TOC in the aqueous phase of this case is 16 ppm, which is only 18.75% of the TOC (extractant) loss rate in the aqueous phase of the conventional process.

[0071] i) Alkali precipitation: After removing oil from the nickel sulfate solution obtained by back-extraction with the nickel-specific extractant HBL110 in step h), the solution is subjected to alkali precipitation with 20% sodium carbonate aqueous solution until the pH value is 9.0. The solution is then filtered to obtain alkali precipitation mother liquor (where Ni: 0.0098 g / L) and nickel carbonate (where Ni: 45.06% on a dry basis).

[0072] j) Primary alkaline precipitation: After removing oil from the raffinate (nickel extraction residue) of the nickel-specific extractant HBL110 in step h), the residue is subjected to alkaline precipitation with 20% soda ash aqueous solution until the pH value reaches 3.8. The residue is then filtered to obtain primary alkaline precipitation residue and primary alkaline precipitation mother liquor.

[0073] k) Aluminum removal from primary alkali precipitate residue: The primary alkali precipitate residue obtained in step j) is directly reused in the leachate of step d) for neutralization and precipitation.

[0074] l) Secondary alkaline precipitation: Filter the mother liquor obtained from the primary alkaline precipitation in step j) to obtain the secondary alkaline precipitation mother liquor and the secondary alkaline precipitation residue.

Claims

1. A method for resource processing and comprehensive utilization of low-nickel high-impurity material, comprising the following steps: a) pretreatment: the low-nickel high-impurity material is slurried in a slurry tank using desalting water or washing water to obtain slurry, and the slurry is filtered by overflow through the screen mesh of the slurry tank to an oxidation acid leaching tank; b) oxidation acid leaching: concentrated sulfuric acid and hydrogen peroxide are added to the slurry obtained in step a) in the oxidation acid leaching tank for oxidation acid leaching to obtain qualified leaching slurry; c) filtration and desalting water multi-stage countercurrent washing: the qualified leaching slurry obtained in step b) is filtered to obtain leaching residue and leaching liquid; d) leaching liquid neutralization and precipitation: the leaching liquid obtained in step c) is neutralized to obtain neutralization and precipitation slurry; e) filtration and no washing: the neutralization and precipitation slurry obtained in step d) is filtered to obtain neutralization residue and neutralization liquid; f) sulfuric acid aging silicon removal: the neutralization residue obtained in step e) is subjected to sulfuric acid aging silicon removal and then returned to step b) for oxidation acid leaching; g) copper removal using copper extractant LIX984: the neutralization liquid obtained in step e) is subjected to copper removal using copper extractant to obtain raffinate with Cu≤0.1 g / L; h) nickel enrichment using nickel specific extractant HBL110: the copper-removed liquid obtained in step g) is subjected to nickel enrichment using nickel specific extractant HBL110 to obtain raffinate with Ni≤0.1 g / L; the nickel specific extractant HBL110 loaded is subjected to back extraction using 0.7-0.75 mol / L dilute sulfuric acid to obtain nickel sulfate solution; i) alkali precipitation: the nickel sulfate solution obtained by back extraction of the nickel specific extractant HBL110 in step h) is subjected to oil removal and then subjected to alkali precipitation using pure alkali aqueous solution to pH 8.5-9.0 to obtain alkali precipitation mother liquor and nickel carbonate; j) primary alkali precipitation: the raffinate of the nickel specific extractant HBL110 in step h) is subjected to oil removal and then subjected to alkali precipitation using pure alkali aqueous solution to pH 3.5-4.0 to obtain primary alkali precipitation residue and primary alkali precipitation mother liquor; k) primary alkali precipitation residue aluminum removal: the primary alkali precipitation residue obtained in step j) is directly reused in step d) for leaching liquid neutralization and precipitation; or the primary alkali precipitation residue is periodically extracted, subjected to overalkalization to pH 12.0-13.5 using sodium hydroxide aqueous solution or calcium hydroxide aqueous solution, and subjected to aluminum removal to obtain overalkalization mother liquor and overalkalization precipitation residue; l) secondary alkali precipitation: the primary alkali precipitation mother liquor obtained in step j) is filtered to obtain secondary alkali precipitation mother liquor and secondary alkali precipitation residue. In step a), the liquid-solid mass ratio is 5-6:

1. In step b), the amount of concentrated sulfuric acid is 1.8-2.0 times the mass of nickel in the low-nickel high-impurity material; the concentration of hydrogen peroxide is 3%-8%, and the amount is 3.0-4.0 times the mass of nickel. In step b), the oxidation acid leaching reaction temperature is 70-80℃, the stirring reaction time is 4-5 hours, and the reaction end point pH value is 1.6-1.

8. In step d), the temperature is 70-80℃, the stirring reaction time is 1-2 hours, and the neutralization and precipitation pH value is 2.0-2.

5. In step f), the temperature is 100-140℃, and the aging time is 3-4 hours. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ 2. The method of claim 1, wherein, ​ 3. The method of claim 1, wherein, ​ 4. The method according to any one of claims 1 to 3, wherein, ​ 5. The method of claim 1, wherein, ​ 6. The method of claim 1, wherein, ​ 7. The method of claim 1, wherein, In step g), a small amount of antioxidant additive is added in the extraction process, which is selected from ascorbic acid, glucose, and the addition amount is 0.1‰-0.2‰ of the extractant.

8. The method of claim 1, wherein, In step g), the copper-loaded extractant is stripped by 1.8-2 mol / L dilute sulfuric acid to obtain a copper sulfate solution.

9. The method of claim 1, wherein, In step h), a small amount of antioxidant additive is added in the extraction process, which is selected from ascorbic acid, glucose, and the addition amount is 0.1‰-0.2‰ of the extractant.