A method of processing laterite nickel ore

Abstract

The application provides a method for processing laterite nickel ore, which comprises the following steps: (1) the laterite nickel ore is crushed and screened to meet the leaching particle size requirement; (2) the laterite nickel ore is treated by leaching with sulfuric acid to obtain a laterite nickel ore leaching solution; (3) the laterite nickel ore leaching solution is subjected to first precipitation treatment to obtain a nickel-cobalt-containing solution and an iron-aluminum residue; (4) the nickel-cobalt-containing solution is subjected to second precipitation treatment to obtain a nickel-cobalt sulfate solution and a gypsum ore slurry; and (5) the nickel-cobalt sulfate solution is subjected to extraction treatment to obtain battery-grade nickel sulfate and a cobalt sulfate solution. The application realizes the synergistic recovery of nickel and cobalt by using CPH88 extractant, and directly obtains a battery-grade nickel-cobalt sulfate solution. The method has a short process flow, is simple to operate and has high extraction efficiency.

Description

Technical Field

[0001] This invention belongs to the field of metallurgy and relates to a method for processing laterite nickel ore. Background Technology

[0002] Nickel is an important non-ferrous metal raw material with abundant reserves on Earth. Nickel ore is mainly divided into copper-nickel sulfide ore and nickel oxide ore, with the development and utilization of nickel oxide ore primarily based on laterite nickel ore. Currently, there are two main production processes for nickel products from laterite nickel ore: pyrometallurgical and hydrometallurgical processes. Hydrometallurgical processes include pre-reduction-ammonium leaching, atmospheric pressure acid leaching, high pressure acid leaching, and bacterial leaching. Projects using hydrometallurgical processes to process laterite nickel ore generally employ a process of high pressure acid leaching-thickening and separation-iron and aluminum removal-nickel-cobalt precipitation to prepare nickel-cobalt hydroxide intermediates or nickel-cobalt sulfide intermediates. These intermediates are then further processed using leaching-purification-evaporation crystallization or electrowinning processes to produce final products such as nickel sulfate, cobalt sulfate, or electrolytic nickel and cobalt. For processes using nickel-cobalt hydroxide as an intermediate product, sodium hydroxide or magnesium oxide is generally used as a neutralizing agent for nickel-cobalt precipitation. The nickel and cobalt are recovered through the neutralization and precipitation reaction, while sodium sulfate or magnesium sulfate is generated in the solution, resulting in sodium- or magnesium-containing process wastewater.

[0003] To meet domestic restrictions on the salinity of discharged wastewater, this invention provides a method for treating laterite nickel ore. This method employs a novel extraction and separation system that enables the synergistic recovery of nickel and cobalt, yielding a battery-grade nickel-cobalt sulfate solution in one step. Furthermore, the concentration of nickel metal ions in the effluent phase meets the requirements for direct discharge.

[0004] CN109971977A discloses a method for recovering metallic nickel and cobalt from laterite nickel ore leaching solution. The method includes the following steps: a) recovering nickel from the laterite nickel ore leaching solution using a continuous ion exchange device and collecting the adsorption tail liquid; b) passing the adsorption tail liquid collected in step a, after nickel ion recovery, through a chelating resin at a certain temperature and flow rate to adsorb and recover cobalt; after cobalt recovery through the chelating resin, cobalt ions in the laterite nickel ore leaching solution are adsorbed onto the chelating resin for recovery, and the adsorption tail liquid is a laterite nickel ore leaching solution containing trace amounts of nickel and cobalt; d) the cobalt ions adsorbed on the chelating resin are washed off with a chemical reagent of a certain concentration at a certain flow rate and then collected; e) the chelating resin, after being washed with the chemical reagent, is reused in the nickel recovery adsorption tail liquid of the laterite nickel ore leaching solution to adsorb and recover cobalt. This method can fully recover nickel and cobalt ions from the laterite nickel ore leaching solution, but its operation is complex and difficult to control.

[0005] CN102268537B discloses a method for extracting cobalt and nickel from laterite nickel ore. The method includes: pre-treating the laterite nickel ore by roasting; adjusting the roasted material into a slurry with water; directly adding ion exchange resin for leaching and adsorption of nickel and cobalt; separating the ion exchange resin from the slurry; acid eluting the resin to remove nickel and cobalt; and then separating the eluent by solvent extraction to separate nickel and cobalt. The obtained nickel-containing and cobalt-containing solutions are directly used for electrolytic production of metallic nickel and cobalt, or for the production of corresponding nickel and cobalt salts. This method simplifies the smelting process for hydrometallurgical recovery of cobalt and nickel from laterite nickel ore, integrating the leaching, impurity removal, concentration, and enrichment of nickel and cobalt into a single step. It eliminates the need for solid-liquid separation and slag washing steps, reducing water consumption, slurry processing volume, and subsequent wastewater treatment. The process achieves a high nickel and cobalt recovery rate and is simple to operate, saving on equipment investment costs, reducing chemical raw material consumption, and simplifying many operational management aspects. However, its recovery rate is only about 90%, and the remaining residual metal cannot be recycled, resulting in waste.

[0006] The above methods have problems such as complex operation, difficulty in control, or low recovery rate. Therefore, it is necessary to develop a method for processing laterite nickel ore with high recovery rate and simple operation. Summary of the Invention

[0007] The purpose of this invention is to provide a method for processing laterite nickel ore, wherein the method utilizes CPH88 extractant to achieve synergistic recovery of nickel and cobalt, directly yielding a battery-grade nickel-cobalt sulfate solution. This method features a short process flow, simple operation, and high extraction efficiency.

[0008] To achieve this objective, the present invention employs the following technical solution:

[0009] This invention provides a method for processing laterite nickel ore, the method comprising the following steps:

[0010] (1) The laterite nickel ore is crushed, screened and leached in one step to obtain laterite nickel ore leachate;

[0011] (2) The laterite nickel ore leaching solution obtained in step (1) is subjected to a first precipitation treatment to obtain a nickel-cobalt-containing solution and iron-aluminum slag;

[0012] (3) The nickel-cobalt-containing solution described in step (2) is subjected to a second precipitation treatment, followed by two-step leaching to obtain nickel-cobalt sulfate solution and gypsum slurry;

[0013] (4) The nickel-cobalt sulfate solution obtained in step (3) is subjected to impurity removal and extraction treatment to obtain battery-grade nickel sulfate and cobalt sulfate solution;

[0014] In step (4), the extractant used in the extraction process is an organic acid extractant, specifically a self-synthesized CPH88, which includes a carboxylic acid extractant. The structural formula of the carboxylic acid extractant is shown in Formula I.

[0015]

[0016] Among them, -C8H 17 It is a straight-chain or branched alkyl group.

[0017] This invention uses CPH88 extractant, which has the characteristic of preferentially extracting nickel under low acid conditions, and the extraction process exhibits good phase separation, fast phase separation speed, and low water solubility.

[0018] Preferably, the particle size of the sieve in step (1) is 100-200 mesh.

[0019] Preferably, the leaching agent in step (1) is hydrochloric acid and / or sulfuric acid.

[0020] Preferably, the precipitant for the first precipitation treatment in step (2) is any one or a combination of at least two of NaOH, ammonia, sodium carbonate, sodium bicarbonate or oxalic acid.

[0021] Preferably, the concentration of the precipitant is 0.1 to 5.5 mol / L, for example: 0.1 mol / L, 0.5 mol / L, 1 mol / L, 2 mol / L, 3 mol / L, 4 mol / L, 5 mol / L or 5.5 mol / L, etc.

[0022] Preferably, in step (3), the precipitant for the second precipitate is limestone and / or lime slurry.

[0023] Preferably, the concentration of the precipitant is 15-30%, for example: 15%, 18%, 20%, 22%, 25%, 27% or 30%, etc.

[0024] Preferably, the leaching agent in the two-step leaching process of step (3) is sulfuric acid.

[0025] Preferably, the extractant needs to be saponified before the extraction process described in step (4).

[0026] Preferably, the saponifying agent in the saponification treatment is an alkaline compound.

[0027] Preferably, the alkaline compound includes any one or a combination of at least two of sodium hydroxide solution, potassium hydroxide, magnesium oxide, or ammonia water.

[0028] Preferably, the mass fraction of the alkaline compound is 15% to 36%, for example: 15%, 17%, 19%, 20%, 22%, 24%, 26%, 28%, 30%, 32%, or 36%, etc.

[0029] Preferably, the impurity removal process in step (4) is used.

[0030] Preferably, the impurity removal extractant used in the impurity removal treatment is P204 extractant.

[0031] Preferably, the P204 extractant needs to be diluted with a diluent.

[0032] Preferably, the volume fraction of P204 is between 5% and 35%, for example: 5%, 10%, 15%, 20%, 25%, 30% or 35%, etc.

[0033] Preferably, the diluent for the P204 extractant includes any one or a combination of at least two of solvent oil, kerosene, Escaid110, and dodecane, preferably kerosene, and more preferably sulfonated kerosene.

[0034] The P204 extraction and impurity removal process described in this invention includes saponification stage 1-2, extraction stage 1-20, washing stage 1-15, and back-extraction stage 3-9, etc.

[0035] Preferably, the saponification stage is 1 to 2, for example, 1 or 2, but not limited to the listed values; other unlisted values ​​within this range also apply.

[0036] Preferably, the extraction stages are 1 to 20, for example: 1, 3, 5, 7, 10, 12, 15 or 20.

[0037] Preferably, the washing stages are 1 to 15, for example: 1, 3, 5, 7, 10, 12 or 15, etc.

[0038] Preferably, the back-extraction stage has 3 to 9 stages, for example: 3, 4, 5, 6, 7, 8 or 9.

[0039] Preferably, the molar fraction of the extractant in step (4) is 0.2 to 1.0 mol / L, for example: 0.2 mol / L, 0.3 mol / L, 0.4 mol / L, 0.5 mol / L, 0.6 mol / L, 0.7 mol / L, 0.8 mol / L, 0.9 mol / L or 1.0 mol / L, etc.

[0040] Preferably, the diluent for the extractant includes any one or a combination of at least two of kerosene, Escaid 110, solvent oil, hexane, heptane, and dodecane.

[0041] Preferably, the dodecane is n-dodecane.

[0042] The CPH88 extraction and separation process described in this invention includes saponification stage 1-2, extraction stage 1-30, washing stage 1-20, and back-extraction stage 3-9, etc.

[0043] Preferably, the saponification stage is 1 to 2 stages, for example: 1 or 2.

[0044] Preferably, the extraction stages are 1 to 30, for example: 1, 3, 5, 7, 10, 12, 15, 20 or 30, etc.

[0045] Preferably, the washing stages are 1 to 20, for example: 1, 3, 5, 7, 10, 12, 15 or 20.

[0046] Preferably, the back-extraction stage has 3 to 9 stages, for example: 3, 4, 5, 6, 7, 8 or 9.

[0047] Preferably, the loaded organic phase must be washed before the impurity removal and extraction processes described in step (4) and then back-extracted.

[0048] Preferably, the detergent used for washing is ultrapure water with a certain pH value.

[0049] Preferably, the washing process uses sulfuric acid to adjust the pH of the ultrapure water.

[0050] Preferably, the pH value of the detergent is 0.5 to 2.5, for example: 0.5, 0.8, 1.0, 1.2, 1.5, 1.8, 2.0, 2.3 or 2.5, etc.

[0051] Preferably, the stripping agent comprises hydrochloric acid and / or sulfuric acid.

[0052] Preferably, the concentration of the stripping agent is 2 to 6 mol / L, for example: 2 mol / L, 3 mol / L, 4 mol / L, 5 mol / L or 6 mol / L, etc.

[0053] Preferably, the equipment for the impurity removal and extraction processes is a mixing and clarification tank.

[0054] Preferably, the volume ratio of the mixing chamber to the clarification chamber in the mixing and clarification tank is 1:(1 to 4), for example: 1:1, 1:2, 1:3 or 1:4, etc.

[0055] As a preferred embodiment of the present invention, the method for processing laterite nickel ore includes the following steps:

[0056] (1) After crushing the laterite nickel ore, the residue with a particle size >100 mesh is screened and leached in one step with hydrochloric acid and / or sulfuric acid to obtain laterite nickel ore leachate.

[0057] (2) The laterite nickel ore leaching solution obtained in step (1) is subjected to a first precipitation treatment with a precipitant of concentration of 0.1 to 5.5 mol / L to obtain a nickel-cobalt-containing solution and iron-aluminum slag;

[0058] (3) The nickel-cobalt solution in step (2) is subjected to a second precipitation treatment using a precipitant with a concentration of 15-30%, and then subjected to two-step leaching with sulfuric acid to obtain nickel-cobalt sulfate solution and gypsum slurry.

[0059] (4) Dilute the P204 extractant to a volume fraction of 5-35% using a diluent, and then saponify it using a saponifying agent with a content of 15-36%.

[0060] (5) Extract the nickel cobalt sulfate solution obtained in step (3) using the saponified P204 extractant described in step (4), then wash with a detergent with a pH of 0.5 to 2.5, and back-extract with a back-extractant with a concentration of 2 to 6 mol / L;

[0061] (6) Dilute the CPH88 extract to a volume fraction of 25% using a diluent, and then saponify it using a saponifying agent with a content of 15-36%.

[0062] (7) The nickel-cobalt sulfate solution after back-extraction in step (5) is extracted using the saponified CPH88 extractant in step (6), then washed with a detergent with a pH of 0.5 to 2.5, and back-extracted with a back-extractant with a concentration of 2 to 6 mol / L to obtain a battery-grade nickel-cobalt sulfate solution.

[0063] Compared with the prior art, the present invention has the following beneficial effects:

[0064] (1) This invention uses CPH88 extractant to achieve synergistic recovery of nickel and cobalt, directly obtaining battery-grade nickel-cobalt sulfate solution. The method has a short process flow, is easy to operate, and has high extraction efficiency.

[0065] (2) The method for treating laterite nickel ore described in this invention can achieve a metal recovery rate of over 99.5%, and the nickel content in the leaching wastewater is only about 2 mg / L, the cobalt content is only 1 mg / L, the iron and aluminum content is less than 1 mg / L, and the magnesium content in the nickel cobalt sulfate solution is less than 4 mg / L and the calcium content is less than 1 mg / L, which meets the national standard requirements. Attached Figure Description

[0066] Figure 1 This is a schematic diagram of the recycling method in Embodiment 1 of the present invention. Detailed Implementation

[0067] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0068] The CPH88 extractant used in the embodiments of this invention was prepared by the following method:

[0069] The preparation method includes the following steps:

[0070]

[0071] 20 g of pyridine dicarboxylic acid was added to a 500 mL round-bottom flask. While stirring at room temperature, 200 mL of thionyl chloride was slowly added dropwise. A rise in temperature indicated the reaction had occurred. After the addition was complete, the mixture was refluxed for 30 minutes, and excess thionyl chloride was removed by distillation. Subsequently, 200 mL of dichloromethane and 24 g of triethylamine (approximately 2 eq) were added to the flask, followed by dropwise addition of 28.9 g of diisooctylamine (1 eq). The reaction was allowed to proceed at room temperature for 1 hour, after which the reaction was stopped. The product was washed twice with hydrochloric acid (pH=1), then once with water, dried over sodium sulfate, and the solvent was evaporated to obtain 34.6 g of the target product.

[0072] Characterization data: 13 C NMR(101MHz, CDCl3)δ167.1(s),149.3(s),144.2(s),140.7(s),127.6(m),51.5(m), 32.31–31.38(m),29.37(m),27.2(m),24.3(m),14.1(d,J=4.4Hz); 11.3(d,J=5.9Hz); 1 H NMR (400MHz, CDCl3) δ12.1(1H), 8.79(1H), 8.68(1H), 8.49(1H), 2.72(4H), 1.92(2H), 1.27(16H), 0.89(6H), 0.85(6H); MS: 390.3.

[0073] Example 1

[0074] This embodiment provides a method for processing lateritic nickel ore. The composition of the lateritic nickel ore in this embodiment is shown in Table 1.

[0075] Table 1

[0076] element TFe Ni Co <![CDATA[Al2O3]]> CaO MgO wt% 15.4 1.7 0.03 3.9 3.5 15.0

[0077] (1) The above-mentioned laterite nickel ore was crushed and screened to 150 mesh and then leached with sulfuric acid to obtain a leachate;

[0078] (2) Add sodium hydroxide with a concentration of 0.1 mol / L to the leachate in step (1), control the reaction temperature to 40°C, adjust the pH to 2, and after the first precipitation treatment, generate iron-aluminum slag precipitate and nickel-cobalt leaching solution.

[0079] (3) Limestone is added to the nickel-cobalt leaching solution in step (2), and the reaction temperature and pH are controlled. After the second precipitation and sulfuric acid leaching treatment, gypsum slurry and nickel-cobalt sulfate solution are obtained. The concentrations of each element in the nickel-cobalt sulfate solution are shown in Table 2.

[0080] Table 2

[0081] element Fe Ni Co Al Ca Mg g / L 0.20 4.95 0.15 0.19 0.34 7.0

[0082] (4) Use P204 to remove impurities from the nickel-cobalt sulfate solution obtained in step (3). The volume fraction of the extracted organic phase is 10%. Sulfonated kerosene is used as a diluent. The degree of saponification is 23%. The alkaline compound used for saponification is NH4OH with a mass fraction of 26%. The flow ratio of the extracted organic phase and nickel-cobalt sulfate is 1:1. A mixing and clarification tank with a mixing and clarification chamber ratio of 1:2 is selected. There are 2 stages of saponification, 8 stages of extraction, 6 stages of washing, and 3 stages of back-extraction. The washing agent is sulfuric acid ultrapure water with pH=1.5. Countercurrent fractional extraction is performed. 3 mol / L sulfuric acid is used as the back-extraction agent to obtain an impurity solution containing iron and aluminum, a regenerated organic phase, and a nickel-cobalt calcium-magnesium aqueous phase. The nickel-cobalt calcium-magnesium aqueous phase is sent for analysis.

[0083] Nickel-cobalt extraction was performed using CPH88 with a volume fraction of 25% in the organic phase. Sulfonated kerosene was used as a diluent, and the degree of saponification was 13%. The flow ratio of the organic phase to nickel-cobalt sulfate was 1:4. A mixing and clarification tank with a 1:2 mixing-to-clarification ratio was selected. The extraction process consisted of 2 stages of saponification, 15 stages of extraction, 8 stages of washing, and 4 stages of back-extraction. The washing agent was sulfuric acid and ultrapure water with a pH of 1.0. Countercurrent fractionation extraction was used, and 2 mol / L sulfuric acid was selected as the back-extraction agent to obtain a nickel-cobalt sulfate solution. The organic phase and raffinate were then regenerated. The nickel-cobalt sulfate solution and the raffinate were sent for analysis, and the results are shown in Table 3.

[0084] Table 3

[0085] element g / L Fe Ni Co Al Ca Mg Nickel-cobalt-calcium-magnesium aqueous phase 0.001 4.63 0.13 0.001 0.30 6.82 Extraction wastewater <0.001 0.002 0.001 <0.001 0.26 6.50 Nickel cobalt sulfate solution <0.001 114.2 3.50 <0.001 0.001 0.004

[0086] Table 3 shows that the nickel content in the raffinate wastewater is 2 mg / L and the cobalt content is 1 mg / L, with a metal recovery rate greater than 99.5%. The magnesium content in the nickel cobalt sulfate solution is 4 mg / L and the calcium content is 1 mg / L, meeting the national standard requirements.

[0087] Example 2

[0088] This embodiment provides a method for processing lateritic nickel ore. The composition of the lateritic nickel ore in this embodiment is shown in Table 4.

[0089] Table 4

[0090] element TFe Ni Co Al2O3 CaO MgO wt% 20.0 1.65 0.08 4.5 4.0 20.0

[0091] (1) The above-mentioned laterite nickel ore was crushed and screened to 200 mesh and then leached with sulfuric acid to obtain a leachate;

[0092] (2) Add sodium carbonate with a concentration of 0.5 mol / L to the leachate in step (1), control the reaction temperature and pH, and after the first precipitation treatment, generate iron-aluminum slag precipitate and nickel-cobalt leaching solution;

[0093] (3) Limestone is added to the nickel-cobalt leaching solution in step (2), and the reaction temperature is controlled at 40°C and pH = 11. After the second precipitation and sulfuric acid leaching treatment, gypsum slurry and nickel-cobalt sulfate solution are obtained. The concentrations of each element in the nickel-cobalt sulfate solution are shown in Table 5.

[0094] Table 5

[0095] element Fe Ni Co Al Ca Mg g / L 0.25 5.20 0.17 0.23 0.32 7.3

[0096] (4) Use P204 to remove impurities from the nickel-cobalt sulfate solution obtained in step (3). The volume fraction of the extracted organic phase is 15%. Sulfonated kerosene is used as a diluent. The degree of saponification is 30%. The alkaline compound used for saponification is 30% NaOH by mass. The flow ratio of the extracted organic phase and nickel-cobalt sulfate is 1:1.2. A mixing and clarification tank with a mixing and clarification chamber ratio of 1:2 is selected. There are 2 stages of saponification, 5 stages of extraction, 4 stages of washing, and 3 stages of back-extraction. The washing agent is sulfuric acid ultrapure water with pH=1.5. Countercurrent fractional extraction is performed. 3 mol / L sulfuric acid is used as the back-extraction agent to obtain an impurity solution containing iron and aluminum, a regenerated organic phase, and a nickel-cobalt calcium-magnesium aqueous phase. The nickel-cobalt calcium-magnesium aqueous phase is sent for analysis.

[0097] Nickel-cobalt extraction was performed using CPH88 with a volume fraction of 25% in the organic phase. Escaid110 was used as a diluent, achieving a saponification degree of 25%. The flow ratio of the organic phase to nickel-cobalt sulfate was 1:4. A mixing and clarification tank with a 1:2 mixing-to-clarification ratio was selected. The extraction process consisted of two stages of saponification, 13 stages of extraction, 8 stages of washing, and 3 stages of back-extraction. The washing agent was ultrapure water with sulfuric acid at pH 1.0. Countercurrent fractionation extraction was used, and 2 mol / L sulfuric acid was selected as the back-extraction agent to obtain a nickel-cobalt sulfate solution. The organic phase and raffinate were then regenerated. The nickel-cobalt sulfate solution and raffinate were sent for analysis, and the results are shown in Table 6.

[0098] Table 6

[0099]

[0100]

[0101] Table 6 shows that the nickel and cobalt contents in the raffinate wastewater are both less than 1 mg / L, the metal recovery rate is greater than 99.8%, and the magnesium content in the nickel cobalt sulfate solution is 3 mg / L and the calcium content is less than 1 mg / L, which meets the national standard requirements.

[0102] Comparative Example 1

[0103] Using the nickel-cobalt sulfate solution from Example 2, under the same conditions, the extractant for nickel-cobalt extraction was changed from CPH88 to P507 (2-ethylhexyl phosphate mono-2-ethylhexyl ester). The aqueous phase containing nickel, cobalt, calcium, and magnesium, the raffinate wastewater, and the nickel-cobalt sulfate solution were sent for testing, and the results are shown in Table 7.

[0104] Table 7

[0105] element g / L Fe Ni Co Al Ca Mg Nickel-cobalt-calcium-magnesium aqueous phase <0.001 4.90 0.17 <0.001 0.28 7.0 Extraction wastewater <0.001 0.03 0.01 <0.001 0.26 6.50 Nickel cobalt sulfate solution <0.001 115.3 3.85 <0.001 0.003 0.01

[0106] The test data showed that the nickel content in the raffinate wastewater was 30 mg / L, the cobalt content was 10 mg / L, and the metal recovery rate was 99.2%. The magnesium content in the nickel cobalt sulfate solution was 10 mg / L and the calcium content was 3 mg / L, indicating that the magnesium content was too high.

[0107] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for processing lateritic nickel ore, characterized in that, The method includes the following steps: (1) The laterite nickel ore is subjected to crushing-screening-one-step leaching to obtain laterite nickel ore leaching solution; the leaching agent of the one-step leaching is hydrochloric acid and / or sulfuric acid; (2) The laterite nickel ore leaching solution obtained in step (1) is subjected to a first precipitation treatment to obtain a nickel-cobalt-containing solution and iron-aluminum slag; (3) The nickel-cobalt-containing solution described in step (2) is subjected to a second precipitation treatment, followed by two-step leaching to obtain nickel-cobalt sulfate solution and gypsum slurry; (4) The nickel-cobalt sulfate solution obtained in step (3) is subjected to impurity removal and extraction treatment to obtain battery-grade nickel sulfate and cobalt sulfate solution; The extractant used in step (4) is CPH88, a carboxylic acid extractant; the structural formula of the carboxylic acid extractant is shown in Formula I: Formula I Among them, -C8H 17 It is a straight-chain or branched alkyl group; Before the extraction process described in step (4), the extractant needs to be saponified. The saponifying agent used in the saponification process is an alkaline compound; The mass fraction of the alkaline compound is 15-36%.

2. The method for processing laterite nickel ore as described in claim 1, characterized in that, The particle size of the sieving in step (1) is 100~200 mesh.

3. The method for processing laterite nickel ore as described in claim 1, characterized in that, Step (2) The precipitant for the first precipitation treatment is any one or a combination of at least two of NaOH, ammonia, sodium carbonate, sodium bicarbonate or oxalic acid.

4. The method for processing laterite nickel ore as described in claim 3, characterized in that, The concentration of the precipitant is 0.1~5.5 mol / L.

5. The method for processing laterite nickel ore as described in claim 1, characterized in that, In step (3), the precipitant for the second precipitate is limestone and / or lime slurry.

6. The method for processing laterite nickel ore as described in claim 5, characterized in that, The concentration of the precipitant is 15-30%.

7. The method for processing laterite nickel ore as described in claim 1, characterized in that, The leaching agent in step (3) is sulfuric acid.

8. The method for processing laterite nickel ore as described in claim 1, characterized in that, The alkaline compound includes any one or a combination of at least two of sodium hydroxide solution, potassium hydroxide, magnesium oxide, or ammonia water.

9. The method for processing laterite nickel ore as described in claim 1, characterized in that, The impurity removal extractant used in the impurity removal treatment is P204 extractant.

10. The method for processing laterite nickel ore as described in claim 9, characterized in that, The P204 extractant needs to be diluted with a diluent.

11. The method for processing laterite nickel ore as described in claim 10, characterized in that, The volume fraction of P204 is between 5% and 35%.

12. The method for processing laterite nickel ore as described in claim 10, characterized in that, The diluent for the P204 extractant includes any one or a combination of at least two of the following: solvent oil, kerosene, Escaid 110, and dodecane.

13. The method for processing laterite nickel ore as described in claim 12, characterized in that, The diluent for the P204 extractant is kerosene.

14. The method for processing laterite nickel ore as described in claim 13, characterized in that, The diluent for the P204 extractant is sulfonated kerosene.

15. The method for processing laterite nickel ore as described in claim 1, characterized in that, The molar fraction of the extractant in step (4) is 0.2~1.0 mol / L.

16. The method for processing laterite nickel ore as described in claim 15, characterized in that, The diluent for the extractant includes any one or a combination of at least two of the following: kerosene, Escaid 110, solvent oil, hexane, heptane, and dodecane.

17. The method for processing laterite nickel ore as described in claim 16, characterized in that, The dodecane in question is n-dodecane.

18. The method for processing laterite nickel ore as described in claim 1, characterized in that, Before the impurity removal and extraction processes described in step (4), the loaded organic phase must be washed before back-extraction.

19. The method for processing laterite nickel ore as described in claim 18, characterized in that, The detergent used for washing is ultrapure water with a certain pH value.

20. The method for processing laterite nickel ore as described in claim 19, characterized in that, The washing process uses sulfuric acid to adjust the pH of the ultrapure water.

21. The method for processing laterite nickel ore as described in claim 19, characterized in that, The detergent has a pH value of 0.5 to 2.

5.

22. The method for processing laterite nickel ore as described in claim 18, characterized in that, The stripping agents include hydrochloric acid and / or sulfuric acid.

23. The method for processing lateritic nickel ore as described in claim 22, characterized in that, The concentration of the stripping agent is 2~6 mol / L.

24. The method for processing laterite nickel ore as described in claim 1, characterized in that, The equipment used for impurity removal and extraction is a mixing and clarification tank.

25. The method for processing lateritic nickel ore as described in claim 24, characterized in that, The volume ratio of the mixing chamber to the clarification chamber in the mixing and clarification tank is 1:(1~4).

26. The method for processing laterite nickel ore as described in claim 1, characterized in that, The method for processing laterite nickel ore includes the following steps: (1) After crushing the laterite nickel ore, the residue is screened into particles with a size >100 mesh, and then leached in one step with hydrochloric acid and / or sulfuric acid to obtain laterite nickel ore leachate; (2) The laterite nickel ore leaching solution obtained in step (1) is subjected to a first precipitation treatment with a precipitant of concentration of 0.1~5.5mol / L to obtain a nickel-cobalt-containing solution and iron-aluminum slag; (3) The nickel-cobalt solution in step (2) is subjected to a second precipitation treatment using a precipitant with a concentration of 15-30%, and then subjected to two-step leaching with sulfuric acid to obtain nickel-cobalt sulfate solution and gypsum slurry; (4) Dilute the P204 extractant to a volume fraction of 5-35% using a diluent, and then saponify it using a saponifying agent with a content of 15-36%. (5) Extract the nickel cobalt sulfate solution obtained in step (3) using the saponified P204 extractant described in step (4), then wash it with a detergent with a pH of 0.5 to 2.5, and back-extract it with a back-extractant with a concentration of 2 to 6 mol / L; (6) Dilute the CPH88 extractant to 25% by volume with a diluent, and then saponify it with a saponifying agent of 15-36% content; (7) The nickel-cobalt sulfate solution after back-extraction in step (5) is extracted using the saponified CPH88 extractant in step (6), then washed with a detergent with a pH of 0.5 to 2.5, and back-extracted with a back-extractant with a concentration of 2 to 6 mol / L to obtain a battery-grade nickel-cobalt sulfate solution.

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