Method for low-cost extraction and separation of battery-grade nickel and cobalt from laterite-nickel ore

Abstract

A method for low-cost extraction and separation of battery-grade nickel and cobalt from laterite-nickel ore, comprising the following steps: adjusting a pH value of a laterite-nickel ore high-pressure leachate to 2.5 or above to obtain a leachate A; introducing the leachate A into a continuous ion exchange resin device to adsorb nickel to obtain a nickel-adsorbed resin and a resin adsorption tail liquid; desorbing the nickel-adsorbed resin to obtain a first nickel salt solution; performing extraction, washing and back-extraction on the first nickel salt solution by means of an extraction organic phase to obtain a battery-grade nickel solution of a target concentration; adding a reducing agent into the obtained resin adsorption tail liquid, adding a precipitant after the reaction to adjust the pH value of the resin adsorption tail liquid to 7-8, and performing pressure filtration to obtain a cobalt hydroxide intermediate product; and preparing a battery-grade cobalt salt solution of a target concentration by using the cobalt hydroxide intermediate product as a raw material. According to the method, nickel and cobalt are separated at an early stage of a metallurgical process, thereby solving the problem of a tedious process flow of nickel and cobalt extraction and separation, saving a large amount of usage of a flocculant and liquid alkali, and reducing costs.

Description

Method for low-cost extraction and separation of battery-grade nickel and cobalt from laterite nickel ore Technical Field

[0001] The invention belongs to the technical field of hydrometallurgy, and in particular relates to a method for low-cost extraction and separation of battery-grade nickel and cobalt from laterite nickel ore. Background Art

[0002] Currently, after being processed in the beneficiation section, laterite nickel ore is sequentially extracted through high-pressure leaching, circulating leaching, pre-neutralization, CCD washing, two-stage iron and aluminum removal, and two-stage nickel and cobalt precipitation to obtain the MHP (nickel cobalt hydroxide) intermediate product. MHP then undergoes slurrying, acid dissolution, and impurity removal to obtain a nickel-cobalt solution containing impurities. These solutions are then subjected to P204 impurity removal and P507 magnesium extraction to obtain a nickel sulfate solution, which is then enriched through a dedicated P507 line to obtain a pure nickel-cobalt solution. In addition, in order to separate nickel and cobalt in the extraction section, a C272 extractant is often required. At the same time, due to the poor ability of these extractants to separate nickel, cobalt, and impurities, the cobalt-nickel solution sometimes needs to be further purified by additional C272 and P204 extraction lines. Finally, battery-grade nickel salt crystals are obtained by recrystallization.

[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. A large amount of liquid alkali is required for the second stage of nickel-cobalt precipitation. This significantly increases the cost of hydrometallurgical extraction of nickel and cobalt, and the process has a low fault tolerance rate.

[0004] Summary of the Invention

[0005] The purpose of the present invention is to overcome the above technical deficiencies and provide a method for low-cost extraction and separation of battery-grade nickel and cobalt from laterite nickel ore, thereby solving the technical problems of high cost and complicated process steps in the prior art of extracting nickel and cobalt from laterite nickel ore.

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

[0007] In a first aspect, the present invention provides a method for low-cost extraction and separation of battery-grade nickel and cobalt from laterite nickel ore, comprising the following steps:

[0008] Step (1): adjusting pH: adjusting the pH of the laterite nickel ore high-pressure leaching solution to above 2.5 to obtain leachate A;

[0009] Step (2): extracting nickel with resin: passing the leachate A through a continuous ion exchange resin device to adsorb nickel, thereby obtaining a nickel adsorption resin and a resin adsorption tail liquid; desorbing the nickel adsorption resin to obtain a first nickel salt solution;

[0010] Step (3): extraction and enrichment: extracting the first nickel salt solution with an extraction organic phase having a dilution rate of 10-60% and a saponification rate of 20-70% to obtain a first nickel-loaded organic phase; washing the first nickel-loaded organic phase to obtain a second nickel-loaded organic phase; and stripping the second nickel-loaded organic phase with a stripping solution to obtain a second nickel salt solution, wherein the second nickel salt solution is a battery-grade nickel solution of target concentration;

[0011] Step (4): Cobalt precipitation: adding a reducing agent to the resin adsorption tail liquid obtained in step (2), reacting for 0.1 to 1 hour, adding a precipitant to adjust the pH of the resin adsorption tail liquid to 7 to 8, and finally filtering to obtain a cobalt hydroxide intermediate;

[0012] Step (5): Using the cobalt hydroxide intermediate as a raw material, prepare a battery-grade cobalt salt solution of target concentration.

[0013] Preferably, in step (1), the pH regulator is one or more of limestone, lime milk, liquid alkali and ammonia water, which can be selected according to the situation.

[0014] Preferably, in step (2), the flow rate of leachate A into the continuous ion exchange resin device is 1 to 10 BV / h, including but not limited to 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 BV / h; the adsorption time is 1 to 24 hours; when the nickel concentration in the resin adsorption tail liquid is greater than 3 mg / L, the leachate A is stopped.

[0015] Preferably, in step (2), the number of series-connected resin columns in the continuous ion exchange resin device is 2 to 35 stages (including but not limited to 2, 3, 5, 7, 8, 10, 12, 15, 18, 20, 23, 25, 28, 30 or 35 stages, etc.), and the resin is LSC-495.

[0016] Preferably, in step (2), the nickel adsorption resin is desorbed using a first acid solution at a flow rate of 0.5 to 3 BV / h, and the desorption time is 0.5 h to 2 h, wherein the flow rate includes but is not limited to 0.5, 1, 1.5, 2, 2.5 or 3 BV / h, and the desorption time is but is not limited to 0.5, 1, 1.5 or 2 h; the first acid solution is one or more of a sulfuric acid solution, a hydrochloric acid solution, an oxalic acid solution and an acetic acid solution with a mass fraction of 5% to 20%, and the mass fraction of the first acid solution includes but is not limited to 5, 8, 10, 12, 15, 18 or 20%.

[0017] Preferably, in step (2), the concentration of the first nickel salt solution is 20 to 30 g / L. Further preferably, part of the first nickel salt solution is used as a washing liquid for washing impurities from the resin; step (2) further comprises: first washing the nickel adsorption resin with the first nickel salt solution and then desorbing the impurities; the washing with the first nickel salt solution specifically comprises washing the nickel adsorption resin with part of the first nickel salt solution obtained from the previous desorption at a flow rate of 1 to 10 BV / h, including but not limited to 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 BV / h; to wash and remove impurities such as Co, Mn, Fe, Al, Cr, Zn, Ca, and Mg adsorbed on the nickel adsorption resin.

[0018] Preferably, in step (2), the desorbed resin is washed with pure water at a flow rate of 2 to 10 BV / h, and the washed resin is directly subjected to the next nickel adsorption cycle.

[0019] Preferably, in step (3), the extracted organic phase is prepared from an extractant, a diluent and a saponifier; wherein the extractant is P507, Versatic 10, DY319, HBL110 or HBL119, the diluent is kerosene, sulfonated kerosene or Escaid 110, the saponifier is one or more of liquid alkali, ammonia water and nickel hydroxide, and the saponification level is 1 to 2.

[0020] Preferably, the extraction in step (3) specifically includes: passing the prepared extraction organic phase and the first nickel salt solution into a continuous extraction tank, controlling the flow ratio of the extraction organic phase to the first nickel salt solution to be 1:0.05-1, and the extraction stage to be 1-9 stages; wherein the flow ratio of the extraction organic phase to the first nickel salt solution includes but is not limited to 1:0.05, 1:0.1, 1:0.15, 1:0.2, 1:0.25, 1:0.3, 1:0.35, 1:0.4, 1:0.45, 1:0.5, 1:0.55, 1:0.6, 1:0.65, 1:0.7, 1:0.8, 1:0.9 or 1:1, etc.; the extraction stage includes but is not limited to 1, 2, 3, 4, 5, 6, 7, 8 or 9, etc.

[0021] Preferably, in step (3), the first nickel-loaded organic phase is washed with a second acid solution, the flow ratio of the second acid solution to the first nickel-loaded organic phase is 1:1-25 (including but not limited to 1:1, 1:5, 1:10, 1:15, 1:20 or 1:25, etc.), and the washing stages are 1-8 stages (including but not limited to 1, 2, 3, 4, 5, 6 or 7, etc.); the second acid solution is a 0.01-0.5 mol / L sulfuric acid solution, hydrochloric acid solution, oxalic acid solution or acetic acid solution. The second acid solution can wash various trace impurities such as Co, Mn, Fe, Al, Cr, Zn, Ca, Mg in the nickel-loaded organic phase, and its concentration is including but not limited to 0.01, 0.05, 0.1, 0.2, 0.3, 0.4, 0.45 or 0.5 mol / L, etc.

[0022] Preferably, the stripping solution in step (3) is a sulfuric acid solution, a hydrochloric acid solution, an oxalic acid solution or an acetic acid solution, and the hydrogen ion concentration in the stripping solution is 5 to 6 mol / L, including but not limited to 5, 5.2, 5.5, 5.7 or 6 mol / L; the flow ratio of the stripping solution to the second nickel-loaded organic phase is 1:0.03 to 1 (including but not limited to 1:0.03, 1:0.05, 1:0.15, 1:0.5, 1:0.8, 1:0.9 or 1:1, etc.), and the stripping stage is 1 to 9 (including but not limited to 1, 2, 3, 4, 5, 6, 7, 8 or 9, etc.).

[0023] Preferably, the concentration of the battery-grade nickel solution in step (3) is 120-130 g / L.

[0024] Preferably, in step (3), the blank organic phase after stripping is washed with pure water and then saponified before entering the next extraction cycle. The flow ratio of pure water to the blank organic phase is 1:0.5 to 5 (including but not limited to 1:0.5, 1:1, 1:2, 1:3, 1:4 or 1:5, etc.), and the number of washing stages is 1 to 3.

[0025] Preferably, in step (4), the reducing agent includes sodium thiosulfate, sodium metabisulfite, sodium hypochlorite, sodium chlorate or hydrogen peroxide, and 4 to 6 kg of the reducing agent is added to each cubic meter of resin adsorption tail liquid; the precipitating agent includes lime milk or liquid caustic soda.

[0026] The resin adsorption tail liquid obtained in step (2) contains a small amount of cobalt. The role of adding the reducing agent is to prevent manganese from being rapidly oxidized to form oxides during cobalt precipitation, thereby reducing the main content of cobalt in cobalt hydroxide.

[0027] Preferably, in step (5), the cobalt hydroxide intermediate is sequentially subjected to slurry acid dissolution, extraction and impurity removal, and cobalt extraction and enrichment to obtain a battery-grade cobalt salt solution of target concentration.

[0028] Further preferably, in step (5), the cobalt hydroxide intermediate is pumped into the slurry acid dissolution system of the production line for cobalt leaching, and then the leachate is sequentially pumped into the production line P204 extraction and impurity removal line → cobalt extraction and enrichment line to obtain a battery-grade cobalt salt solution with a target concentration of about 115 to 125 g / L; wherein the cobalt enrichment extractant is P507, Vertasic 10, DY319, HBL110 or HBL119. The purpose of P204 extraction is to remove impurities such as Fe, Al, Cr, Ca, Mn, and Zn. The specific slurry acid dissolution system, P204 extraction and impurity removal line, and cobalt extraction and enrichment line are all relatively mature technologies in this field. Those skilled in the art can select or adjust them according to the situation to achieve a battery-grade cobalt salt solution with the target concentration, and are not specifically limited here.

[0029] The above-mentioned step (3) of extracting and enriching nickel and steps (4) to (5) can be carried out in parallel, and their sequence numbers do not constitute a limitation on the process sequence.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] In the present invention, the high-pressure leachate of laterite nickel ore is subjected to pre-iron removal treatment after pH adjustment, and then nickel is directly extracted using a continuous ion exchange resin device, and a high-concentration battery-grade nickel solution is prepared in combination with a subsequent two-step extraction and enrichment process. A small amount of cobalt mixed in the resin adsorption tail liquid is precipitated and enriched with lime milk by reducing manganese to obtain a cobalt hydroxide intermediate, which can be used as a raw material for preparing a battery-grade cobalt solution of the target concentration. This method breaks through the existing process ideas and methods for extracting and preparing battery-grade nickel-cobalt crystals from laterite nickel ore, and separates nickel and cobalt in the early stage of the metallurgical process, which not only improves the fault tolerance of the process and solves the cumbersome process flow problems during nickel-cobalt extraction and separation, but also saves the use of a large amount of flocculants and the problem of large-scale consumption of liquid alkali when preparing MHP, significantly reducing the cost of extracting and preparing battery-grade nickel-cobalt. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] FIG1 is a flow chart of the treatment process of the present invention. DETAILED DESCRIPTION

[0033] 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.

[0034] The present invention is further described in detail below through specific examples. To avoid redundancy, the components of the laterite nickel ore high-pressure leaching solution used in the examples of the present invention are described as shown in Table 1 below.

[0035] Table 1 Laterite nickel ore high pressure leaching solution

[0036] The resin used is LSC-495.

[0037] Example 1

[0038] 1 , the method for low-cost extraction and separation of battery-grade nickel and cobalt from laterite nickel ore of the present invention comprises the following steps:

[0039] Step (1): The pH of the laterite nickel ore high-pressure leaching solution was adjusted to 3.5 using lime milk. The composition of the solution is shown in Table 2 below.

[0040] Table 2 Laterite nickel ore high pressure leaching solution (pH=3.5)

[0041] Step (2): The high-pressure leachate is passed through a continuous ion exchange resin device at a flow rate of 3 BV / h to adsorb nickel. The number of series stages of the resin column is 20. When the nickel concentration in the resin adsorption tail liquid is greater than 3 mg / L, the leachate is stopped. Then, a portion of the first nickel sulfate solution (preferably about 1 / 5) obtained by subsequent desorption of the resin is used to wash the impurities such as Co, Mn, Fe, Al, Cr, Zn, Ca, and Mg adsorbed on the resin at a flow rate of 4 BV / h. Finally, a 15% sulfuric acid solution is used to desorb the nickel on the resin at a flow rate of 2 BV / h for 1.5 hours. The composition of the enriched first nickel sulfate solution is shown in Table 3. The desorbed resin is washed with pure water at a flow rate of 4 BV / h. The washed resin is directly subjected to the next nickel adsorption cycle.

[0042] Table 3 Composition of the first nickel sulfate solution

[0043] Step (3): Using kerosene as a diluent and liquid caustic soda as a saponifying agent, a DY319 extracted organic phase with a dilution ratio of 50% and a saponification ratio of 70% was prepared, with a saponification stage of 1. The prepared DY319 extracted organic phase and the above-mentioned nickel sulfate solution were passed into a continuous extraction tank, with an extraction stage of 8, and a flow ratio of the extracted organic phase to the first nickel sulfate solution of 2:1. The washing liquid in the washing section used a sulfuric acid solution with a concentration of 0.05 mol / L, and the flow ratio of the washing liquid to the first nickel-loaded organic phase was 1:20. The washing stage was 7. The washed washing liquid was passed into the extraction stage for further nickel recovery. Sulfuric acid with a hydrogen ion concentration of 5.5 mol / L was used as a stripping liquid, and the flow ratio of the stripping liquid to the washed second nickel-loaded organic phase was 20:1. The stripping stage was 7. The composition of the resulting second nickel sulfate solution is shown below. The blank organic phase after stripping is washed with pure water and then saponified to enter the next round of extraction cycle. The flow ratio of pure water to the blank organic phase is 1 to 5, and the number of washing stages is 2.

[0044] Table 4 Composition of the second nickel sulfate solution

[0045] Step (4): Add sodium thiosulfate to the resin adsorption tail liquid containing a small amount of cobalt obtained in step (2) and react for 20 minutes. The solid-liquid ratio is 5kg / m 3 Then, lime milk is added to adjust the pH to 7.8. The mass fraction of Co in the cobalt hydroxide intermediate obtained by filter pressing can reach 6%.

[0046] Step (5): The cobalt hydroxide is pumped into the slurry acid dissolution system of the production line for cobalt leaching, and then the leachate is sequentially pumped into the production line P204 extraction and impurity removal line → cobalt extraction and enrichment line to obtain a battery-grade cobalt salt solution with a target concentration of about 120g / L.

[0047] Example 2

[0048] The concentration of most impurities in the nickel sulfate solution directly used to prepare battery-grade materials is less than 1 mg / L. In order to further reduce the concentration of impurities in the nickel sulfate solution obtained in Example 1, the following adjustments are made based on Example 1.

[0049] Based on Example 1, the number of series-connected resin columns was increased to 23, and other process conditions remained unchanged. The composition of the obtained nickel sulfate solution was shown in Table 5 below.

[0050] Table 5 Composition of the first nickel sulfate solution

[0051] From the comparison of Table 3 and Table 5, it can be seen that increasing the number of series-connected resin columns within an appropriate range is beneficial to reducing the impurity concentration, thereby improving the purity of the obtained nickel sulfate solution.

[0052] The flow ratio of the extracted organic phase to the nickel sulfate solution in the extraction section was reduced to 1.87:1, and other conditions remained unchanged. The composition of the obtained nickel solution was as follows.

[0053] Table 6 Composition of the second nickel sulfate solution

[0054] Example 3

[0055] Step (1): The high-pressure leaching solution of laterite nickel ore is adjusted to 4.8, and its composition is as follows.

[0056] Table 7 Laterite nickel ore high pressure leaching solution (pH = 4.8)

[0057] It can be seen from Table 2 and Table 7 that when the pH value of the laterite nickel ore high-pressure leaching solution is appropriately increased, the amount of other impurity ions is significantly reduced, especially iron, aluminum, manganese, and zinc.

[0058] Step (2): The number of series-connected resin columns was changed to 15, and other process conditions remained unchanged. The composition of the nickel sulfate solution obtained by desorption was as follows.

[0059] Table 8 Composition of the first nickel sulfate solution

[0060] As can be seen from the comparison of Table 3 and Table 8, although the series connection number of the resin column decreases, the content of nickel increases significantly, while the content of cobalt and other impurities decreases significantly. It can be seen that the content of impurities in the resin adsorption tail liquid directly and significantly affects the adsorption capacity of the resin for nickel. This shows that appropriately increasing the pH value of the laterite nickel ore high-pressure leaching solution is conducive to subsequent resin adsorption enrichment. When the impurity concentration in the high-pressure leaching solution is significantly reduced, the series connection number of the resin can be shortened within a certain range. At the same time, the efficiency of the resin in extracting nickel is not only higher, but also the final adsorption capacity of nickel is also greater.

[0061] Step (3): Since the nickel concentration in the resin adsorption tail liquid increases and the impurity content decreases, the flow ratio of the organic phase extracted in the extraction section DY319 to the above-mentioned nickel sulfate solution is changed to 2.35, and the number of washing stages can be shortened to 3. All other process conditions remain unchanged. The composition of the obtained nickel solution is as follows.

[0062] Table 9 Composition of the second nickel sulfate solution

[0063] As can be seen from Tables 4 and 9, reducing the impurity content in the raw material section of the laterite nickel ore high-pressure leaching solution can significantly increase the nickel concentration in the nickel sulfate obtained by stripping and reduce the impurity concentration therein.

[0064] Step (4): All process conditions remain unchanged from those in Example 1. Since the impurity concentration in the tail liquid of the resin adsorption is greatly reduced, the mass fraction of Co in the cobalt hydroxide intermediate obtained by filter pressing can be increased to 8%.

[0065] Different from the existing technology, in the present invention, the high-pressure leachate of laterite nickel ore is pre-iron-removed, and then nickel is directly extracted using a continuous ion exchange resin device, and a high-concentration battery-grade nickel solution is prepared in combination with a subsequent two-step extraction and enrichment process. The small amount of cobalt mixed in the resin adsorption tail liquid is precipitated and enriched with lime milk by reducing manganese, and then acid-dissolved, and finally a battery-grade cobalt solution of the target concentration is obtained through extraction, impurity removal and enrichment processes. This method breaks through the existing process ideas and methods for extracting and preparing battery-grade nickel crystals from laterite nickel ore, and separates nickel and cobalt in the early stage of the metallurgical process. It not only solves the cumbersome process flow problems during nickel and cobalt extraction and separation, improves the fault tolerance of the process, but also saves a lot of flocculants and liquid alkali use problems, greatly reducing the cost of battery-grade nickel and cobalt extraction and separation.

[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 method for low-cost extraction and separation of battery-grade nickel and cobalt from laterite nickel ore, characterized in that, it includes the following steps: Step (1): Adjust the pH: Adjust the pH of the high-pressure leaching solution of laterite nickel ore to above 2.5 to obtain leaching solution A; Step (2): Nickel extraction by resin: Pass the above leaching solution A into a continuous ion exchange resin device to adsorb nickel, obtaining nickel-adsorbed resin and resin adsorption tail liquor; the nickel-adsorbed resin is desorbed to obtain a first nickel salt solution; Step (3): Extraction and enrichment: Use an extraction organic phase with a dilution rate of 10-60% and a saponification rate of 20-70% to extract the first nickel salt solution to obtain a first nickel-loaded organic phase; Wash the first nickel-loaded organic phase to obtain a second nickel-loaded organic phase; The second nickel-loaded organic phase is then back-extracted with a back-extraction solution to obtain a second nickel salt solution, and the second nickel salt solution is a battery-grade nickel solution with a target concentration; Step (4): Cobalt precipitation: Add a reducing agent to the resin adsorption tail liquor obtained in step (2), react for 0.1-1 h, then add a precipitant to adjust the pH of the resin adsorption tail liquor to 7-8, and finally filter to obtain a cobalt hydroxide intermediate product; Step (5): Use the cobalt hydroxide intermediate product as a raw material to prepare a battery-grade cobalt salt solution with a target concentration.

2. The method for low-cost extraction and separation of battery-grade nickel and cobalt from laterite nickel ore according to claim 1, characterized in that, in step (1), the pH regulator is one or more of limestone, lime milk, liquid alkali and ammonia water, and can be selected according to the situation.

3. The method for low-cost extraction and separation of battery-grade nickel and cobalt from laterite nickel ore according to claim 1, characterized in that, in step (2), the flow rate of leaching solution A passing into the continuous ion exchange resin device is 1-10 BV / h, and when the nickel concentration in the resin adsorption tail liquor > 3 mg / L, stop feeding leaching solution A.

4. The method for low-cost extraction and separation of battery-grade nickel and cobalt from laterite nickel ore according to claim 1, characterized in that, in step (2), the series connection stage number of the resin columns in the continuous ion exchange resin device is 2-35 stages, and the resin is LSC-495.

5. The method for low-cost extraction and separation of battery-grade nickel and cobalt from laterite nickel ore according to claim 1, characterized in that, in step (2), the nickel-adsorbed resin is desorbed with a first acid solution at a flow rate of 0.5-3 BV / h, and the desorption time is 0.5 h-2 h; the first acid solution is one or more of a sulfuric acid solution, hydrochloric acid solution, oxalic acid solution and acetic acid solution with a mass fraction of 5%-20%.

6. The method for low-cost extraction and separation of battery-grade nickel and cobalt from laterite nickel ore according to claim 1 or 6, characterized in that, in step (2), the concentration of the first nickel salt solution is 20-30 g / L; step (2) also includes: washing the nickel-adsorbed resin with a part of the first nickel salt solution obtained from the previous desorption at a flow rate of 1-10 BV / h, and then performing desorption.

7. The method for low-cost extraction and separation of battery-grade nickel and cobalt from laterite nickel ore according to claim 1 or 6, characterized in that, in step (2), the desorbed resin is washed with pure water at a flow rate of 2-10 BV / h, and the washed resin is directly subjected to the next round of nickel adsorption cycle.

8. The method for low-cost extraction and separation of battery-grade nickel and cobalt from laterite nickel ore according to claim 1, characterized in that, in step (3), the extraction organic phase is prepared from an extractant, a diluent and a saponifying agent; wherein, the extractant is P507, Versatic 10, DY319, HBL110 or HBL119, the diluent is kerosene, sulfonated kerosene or Escaid 110, the saponifying agent is one or more of liquid alkali, ammonia water and nickel hydroxide, and the saponification stage number is 1 to 2 stages.

9. The method for low-cost extraction and separation of battery-grade nickel and cobalt from laterite nickel ore according to claim 1, characterized in that, the extraction in step (3) specifically includes: introducing the prepared extraction organic phase and the first nickel salt solution into a continuous extraction tank, controlling the flow rate ratio of the extraction organic phase to the first nickel salt solution to be 1:0.05 to 1, and the extraction stage number to be 1 to 9 stages.

10. The method for low-cost extraction and separation of battery-grade nickel and cobalt from laterite nickel ore according to claim 1, characterized in that, in step (3), the first nickel-loaded organic phase is washed with a second acid solution, the flow rate ratio of the second acid solution to the first nickel-loaded organic phase is 1:1 to 25, and the washing stage number is 1 to 8 stages; the second acid solution is a sulfuric acid solution, hydrochloric acid solution, oxalic acid solution or acetic acid solution with a concentration of 0.01 to 0.5 mol / L.

11. The method for low-cost extraction and separation of battery-grade nickel and cobalt from laterite nickel ore according to claim 1, characterized in that, the stripping solution in step (3) is a sulfuric acid solution, hydrochloric acid solution, oxalic acid solution or acetic acid solution, and the hydrogen ion concentration in the stripping solution is 5 to 6 mol / L; the flow rate ratio of the stripping solution to the second nickel-loaded organic phase is 1:0.03 to 1, and the stripping stage number is 1 to 9 stages.

12. The method for low-cost extraction and separation of battery-grade nickel and cobalt from laterite nickel ore according to claim 1, characterized in that, the concentration of the battery-grade nickel solution in step (3) is 120 to 130 g / L.

13. The method for low-cost extraction and separation of battery-grade nickel and cobalt from laterite nickel ore according to claim 1, characterized in that, in step (3), the blank organic phase after stripping is washed with pure water and then saponified, and enters the next round of extraction cycle, the flow rate ratio of pure water to the blank organic phase is 1:0.5 to 5, and the washing stage number is 1 to 3 stages.

14. The method for low-cost extraction and separation of battery-grade nickel and cobalt from laterite nickel ore according to claim 1, characterized in that, in step (4), the reducing agent includes sodium thiosulfate, sodium metabisulfite, sodium hypochlorite, sodium chlorate or hydrogen peroxide, and 4 to 6 kg of reducing agent is added to each cubic meter of the resin adsorption tail liquid; the precipitating agent includes lime milk or liquid alkali.

15. The method for low-cost extraction and separation of battery-grade nickel and cobalt from laterite nickel ore according to claim 1, characterized in that, In step (5), the cobalt hydroxide intermediate product is successively subjected to pulping acid dissolution, extraction for impurity removal, and cobalt extraction and enrichment to obtain a battery-grade cobalt salt solution with a target concentration; P204 is used for extraction and impurity removal; the extractants used for cobalt extraction and enrichment are P507, Vertasic 10, DY319, HBL110, or HBL119; the target concentration of the battery-grade cobalt salt solution is 115-120 g / L.

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