Method for preparing nickel sulfate and cobalt sulfate from nickel feed liquid

Abstract

The invention belongs to the technical field of hydrometallurgy, and discloses a method for preparing nickel sulfate and cobalt sulfate from nickel feed liquid. The method comprises the following steps: 1) carrying out first extraction on the nickel feed liquid by using a nickel-cobalt extraction agent to obtain a first organic phase and first raffinate; 2) washing the first organic phase with a first washing solution, wherein the first washing solution comprises sulfuric acid and nickel sulfate; (3) the washed first organic phase is subjected to reverse extraction, and a first regenerated organic extraction agent and nickel-cobalt enrichment liquid are obtained; 4) performing second extraction on the nickel-cobalt enriched liquid by using an impurity extracting agent to obtain a second organic phase and a mixed solution of nickel sulfate and cobalt sulfate; 5) washing the second organic phase by using a sulfuric acid solution, and 6) carrying out reverse extraction on the washed second organic phase to obtain a reverse extraction solution and a second regenerated organic extracting.By adopting the method provided by the invention, nickel and cobalt enrichment can be realized from the high-calcium-magnesium solution, impurity ions can be effectively removed, the process is simple, and the cost is low.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydrometallurgy, and relates to a method for preparing nickel sulfate and cobalt sulfate using a nickel feed solution. Background Art

[0002] At present, with the development of the new energy vehicle market, high-purity nickel sulfate solution is widely demanded as a source of nickel in polymetallic mixtures. The purification methods of nickel sulfate solution mainly include chemical precipitation method and extraction process. In the extraction process, nickel feed solution is generally produced by leaching for subsequent extraction. In the nickel feed solution at the leaching end, in addition to Ni 2+ it also contains Co 2+ , Mg 2+ , Ca 2+ , Mn 2+ , Cu 2+ , Fe 3+ and one or more metal impurity ions among others. The traditional extraction process obtains a high-purity nickel sulfate solution without Cl through a three-stage process of "primary impurity extraction - secondary impurity extraction - extraction enrichment". However, this purification process is complex and costly. Moreover, in the traditional P204 impurity extraction process, sulfuric acid washing and stripping are used, which will cause calcium sulfate scaling in the extraction tank and affect the normal operation of the extraction production line; while using dilute hydrochloric acid as the washing acid for washing will result in Co and Ni products being chloride salts after washing, and the waste washing liquid after washing will cause Cl to exceed the standard when recycled to the sulfate leaching system, so the recycled washing liquid cannot be reused.

[0003] Therefore, providing a method for preparing nickel sulfate solution to simplify the process flow, reduce production costs, and avoid the problems of calcium sulfate structure in the extraction tank and Cl exceeding the standard caused by the reuse of the washing liquid to the sulfate system is a technical problem that needs to be solved urgently at present. Summary of the Invention

[0004] Aiming at the above technical problems existing in the prior art, the purpose of the present invention is to provide a method for preparing nickel sulfate and cobalt sulfate using a nickel feed solution.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] The present invention provides a method for preparing nickel sulfate and cobalt sulfate using a nickel feed solution. The nickel feed solution includes nickel ions, cobalt ions and impurity ions. The impurity ions include at least one of manganese ions, calcium ions and magnesium ions. The method includes the following steps:

[0007] (1) Using a nickel-cobalt extractant to perform a first extraction on the nickel feed solution to obtain a first organic phase and a first raffinate. The nickel ions and cobalt ions are extracted into the first organic phase, and the calcium ions and magnesium ions enter the first raffinate;

[0008] (2) Wash the first organic phase obtained in step (1) with a first washing solution to obtain the washed first organic phase; wherein, the first washing solution includes sulfuric acid and nickel sulfate.

[0009] (3) Back-extract the washed first organic phase obtained in step (2) to obtain a first regenerated organic extractant and a nickel-cobalt enriched solution.

[0010] (4) Use an impurity extraction agent to perform a second extraction on the nickel-cobalt enriched solution to obtain a second organic phase and a mixed solution of nickel sulfate and cobalt sulfate, and the impurity ions are extracted into the second organic phase.

[0011] (5) Wash the second organic phase with a second washing solution to obtain the washed second organic phase; wherein, the second washing solution is a sulfuric acid solution.

[0012] (6) Back-extract the washed second organic phase obtained in step (5) to obtain a back-extract solution and a second regenerated organic extractant.

[0013] The following are the preferred technical solutions of the present invention, but do not limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the technical objectives and beneficial effects of the present invention can be better achieved.

[0014] Preferably, based on the total mass of the nickel feed solution, the content of nickel ions is 3 g / L to 5 g / L, the content of cobalt ions is 0.3 g / L to 0.35 g / L, the content of manganese ions is 2 g / L to 3 g / L, the content of calcium ions is 0.5 g / L to 0.6 g / L, and the content of magnesium ions is 7 g / L to 8 g / L.

[0015] As a preferred technical solution of the method of the present invention, in the extraction process of step (1), the extraction phase ratio O / A is 1:(2.5 - 3.5).

[0016] Preferably, in the extraction process of step (1), the nickel-cobalt extractant includes DY319 extractant and kerosene, and the mass ratio of the DY319 extractant in the nickel-cobalt extractant is 25% to 35%.

[0017] Preferably, in the extraction process of step (1), the saponification rate is 35% to 45%.

[0018] Preferably, in the extraction process of step (1), when nickel ions and cobalt ions are completely extracted, part of the manganese ions are extracted into the first organic phase.

[0019] As a preferred technical solution of the method of the present invention, the concentration of sulfuric acid in the first washing solution in step (2) is 0.15N - 0.3N, and the concentration of nickel sulfate in the first washing solution is 5g / L - 8g / L.

[0020] Preferably, the waste washing solution generated in step (2) is the third washing solution, and the third washing solution is recycled to the extraction process in step (1).

[0021] Preferably, in the stripping process of step (3), the stripping agent used is a sulfuric acid solution.

[0022] Preferably, after the stripping process of step (3), the organic phase obtained by stripping is subjected to a first water wash to obtain a first regenerated organic extraction agent, and the first regenerated organic extraction agent is recycled to the extraction process in step (1). The waste washing solution generated by the first water wash is the fourth washing solution, and the fourth washing solution is used to prepare a sulfuric acid solution.

[0023] Preferably, the impurity extraction agent in step (4) includes a P204 extraction agent.

[0024] Preferably, the second washing solution in step (5) is a sulfuric acid solution with a normal concentration of 0.15N - 0.3N.

[0025] Preferably, the waste washing solution generated in step (5) is the fifth washing solution, and the fifth washing solution is recycled to the leaching section in the preparation process of the nickel feed solution.

[0026] Preferably, in the stripping process of step (6), the stripping agent used is a sulfuric acid solution.

[0027] Preferably, after the stripping process of step (6), the organic phase obtained by stripping is subjected to a second water wash to obtain a second regenerated organic extraction agent, and the second regenerated organic extraction agent is recycled to the extraction process in step (4). The waste washing solution generated by the second water wash is the sixth washing solution, and the sixth washing solution is used to prepare a sulfuric acid solution.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] (1) By using a nickel-cobalt extraction agent to extract the nickel feed solution, the method of the present invention can enrich nickel and cobalt from a high-calcium and magnesium solution. Then, by using the first washing solution containing nickel sulfate and sulfuric acid to wash the organic phase, it is possible to use the nickel metal in the first washing solution to replace other impurity ions in the organic phase, so that the washed organic phase is a pure nickel-cobalt loaded organic phase, which is beneficial to both the enrichment of nickel concentration and the removal of impurities. After the above steps, the concentration of calcium ions in the nickel-cobalt enriched solution is low. Therefore, using a sulfuric acid solution as the second washing solution for washing will not cause calcium sulfate scaling, and moreover, the waste washing solution after washing with the sulfuric acid solution can be recycled to the leaching section in the preparation process of the nickel feed solution.

[0030] (2) The method of the present invention simplifies the process flow and reduces the production cost compared with the three-stage process of "primary impurity extraction - secondary impurity extraction - extraction enrichment" in the prior art.

[0031] (3) The nickel sulfate and cobalt sulfate in the mixed solution obtained by the method of the present invention have high purity. The content of nickel sulfate in the mixed solution is above 118 g / L, the content of cobalt sulfate is above 9 g / L, the content of Mn 2+ is below 0.2 mg / L, the content of Ca 2+ is below 0.3 mg / L, and the content of Mg 2+ is below 0.3 mg / L. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a process flow chart of a method for preparing nickel sulfate and cobalt sulfate using a nickel feed solution provided by an embodiment of the present invention.

[0033] Figure 2 is a process flow chart of a method for preparing nickel sulfate and cobalt sulfate using a nickel feed solution provided by another embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] The technical solutions of the present invention will be further described below with reference to the drawings and through specific embodiments.

[0035] The specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0036] An embodiment of the present invention provides a method for preparing nickel sulfate and cobalt sulfate using a nickel feed solution. The process flow chart is shown in Figure 1 , the nickel feed solution includes nickel ions, cobalt ions and impurity ions, and the impurity ions include at least one of manganese ions, calcium ions and magnesium ions. The method includes the following steps:

[0037] (1) Perform a first extraction on the nickel feed solution using a nickel-cobalt extractant to obtain a first organic phase and a first raffinate. The nickel ions and cobalt ions are extracted into the first organic phase, and the calcium ions and magnesium ions enter the first raffinate;

[0038] (2) Wash the first organic phase obtained in step (1) with a first washing solution to obtain a washed first organic phase; wherein, the first washing solution includes sulfuric acid and nickel sulfate;

[0039] (3) Perform back-extraction on the washed first organic phase obtained in step (2) to obtain a first regenerated organic extractant and a nickel-cobalt enriched solution;

[0040] (4) The nickel-cobalt enriched solution is subjected to a second extraction using a impurity extraction agent to obtain a second organic phase and a mixed solution of nickel sulfate and cobalt sulfate, and the impurity ions are extracted into the second organic phase;

[0041] (5) The second organic phase is washed with a second washing solution to obtain a washed second organic phase; wherein, the second washing solution is a sulfuric acid solution;

[0042] (6) The washed second organic phase obtained in step (5) is subjected to back extraction to obtain a back extraction solution and a second regenerated organic extraction agent.

[0043] In the method of one embodiment of the present invention, by using a nickel-cobalt extraction agent to extract a nickel feed solution, nickel and cobalt can be enriched from a high-calcium and magnesium solution, and then the organic phase is washed with a first washing solution containing nickel sulfate and sulfuric acid, which can use the nickel metal in the first washing solution to replace other impurity ions in the organic phase, so that the washed organic phase is a pure nickel-cobalt loaded organic phase, which is beneficial to both the enrichment of nickel concentration and the removal of impurities. After the above steps, the concentration of calcium ions in the nickel-cobalt enriched solution is low. Therefore, using a sulfuric acid solution as the second washing solution for washing will not cause calcium sulfate scaling, and moreover, the waste washing solution after washing with the sulfuric acid solution can be recycled to the leaching section of the nickel feed solution preparation process.

[0044] In the method of one embodiment of the present invention, using an impurity extraction agent to perform a second extraction on the nickel-cobalt enriched solution can achieve the purpose of purification and impurity removal, which optimizes the problems of large acid-base consumption, high cost in the impurity extraction section of the conventional extraction and purification process, and calcium sulfate scaling in the P204 impurity extraction line.

[0045] The method provided by one embodiment of the present invention simplifies the process flow and reduces the production cost compared with the 3-stage process of "primary impurity extraction - secondary impurity extraction - extraction and enrichment" in the prior art.

[0046] The purity of nickel sulfate and cobalt sulfate in the mixed solution of nickel sulfate and cobalt sulfate obtained by the method provided by one embodiment of the present invention is high. Among them, the high purity of nickel sulfate and cobalt sulfate means that the content of nickel sulfate in the mixed solution is above 118 g / L, and the content of cobalt sulfate is above 9 g / L.

[0047] In one embodiment, in the mixed solution of nickel sulfate and cobalt sulfate, the content of nickel sulfate is 118 g / L to 130 g / L, for example, it can be 118 g / L, 120 g / L, 121 g / L, 122 g / L, 123 g / L, 124 g / L, 125 g / L, 126 g / L, 127 g / L, 128 g / L, 129 g / L or 130 g / L, etc.; the content of cobalt sulfate is 9 g / L to 10 g / L, for example, it can be 9 g / L, 9.2 g / L, 9.3 g / L, 9.4 g / L, 9.5 g / L, 9.6 g / L, 9.7 g / L, 9.8 g / L or 10 g / L, etc.; the content of Mn 2+ is below 0.2 mg / L, and the content of Ca 2+ is below 0.3 mg / L, and the content of Mg 2+ is below 0.3 mg / L.

[0048] In one embodiment, based on the total mass of the nickel feed liquid, the content of nickel ions is 3 g / L to 5 g / L, for example, it can be 3 g / L, 3.2 g / L, 3.5 g / L, 3.7 g / L, 4 g / L, 4.3 g / L, 4.6 g / L or 5 g / L, etc.; the content of cobalt ions is 0.3 g / L to 0.35 g / L, for example, it can be 0.3 g / L, 0.31 g / L, 0.32 g / L, 0.33 g / L, 0.34 g / L or 0.35 g / L, etc.; the content of manganese ions is 2 g / L to 3 g / L, for example, it can be 2 g / L, 2.2 g / L, 2.3 g / L, 2.4 g / L, 2.5 g / L, 2.6 g / L, 2.8 g / L or 3 g / L, etc.; the content of calcium ions is 0.5 g / L to 0.6 g / L, for example, it can be 0.5 g / L, 0.52 g / L, 0.53 g / L, 0.54 g / L, 0.55 g / L, 0.57 g / L, 0.58 g / L or 0.6 g / L, etc.; the content of magnesium ions is 7 g / L to 8 g / L, for example, it can be 7 g / L, 7.2 g / L, 7.3 g / L, 7.5 g / L, 7.7 g / L, 7.8 g / L or 8 g / L, etc.

[0049] Using the method provided by one embodiment of the present invention to treat the nickel feed liquid with high calcium and magnesium can not only effectively enrich nickel and cobalt elements, but also efficiently remove calcium ions, magnesium ions and other impurity ions. The method of the present invention can obtain a mixed solution of nickel sulfate and cobalt sulfate, and the purity of nickel sulfate and cobalt sulfate in this mixed solution is high. In one embodiment, the nickel feed liquid is derived from the iron and aluminum removal feed liquid in the second stage of laterite nickel ore.

[0050] In one embodiment, in the extraction process of step (1), the extraction phase ratio O / A is 1:(2.5 - 3.5), for example, it can be 1:2.5, 1:2.6, 1:2.7, 1:2.8, 1:2.9, 1:3, 1:3.1, 1:3.2, 1:3.4 or 1:3.5, etc.

[0051] In one embodiment, in the extraction process of step (1), the nickel-cobalt extractant includes DY319 extractant and kerosene, and the mass ratio of the DY319 extractant in the nickel-cobalt extractant is 25% - 35%, for example, it can be 25%, 26%, 28%, 30%, 31%, 32%, 34% or 35%, etc.

[0052] In one embodiment, in the extraction process of step (1), the saponification rate is 35% - 45%, for example, it can be 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44% or 45%, etc.

[0053] In one embodiment, in the extraction process of step (1), when nickel ions and cobalt ions are completely extracted, part of the manganese ions are extracted into the first organic phase. In this case, the stripping solution is the manganese stripping solution.

[0054] In one embodiment, manganese sulfate can also be recovered from the manganese stripping solution by the method.

[0055] In one embodiment, 50% of all the manganese can be extracted into the first organic phase, and the remaining 50% of the manganese enters the first raffinate.

[0056] In one embodiment, the concentration of sulfuric acid in the first washing solution of step (2) is 0.15N - 0.3N, for example, it can be 0.15N, 0.2N, 0.25N or 0.3N, etc.; the concentration of nickel sulfate in the first washing solution is 5g / L - 8g / L, for example, it can be 5g / L, 5.5g / L, 6g / L, 6.5g / L, 7g / L, 7.5g / L or 8g / L, etc.

[0057] In one embodiment, the first washing solution is obtained by mixing a sulfuric acid solution and a nickel sulfate solution. By preparing the first washing solution in this way, the uniformity of each component can be better ensured.

[0058] In one embodiment, the waste washing liquid generated in step (2) is the third washing liquid, and the third washing liquid is recycled to the extraction process in step (1). Since when the first washing liquid is used for washing in step (2), impurity ions (such as calcium ions, magnesium ions, manganese ions) can be washed into the waste washing liquid, and it is also possible to wash down a small part of nickel ions or cobalt ions. Therefore, through this recycling step, the recovery rate of valuable recyclable metal ions (such as nickel ions, cobalt ions) can be increased.

[0059] In one embodiment, in the stripping process of step (3), the stripping agent used is a sulfuric acid solution.

[0060] In one embodiment, after the stripping process of step (3), the organic phase obtained by stripping is subjected to a first water wash to obtain a first regenerated organic extraction agent, and the first regenerated organic extraction agent is recycled to the extraction process in step (1). The waste washing liquid generated by the first water wash is the fourth washing liquid, and the fourth washing liquid is used to prepare the sulfuric acid solution.

[0061] In one embodiment, the impurity extraction agent in step (4) includes a P204 extraction agent.

[0062] In the embodiment of the present invention, the P204 extraction agent can be a commercially available reagent or a P204 extraction agent recovered from the production line. In one embodiment, the P204 extraction agent recovered from the production line contains impurity ion iron. In this case, after washing with the second washing liquid and stripping, an anti-iron step should be carried out, and the impurity iron can be removed through the anti-iron step.

[0063] In one embodiment, the second washing liquid in step (5) is a sulfuric acid solution with a normal concentration of 0.15N to 0.3N. Exemplarily, the normal concentration can be 0.15N, 0.17N, 0.18N, 0.2N, 0.22N, 0.24N, 0.25N, 0.28N or 0.3N, etc.

[0064] In one embodiment, the waste washing liquid generated by the washing in step (5) is the fifth washing liquid, and the fifth washing liquid is recycled to the leaching section in the preparation process of the nickel feed liquid.

[0065] In one embodiment, in the stripping process of step (6), the stripping agent used is a sulfuric acid solution.

[0066] In one embodiment, after the stripping process of step (6), the organic phase obtained by stripping is subjected to a second water wash to obtain a second regenerated organic extraction agent, and the second regenerated organic extraction agent is recycled to the extraction process in step (4). The waste washing liquid generated by the second water wash is the sixth washing liquid, and the sixth washing liquid is used to prepare the sulfuric acid solution.

[0067] The numerical ranges described in the present invention include not only the above-listed point values, but also any point values between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the described ranges.

[0068] Example 1

[0069] A method for preparing nickel sulfate and cobalt sulfate from a nickel feed solution, the process flow chart of which is shown in Figure 2 , the nickel feed solution includes Ni 2+ , Co 2+ and impurity ions, the impurity ions include Mn 2+ , Ca 2+ and Mg 2+ , the content of Ni 2+ is 4 g / L, the content of Co 2+ is 0.3 g / L, the content of Mn 2+ is 2.5 g / L, the content of Ca 2+ is 0.5 g / L, the content of Mg 2+ is 7.5 g / L, and the method includes the following steps:

[0070] (1) First extraction: A mixture of DY319 extractant and kerosene (the mass ratio of DY319 extractant in the mixture is 30%) is used as the cobalt-nickel extractant. The nickel feed solution is extracted with the cobalt-nickel extractant, the extraction phase ratio O / A is 1:3, and the saponification rate is 40%, to obtain the first organic phase and the first raffinate after extraction;

[0071] Nickel ions and cobalt ions are extracted into the first organic phase. When the extraction of nickel ions and cobalt ions is complete, 50% of the manganese ions are extracted into the first organic phase. Magnesium ions and calcium ions enter the first raffinate.

[0072] (2) Loading organic washing: A first washing solution is prepared using a sulfuric acid solution with a normal concentration of 0.2 N and a nickel sulfate solution with a concentration of 35 g / L. In the prepared first washing solution, the concentration of sulfuric acid is 0.2 N and the concentration of nickel sulfate is 7 g / L. The first organic phase obtained in step (1) is washed with the first washing solution, and the nickel metal in the first washing solution is used to replace the impurity ions in the first organic phase, so that the washed organic phase is a pure nickel-cobalt loaded organic phase, which is beneficial to both the enrichment of nickel concentration and the removal of impurities;

[0073] The waste washing solution after washing the first organic phase is recycled to step (1) for the first extraction.

[0074] (3) Obtaining nickel-cobalt enriched solution: The organic phase washed in step (2) is back-extracted with a sulfuric acid solution, and the back-extracted organic phase is washed with water to obtain the first regenerated organic extractant and the nickel-cobalt enriched solution;

[0075] The first regenerated organic extractant is returned to step (1) for recycling.

[0076] (4) Second extraction: Using P204 extractant as an impurity extraction agent, extract the nickel-cobalt enriched solution obtained in step (3) with the impurity extraction agent to obtain a second organic phase and a mixed solution of nickel sulfate and cobalt sulfate;

[0077] (5) Loading organic washing: Using a sulfuric acid solution with a normal concentration of 0.2N as the second washing solution, wash the second organic phase in step (4). The calcium concentration in the waste washing solution after washing is low and will not cause calcium sulfate scaling. This waste washing solution can be used in the leaching section during the preparation of nickel feed solution;

[0078] (6) Stripping: Strip the second organic phase after washing in step (5), and wash the stripped organic phase with water to obtain a second regenerated organic extractant and a manganese stripping solution;

[0079] The second regenerated organic extractant is returned to step (4) for recycling;

[0080] The manganese stripping solution is used to recover manganese sulfate.

[0081] Test the mixed solution of nickel sulfate and cobalt sulfate obtained in this example, and test the contents of nickel sulfate, cobalt sulfate, and impurity ions therein. The results are shown in Table 1.

[0082] Example 2

[0083] This example provides a method for preparing nickel sulfate and cobalt sulfate from nickel feed solution. The difference from Example 1 is that in the first washing solution, the concentration of nickel sulfate is 3 g / L.

[0084] Test the mixed solution of nickel sulfate and cobalt sulfate obtained in this example, and test the contents of nickel sulfate, cobalt sulfate, and impurity ions therein. The results are shown in Table 1.

[0085] Example 3

[0086] This example provides a method for preparing nickel sulfate and cobalt sulfate from nickel feed solution. The difference from Example 1 is that in the first washing solution, the concentration of nickel sulfate is 10 g / L.

[0087] Test the mixed solution of nickel sulfate and cobalt sulfate obtained in this example, and test the contents of nickel sulfate, cobalt sulfate, and impurity ions therein. The results are shown in Table 1.

[0088] Example 4

[0089] A method for preparing nickel sulfate and cobalt sulfate from nickel feed solution, wherein the nickel feed solution includes Ni 2+ , Co 2+and impurity ions, where the impurity ions include Mn 2+ , Ca 2+ and Mg 2+ , Ni 2+ has a content of 3 g / L, Co 2+ has a content of 0.32 g / L, Mn 2+ has a content of 2 g / L, Ca 2+ has a content of 0.55 g / L, Mg 2+ has a content of 8 g / L, and includes the following steps:

[0090] (1) First extraction: A mixture of DY319 extractant and kerosene (the mass ratio of DY319 extractant in this mixture is 25%) is used as the cobalt-nickel extractant. The nickel feed solution is extracted with the cobalt-nickel extractant. The extraction phase ratio O / A is 1:3.5, and the saponification rate is 45%, obtaining the first organic phase after extraction and the first raffinate;

[0091] Nickel ions and cobalt ions are extracted into the first organic phase. When the nickel ions and cobalt ions are completely extracted, 47% of the manganese ions are extracted into the first organic phase. Magnesium ions and calcium ions enter the first raffinate.

[0092] (2) Loaded organic washing: A first washing solution is prepared using a sulfuric acid solution with a normal concentration of 0.3 N and a nickel sulfate solution with a concentration of 30 g / L. In the prepared first washing solution, the concentration of sulfuric acid is 0.3 N, and the concentration of nickel sulfate is 6 g / L. The first organic phase from step (1) is washed with the first washing solution. The nickel metal in the first washing solution is used to replace the impurity ions in the first organic phase, making the washed organic phase a pure nickel-cobalt loaded organic phase, which is beneficial for both the enrichment of nickel concentration and the removal of impurities;

[0093] The waste washing solution after washing the first organic phase is recycled to step (1) for the first extraction.

[0094] (3) Obtaining nickel-cobalt enriched solution: The organic phase washed in step (2) is back-extracted using a sulfuric acid solution, and the back-extracted organic phase is washed with water to obtain the first regenerated organic extractant and the nickel-cobalt enriched solution;

[0095] The first regenerated organic extractant is returned to step (1) for recycling.

[0096] (4) Second extraction: P204 extractant is used as the impurity extraction agent. The nickel-cobalt enriched solution obtained in step (3) is extracted with the impurity extraction agent to obtain the second organic phase and a mixed solution of nickel sulfate and cobalt sulfate;

[0097] (5) Load organic washing: Use a sulfuric acid solution with a normal concentration of 0.2N as the second washing solution to wash the second organic phase in step (4). The calcium concentration in the waste washing solution after washing is low and will not cause calcium sulfate scaling. This waste washing solution can be used in the leaching section of the nickel feed solution preparation process.

[0098] (6) Back extraction: Perform back extraction on the second organic phase after washing in step (5), and wash the organic phase obtained by back extraction to obtain a second regenerated organic extractant and a manganese back extraction solution.

[0099] The second regenerated organic extractant is returned to step (4) for recycling.

[0100] The manganese back extraction solution is used to recover manganese sulfate.

[0101] Test the mixed solution of nickel sulfate and cobalt sulfate obtained in this example to measure the contents of nickel sulfate, cobalt sulfate, and impurity ions. The results are shown in Table 1.

[0102] Example 5

[0103] A method for preparing nickel sulfate and cobalt sulfate from a nickel feed solution, the process flow chart of which is shown in Figure 2 , the nickel feed solution includes Ni 2+ , Co 2+ and impurity ions, the impurity ions include Mn 2+ , Ca 2+ and Mg 2+ , the content of Ni 2+ is 5 g / L, the content of Co 2+ is 0.35 g / L, the content of Mn 2+ is 3 g / L, the content of Ca 2+ is 0.6 g / L, the content of Mg 2+ is 7 g / L, and the method includes the following steps:

[0104] (1) First extraction: Use a mixture of DY319 extractant and kerosene (the mass ratio of DY319 extractant in this mixture is 35%) as the cobalt-nickel extractant to extract the nickel feed solution. The extraction phase ratio O / A is 1:2.5, and the saponification rate is 35% to obtain the extracted first organic phase and the first raffinate.

[0105] Nickel ions and cobalt ions are extracted into the first organic phase. When nickel ions and cobalt ions are completely extracted, 55% of manganese ions are extracted into the first organic phase. Magnesium ions and calcium ions enter the first raffinate.

[0106] (2)Loading organic washing: Prepare the first washing solution using a sulfuric acid solution with a normal concentration of 0.15N and a nickel sulfate solution with a concentration of 40 g / L. In the prepared first washing solution, the concentration of sulfuric acid is 0.15N, and the concentration of nickel sulfate is 8 g / L. Wash the first organic phase in step (1) with the first washing solution, and use the nickel metal in the first washing solution to replace the impurity ions in the first organic phase, so that the washed organic phase is a pure nickel-cobalt loaded organic phase, which is beneficial to both the enrichment of nickel concentration and the removal of impurities;

[0107] The waste washing solution after washing the first organic phase is recycled to step (1) for the first extraction.

[0108] (3)Obtain nickel-cobalt enriched solution: Use a sulfuric acid solution to back-extract the organic phase washed in step (2), and wash the back-extracted organic phase with water to obtain the first regenerated organic extractant and the nickel-cobalt enriched solution;

[0109] The first regenerated organic extractant is returned to step (1) for recycling.

[0110] (4)Second extraction: Use P204 extractant as an impurity extraction agent, and extract the nickel-cobalt enriched solution obtained in step (3) with the impurity extraction agent to obtain a second organic phase and a mixed solution of nickel sulfate and cobalt sulfate;

[0111] (5)Loading organic washing: Use a sulfuric acid solution with a normal concentration of 0.3N as the second washing solution to wash the second organic phase in step (4). The calcium concentration in the waste washing solution after washing is low and will not cause calcium sulfate scaling. This waste washing solution can be used in the leaching section of the nickel feed solution preparation process;

[0112] (6)Back-extract: Back-extract the second organic phase washed in step (5), and wash the back-extracted organic phase with water to obtain the second regenerated organic extractant and the manganese back-extract solution;

[0113] The second regenerated organic extractant is returned to step (4) for recycling;

[0114] The manganese back-extract solution is used to recover manganese sulfate.

[0115] Test the mixed solution of nickel sulfate and cobalt sulfate obtained in this example, and test the contents of nickel sulfate, cobalt sulfate, and impurity ions in it. The results are shown in Table 1.

[0116] Comparative Example 1

[0117] The difference between this comparative example and Example 1 is that the first washing solution does not contain nickel sulfate.

[0118] Test the mixed solution of nickel sulfate and cobalt sulfate obtained in this comparative example, and test the contents of nickel sulfate, cobalt sulfate, and impurity ions in it. The results are shown in Table 1.

[0119] Comparative Example 2

[0120] The difference between this comparative example and Example 1 is that the cobalt-nickel extractant in step (1) is replaced with P204 extractant, and the impurity ions are extracted into the organic phase, while the nickel ions and cobalt ions enter the raffinate. Steps (2)-(6) are not carried out.

[0121] The raffinate obtained in this comparative example was tested for the contents of nickel sulfate, cobalt sulfate and impurity ions, and the results are shown in Table 1.

[0122] Comparative Example 3

[0123] The difference between this comparative example and Example 1 is that steps (4)-(6) are not carried out.

[0124] The nickel-cobalt enriched solution obtained in this comparative example was tested for the contents of nickel sulfate, cobalt sulfate and impurity ions, and the results are shown in Table 1.

[0125] Table 1

[0126]

[0127] It can be seen from Table 1 that the method of the present invention can achieve nickel-cobalt enrichment from a high-calcium and high-magnesium solution and effectively remove impurity ions. The purity of nickel sulfate and cobalt sulfate in the mixed solution of nickel sulfate and cobalt sulfate obtained by the method of the present invention is high. The content of nickel sulfate in the mixed solution is above 118 g / L, the content of cobalt sulfate is above 9 g / L, the content of Mn 2+ is below 0.2 mg / L, the content of Ca 2+ is below 0.3 mg / L, and the content of Mg 2+ is below 0.3 mg / L.

[0128] Moreover, compared with the three-stage process of "primary impurity extraction - secondary impurity extraction - extraction enrichment" in the prior art, the method of the present invention simplifies the process flow and reduces the production cost.

[0129] Furthermore, by comparing Example 1 with Examples 2-3, it can be seen that the concentration of nickel sulfate in the first washing solution of Example 2 is relatively low, resulting in a decrease in nickel concentration increase and impurity washing effect. The concentration of nickel sulfate in the first washing solution of Example 3 is relatively high, and the impurity washing effect is acceptable, but the nickel metal is not displaced onto the loaded organic phase, which will lead to an increase in the nickel content in the washing solution and affect the extraction performance in the extraction section, and further affect the increase in nickel concentration in the nickel sulfate and cobalt sulfate solutions.

[0130] The washing solution of Comparative Example 1 does not contain nickel sulfate, and compared with Example 2, the increase in nickel concentration and the impurity washing effect are further reduced.

[0131] In Comparative Example 2, the type of extractant was changed. In Comparative Example 3, the processes of secondary extraction, scrubbing of the loaded organic phase, and stripping were cancelled, resulting in the inability to balance the effective enrichment of nickel and cobalt and a significant decrease in the removal effect of impurity ions.

[0132] The applicant declares that the detailed method of the present invention is illustrated by the above embodiments, but the present invention is not limited to the above detailed method, that is, it does not mean that the present invention must rely on the above detailed method to be implemented. Those skilled in the art should understand that any improvement to the present invention, the equivalent substitution of each raw material of the product of the present invention, the addition of auxiliary components, and the selection of specific methods, etc., all fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A method for preparing nickel sulfate and cobalt sulfate using a nickel feed solution, characterized in that, The nickel feed solution includes nickel ions, cobalt ions, and impurity ions. The impurity ions include at least one of manganese ions, calcium ions, and magnesium ions. The method includes the following steps: (1) Perform a first extraction on the nickel feed solution using a nickel-cobalt extractant to obtain a first organic phase and a first raffinate. The nickel ions and cobalt ions are extracted into the first organic phase, and the calcium ions and magnesium ions enter the first raffinate; (2) Wash the first organic phase obtained in step (1) with a first washing solution to obtain a washed first organic phase; wherein, the first washing solution includes sulfuric acid and nickel sulfate; (3) Perform back-extraction on the washed first organic phase obtained in step (2) to obtain a first regenerated organic extractant and a nickel-cobalt enriched solution; (4) Perform a second extraction on the nickel-cobalt enriched solution using an impurity extractant to obtain a second organic phase and a mixed solution of nickel sulfate and cobalt sulfate. The impurity ions are extracted into the second organic phase; (5) Wash the second organic phase with a second washing solution to obtain a washed second organic phase; wherein, the second washing solution is a sulfuric acid solution; (6) Perform back-extraction on the washed second organic phase obtained in step (5) to obtain a back-extraction solution and a second regenerated organic extractant.

2. The method for preparing nickel sulfate and cobalt sulfate using a nickel feed solution according to claim 1, wherein, Based on the total mass of the nickel feed solution, the content of nickel ions is 3 g / L to 5 g / L, the content of cobalt ions is 0.3 g / L to 0.35 g / L, the content of manganese ions is 2 g / L to 3 g / L, the content of calcium ions is 0.5 g / L to 0.6 g / L, and the content of magnesium ions is 7 g / L to 8 g / L.

3. The method for preparing nickel sulfate and cobalt sulfate using a nickel feed solution according to claim 1, characterized in that, In the extraction process of step (1), the extraction phase ratio O / A is 1:(2.5 - 3.5); and / or, In the extraction process of step (1), the nickel-cobalt extractant includes DY319 extractant and kerosene, and the mass ratio of the DY319 extractant in the nickel-cobalt extractant is 25% - 35%; and / or, In the extraction process of step (1), the saponification rate is 35% - 45%; and / or, In the extraction process of step (1), when the nickel ions and cobalt ions are completely extracted, part of the manganese ions are extracted into the first organic phase.

4. The method for preparing nickel sulfate and cobalt sulfate using a nickel feed solution according to claim 1, characterized in that, The concentration of sulfuric acid in the first washing solution of step (2) is 0.15 N - 0.3 N, and the concentration of nickel sulfate in the first washing solution is 5 - 8 g / L.

5. The method for preparing nickel sulfate and cobalt sulfate using a nickel feed solution according to claim 1, characterized in that, The waste washing solution generated in step (2) is the third washing solution, and the third washing solution is recycled to the extraction process of step (1).

6. The method for preparing nickel sulfate and cobalt sulfate using a nickel feed solution according to claim 1, characterized in that, In the back-extraction process of step (3), the back-extraction agent used is a sulfuric acid solution; and / or After the back-extraction process of step (3), perform a first water wash on the back-extracted organic phase to obtain a first regenerated organic extractant. The first regenerated organic extractant is recycled to the extraction process of step (1). The waste washing solution generated by the first water wash is the fourth washing solution, and the fourth washing solution is used to prepare a sulfuric acid solution.

7. The method for preparing nickel sulfate and cobalt sulfate using a nickel feed solution according to claim 1, characterized in that, The impurity extractant in step (4) includes P204 extractant.

8. The method for preparing nickel sulfate and cobalt sulfate using a nickel feed solution according to claim 1, characterized in that, The second washing solution in step (5) is a sulfuric acid solution with an equivalent concentration of 0.15 N - 0.3 N; and / or, The waste washing liquid generated in step (5) is the fifth washing liquid, and the fifth washing liquid is recycled to the leaching section in the preparation process of the nickel feed liquid.

9. The method for preparing nickel sulfate and cobalt sulfate using a nickel feed solution according to claim 1, characterized in that, In the stripping process described in step (6), the stripping agent used is a sulfuric acid solution; and / or, After the stripping process described in step (6), the organic phase obtained by stripping is subjected to a second water wash to obtain a second regenerated organic extractant, and the second regenerated organic extractant is recycled to the extraction process described in step (4). The waste washing liquid generated by the second water wash is the sixth washing liquid, and the sixth washing liquid is used to prepare a sulfuric acid solution.

10. The method for preparing nickel sulfate and cobalt sulfate using a nickel feed solution according to claim 1, characterized in that, The stripping liquid is used to recover manganese sulfate.

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