Method for preparing nickel sulfate from nickel raw material lixivium

Abstract

The invention relates to the field of hydrometallurgy, in particular to a method for preparing nickel sulfate from nickel raw material leachate. The trend of the washing liquid in the traditional process is changed in the technological process, so that the amount of the washing liquid entering the nickel sulfate solution is reduced, the concentration of nickel ions in the nickel sulfate solution before evaporation is improved, and the unit cost of evaporative crystallization of nickel sulfate is reduced. P507 cobalt extraction washing liquid enters a P204 impurity extraction and soap conversion section, P507 magnesium extraction washing liquid enters a P507 cobalt extraction and soap conversion section and / or the P204 impurity extraction and soap conversion section, Cy272 magnesium extraction washing liquid enters a P507 magnesium extraction and soap conversion section, the P507 cobalt extraction and soap conversion section and / or the P204 impurity extraction and soap conversion section, and the washing liquid is transferred to the previous procedure and enters the soap conversion section instead of entering an extraction system; washing liquid is discharged out of the system in the form of sodium sulfate wastewater, so that the water phase amount of the system is reduced, and the nickel ion concentration in the nickel sulfate solution is improved.

Description

Technical Field

[0001] The invention relates to the field of hydrometallurgy, and in particular to a method for preparing nickel sulfate from a nickel raw material leaching solution. Background Art

[0002] In the hydrometallurgy of nickel, different processes are used according to the properties of the raw materials, which can be roughly divided into: leaching-iron and aluminum removal-extraction and impurity removal-oil removal-evaporation and crystallization. For example, battery-grade nickel sulfate is made from nickel raw materials such as nickel hydroxide, nickel sulfide, and high matte nickel. The nickel ion concentration after leaching is basically between 100 and 120 g / L. After extraction, due to the introduction of the post-washing liquid and when other impurity elements are less, the nickel ion concentration in the nickel sulfate solution after extraction, purification and impurity removal is about 100 g / L. Under the condition of unchanged annual production capacity, the volume of extraction and purification solution required for evaporation and crystallization to produce nickel sulfate crystals will become larger, and the evaporation cost will be relatively high, reaching an evaporation and crystallization cost of about 3,000 yuan / tNi. If the nickel ion concentration before evaporation is high, about 140 g / L, the leaching liquid-solid ratio can also be increased in the leaching stage to increase the nickel ion concentration, but at the same time, the total ion concentration in the entire leachate will be too high, almost close to saturation, and it is easy to precipitate crystals with temperature fluctuations, which is not conducive to production operation.

[0003] In the traditional process of using nickel raw materials to make battery-grade nickel sulfate solution, in the extraction and impurity removal section, the P507 cobalt extraction washing liquid enters the P507 cobalt extraction section, the P507 magnesium extraction washing liquid enters the P507 magnesium extraction section, and the Cy272 deep magnesium extraction section washing liquid enters the Cy272 extraction section. This solution will cause the entire washed liquid to enter the nickel sulfate solution, increasing the amount of water phase in the entire system and reducing the nickel ion concentration in the nickel sulfate solution.

[0004] There is also a scheme in the prior art to open the washing liquid extracted by P204, the washing liquid extracted by P507, and the washing liquid extracted by Cy272 to the outside of the system. Although such a scheme can reduce the increase in nickel ion concentration in the system due to the introduction of the washing liquid, the open-circuited washing liquid needs to be precipitated with alkali to remove nickel and cobalt metals in the washing liquid, which reduces the direct recovery rate of the entire system.

[0005] In order to overcome the shortcomings of the above methods, improve enterprise benefits, increase the ion concentration in the nickel sulfate solution before evaporation, increase energy and reduce consumption, and reduce the cost of evaporation and crystallization, it is necessary to find a method to increase the nickel ion concentration in the evaporated nickel sulfate solution. Summary of the invention

[0006] In view of this, the technical problem to be solved by the present invention is to provide a method for preparing nickel sulfate from a nickel raw material leachate. The method provided by the present invention can prepare a nickel sulfate solution with a high nickel ion concentration from the nickel raw material leachate, thereby reducing the volume of the extraction and purification solution required for evaporation and crystallization to produce nickel sulfate crystals, and preparing nickel sulfate crystals with lower energy consumption, thereby reducing the preparation cost.

[0007] The present invention provides a method for preparing nickel sulfate from a nickel raw material leaching solution, comprising:

[0008] S1) after sequentially saponifying and converting the P204 extractant, extracting and removing impurities from the nickel raw material leaching solution with the P204 extractant to obtain a P204 raffinate and a P204 extract;

[0009] S2) after sequentially saponifying and converting the P507 extractant, the obtained P507 extractant is used to extract the P204 raffinate obtained in step S1) to remove cobalt ions, thereby obtaining a P507 cobalt raffinate and a P507 cobalt extract;

[0010] The P507 cobalt extract is washed, and the washed solution is returned to step S1) for soap conversion;

[0011] S3) after sequentially saponifying and converting the P507 extractant, the P507 cobalt raffinate obtained in step S2) is extracted with the obtained P507 extractant to remove magnesium ions, thereby obtaining a P507 magnesium raffinate and a P507 magnesium extract;

[0012] Washing the P507 magnesium extract, and returning the washed solution to one or more of step S1) and step S2) for soap conversion;

[0013] S4) after sequentially saponifying and converting the Cy272 extractant, the obtained Cy272 extractant is used to extract the P507 magnesium raffinate obtained in step S3) to remove magnesium ions, thereby obtaining nickel sulfate and Cy272 extract;

[0014] The Cy272 extract is washed, and the washed solution is returned to one or more of step S1), step S2) and step S3) for soap transfer.

[0015] The method for preparing nickel sulfate from a nickel raw material leachate provided by the present invention is a method for preparing nickel sulfate from a nickel raw material leachate by hydrometallurgy, wherein the nickel raw material in the nickel raw material leachate is selected from one or more of nickel hydroxide, nickel sulfide or high nickel matte. In certain embodiments of the present invention, the nickel raw material leachate is a mixed solution of nickel cobalt sulfate of nickel, cobalt, magnesium, copper, manganese, zinc, calcium, iron and aluminum, and the element content is as follows: Ni ≥ 80 g / L, Co ≥ 5 g / L, Mg: 2 ~ 10 g / L, Cu: ≥ 1 g / L, Mn: ≥ 1g / L, Zn: ≥ 1 g / L, Fe ≤ 0.05 g / L, AL ≤ 0.05 g / L, Ca ≤ 0.7 g / L.

[0016] The method for preparing nickel sulfate from nickel raw material leachate provided by the present invention comprises steps S1) to S4). Specifically, in step S1), the present invention first saponifies the P204 extractant in the saponification section, and then performs soap conversion on the saponified material in the soap conversion section. The saponification described in the present invention is a method of saponifying the extractant well known to those skilled in the art, specifically, adding liquid alkali to saponify the P204 extractant in the saponification section, and the liquid alkali is a liquid alkali for saponification well known to those skilled in the art. In certain embodiments of the present invention, the liquid alkali is a sodium hydroxide solution with a mass content of 30 to 32%. The soap conversion described in the present invention specifically uses the post-washing liquid of the extract obtained in the subsequent extraction section as the pre-soap conversion liquid to convert the saponified extractant, so as to avoid the introduction of the saponified liquid alkali cation into the aqueous phase.

[0017] The present invention extracts and removes impurities from the nickel raw material leachate with a P204 extractant that has been subjected to saponification and soap conversion in sequence, thereby obtaining a P204 raffinate and a P204 extract. The obtained P204 raffinate enters step S2). When the amount of the post-washing liquid in the subsequent stage is not enough for the amount of pre-soap conversion liquid required for the soap conversion stage, a portion of the P204 raffinate needs to be used as the pre-soap conversion liquid to prevent the organic matter after saponification from entering the extraction stage without soap conversion, resulting in excessive impurity elements.

[0018] The obtained P204 extract is washed with a pre-washing liquid to obtain an aqueous phase after washing of the P204 extract and an organic phase after washing of the P204 extract. The aqueous phase after washing of the P204 extract is the post-washing liquid of the P204 extract. The obtained organic phase after washing of the P204 extract can be subjected to back extraction to obtain a blank organic phase which is returned to the saponification section of step S1) for repeated use. The pre-washing liquid of the present invention is sulfuric acid, specifically 0.6-2.1 mol / L sulfuric acid, preferably 0.8-1.0 mol / L sulfuric acid. The post-washing liquid of the P204 extract is incorporated into the nickel leaching solution for extraction and impurity removal.

[0019] In step S2), the present invention first saponifies the P507 extractant in the saponification section, then performs soap conversion in the soap conversion section, and then uses the P507 extractant that has been saponified and soap converted to extract the P204 raffinate obtained in step S1) to remove cobalt ions, thereby obtaining a P507 cobalt raffinate and a P507 cobalt extract. The saponification and soap conversion are the same as those described above and will not be described in detail.

[0020] The obtained P507 cobalt raffinate enters step S3). The obtained P507 cobalt extract is washed with a pre-washing liquid to obtain a P507 cobalt extract washed aqueous phase and a P507 cobalt extract washed organic phase, wherein the P507 cobalt extract washed aqueous phase is the P507 cobalt extract washed liquid; the pre-washing liquid is sulfuric acid, specifically 0.6-2.1 mol / L sulfuric acid, preferably 0.8-1.0 mol / L sulfuric acid.

[0021] In the present invention, the obtained P507 cobalt extract is washed and the organic phase is stripped to obtain a blank organic phase which is returned to the saponification section of step S2) for reuse. The washed P507 cobalt extract is returned to the soap transfer section of step S1) to be soap transferred together with the saponified P204 extractant. The main reactions involved are: Me 2+ +2NaR=MeR+2Na + , wherein Me represents metal Co, Mg, Ni, NaR represents organic after saponification, and MeR represents organic after soap conversion. This process requires controlling the obtained P507 cobalt extract after washing to a certain pH and a certain O / A condition. In certain embodiments of the present invention, the O / A of the P507 cobalt extract after washing is (20-40): 1; the pH is 3.8-4.8.

[0022] In step S3), the present invention first saponifies the P507 extractant in the saponification section, then performs soap conversion in the soap conversion section, and then uses the P507 extractant that has been saponified and soap converted to extract the P507 cobalt raffinate obtained in step S2) to remove magnesium ions, thereby obtaining a P507 magnesium raffinate and a P507 magnesium extract. The saponification and soap conversion are the same as those described above and will not be described in detail.

[0023] The obtained P507 magnesium raffinate enters step S4). The obtained P507 magnesium extract is washed with a pre-washing liquid to obtain a P507 magnesium extract washed aqueous phase and a P507 magnesium extract washed organic phase, wherein the P507 magnesium extract washed aqueous phase is the P507 magnesium extract washed liquid; the pre-washing liquid is sulfuric acid, specifically 0.6-2.1 mol / L sulfuric acid, preferably 0.8-1.0 mol / L sulfuric acid.

[0024] In the present invention, the organic phase obtained after washing the P507 magnesium extract is stripped to obtain a blank organic phase which is returned to the saponification section of step S3) for reuse. The washed liquid of the P507 magnesium extract is returned to the soap conversion section of one or more steps of step S1) and step S2) for soap conversion. The main reactions involved are as follows: Me 2+ +2NaR=MeR+2Na + , wherein Me represents metal Mg and Ni, NaR represents organic after saponification, and MeR represents organic after soap conversion. This process requires controlling the obtained P507 magnesium extract after washing to a certain pH and a certain O / A condition. In certain embodiments of the present invention, the O / A of the P507 magnesium extract after washing is (20-40): 1; the pH is 4.5-5.5.

[0025] In step S4), the present invention first saponifies the Cy272 extractant in the saponification section, then performs soap conversion in the soap conversion section, and then uses the Cy272 extractant that has been saponified and soap converted in sequence to extract the P507 magnesium raffinate obtained in step S3) to remove magnesium ions, thereby obtaining the Cy272 raffinate and the Cy272 extract.

[0026] Wherein, the Cy272 raffinate is a nickel sulfate solution, and the obtained Cy272 raffinate is deoiled and evaporated to obtain nickel sulfate crystals. The obtained Cy272 extract is washed with a pre-washing liquid to obtain an aqueous phase after the Cy272 extract is washed and an organic phase after the Cy272 extract is washed. The aqueous phase after the Cy272 extract is washed is the post-washing liquid of the Cy272 extract; the pre-washing liquid is sulfuric acid, specifically 0.6~2.1 mol / L sulfuric acid, preferably 0.8~1.0 mol / L sulfuric acid. In the present invention, the obtained organic phase after the Cy272 extract is washed can be subjected to back extraction to obtain a blank organic phase, which is returned to the saponification section of this step S4) for reuse. The obtained post-washing liquid of the Cy272 extract is returned to one or more of steps S1), step S2) and step S3) for soap conversion, and the main reactions involved are as follows: Ni 2+ +2NaR=NiR+2Na + , NaR represents organic after saponification, and MeR represents organic after soap conversion. This process requires controlling the pH and O / A conditions of the washed solution of the Cy272 extract obtained. In certain embodiments of the present invention, the O / A of the washed solution of the Cy272 extract is (20-40): 1; the pH is 5.0-6.0.

[0027] The present invention provides a method for preparing nickel sulfate from a nickel raw material leachate. The present invention reduces the amount of washed liquid entering the nickel sulfate solution by changing the direction of the washed liquid in the traditional process during the process, increases the nickel ion concentration in the nickel sulfate solution before evaporation, and reduces the unit cost of evaporated crystallized nickel sulfate. That is, the P507 cobalt extraction washed liquid enters the P204 impurity extraction and soap conversion section, the P507 magnesium extraction washed liquid enters the P507 cobalt extraction and soap conversion section and / or the P204 impurity extraction and soap conversion section, and the Cy272 magnesium extraction washed liquid enters the P507 magnesium extraction and soap conversion section, the P507 cobalt extraction and soap conversion section and / or the P204 impurity extraction and soap conversion section, and the washed liquid is transferred to the previous process, does not enter the extraction system but enters the soap conversion section, and the washed liquid is discharged from the system in the form of sodium sulfate wastewater, thereby reducing the amount of water phase in the system, thereby increasing the nickel ion concentration in the nickel sulfate solution.

[0028] Compared with the traditional process, the present invention has the following advantages:

[0029] (1) The nickel ion concentration in the nickel sulfate solution before evaporation can be increased from 100-120 g / L after impurity removal in the conventional process to about 140 g / L, and the amount of crystallization water evaporated per ton of nickel is reduced by 21.43% (the nickel ion concentration in the nickel sulfate after impurity removal in the conventional process is calculated as 110 g / L, and the nickel ion concentration in the nickel sulfate of the present invention is calculated as 140 g / L).

[0030] (2) By increasing the nickel ion concentration before nickel sulfate evaporation, the production cost of evaporation and crystallization per ton of nickel can be reduced from 3,000 yuan / tNi to 2,400 yuan / tNi, and the evaporation and crystallization capacity can be increased.

[0031] (3) The method of the present invention has strong applicability to raw materials for producing battery-grade nickel sulfate crystals, has the advantages of simple process and high selectivity, and has the prospect of industrial promotion. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 The present invention is a schematic flow chart of the method for preparing nickel sulfate from nickel raw material leaching solution. DETAILED DESCRIPTION

[0033] The present invention discloses a method for preparing nickel sulfate from a nickel raw material leachate. Those skilled in the art can refer to the content of this article and appropriately improve the process parameters to achieve it. It is particularly important to point out that all similar substitutions and modifications are obvious to those skilled in the art, and they are all considered to be included in the present invention. The method and application of the present invention have been described through preferred embodiments, and relevant personnel can obviously modify or appropriately change and combine the method and application of this article without departing from the content, spirit and scope of the present invention to implement and apply the technology of the present invention.

[0034] like Figure 1 As shown, Figure 1 The present invention is a schematic flow chart of the method for preparing nickel sulfate from a nickel raw material leachate. Specifically, Examples 1 to 4 of the present invention were tested according to the following steps:

[0035] The nickel raw material leachate is used as the pre-extraction liquid to sequentially perform P204 extraction, P507 cobalt extraction, P507 magnesium extraction and Cy272 magnesium extraction, wherein the P204 extraction is performed using a P204 extractant, the P204 extractant is preliminarily saponified by adding liquid alkali in the saponification section and then enters the soap conversion section for soap conversion, and the raffinate obtained by the P204 extraction enters the P507 cobalt extraction. After the extract obtained by the P204 extraction is washed with water, the obtained organic phase is back-extracted with the pre-extraction liquid to obtain a blank organic phase that is returned to saponification; the obtained aqueous phase, i.e., the P204 impurity washing liquid, is returned to the P204 extraction as the post-washing liquid for extraction.

[0036] P507 cobalt extraction uses P507 extractant to extract cobalt ions. The P507 extractant is first added with liquid alkali in the saponification section for saponification and then enters the soap conversion section for soap conversion. The raffinate obtained by P507 cobalt extraction enters P507 magnesium extraction. After the extract obtained by P507 cobalt extraction is washed with water, the obtained organic phase is stripped with the stripping pre-liquid, and the obtained blank organic phase is returned to saponification; the obtained aqueous phase, i.e., the P507 cobalt extraction washing liquid, is treated according to the following Examples 1 to 4.

[0037] P507 magnesium extraction uses P507 extractant to extract magnesium ions. The P507 extractant is first added with liquid alkali in the saponification section for saponification and then enters the soap conversion section for soap conversion. The raffinate obtained by P507 magnesium extraction enters Cy272 magnesium extraction. After the extract obtained by P507 magnesium extraction is washed with water, the obtained organic phase is stripped with the stripping pre-liquid, and the obtained blank organic phase is returned to saponification; the obtained aqueous phase, i.e., the P507 magnesium extraction washing liquid, is treated according to the following Examples 1 to 4.

[0038] Cy272 magnesium extraction uses Cy272 extractant to extract magnesium ions. The Cy272 extractant is added with liquid alkali in the saponification section for saponification before entering the soap conversion section for soap conversion. The raffinate obtained by Cy272 magnesium extraction is a nickel sulfate solution. After the extract obtained by Cy272 magnesium extraction is washed with water, the obtained organic phase is stripped with the stripping pre-liquid, and the obtained blank organic phase is returned to saponification; the obtained aqueous phase, i.e., the Cy272 magnesium extraction washing liquid, is treated according to the following Examples 1 to 4.

[0039] Examples 1 to 4 of the present invention and Comparative Example 1 are all tested using the same batch of nickel raw material leachate, with a processing capacity of 23.75 kg. The nickel raw material leachate is a nickel cobalt sulfate mixed solution of nickel, cobalt, magnesium, copper, manganese, zinc, calcium, iron, and aluminum, with the following element contents: Ni: 95 g / L, Co: 10.5 g / L, Mg: 2.4 g / L, Cu: 1.05 g / L, Mn: 10 g / L, Zn: 1.3 g / L, Fe: 0.002 g / L, AL: 0.005 g / L, Ca: 0.6 g / L.

[0040] The liquid caustic soda used in Examples 1 to 4 of the present invention is a sodium hydroxide solution with a mass content of 31%, and the amount used is 7949 g.

[0041] The pre-stripping solution used in Examples 1 to 4 of the present invention is a 2 mol / L sulfuric acid solution, and the amount used is 15.90 L.

[0042] The present invention will be further described below in conjunction with embodiments:

[0043] Example 1

[0044] The P507 cobalt extraction washing liquid at pH = 4.2, O / A = 20:1, all enters the P204 impurity extraction and soap conversion section;

[0045] The P507 magnesium extraction washing liquid is at pH=4.5, O / A=20:1, and all enters the P507 cobalt extraction and soap conversion section;

[0046] The Cy272 washing liquid was at pH = 4.5, O / A = 20:1, and all entered the P507 magnesium extraction and soap conversion section;

[0047] After extraction and impurity removal, the nickel ion concentration in the nickel sulfate solution was 143.98 g / L.

[0048] Example 2

[0049] The P507 cobalt extraction washing liquid at pH = 4.2, O / A = 20:1, all enters the P204 impurity extraction and soap conversion section;

[0050] The P507 magnesium extraction washing liquid was placed at pH = 4.5, O / A = 20:1, and entered the P507 cobalt extraction and soap conversion section and the P204 impurity extraction and soap conversion section at a volume ratio of 1:1 respectively;

[0051] The Cy272 washing solution was added to the P507 magnesium extraction and soap conversion section and the P507 cobalt extraction and soap conversion section at a volume ratio of 1:1 at pH=4.5 and O / A=20:1.

[0052] After extraction and impurity removal, the nickel ion concentration in the nickel sulfate solution was 138.28 g / L.

[0053] Example 3

[0054] The P507 cobalt extraction washing liquid at pH = 4.2, O / A = 20:1, all enters the P204 impurity extraction and soap conversion section;

[0055] The P507 magnesium extraction washing liquid is at pH=4.5, O / A=20:1, and all enters the P204 impurity extraction and soap conversion section;

[0056] The Cy272 washing solution was placed at pH = 4.5, O / A = 20:1, and entered the P507 magnesium extraction and soap conversion section, the P507 cobalt extraction and soap conversion section, and the P204 impurity extraction and soap conversion section in a volume ratio of 1:1:1.

[0057] After extraction and impurity removal, the nickel ion concentration in the nickel sulfate solution was 145.32 g / L.

[0058] Example 4

[0059] The P507 cobalt extraction washing liquid at pH=4.5, O / A=30:1, all enters the P204 impurity extraction and soap conversion section;

[0060] The P507 magnesium extraction washing liquid is at pH=5.0, O / A=30:1, and enters the P507 cobalt extraction and soap conversion section and the P204 impurity extraction and soap conversion section respectively according to a volume ratio of 1:1;

[0061] The Cy272 washing solution was placed at pH=5.5, O / A=30:1, and entered the P507 magnesium extraction and soap conversion section, the P507 cobalt extraction and soap conversion section, and the P204 impurity extraction and soap conversion section in a volume ratio of 1:1:1.

[0062] After extraction and impurity removal, the nickel ion concentration in the nickel sulfate solution was 144.39 g / L.

[0063] Comparative Example 1

[0064] Take 23.75kg of nickel raw materials from the same batch for leaching. After leaching, remove iron and aluminum to obtain pre-extraction liquid. The pre-extraction liquid is sequentially subjected to P204 extraction, P507 cobalt extraction, P507 magnesium extraction and Cy272 magnesium extraction. The P204 extraction is carried out using P204 extractant. The P204 extractant is preliminarily saponified by adding liquid alkali in the saponification section and then enters the soap conversion section for soap conversion. The raffinate obtained by P204 extraction enters P507 cobalt extraction. The extract obtained by P204 extraction is washed with 1.5N sulfuric acid at O / A=20:1, and the obtained organic phase is stripped with 4N sulfuric acid pre-extraction liquid at O / A=10:1 to obtain a blank organic phase, which is returned to saponification; the obtained aqueous phase, i.e., the P204 impurity washing liquid, is returned to the P204 extraction as the post-washing liquid for extraction.

[0065] P507 cobalt extraction uses P507 extractant to extract cobalt ions. The P507 extractant is first added with liquid alkali in the saponification section for saponification and then enters the soap conversion section for soap conversion. The raffinate obtained by P507 cobalt extraction enters P507 magnesium extraction. The extract obtained by P507 cobalt extraction is washed with 1.5N sulfuric acid at O / A=20:1, and the obtained organic phase is stripped with 4N sulfuric acid pre-extraction liquid at O / A=10:1, and the obtained blank organic is returned to saponification; the obtained aqueous phase, i.e., the P507 cobalt extraction washing liquid, enters the P507 cobalt extraction section for extraction and is combined with the P507 cobalt extraction raffinate to enter the system.

[0066] P507 magnesium extraction uses P507 extractant to extract magnesium ions. The P507 extractant is first added with liquid alkali in the saponification section for saponification and then enters the soap conversion section for soap conversion. The raffinate obtained by P507 magnesium extraction enters Cy272 magnesium extraction. The extract obtained by P507 magnesium extraction is washed with 1.5N sulfuric acid at O / A=20:1, and the obtained organic phase 4N sulfuric acid pre-extraction liquid is stripped at O / A=10:1, and the obtained blank organic is returned to saponification; the obtained aqueous phase, i.e., the P507 magnesium extraction washing liquid, enters the P507 magnesium extraction section for extraction and is combined with the P507 magnesium extraction raffinate to enter the system.

[0067] Cy272 magnesium extraction uses Cy272 extractant to extract magnesium ions. The Cy272 extractant is first added with liquid alkali in the saponification section for saponification and then enters the soap conversion section for soap conversion. The raffinate obtained by Cy272 magnesium extraction is a nickel sulfate solution. The extract obtained by Cy272 magnesium extraction is washed with 1.5N sulfuric acid at O / A=20:1, and the obtained organic phase is back-extracted with 4N sulfuric acid back-extraction pre-liquid at O / A=10:1, and the blank organic phase is returned to saponification; the obtained aqueous phase, i.e., Cy272 magnesium extraction washing liquid, enters the Cy272 magnesium extraction section for extraction and is combined with the Cy272 magnesium extraction raffinate to enter the system.

[0068] After extraction and impurity removal, the nickel ion concentration in the nickel sulfate solution was 102.36 g / L.

[0069] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for preparing nickel sulfate from a nickel raw material leachate, characterized in that: include: S1) after sequentially saponifying and converting the P204 extractant, extracting and removing impurities from the nickel raw material leaching solution with the P204 extractant to obtain a P204 raffinate and a P204 extract; S2) after sequentially saponifying and converting the P507 extractant, the obtained P507 extractant is used to extract the P204 raffinate obtained in step S1) to remove cobalt ions, thereby obtaining a P507 cobalt raffinate and a P507 cobalt extract; The P507 cobalt extract is washed, and the washed solution is returned to step S1) for soap conversion; S3) after sequentially saponifying and converting the P507 extractant, the P507 cobalt raffinate obtained in step S2) is extracted with the obtained P507 extractant to remove magnesium ions, thereby obtaining a P507 magnesium raffinate and a P507 magnesium extract; Washing the P507 magnesium extract, and returning the washed solution to one or more of step S1) and step S2) for soap conversion; S4) after sequentially saponifying and converting the Cy272 extractant, the obtained Cy272 extractant is used to extract the P507 magnesium raffinate obtained in step S3) to remove magnesium ions, thereby obtaining nickel sulfate and Cy272 extract; The Cy272 extract is washed, and the washed solution is returned to one or more of step S1), step S2) and step S3) for soap transfer.

2. The method according to claim 1, characterized in that In step S2), the O / A of the washed solution is (20-40):

1.

3. The method according to claim 1, characterized in that In step S2), the pH of the washed solution is 3.8-4.

8.

4. The method according to claim 1, characterized in that: In step S3), the O / A of the washed solution is (20-40):

1.

5. The method according to claim 1, characterized in that In step S3), the pH of the washed solution is 4.5-5.

5.

6. The method according to claim 1, characterized in that In step S4), the O / A of the washed solution is (20-40):

1.

7. The method according to claim 1, characterized in that In step S4), the pH of the washed solution is 5.0-6.

0.

8. The method according to any one of claims 1 to 7, characterized in that: In step S1), the obtained P204 extract is washed, and the washed solution is added to the nickel leaching solution for extraction and impurity removal.

9. The method according to claim 8, characterized in that The nickel raw material in the nickel raw material leaching solution is selected from one or more of nickel hydroxide, nickel sulfide or nickel matte.

10. The method according to claim 8, characterized in that Step S4) is specifically as follows: After saponifying and converting the Cy272 extractant in sequence, the obtained Cy272 extractant is used to extract the P507 magnesium raffinate obtained in step S3) to remove magnesium ions, thereby obtaining a Cy272 raffinate and a Cy272 extract; The obtained Cy272 raffinate is deoiled and evaporated for crystallization to obtain nickel sulfate crystals.

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