Two-step extraction process for preparing battery-grade nickel from laterite-nickel ore high-pressure leach solution

Abstract

The present invention relates to a two-step extraction process for preparing battery-grade nickel from a laterite-nickel ore high-pressure leach solution, comprising the following steps: preparing an extraction organic phase; mixing the extraction organic phase with a laterite-nickel ore high-pressure leach solution having a pH value of 2-5 and performing extraction to obtain a first nickel-loaded organic phase; using a pickling acid to wash the first nickel-loaded organic phase to obtain a second nickel-loaded organic phase; using a first stripping acid to strip Ni from the second nickel-loaded organic phase to obtain a first-stage stripped solution; adding an acid solution to the first-stage stripped solution to prepare a second stripping acid, and introducing the second stripping acid into a stripping section for second-stage stripping to obtain a second-stage stripped solution; and subjecting the second-stage stripped solution to a saponification-based impurity removal extraction line to obtain a battery-grade nickel solution. In the present invention, the battery-grade nickel is prepared by utilizing a two-step extraction process of segmented stripping and subsequent saponification-based extraction and impurity removal. The problem that extraction agents are not acid-resistant is solved, and the concentration of nickel in the final stripped solution is guaranteed; in addition, by placing the extraction and impurity removal step at the end, nickel is effectively enriched, the subsequent crystallization cost is reduced, and the resulting nickel-enriched solution is purified.

Description

Two-step extraction process for preparing battery-grade nickel from high-pressure leaching solution of laterite nickel ore Technical Field

[0001] The invention belongs to the technical field of hydrometallurgy, and in particular relates to a two-step extraction process for preparing battery-grade nickel from a high-pressure leaching solution of laterite nickel ore. Background Art

[0002] Currently, laterite nickel ore is extracted through a sequential process of high-pressure leaching, circulating leaching, pre-neutralization, CCD washing, secondary iron and aluminum removal, and secondary nickel and cobalt precipitation to produce the intermediate MHP product. The MHP then undergoes slurrying, acid dissolution, and impurity removal to produce a nickel-cobalt solution containing impurities. This solution then undergoes P204 impurity removal and P507 magnesium stripping to produce a nickel sulfate solution. This solution then passes through a dedicated P507 enrichment line to obtain a pure nickel solution. Furthermore, C272 extractant is often required in the extraction stage to separate nickel and cobalt. Furthermore, due to the poor ability of these extractants to separate nickel, cobalt, and impurities, the nickel solution may require additional C272 extraction and purification lines for further impurity removal. Finally, recrystallization produces battery-grade nickel salt crystals. It is important to note that some extractants, such as HBL110 and HBL119, have limited acid resistance. This limits the acid concentration in the stripping stage, limiting their ability to enrich valuable metals and directly affecting the cost of subsequent crystallization of the valuable metal salt solution. However, few people have paid attention to and solved the problem of extractants being acid-resistant.

[0003] The current hydrometallurgical process for extracting battery-grade nickel from laterite nickel ore is not only cumbersome but also time-consuming and material-intensive. For example, flocculants must be used in each step of MHP preparation, including washing, impurity removal, and nickel-cobalt precipitation. Large amounts of liquid caustic soda are required for the second stage of nickel-cobalt precipitation, significantly increasing the cost of hydrometallurgical nickel extraction.

[0004] Summary of the Invention

[0005] The purpose of the present invention is to overcome the above-mentioned technical deficiencies and provide a two-step extraction process for preparing battery-grade nickel from a high-pressure leachate of laterite nickel ore. This process not only solves the technical problems of the prior art in extracting battery-grade nickel, which is complicated and costly, but also develops a staged stripping process.

[0006] In order to achieve the above technical purpose, the technical solution provided by the present invention is:

[0007] In a first aspect, the present invention provides a two-step extraction process for preparing battery-grade nickel from a laterite nickel ore high-pressure leachate, comprising the following steps:

[0008] (1) preparing an organic phase for extraction;

[0009] (2) extracting nickel: mixing the extracted organic phase with a laterite nickel ore high-pressure leaching solution having a pH value of 2 to 5 to obtain a first nickel-loaded organic phase;

[0010] (3) washing: washing the first nickel-loaded organic phase with washing acid to obtain a second nickel-loaded organic phase;

[0011] (4) One-stage stripping: stripping the Ni in the second nickel-loaded organic phase with the first counter-acid to obtain a one-stage stripping solution;

[0012] (5) Second stage stripping: Acid solution is added to the first stage stripping solution to prepare H + The second back acid with a concentration of 0.1 to 4 mol / L is passed into the stripping section of step (4) for two-stage stripping to obtain a second-stage stripping solution with a nickel concentration of greater than 80 g / L of the required purity;

[0013] (6) The second-stage stripping liquid passes through a soap removal and impurity removal extraction line to obtain a battery-grade nickel solution.

[0014] Preferably, in step (1), the step of preparing the extracted organic phase comprises: mixing an extractant with a diluent, and then saponifying to obtain a prepared extracted organic phase; the dilution rate of the extractant is 10-60% (including but not limited to 10, 20, 30, 40, 50 or 60%, etc.), the saponification rate is 10-70% (including but not limited to 10, 20, 30, 40, 50, 60 or 70%, etc.), and the saponification level is 1-2.

[0015] More preferably, the extractant is P507 or HBL110, the diluent is sulfonated kerosene or Escaid110, and the saponifier is liquid alkali or ammonia water.

[0016] Preferably, in step (2), 10-15% lime milk is used to adjust the pH of the laterite nickel ore high-pressure leaching solution.

[0017] Preferably, in step (2), the flow ratio of the extracted organic phase to the laterite nickel ore high-pressure leachate is 2:0.5-3 (including but not limited to 2:0.5, 2:0.6, 2:0.7, 2:0.8, 2:1, 2:1.5, 2:2, 2:2.2, 2:2.5, 2:2.7 or 2:3, etc.), and the extraction stage is 2-10 (including but not limited to 2, 3, 4, 5, 6, 7, 8, 9 or 10, etc.).

[0018] Preferably, in step (3), the washing acid is a sulfuric acid solution, hydrochloric acid solution, oxalic acid solution or nitric acid solution with a concentration of 0.05 to 0.7 mol / L, and the washing acid concentration includes but is not limited to 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6 or 0.7 mol / L. The washing acid is used to wash away the Co, Mn, Mg, Ca, Fe, Al, Cr, Zn and Si impurities in the first nickel-loaded organic phase.

[0019] Preferably, in step (3), the flow ratio of the washing acid to the first nickel-loaded organic phase is 1:1 to 30, including but not limited to 1:1, 1:3, 1:5, 1:10, 1:15, 1:20, 1:25 or 1:30; the number of washing stages is 2 to 9, including but not limited to 2, 3, 4, 5, 6, 7, 8 or 9; the washing liquid obtained after washing is returned to step (2) for reuse in extraction and nickel extraction.

[0020] Preferably, in step (4), the first acid is H + Sulfuric acid solution, hydrochloric acid solution, oxalic acid solution or nitric acid solution with a concentration of 0.05 to 4 mol / L; the first acid reflux concentration includes but is not limited to 0.05, 0.1, 0.5, 1, 1.5, 2, 2.5, 3, 3.5 or 4 mol / L.

[0021] Preferably, in step (4), the flow ratio of the first back acid to the second nickel-loaded organic phase is 1:1 to 30, including but not limited to 1:1, 1:3, 1:5, 1:8, 1:10, 1:15, 1:20, 1:25 or 1:30; the number of back extraction stages is 3 to 10, including but not limited to 3, 4, 5, 6, 7, 8 or 10; the blank organic phase after back extraction is washed with pure water and then saponified, and then returned to step (2) for reuse in extraction and nickel extraction.

[0022] Preferably, in step (5), the acid solution added is sulfuric acid solution, hydrochloric acid solution, oxalic acid solution or nitric acid solution.

[0023] Preferably, in step (5), the flow ratio of the second acid back to the second nickel-loaded organic phase is 1:1 to 30, including but not limited to 1:1, 1:3, 1:5, 1:8, 1:10, 1:15, 1:20, 1:25 or 1:30, etc.; the number of stripping stages is 3 to 10, including but not limited to 3, 4, 5, 6, 7, 8 or 10, etc.

[0024] Preferably, in step (6), the soap conversion and impurity removal extraction line is a production line P204 impurity removal extraction line, including saponification and nickel sulfate soap conversion steps, and the saponification uses sodium hydroxide or ammonia water; wherein, P204 is used to further remove a small amount of various impurities such as Fe, Al, Mn, Ca, Cu, Zn, Cr, etc. in the second-stage stripping solution, and at the same time, nickel in the organic phase is extracted during the soap conversion process to further increase the nickel concentration in the second-stage stripping solution to reach the industry standard of 120 to 130 g / L. The specific P204 extraction and impurity removal line is a relatively mature technology in this field. Those skilled in the art can select or adjust it according to the situation to achieve the target concentration of battery-grade nickel concentration, and no specific limitation is made here.

[0025] The main mechanism of action of the present invention:

[0026] The present invention adopts a new two-step extraction process. After the pH of the high-pressure leachate of laterite nickel ore is pre-adjusted, a nickel solution with the required purity and a nickel concentration greater than 80g / L is obtained by staged stripping. Then, various impurities such as Cu are removed by soap extraction, and nickel is further enriched to the target concentration to obtain a battery-grade nickel solution.

[0027] In order to reduce the concentration of various impurities in the second-stage stripping solution, the present invention can regulate the following parameters:

[0028] (1) Extraction section: Appropriately reduce the flow rate of the organic phase extracted in the extraction section or reduce the number of stages of the extraction section so that the extractant extracts less impurities.

[0029] (2) Washing section: Increase the flow rate or concentration of washing acid to fully wash impurities.

[0030] (3) Stripping section: Increase the number of stripping sections to pull various impurities back in the stripping section; appropriately reduce the stripping liquid concentration in the stripping section and increase the number of stripping sections.

[0031] However, in order to take into account the nickel concentration in the final second-stage stripping solution, the present invention preferably adjusts the above parameters to achieve a high nickel concentration in the second-stage stripping solution while minimizing the impurity content.

[0032] Compared with the prior art, the beneficial effects of the present invention include:

[0033] The present invention combines a two-step extraction process of segmented stripping and subsequent soap extraction and impurity removal to prepare a battery-grade nickel solution. The segmented stripping solves the problem of the extractant's acid resistance and ensures the nickel concentration in the final stripping solution. The extraction and impurity removal step is placed after the nickel enrichment step, which not only effectively enriches nickel and reduces the subsequent crystallization cost of nickel sulfate, but also improves the purity of the final nickel-enriched solution.

[0034] In addition, the present invention breaks through the current process of extracting battery-grade nickel from laterite nickel ore, solves the problems of lengthy process flow and large consumption of various auxiliary materials such as acids, alkalis, and flocculants when preparing battery-grade nickel solution, and greatly simplifies the process of preparing battery-grade nickel from laterite nickel ore. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] FIG1 is a flow chart of the treatment process of the present invention. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0037] The composition of the laterite nickel ore high-pressure leaching solution adjusted to pH 4 used in the following examples of the present invention is shown in Table 1 below.

[0038] Table 1 Composition of laterite nickel ore high pressure leaching solution (pH=4)

[0039] Example 1

[0040] Referring to FIG1 , a two-step extraction process for preparing battery-grade nickel from a laterite nickel ore high-pressure leachate of the present invention comprises the following steps:

[0041] (1) Preparation of HBL110 extraction organic phase: dilution rate is 40%, saponification rate is 70%, saponification is carried out with 30% NaOH, and saponification grade is 1.

[0042] (2) The extracted organic phase and the laterite nickel ore high-pressure leaching solution (pH = 4) are introduced into a continuous extraction tank at a certain flow rate. The inlet flow rate ratio of the extracted organic phase to the laterite nickel ore high-pressure leaching solution (pH = 4) is 0.9:1. The number of extraction stages is 8, and the nickel-loaded extracted organic phase and the raffinate are obtained. The raffinate composition is as follows.

[0043] Table 2 Raffinate composition

[0044] (3) The impurities Co, Mn, Mg, Ca, Fe, Al, Cr, Zn and Si in the organic phase were washed and extracted with a 0.15 mol / L sulfuric acid solution. The flow ratio of the sulfuric acid solution to the first nickel-loaded organic phase was 0.25:1, and the number of washing stages was 9. The washed washing solution was introduced into the laterite nickel ore high-pressure leaching solution (pH = 4) in the inlet tank for further extraction and recovery of nickel.

[0045] (4) Use H + The second nickel-loaded organic phase was stripped using 2.4 mol / L sulfuric acid as the first stripping solution. The flow ratio of sulfuric acid to the second nickel-loaded organic phase was 1:13, and the number of stripping stages was eight. The resulting first stripping solution had the following composition. The blank organic phase after stripping was washed with pure water at a 1:1 volume ratio and then saponified before entering the next extraction cycle.

[0046] Table 3 Composition of the first stage stripping solution

[0047] (5) Add sulfuric acid to the first stripping solution to prepare H + A second stripping solution with a concentration of 2.4 mol / L was passed into the stripping stage. The flow ratio of this second stripping solution to the second nickel-loaded organic phase was also 1:13. The number of stripping stages was 7, and the resulting second stripping solution had the following composition. The blank organic phase after the second stripping stage was washed with pure water at a 1:1 volume ratio and then saponified before entering the next extraction cycle.

[0048] Table 4 Second stage stripping liquid composition

[0049] (6) The second-stage stripping liquid is passed into the production line P204 sodium hydroxide → nickel sulfate soap conversion impurity removal extraction line, and P204 is used to further remove a small amount of various impurities such as Fe, Al, Mn, Ca, Cu, Zn, Cr, etc. in the second-stage stripping liquid. At the same time, the nickel in the organic phase is extracted during the sodium hydroxide → nickel sulfate soap conversion process to further increase the nickel concentration in the second-stage stripping liquid to reach the industry standard of 120-130 g / L.

[0050] Example 2

[0051] In order to increase the nickel concentration in the second stage stripping solution and reduce the pressure of the P204 soap removal extraction line to further enrich nickel to the target concentration,

[0052] On the basis of Example 1, H + The concentration was increased to 3 mol / L, the flow ratio of the first stripping solution to the second nickel-loaded organic phase was reduced to 1:16.5, the number of stripping stages was 8, and the composition of the first stripping solution obtained was shown in Table 5 below.

[0053] Table 5 Composition of the first stage stripping solution

[0054] From the comparison between Table 3 and Table 5, it can be seen that an appropriate increase in the concentration of the first stripping solution is beneficial to increasing the nickel concentration in the obtained first-stage stripping solution.

[0055] Add sulfuric acid to the first stripping solution and continue to prepare H + The concentration of the second stripping solution was 3 mol / L, and other process parameters remained unchanged from Example 1. The composition of the obtained second-stage stripping solution is shown in Table 6 below.

[0056] Table 6 Composition of the second stage stripping solution

[0057] From the comparison of Table 4 and Table 6, it can be seen that the nickel concentration increased significantly, which obviously reduced the pressure on the P204 soap removal extraction line to further enrich nickel.

[0058] To avoid redundancy, the present invention will start from different perspectives when describing the embodiments, based on the aforementioned cases, and provide as many process adjustment ideas and parameters as possible.

[0059] Example 3

[0060] The only difference from Example 2 is that the washing acid concentration in the washing section of step (3) is increased to 0.2 mol / L and the number of washing stages is reduced to 7.

[0061] The results showed that the washing effect was substantially the same as or even slightly better than that of Example 2, indicating that increasing the washing acid concentration within a reasonable range can reduce the number of washing stages, thereby reducing the time cost of extraction and improving production efficiency.

[0062] Example 4

[0063] The only difference from Example 1 is that the dilution rate of the extracted organic phase is increased to 50%, and the inlet flow ratio of the extracted organic phase to the laterite nickel ore high-pressure leaching solution (pH=4) is reduced to 0.72:1.

[0064] In order to achieve the same effect of washing impurities such as Fe, Al, Mn, Ca, Cu, Zn, Cr in the nickel-loaded organic phase, the concentration of the washing acid in the washing section needs to be increased, and the back acid in the stripping section also needs to be increased to an appropriate concentration in order to achieve the effect of fully stripping and washing the metallic nickel in the organic phase.

[0065] This invention innovatively proposes a two-step extraction process for preparing battery-grade nickel from laterite nickel ore high-pressure leachate, combining segmented stripping and subsequent soap extraction and impurity removal. This breakthrough represents a significant improvement over the current process for extracting battery-grade nickel from laterite nickel ore, resolving the cumbersome process flow and the high consumption of various auxiliary materials, such as acids, alkalis, and flocculants, during the preparation of battery-grade nickel. This significantly simplifies the process for preparing battery-grade nickel from laterite nickel ore. After pre-adjusting the pH of the laterite nickel ore high-pressure leachate, segmented stripping is used to address the acid resistance of the extractant, yielding a nickel solution with a concentration greater than 80 g / L. Subsequently, soap extraction is used to remove Cu while further enriching nickel to 120 g / L, yielding a battery-grade nickel solution. Furthermore, unlike the current extraction method of first extracting impurities and then extracting and enriching the target metal, this patent places the extraction and impurity removal step at the end, which not only further enriches the target metal and reduces subsequent crystallization costs, but also further purifies the resulting nickel-enriched solution.

[0066] The specific embodiments of the present invention described above do not limit the scope of protection of the present invention. Any other corresponding changes and modifications made based on the technical concept of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A two-step extraction process for preparing battery-grade nickel from laterite nickel ore high-pressure leaching solution, characterized in that, it includes the following steps: (1) Prepare the extraction organic phase; (2) Extract nickel: Mix the extraction organic phase with the laterite nickel ore high-pressure leaching solution with a pH value of 2-5, and extract to obtain the first nickel-loaded organic phase; (3) Wash: Wash the first nickel-loaded organic phase with washing acid to obtain the second nickel-loaded organic phase; (4) First-stage stripping: Strip Ni in the second nickel-loaded organic phase with the first stripping acid to obtain the first-stage stripping solution; (5) Second-stage stripping: Add acid solution to the first-stage stripping solution to prepare a second-stage stripping acid with an H + concentration of 0.1 - 4 mol / L, and introduce it into the stripping section of step (4) for second-stage stripping to obtain a second-stage stripping solution with a nickel concentration greater than 80 g / L; (6) The second-stage stripping solution passes through the saponification removal of impurities extraction line to obtain the battery-grade nickel solution.

2. The two-step extraction process for preparing battery-grade nickel from laterite nickel ore high-pressure leaching solution according to claim 1, characterized in that, in the step (1), the preparation steps of the extraction organic phase include: mixing the extractant with the diluent, and then saponifying to obtain the prepared extraction organic phase; wherein, the dilution rate of the extractant is 10-60%, the saponification rate is 10-70%, and the saponification stage number is 1-2 stages.

3. The two-step extraction process for preparing battery-grade nickel from laterite nickel ore high-pressure leaching solution according to claim 2, characterized in that, the extractant is P507 or HBL110, the diluent is sulfonated kerosene or Escaid110, and the saponifying agent is liquid alkali or ammonia water.

4. The two-step extraction process for preparing battery-grade nickel from laterite nickel ore high-pressure leaching solution according to claim 1, characterized in that, in the step (2), 10-15% lime milk is used to adjust the pH in the laterite nickel ore high-pressure leaching solution.

5. The two-step extraction process for preparing battery-grade nickel from laterite nickel ore high-pressure leaching solution according to claim 1, characterized in that, in the step (2), the flow ratio of the extraction organic phase to the laterite nickel ore high-pressure leaching solution is 2:0.5-3, and the extraction stage number is 2-10 stages.

6. The two-step extraction process for preparing battery-grade nickel from laterite nickel ore high-pressure leaching solution according to claim 1, characterized in that, in the step (3), the washing acid is a sulfuric acid solution, hydrochloric acid solution, oxalic acid solution or nitric acid solution with a concentration of 0.05-0.7 mol / L.

7. The two-step extraction process for preparing battery-grade nickel from laterite nickel ore high-pressure leaching solution according to claim 1, characterized in that, in the step (3), the flow ratio of the washing acid to the first nickel-loaded organic phase is 1:1-30, and the washing stage number is 2-9 stages.

8. The two-step extraction process for preparing battery-grade nickel from laterite nickel ore high-pressure leaching solution according to claim 1, characterized in that, in the step (4), the first stripping acid is a sulfuric acid solution, hydrochloric acid solution, oxalic acid solution or nitric acid solution with a concentration of 0.05-4 mol / L; the flow ratio of the first stripping acid to the second nickel-loaded organic phase is 1:1-30, and the stripping stage number is 3-10 stages.

9. The two-step extraction process for preparing battery-grade nickel from laterite nickel ore high-pressure leaching solution according to claim 1, characterized in that, in the step (5), the added acid solution is a sulfuric acid solution, hydrochloric acid solution, oxalic acid solution or nitric acid solution; the flow ratio of the second stripping acid to the second nickel-loaded organic phase is 1:1-30, and the stripping stage number is 3-10 stages.

10. The two-step extraction process for preparing battery-grade nickel from the high-pressure leaching solution of laterite nickel ore according to claim 1, characterized in that, in step (6), the saponification and impurity removal extraction line is the P204 impurity removal extraction line of the production line, including the saponification and nickel sulfate saponification steps, and sodium hydroxide or ammonia water is used for saponification; the concentration of the battery-grade nickel solution is 120-130 g / L.

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