Method for removing cobalt in nickel chloride solution

Abstract

The invention provides a method for removing cobalt in a nickel chloride solution, which comprises the following steps: adding the nickel chloride solution into an extraction organic phase for extraction, transferring cobalt ions into a loaded organic phase, and retaining nickel ions in a water-phase raffinate; an extraction agent in the extraction organic phase comprises N235, P507 and Cyphos IL 101 (trihexyltetradecyl phosphonium chloride). According to the method, N235, P507 and Cyphos IL 101 are adopted as synergistic extraction agents to extract the nickel chloride solution, the separation effect on impurity ions such as cobalt ions and nickel in the nickel chloride solution is good, the saponification step of traditional extraction is avoided, use of alkali and discharge of waste alkali liquor are reduced, and the method is economical, environmentally friendly and capable of being applied to a complex system; due to the addition of the Cyphos IL 101 ionic liquid in the synergistic extraction system, the stability of the whole extraction system can be improved, the extraction capacity of an organic phase is enhanced, and the influence on the environment is reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of high-purity nickel and relates to a method for removing impurities from nickel electrolytic solution. Background Art

[0002] With the development of economy and science and technology, the demand for high-purity metal materials in high-end manufacturing industry is getting higher and higher. Among them, high-purity nickel metal is widely used in the preparation of integrated circuits, sputtering targets and other fields due to its excellent properties such as high chemical stability and ferromagnetism. The key to preparing high-purity nickel is to obtain a high-purity nickel salt solution. At present, the main methods for purifying nickel salt solutions include ion exchange, chemical precipitation, solvent extraction, etc. Among them, solvent extraction has been widely used due to its advantages such as good deep purification effect, simple process flow, high recovery rate and high level of automation equipment. However, traditional extractants have problems such as environmental pollution, low extraction capacity, high volatility and applicability restrictions. Therefore, the development of a green, efficient and widely applicable extraction system is of great significance for the preparation of high-purity cobalt.

[0003] CN109518006A discloses a method for removing trace cobalt from a nickel chloride solution. The method comprises mixing the extractant Cyanex272 with sulfonated kerosene, first performing sodium soaping with a 300-400 g / L sodium hydroxide solution, and then performing nickel soaping with a nickel chloride solution to obtain a nickel soaped Cyanex272 organic phase. The pH-adjusted nickel chloride solution and the nickel soaped Cyanex272 organic phase are then mixed and subjected to extraction and purification to simultaneously remove cobalt, copper, and iron. After purification, the mass concentration ratio of nickel to cobalt in the solution reaches greater than 400,000. After impurity removal, a pure nickel chloride solution is obtained, with the cobalt content reduced to 0.001 g / L, and the copper and iron contents reduced to 0.0001 g / L. The nickel plate product produced using the impurity-removed solution as raw material has a purity of 99.999%. CN105349780A discloses a method for purifying nickel electrolytic solution for preparing high-purity nickel plates. The method uses Cyanex272, an extractant, to extract and purify a nickel chloride solution with a pH adjusted to remove cobalt, copper, and iron. After purification, the nickel-cobalt content in the solution reaches a ratio of more than 400,000. The extraction process uses a Cyanex272 extractant ratio of 2-10%, a solvent oil ratio of 90-98%, a saponification rate of 30-50%, an extraction ratio of 1:1, and an extraction stage of 2-6. The purified nickel chloride solution is electrolytically deposited in an electrolytic tank. After electrolysis, the nickel plate obtained has a purity of 99.999%, wherein the cobalt and copper contents are less than 1 ppm, and the iron content is less than 2 ppm. Although these existing technologies are effective in removing impurities from nickel chloride solutions, they require the extractant to undergo a saponification reaction before participating in extraction, which not only makes the process more complicated but also requires the use of a large amount of sodium hydroxide solution for saponification. In addition, although the separation performance of Cyanex272 is improved compared to P204 and P507, it has disadvantages such as low saturation load and high cost. Summary of the Invention

[0004] In response to the above technical problems, the present application provides a method for removing cobalt from a nickel chloride solution.

[0005] To achieve the above objectives, this application proposes the following technical solutions: The present invention provides a method for removing cobalt from a nickel chloride solution, comprising: A nickel chloride solution is added to the extraction organic phase for extraction, whereby cobalt ions are transferred to the loaded organic phase and nickel ions are retained in the aqueous raffinate. The extractants in the extraction organic phase include N235, P507, and Cyphos IL 101 (trihexyltetradecylphosphine chloride), and the concentration of Cyphos IL 101 in the extraction organic phase is 0.5-2 mmol / L.

[0006] Furthermore, in the extractant, the molar ratio of N235 to P507 is 2:1~4.

[0007] Furthermore, the O / A ratio of the extraction is 1 to 3:1.

[0008] Furthermore, the extraction is 3 to 6 stage countercurrent extraction.

[0009] Furthermore, the extraction temperature is 20-60°C.

[0010] Furthermore, the extraction organic phase also includes a diluent; the diluent is sulfonated kerosene; and in the extraction organic phase, the volume proportion of the diluent is 75-85%.

[0011] Furthermore, the method further comprises adjusting the pH of the nickel chloride solution to 2-4 before extraction.

[0012] Furthermore, a stripping step is included; the stripping step includes: mixing the loaded organic phase with a stripping agent and performing stripping.

[0013] Furthermore, the stripping agent is 4-4.5 mol / L electronic grade hydrochloric acid.

[0014] Furthermore, the O / A ratio of the stripping is 10-15:1.

[0015] Furthermore, the stripping is 4 to 6 stages of countercurrent stripping.

[0016] Furthermore, a nickel washing step is included between the extraction step and the stripping step; the nickel washing includes: mixing the loaded organic phase with hydrochloric acid having a concentration of 1 to 1.5 mol / L according to an O / A ratio of 10 to 15:1 for washing, and returning the washed aqueous phase as a raw material for the nickel chloride solution in step S1.

[0017] Furthermore, the nickel washing is a 4-6 stage countercurrent nickel washing.

[0018] Furthermore, the concentration of Ni in the nickel chloride solution is 220-240 g / L.

[0019] Furthermore, the impurity ions in the nickel chloride solution include cobalt ions, copper ions, iron ions, lead ions, and zinc ions.

[0020] Compared with the prior art, one or more of the above technical solutions can achieve at least one of the following beneficial effects: The method of the present invention uses N235, P507, and Cyphos IL 101 as synergistic extractants to extract a nickel chloride solution. The method has a good separation effect on nickel and impurity ions such as cobalt ions in the nickel chloride solution, avoids the saponification step of traditional extraction, reduces the use of alkali and the discharge of waste alkali solution, is economical and environmentally friendly, and can be applied to complex systems. The addition of Cyphos IL 101 ionic liquid in the synergistic extraction system can improve the stability of the entire extraction system, enhance the extraction capacity of the organic phase, and reduce the impact on the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 The figure is a process flow chart of the method for removing cobalt from nickel chloride solution in the present invention. DETAILED DESCRIPTION

[0023] The present invention provides a method for removing cobalt from a nickel chloride solution, comprising: A nickel chloride solution is added to the extraction organic phase for extraction, whereby cobalt ions are transferred to the loaded organic phase and nickel ions are retained in the aqueous raffinate. The extractant in the extraction organic phase includes N235, P507, and Cyphos IL 101 (trihexyltetradecylphosphine chloride), and the concentration of Cyphos IL 101 in the extraction organic phase is 0.5 to 2 mmol / L, for example, 0.5 mmol / L, 0.8 mmol / L, 1 mmol / L, 1.2 mmol / L, 1.5 mmol / L, 1.8 mmol / L, 2 mmol / L, etc.

[0024] Compared with traditional extraction methods, the above method optimizes the traditional extraction process, reduces evaporation loss of the organic phase in this method, and is more environmentally friendly. In addition, the ionic liquid Cyphos IL 101 has good solubility in organic solvents, and the resulting organic phase is more stable. The saponification step of the traditional method is eliminated, and the use of strong alkali is greatly reduced, which reduces the use of alkali and the discharge of waste alkali liquid. It is economical and environmentally friendly, can circumvent the restrictions of amine extractants on solution components, can extract and remove cobalt in various systems, and the synergistic extraction of N235, P507, and Cyphos IL 101 has a better impurity removal effect than traditional extraction. The method has the advantages of simple process, applicability to complex systems, high loading capacity, and environmental friendliness.

[0025] The structure of the Cyphos IL 101 (trihexyltetradecylphosphonium chloride) ionic liquid used is shown below: In some preferred embodiments, in the extractant, the molar ratio of N235 to P507 is 2:1-4, for example, 2:1, 2:2, 2:3, 2:4, etc.

[0026] In some preferred embodiments, the O / A ratio of the extraction is 1 to 3:1, for example, 1:1, 2:1, 3:1, etc.

[0027] In some preferred embodiments, the extraction is 3 to 6 stage countercurrent extraction, for example, 3, 4, 5, or 6 stages.

[0028] In some preferred embodiments, the extraction temperature is 20-60°C, for example, 20°C, 25°C, 30°C, 35°C, 40°C, 45°C, 50°C, 55°C, 60°C, etc.

[0029] In some preferred embodiments, the extraction organic phase further includes a diluent; the diluent is sulfonated kerosene; and the volume proportion of the diluent in the extraction organic phase is 75-85%, for example, 75%, 78%, 80%, 82%, 85%, etc.

[0030] In some preferred embodiments, the pH of the nickel chloride solution is adjusted to 2-4, such as 2, 2.5, 3, 3.5, 4, etc., before extraction.

[0031] In some preferred embodiments, a stripping step is further included; the stripping step comprises: mixing the loaded organic phase with a stripping agent for stripping.

[0032] In some preferred embodiments, the stripping agent is 4-4.5 mol / L electronic grade hydrochloric acid.

[0033] In some preferred embodiments, the O / A ratio of the stripping is 10-15:1, for example, 10:1, 11:1, 12:1, 13:1, 14:1, 15:1, etc.; and the stripping is 4-6 stage countercurrent stripping, for example, 4 stage, 5 stage, and 6 stage.

[0034] In some preferred embodiments, a nickel washing step is further included between the extraction step and the stripping step; the nickel washing step comprises: mixing the loaded organic phase with hydrochloric acid having a concentration of 1 to 1.5 mol / L according to an O / A ratio of 10 to 15:1 for washing, and returning the washed aqueous phase as the raw material for the nickel chloride solution in step S1. - The concentration is closely related, so using the washing water phase as the raw material of nickel chloride solution can increase Cl - concentration to improve extraction effect.

[0035] In some preferred embodiments, the nickel washing is 4 to 6 stages of countercurrent nickel washing, such as 4 stages, 5 stages, 6 stages, etc.

[0036] In some preferred embodiments, the concentration of the nickel chloride solution is 220-240 g / L.

[0037] In some preferred embodiments, the impurity ions in the nickel chloride solution include cobalt ions, copper ions, iron ions, lead ions, and zinc ions.

[0038] To facilitate understanding of the present invention, the present invention will be described in more comprehensive and detailed form below in conjunction with the accompanying drawings and preferred embodiments. However, the scope of protection of the present invention is not limited to the following specific embodiments.

[0039] In order to verify the technical effect of the method of the present invention, the following single-stage extraction condition experiment was carried out: Example 1 The method for removing impurities from nickel chloride solution is shown in the flow chart below: Figure 1 Shown, including: Step 1, prepare nickel chloride solution: use nickel chloride hexahydrate crystals and pure water or the washing water in step 5 to mix and prepare a solution to obtain a pre-extraction solution. 2+ The concentration is 220 g / L; Step 2: Prepare the organic phase: the volume ratio of N235:P507 in the organic phase is 2:3, the concentration of Cyphos IL 101 is 0.5 mmol / L, and the volume of sulfonated kerosene accounts for 75%, and the mixture is mixed evenly according to the required volume ratio.

[0040] Step 3, pH adjustment: Use hydrochloric acid to adjust the pH value of the initial pre-extraction solution to 3.5; Step 4, extraction and impurity removal: According to the oil-water phase (O / A) ratio of 1:1, the nickel chloride solution in step 3 and the organic phase in step 2 were mixed and reacted at an appropriate temperature for 10 minutes to obtain a loaded organic phase and an extracted liquid. The compositions of the extracted liquid and the pre-extracted liquid are shown in Table 1.

[0041] Table 1 Changes in some impurity contents before and after nickel chloride extraction (g / L) Comparative Example 1 Comparative Example 1 differs only from Example 1 in that, in step 2, the organic phase composition is different, and the Cyphos IL 101 concentration in the organic phase is 0. Specifically, step 2 involves preparing an organic phase with a volume ratio of N235:P507 = 2:3, with sulfonated kerosene accounting for 75% by volume, and mixing uniformly according to the required volume ratio.

[0042] The components of the post-extraction liquid and pre-extraction liquid are shown in Table 3.

[0043] Table 2 Changes in some impurity contents before and after nickel chloride extraction (g / L) Comparative Example 2 The only difference between Comparative Example 2 and Example 1 is that in step 2, the composition of the prepared organic phase is different, and the extractant in the organic phase is Cyphos IL 101, which does not contain N235 and P507.

[0044] Step 2: Prepare the organic phase: the concentration of Cyphos IL 101 in the organic phase is 0.5 mmol / L, and the rest is sulfonated kerosene.

[0045] The components of the post-extraction liquid and pre-extraction liquid are shown in Table 3.

[0046] Table 3 Changes in some impurity contents before and after nickel chloride extraction (g / L) The data in Table 4 were calculated based on the results of nickel ions and cobalt ions tested in Example 1, Comparative Example 1, and Comparative Example 2. It can be seen from Table 4 that the mixed organic phase of Cyphos IL 101, N235, and P507 has a synergistic effect on the separation of Ni and Co.

[0047] Table 4 Example 2 The method for removing impurities from nickel chloride solution is shown in the flow chart below: Figure 1 Shown, including: Step 1, prepare nickel chloride solution: use nickel chloride hexahydrate crystals and pure water or the washing water in step 5 to mix and prepare a solution to obtain a pre-extraction solution. 2+ The concentration is 220 g / L; Step 2: Prepare the organic phase: the volume ratio of N235:P507 in the organic phase is 2:3, the concentration of Cyphos IL 101 is 0.5 mmol / L, and the volume of sulfonated kerosene accounts for 75%, and the mixture is mixed evenly according to the required volume ratio.

[0048] Step 3, pH adjustment: Use hydrochloric acid to adjust the pH value of the initial pre-extraction solution to 4; Step 4, extraction and impurity removal: The nickel chloride solution in step 3 was mixed with the organic phase in step 2 at an oil-water ratio (O / A) of 1:1, and 6-stage countercurrent extraction was performed with a mixing and clarification ratio of 1:5 (i.e., the volume ratio of the mixing tank to the clarification tank was 1:5) to obtain a loaded organic phase and an extracted liquid. The compositions of the extracted liquid and the pre-extracted liquid are shown in Table 5.

[0049] Step 5, nickel washing: Use 1.5 mol / L hydrochloric acid to mix with the loaded organic phase, with a ratio (O / A) of 13:1, and wash the nickel in 6-stage countercurrent. Return the washed aqueous phase to step 1; Step 6, stripping: the loaded organic phase after the nickel washing step is mixed with a stripping agent, the stripping agent is 4 mol / L electronic grade hydrochloric acid, the phase ratio (O / A) is 14:1, 5-stage countercurrent stripping, and the mixed clarification ratio is 1:5.

[0050] Table 5 Changes in some impurity contents before and after nickel chloride extraction (g / L) Example 3 Step 1, prepare nickel chloride solution: use nickel chloride hexahydrate crystals and pure water or the washing water in step 5 to mix and prepare a solution to obtain a pre-extraction solution. 2+ The concentration is 230 g / L; Step 2: Prepare the organic phase: the volume ratio of N235:P507 in the organic phase is 2:3, the concentration of Cyphos IL 101 is 1.5mmol / L, and the sulfonated kerosene accounts for 80%. Mix them evenly according to the required volume ratio.

[0051] Step 3, pH adjustment: Use hydrochloric acid to adjust the initial solution pH to 4; Step 4, extraction and impurity removal: the oil-water phase ratio (O / A) is 2:1, the nickel chloride solution in step 3 is mixed with the organic phase in step 2 for reaction, 6-stage countercurrent extraction is performed, and the mixing and clarification ratio is 1:5 to obtain a loaded organic phase and a post-extraction liquid. The compositions of the post-extraction liquid and the pre-extraction liquid are shown in Table 6.

[0052] Step 5, nickel washing: use 1.2 mol / L hydrochloric acid and the loaded organic phase mixed with the ratio (O / A) = 12:1, 6-stage countercurrent washing of nickel, and return the washing aqueous phase to step 1; Step 6, stripping: the loaded organic phase is mixed with a stripping agent, the stripping agent is 4 mol / L electronic grade hydrochloric acid, the phase ratio (O / A) is 12:1, 5-stage countercurrent stripping, and the mixed clarification ratio is 1:5.

[0053] Table 6 Changes in some impurity contents before and after nickel chloride extraction (g / L) Example 4 Step 1: Prepare nickel chloride solution: Prepare cobalt chloride solution: Use cobalt chloride hexahydrate crystals and pure water or the washing water in step 5 to mix and prepare a solution. 2+ The concentration is 240 g / L (pre-extraction solution); Step 2: Prepare the organic phase: the volume ratio of N235:P507 in the organic phase is 2:3, the concentration of Cyphos IL 101 is 2.0mmol / L, and the sulfonated kerosene accounts for 85%. Mix them evenly according to the required volume ratio.

[0054] Step 3, pH adjustment: Use hydrochloric acid to adjust the initial solution pH to 3; Step 4, extraction and impurity removal: the oil-water phase ratio (O / A) is 3:1, the nickel chloride solution in step 3 is mixed with the organic phase in step 2 for reaction, 6-stage countercurrent extraction is performed, and the mixing and clarification ratio is 1:5 to obtain a loaded organic phase and a post-extraction liquid. The compositions of the post-extraction liquid and the pre-extraction liquid are shown in Table 7.

[0055] Step 5, nickel washing: use 1.0 mol / L hydrochloric acid and the loaded organic phase mixed with the ratio (O / A) = 12:1, 6-stage countercurrent washing of nickel, and return the washing aqueous phase to step 1; Step 6, stripping: the loaded organic phase is mixed with a stripping agent, the stripping agent is 4 mol / L electronic grade hydrochloric acid, the phase ratio (O / A) is 12:1, 5-stage countercurrent stripping, and the mixed clarification ratio is 1:5.

[0056] Table 7 Changes in some impurity contents before and after nickel chloride extraction (g / L) As can be seen from Tables 1 to 4, compared with the single extractant Cyphos IL 101 or the composite extractants N235 and P507, the composite extractant of Cyphos IL 101, N235, and P507 has a better separation effect on nickel and cobalt, achieving a synergistic extraction and separation effect. As can be seen from Tables 5 to 7, the method of the present invention can achieve good separation of Ni and impurity ions (such as cobalt ions, copper ions, trivalent iron ions, lead ions, zinc ions, etc.), especially the separation effect of Ni and Co is very good.

[0057] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for removing cobalt from a nickel chloride solution, characterized in that: include: A nickel chloride solution is added to an extraction organic phase for extraction, cobalt ions are transferred to the loaded organic phase, and nickel ions are retained in the aqueous phase raffinate; the extractant in the extraction organic phase includes N235, P507 and Cyphos IL 101 (trihexyltetradecylphosphine chloride), and the concentration of Cyphos IL 101 in the extraction organic phase is 0.5-2 mmol / L.

2. The method for removing cobalt from a nickel chloride solution according to claim 1, wherein: In the extractant, the molar ratio of N235 to P507 is 2:1-4.

3. The method for removing cobalt from a nickel chloride solution according to claim 1, wherein: The O / A ratio of the extraction is 1 to 3:1; The extraction is 3 to 6 levels of countercurrent extraction; The extraction temperature is 20-60°C.

4. The method for removing cobalt from a nickel chloride solution according to claim 1, wherein: The extraction organic phase also includes a diluent; the diluent is sulfonated kerosene; in the extraction organic phase, the volume proportion of the diluent is 75-85%.

5. The method for removing cobalt from a nickel chloride solution according to claim 1, wherein: The method also includes adjusting the pH of the nickel chloride solution to 2-4 before extraction.

6. The method for removing cobalt from a nickel chloride solution according to claim 1, wherein: The stripping step is also included; the stripping step includes: mixing the loaded organic phase with a stripping agent to perform stripping; The stripping agent is 4-4.5 mol / L electronic grade hydrochloric acid.

7. The method for removing cobalt from a nickel chloride solution according to claim 6, wherein: The O / A ratio of the stripping is 10-15:1; the stripping is 4-6 stages of countercurrent stripping.

8. The method for removing cobalt from a nickel chloride solution according to claim 6 or 7, wherein: A nickel washing step is also included between the extraction step and the stripping step; the nickel washing includes: mixing the loaded organic phase with hydrochloric acid having a concentration of 1-1.5 mol / L at an O / A ratio of 10-15:1 for washing, and returning the washed aqueous phase as a raw material for the nickel chloride solution in step S1.

9. The method for removing cobalt from a nickel chloride solution as claimed in claim 8, wherein: The nickel washing is 4 to 6 stages of countercurrent nickel washing.

10. The method for removing cobalt from a nickel chloride solution according to claim 8, wherein: The concentration of Ni in the nickel chloride solution is 220-240 g / L; The impurity ions in the nickel chloride solution include cobalt ions, copper ions, iron ions, lead ions and zinc ions.

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