Method for removing impurities from nickel sulfate stock solution and application thereof

Abstract

The application discloses a method for removing impurities from a nickel sulfate raw solution and application thereof, and belongs to the technical field of extraction separation. The method for removing impurities provided by the application adds HBL116 extraction for C272 / P507 magnesium washing liquid on the basis of traditional P204 extraction combined with C272 / P507 extraction, and uses the stripping liquid of HBL116 for secondary washing of P204, and the stripping liquid of P204 is subjected to secondary extraction by using the HBL116 loaded organic phase, so that the yield and purity of target metals such as nickel, cobalt and manganese in the nickel sulfate raw solution can be significantly improved, and the calcium crystallization in the production line during the operation of the method for removing impurities is avoided. The application also provides application of the method for removing impurities.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of extraction separation, in particular to a method for removing impurities from a nickel sulfate raw solution and application thereof. BACKGROUND

[0002] With the rapid development of electric vehicles, the demand for lithium ion batteries is also expanding, and the demand for battery materials such as nickel sulfate and cobalt sulfate is also increasing. The product quality requirements are also getting higher and higher. How to efficiently and low-cost produce nickel sulfate and cobalt sulfate has become a development trend of the industry.

[0003] Battery-grade nickel sulfate or cobalt sulfate has high purity requirements, so it needs to be strictly removed during preparation. In the current method for removing impurities from nickel sulfate solution and cobalt sulfate solution, solvent extraction has the advantages of good selectivity, high metal recovery rate, and fast mass transfer rate, and is an important link in the process of non-ferrous metal enrichment, refining, separation, and purification in industry. It can better achieve the separation of nickel and cobalt.

[0004] In related technologies, there are methods for producing nickel sulfate and cobalt sulfate by using extraction to remove impurities. For example, P204 extractant is often used for extraction to transfer most of the calcium and manganese into the organic phase, while most of the nickel, cobalt, and magnesium remain in the aqueous phase, achieving the separation of nickel, cobalt, and magnesium from calcium and manganese. Then, the organic phase is washed with sulfuric acid of different acidity to wash out nickel, cobalt, and magnesium. The principle is to use H + to replace Ni 2+ , Co 2+ in the organic phase, but in actual production, H + will replace Ni 2+ , Co 2+ and a certain amount of Mn 2+ , Ca 2+ at the same time, which not only cannot achieve effective impurity removal, but also cannot achieve effective separation of Ca 2+The formation of calcium crystals when enriched to a saturated concentration in aqueous solution is another industry problem affecting production; the aqueous phase after P204 extraction is extracted using C272 or P507 to transfer cobalt and magnesium into the organic phase, and nickel is in the aqueous phase, achieving separation of nickel, cobalt and magnesium, and then different acidities are used to wash nickel and magnesium, achieving separation of nickel, cobalt and magnesium, but in actual production, due to the non-selectivity of sulfuric acid washing, cobalt and magnesium will enter the nickel washing solution, and cobalt will also enter the magnesium washing solution, causing metal loss. There are also technologies that attempt to extract and separate nickel, cobalt and magnesium from a nickel sulfate solution derived from waste nickel-hydrogen and nickel-cadmium batteries in one step, which specifically adjusts the pH value of the sulfuric acid leaching solution to 4.5-5.0, then uses P507 to fractionally extract the leaching solution to transfer magnesium and cobalt into the organic phase while most of the nickel remains in the aqueous phase, and then washes the nickel and magnesium separately to achieve the purpose of separating nickel, cobalt and magnesium. However, the nickel and cobalt content in the washing solution is high, and sodium hydroxide precipitation is further used to recover nickel and cobalt in the washing solution, and further treatment is required to obtain the product, and the process flow is extremely complex. There are also technologies that attempt to extract nickel and cobalt from an aqueous leaching solution containing nickel and high-cobalt hydroxide using an extraction method, which first uses P204 to remove impurity ions such as iron, zinc, calcium, copper and manganese in the leaching solution, and then uses P507 to separate nickel and cobalt. Among them, P204 is cheap, but its separation capacity for nickel and cobalt is weak, and it is mainly suitable for the extraction and separation of metal ions at low pH, and is not suitable when the magnesium ion concentration in the leaching solution is high. When P507 and Cyanex272 are used to separate cobalt and nickel from a nickel-cobalt hydroxide leaching solution containing nickel, cobalt and magnesium, cobalt and magnesium need to be extracted first, and then nickel is extracted, which is high in cost and affects the separation of nickel and cobalt. There are also related technologies that attempt to obtain purified nickel compounds from a nickel-cobalt hydroxide hydrochloric acid leaching solution, which first uses P507 to prepare sodium soap by saponification with liquid caustic soda, converts the sodium soap organic phase to a nickel soap organic phase using a nickel chloride solution, removes impurity ions in the nickel-cobalt hydroxide hydrochloric acid leaching solution, and then uses dilute hydrochloric acid to wash the nickel to obtain qualified nickel chloride solution, but the calcium and magnesium in the obtained nickel chloride solution can reach 0.05 g / L and 1 g / L, respectively, and the separation effect of calcium and magnesium and other impurity ions is poor. In addition, there are technologies that attempt to extract and separate nickel, cobalt and magnesium from a nickel-cobalt-magnesium mixed solution, which first uses the sodium salt of saponified 2-ethylhexyl phosphonic acid mono(2-ethylhexyl ester) to extract nickel, cobalt and magnesium in the nickel-cobalt-magnesium mixed solution into the organic phase, and controls the cobalt and magnesium content in the raffinate to obtain pure nickel sulfate solution, and then the organic phase loaded with nickel, cobalt and magnesium is washed in three steps to obtain pure cobalt sulfate solution. This method has high requirements for the impurities in the front solution, high precision in the product production process control, and problems such as incomplete separation of cobalt and magnesium and cobalt loss in the second washing process.

[0005] In summary, in the related art of purifying nickel compounds, either the purity of the obtained product cannot meet the standard, or the purity of the leaching solution needs to be higher, or the recovery rate of the product is not high, or the process construction is difficult. Therefore, the industry hopes to develop a method for removing impurities from nickel sulfate solution to maximize the purity and yield of the product, reduce the complexity of the process, and minimize the construction difficulty. SUMMARY

[0006] The present application aims to at least solve one of the technical problems existing in the prior art. To this end, the present application proposes a method for removing impurities from a nickel sulfate solution, which can effectively improve the recovery rate of nickel, the purity of the obtained nickel product, and also recover by-products cobalt, calcium, manganese and magnesium; in addition, it can also fully avoid the operation difficulty caused by calcium crystallization.

[0007] The present application also provides the application of the above-mentioned impurity removal method.

[0008] According to the embodiments of the first aspect of the present application, a method for removing impurities from a nickel sulfate solution is provided, wherein the nickel sulfate solution contains Ni 2+ , Co 2+ , Mn 2+ , Mg 2+ and Ca 2+ ;

[0009] The impurity removal method comprises the following steps:

[0010] S1. Extracting the nickel sulfate solution with P204 organic phase of nickel soap; obtaining P204 loaded organic phase and P204 raffinate phase;

[0011] S2. Extracting the P204 raffinate phase with a composite extractant of nickel soap, obtaining a composite extractant loaded organic phase and a composite extractant raffinate phase; the composite extractant comprises C272 and P507;

[0012] S3. Washing nickel in the composite extractant loaded organic phase, obtaining a composite extractant after nickel washing phase and a nickel washing solution;

[0013] Washing magnesium in the composite extractant after nickel washing phase, obtaining a magnesium washing solution and a composite extractant after magnesium washing phase;

[0014] S4. Extracting the magnesium washing solution with HBL116 organic phase of sodium soap, obtaining HBL116 loaded organic phase and HBL116 raffinate phase;

[0015] S5. Mixing and extracting the calcium-manganese stripping phase and the HBL116 loaded organic phase, obtaining HBL116 mixed extraction liquid and HBL116 mixed extraction phase;

[0016] S6. stripping the HBL116 mixed extraction phase to obtain a P204 second washing liquid and a HBL116 blank phase;

[0017] S7. washing the P204 loaded organic phase once to obtain a P204 once-washed phase and a nickel sulfate liquid crude product;

[0018] washing the P204 once-washed phase with the P204 second washing liquid to obtain a P204 twice-washed phase and a nickel sulfate liquid crude product;

[0019] stripping the P204 twice-washed phase to obtain the calcium-manganese stripping phase and a P204 blank phase.

[0020] The mechanism of the impurity removal method is as follows:

[0021] In step S1, P204 extracts a large amount of calcium and manganese, a small amount of nickel, cobalt and magnesium, a large amount of nickel, cobalt and magnesium, and a small amount of calcium and manganese remain in the P204 raffinate phase.

[0022] In step S2, the composite extractant extracts almost all of the cobalt, magnesium and calcium in the P204 raffinate phase and a small amount of nickel, and the composite extractant raffinate phase is a high-purity nickel sulfate solution which can be recycled for use after simple oil removal.

[0023] In step S3, the nickel washing liquid obtained by washing nickel contains a certain amount of nickel and cobalt, magnesium and calcium impurities, which can be refluxed to step S2 and mixed with the P204 raffinate phase for extraction.

[0024] In step S3, the magnesium washing liquid obtained by washing magnesium contains almost all of the magnesium and a small amount of nickel. In order to ensure that the magnesium is washed clean, the magnesium washing liquid also contains a certain amount of cobalt; the metals in the magnesium washing phase are basically cobalt and a small amount of calcium and manganese.

[0025] In step S4, HBL116 hardly extracts magnesium, but has a high affinity for other metal ions in the magnesium washing liquid, i.e., the separation of cobalt and magnesium is achieved. Thus, the HBL116 raffinate phase is mainly a sodium magnesium sulfate aqueous solution.

[0026] In step S5, the HBL116 loaded organic phase has a higher affinity for nickel and cobalt than for calcium and manganese, so that the nickel and cobalt in the calcium-manganese stripping phase are extracted, and a certain amount of manganese remains in the HBL116 mixed extraction phase; however, most of the calcium and manganese remain in the HBL116 mixed extraction phase for later recovery; this step achieves the preliminary separation of cobalt and manganese.

[0027] In step S6, the stripping process washes out almost all of the nickel, cobalt and manganese, leaving the HBL116 blank phase.

[0028] In step S7, the P204 loaded organic phase is washed twice, which can wash out most of the nickel and cobalt in P204, so that after the back extraction in step S7, the obtained calcium-manganese back extraction phase mainly contains calcium and manganese, and contains a small amount of nickel and cobalt.

[0029] As can be seen from the steps, there is a cycle between steps S5-S7, so the numbering of the steps does not strictly represent the sequence, but is only for convenience of description. Further, in order to start the above cycle, when performing the first cycle, the P204 second washing liquid or the calcium-manganese back extraction phase needs to be manually prepared.

[0030] According to the impurity removal method provided by the embodiment of the present application, at least the following beneficial effects are achieved:

[0031] The magnesium washing liquid of the composite extractant and the P204 loaded organic phase are treated creatively, and the nickel and cobalt resources are deeply obtained, and the recovery rate of the target metal is improved. Therefore, the fault tolerance of the magnesium washing stage in step S3, the extraction stage in steps S1-S2, and even the cycle process in steps S5-S7 is high. In other words, even if a step deviates, other steps can still compensate for it, and the purity and yield of the final product will not be affected.

[0032] The extractant HBL116 is creatively selected, and the nickel and cobalt metals in the magnesium washing liquid and the calcium-manganese back extraction phase are extracted by the way of segmented extraction. The back extraction liquid obtained by back extraction is used as the P204 second washing liquid, the recovery of the nickel and cobalt metals is realized, and the metal yield is improved. The extractant can be separated into parts to separate cobalt, magnesium and manganese, and compared with the traditional impurity removal step, the process is simplified.

[0033] The calcium-manganese back extraction phase and the HBL116 loaded organic phase are mixed and extracted creatively, and the calcium ions in the mixed extraction liquid after the HBL116 mixed extraction are discharged from the impurity removal system. Therefore, although the cycle is formed in steps S5-S7, the concentration of calcium ions in any stage is low, the problem of calcium crystallization is avoided, and the process operation difficulty of the impurity removal method is reduced.

[0034] And the concentration distribution of calcium is further dispersed by washing the P204 loaded organic phase twice, which can better optimize the calcium crystallization problem.

[0035] In summary, the impurity removal method provided by the present application has the advantages of simple process flow, low process control precision, good product quality, complete separation of nickel, cobalt, manganese, magnesium and other metals, and can meet the requirements of battery-grade materials for nickel sulfate and cobalt sulfate. At the same time, by-products such as magnesium sulfate and calcium-manganese chloride solution can be obtained, and the economic benefits are high.

[0036] According to some embodiments of the present application, in step S1, the nickel sulfate raw solution satisfies the following indexes:

[0037] nickel 90-120 g / L; for example, specifically about 100 g / L or about 110 g / L;

[0038] cobalt 1-15 g / L; for example, specifically about 5 g / L, 8 g / L, 10 g / L or about 12 g / L;

[0039] magnesium 1-5 g / L; for example, specifically about 2 g / L, 3 g / L or about 4 g / L.

[0040] manganese 1-15 g / L. For example, specifically about 5 g / L, 8 g / L, 10 g / L or about 12 g / L.

[0041] According to some embodiments of the present application, in step S1, the nickel sulfate stock solution further includes calcium. The concentration of calcium is 0.3-0.5 g / L.

[0042] According to some embodiments of the present application, in step S1, the nickel sulfate stock solution further includes at least one of iron, zinc, aluminum and copper. The concentration of any one of iron, zinc, copper and aluminum in the nickel sulfate stock solution is ≤0.01 g / L.

[0043] In the nickel sulfate stock solution, the metals such as nickel, cobalt and manganese are in the form of ions dissolved in water, i.e. the nickel sulfate stock solution is a homogeneous aqueous solution. The other aqueous phases involved in the impurity removal method are the same, i.e. they are all homogeneous aqueous solutions in which the metals are in the form of water-soluble ions.

[0044] According to some embodiments of the present application, in step S1, the source of the nickel sulfate stock solution is at least one of a nickel ore leaching solution, a lithium battery positive electrode material leaching solution and a nickel-hydrogen battery leaching solution.

[0045] According to some embodiments of the present application, in step S1, the preparation method of the P204 organic phase of the nickel soap includes the following steps:

[0046] S1a. Mixing the P204 organic phase and a sodium hydroxide solution to prepare a sodium soap;

[0047] S1b. Mixing the P204 organic phase after sodium soap preparation and a nickel sulfate solution to prepare a nickel soap.

[0048] According to some embodiments of the present application, in step S1a, the P204 organic phase includes P204 and a diluent. The type of the diluent includes sulfonated kerosene. The volume percentage of the diluent in the P204 organic phase is 70-80%; for example, specifically about 75%.

[0049] According to some embodiments of the present application, in step S1a, the concentration of the sodium hydroxide solution is 30-35 wt%. For example, it can be about 32 wt%.

[0050] According to some embodiments of the present application, in step S1a, the saponification rate of the sodium soap is 10-40%. For example, it can be about 20%, 25%, 30% or about 35%.

[0051] According to some embodiments of the present application, in step S1b, the concentration of the nickel sulfate solution is 70-80 g / L. For example, it can be about 75 g / L.

[0052] According to some embodiments of the present application, in step S1, the method of extraction is countercurrent extraction.

[0053] According to some embodiments of the present application, in step S1, the number of stages of extraction is 8-12 stages. For example, it can be 10 stages or 11 stages.

[0054] According to some embodiments of the present application, in step S1, the O / A value of extraction is 0.5-5:1. For example, it can be about 1:1, 2:1, 2.5:1, 3:1 or about 4:1.

[0055] According to some embodiments of the present application, in step S1, the equilibrium pH of extraction is 3.5-4.

[0056] According to some embodiments of the present application, in step S1, the P204 raffinate phase satisfies the following indexes:

[0057] Ca≤0.005 g / L; for example, it can be about 0.0005 g / L, 0.001 g / L or about 0.003 g / L;

[0058] Mn≤0.01 g / L. For example, it can be about 0.005 g / L or about 0.008 g / L.

[0059] In actual production, the O / A value of extraction in step S1 can be controlled according to the indexes.

[0060] According to some embodiments of the present application, in step S2, in the composite extractant, the volume ratio of C272 to P507 is 8-10:10-15; for example, it can be 1:1-1.875; further, it can be about 1:1.5.

[0061] According to some embodiments of the present application, in step S2, the composite extractant further includes a diluent. The type of the diluent includes sulfonated kerosene. In the composite extractant, the volume percentage of the diluent is 75-82%; for example, it can be about 80%.

[0062] According to some embodiments of the present application, in step S2, the preparation process of the complex extractant of the nickel soap includes the following steps:

[0063] S2a. Mixing the complex extractant and a sodium hydroxide solution to prepare a sodium soap;

[0064] S2b. Mixing the complex extractant after the sodium soap and a nickel sulfate solution to prepare a nickel soap.

[0065] According to some embodiments of the present application, in step S2a, the concentration of the sodium hydroxide solution is 30-35 wt%. For example, it can be about 32 wt%.

[0066] According to some embodiments of the present application, in step S2a, the saponification rate of the sodium soap is 30-50%. For example, it can be about 40%.

[0067] According to some embodiments of the present application, in step S2b, the concentration of the nickel sulfate solution is 70-80 g / L. For example, it can be about 75 g / L.

[0068] According to some embodiments of the present application, in step S2, the method of extraction includes countercurrent extraction.

[0069] According to some embodiments of the present application, in step S2, the number of stages of extraction is 10-12 stages. For example, it can be 11 stages.

[0070] According to some embodiments of the present application, in step S2, the O / A value of the extraction is 0.5-2:1. For example, it can be about 1:1 or about 1.5:1.

[0071] According to some embodiments of the present application, in step S2, the equilibrium pH of the extraction is ≥5.

[0072] According to some embodiments of the present application, in step S2, it further includes removing oil from the raffinate phase of the complex extractant to obtain a battery-grade nickel sulfate solution. The method of removing oil is activated carbon oil removal.

[0073] According to some embodiments of the present application, the parameters of the nickel sulfate solution are as follows:

[0074] Ni ≥ 105 g / L; for example, it can be about 108 g / L, 110 g / L, 111 g / L, or about 115 g / L;

[0075] Co ≤ 0.005 g / L;

[0076] Mn ≤ 0.001 g / L;

[0077] Mg ≤ 0.005 g / L.

[0078] According to the above parameters, the impurity removal method provided by the application can obtain a nickel sulfate solution with high purity.

[0079] According to some embodiments of the application, the ratio of nickel in the nickel sulfate solution to the nickel in the nickel sulfate stock solution, i.e., the recovery rate of nickel, is ≥99%; further specifically, it can be about 99.5%, 99.9%, or about 99.99%.

[0080] According to some embodiments of the application, in step S3, the washing solution used for washing nickel is a 1-2 mol / L aqueous sulfuric acid solution. For example, it can specifically be about 1.5 mol / L of aqueous sulfuric acid solution.

[0081] According to some embodiments of the application, in step S3, the O / A value of the washing of nickel is 8-12:1. For example, it can specifically be about 9:1, 10:1, or about 11:1.

[0082] According to some embodiments of the application, in step S3, the number of stages of the washing of nickel is 6-8 stages. For example, it can specifically be 7 stages.

[0083] According to some embodiments of the application, in step S3, it further includes returning the nickel washing solution to step S2 and mixing it with the P204 raffinate phase, and extracting with the composite extractant. In this way, the recovery rate of nickel can be further improved.

[0084] According to some embodiments of the application, in step S3, the washing solution used for washing magnesium is a 2-2.5 mol / L aqueous sulfuric acid solution.

[0085] According to some embodiments of the application, in step S3, the number of stages of the washing of magnesium is 13-15 stages. For example, it can specifically be 14 stages.

[0086] According to some embodiments of the application, in step S3, the O / A value of the washing of magnesium is 7-10:1. For example, it can specifically be about 8:1 or about 9:1.

[0087] According to some embodiments of the application, in step S3, the magnesium washing solution meets the following indexes:

[0088] Ni 0-5 g / L; for example, it can specifically be about 0.5 g / L, 1 g / L, 1.5 g / L, 2 g / L, 2.5 g / L, 3 g / L, 3.5 g / L, 4 g / L, or about 4.5 g / L;

[0089] Co 0-27 g / L; for example, it can specifically be about 2 g / L, 4 g / L, 5 g / L, 6 g / L, 7 g / L, 8 g / L, 10 g / L, 15 g / L, 20 g / L, or about 25 g / L;

[0090] Mg 10-25 g / L. For example, it can be about 12 g / L, 15 g / L, 18 g / L, 19 g / L, 20 g / L or about 22 g / L;

[0091] According to some embodiments of the present application, in step S3, the magnesium washing solution further contains Mn; wherein the concentration of Mn is ≤0.01 g / L. For example, it can be about 0.005 g / L or about 0.008 g / L.

[0092] In actual production, the corresponding O / A ratio can be adjusted according to the index.

[0093] According to some embodiments of the present application, the preparation method further comprises stripping the composite extractant blank phase and the crude cobalt sulfate solution from the magnesium washing phase of the composite extractant. The stripping agent used for stripping the magnesium washing phase of the composite extractant is 3.5-4.5 mol / L aqueous sulfuric acid solution, for example, it can be about 4 mol / L aqueous sulfuric acid solution.

[0094] According to some embodiments of the present application, the crude cobalt sulfate solution satisfies the following indexes:

[0095] Ni ≤0.01 g / L; for example, it can be about 0.005 g / L, 0.006 g / L or about 0.007 g / L.

[0096] Co 110-140 g / L; for example, it can be about 115 g / L, 120 g / L, 125 g / L, 130 g / L or about 135 g / L.

[0097] Mn ≤0.5 g / L; for example, it can be about 0.1 g / L, 0.15 g / L, 0.2 g / L, 0.3 g / L or about 0.4 g / L.

[0098] Mg ≤0.01 g / L. For example, it can be about 0.001 g / L, 0.005 g / L or about 0.008 g / L.

[0099] In actual production, the O / A value used for stripping the magnesium washing phase of the composite extractant can be determined according to the standard. Specifically, the stripping here is 5-7 stages, for example, it can be 6 stages; the O / A value is 20-26:1, for example, it can be about 22:1, 23:1 or about 25:1; and the equilibrium pH is 2-2.5.

[0100] According to some embodiments of the present application, the preparation method further comprises extracting the crude cobalt sulfate solution with P204 to obtain a cobalt sulfate solution and a calcium-manganese loaded phase. The P204 used herein and the P204 organic phase obtained in step S1a are equivalent, and are P204 organic phase of sodium soap. The extraction herein mainly removes impurities, and the number of stages is 7-9 stages, for example, specifically 8 stages; the O / A value is 0.8-1.2:1, for example, specifically about 1:1; and the equilibrium pH is 2-2.5.

[0101] Further, the impurity removal method further comprises removing oil from the cobalt sulfate solution, and the method for removing oil is activated carbon oil removal, so as to finally obtain a battery-grade cobalt sulfate solution.

[0102] According to some embodiments of the present application, the parameters of the cobalt sulfate solution are as follows:

[0103] Ni≤0.005g / L; even as low as 0.

[0104] Co 110-130g / L; for example, specifically about 120g / L or about 125g / L;

[0105] Mn≤0.001g / L;

[0106] Mg≤0.005g / L.

[0107] According to the above parameters, the impurity removal method provided by the present application can obtain a cobalt sulfate solution with high purity.

[0108] According to some embodiments of the present application, the ratio of cobalt in the cobalt sulfate solution to cobalt in the nickel sulfate raw solution, i.e. the yield of cobalt, is ≥99%. Further specifically, it can be about 99.5%, 99.9% or about 99.99%.

[0109] According to some embodiments of the present application, the preparation method further comprises stripping the calcium-manganese loaded phase to obtain a calcium-manganese solution. The stripping agent used for stripping is 3.5-4.5mol / L hydrochloric acid aqueous solution, for example, specifically about 4mol / L; the O / A value of stripping is 9-11:1, for example, specifically about 10:1; and the equilibrium pH of stripping is ≤2.5.

[0110] The calcium-manganese solution and the calcium-manganese stripping phase are mixed and used for mixing extraction with the HBL116 loaded organic phase.

[0111] According to some embodiments of the present application, the preparation method further comprises washing iron and chlorine in sequence for the composite extractant blank phase, and then reapplying. Thus, the reagent cost is saved.

[0112] According to some embodiments of the present application, in step S4, the HBL116 organic phase comprises HBL116 and a diluent. The diluent used herein includes sulfonated kerosene. The volume percentage of the diluent in the HBL116 is 50-55%. For example, it can be about 52%.

[0113] According to some embodiments of the present application, in step S4, the HBL116 organic phase of the sodium soap has a saponification rate of 30-50%. For example, it can be about 40%. The treatment method of the sodium soap is to treat it with 30-35wt% sodium hydroxide aqueous solution.

[0114] According to some embodiments of the present application, in step S4, the equilibrium pH of the extraction is 2-3.

[0115] According to some embodiments of the present application, in step S4, the O / A ratio of the extraction is 1-5:1. For example, it can be about 2:1, 3:1 or about 4:1. In actual production, the specific O / A ratio can be determined according to the content of nickel and cobalt in the magnesium washing solution and the calcium-manganese stripping phase (calculated according to the saturated extraction capacity), and at least ensure that the nickel and cobalt in the above two solutions can be theoretically completely extracted.

[0116] According to some embodiments of the present application, in step S4, the extraction method comprises countercurrent extraction.

[0117] According to some embodiments of the present application, in step S4, the extraction is 4-7 stages. For example, it can be 5 stages or 6 stages.

[0118] According to some embodiments of the present application, in step S4, the Co content in the HBL116 raffinate phase is ≤0.01g / L.

[0119] According to some embodiments of the present application, in step S4, the Ni content in the HBL116 raffinate phase is ≤0.001g / L.

[0120] According to some embodiments of the present application, in step S4, the Mn content in the HBL116 raffinate phase is ≤0.0001g / L.

[0121] According to some embodiments of the present application, in step S4, the Mg content in the HBL116 raffinate phase is ≥5g / L. For example, it can be about 5g / L, 10g / L, 15g / L, 19g / L, 20g / L, 21g / L or about 25g / L.

[0122] According to some embodiments of the present application, in step S5, the HBL116 loaded organic phase is further washed with sulfur before the mixed extraction.

[0123] According to some embodiments of the present application, the washing agent used for the sulfur washing is pure water.

[0124] According to some embodiments of the present application, the method of washing sulfur is countercurrent washing. The countercurrent washing is 1-3 stages. For example, it can be specifically 2 stages.

[0125] According to some embodiments of the present application, the O / A value of the sulfur washing is 28-32:1; for example, it can be specifically about 30:1.

[0126] According to some embodiments of the present application, in step S5, the method of mixed extraction is countercurrent extraction.

[0127] According to some embodiments of the present application, in step S5, the number of stages of mixed extraction is 3-5 stages. For example, it can be specifically 4 stages.

[0128] According to some embodiments of the present application, in step S5, the O / A ratio of mixed extraction is 3-10:1. For example, it can be specifically about 4:1, 5:1, 6:1, 7:1, 8:1, or about 9:1.

[0129] According to some embodiments of the present application, in step S5, the equilibrium pH value of mixed extraction is 2-3.

[0130] According to some embodiments of the present application, in step S5, the HBL116 mixed extraction liquid satisfies the following indexes:

[0131] Ni≤0.005g / L; further specifically, it can be ≤0.0001g / L;

[0132] Co≤0.005g / L; further specifically, it can be ≤0.001g / L;

[0133] Ca 0-10g / L; further specifically, it can be about 0.5g / L, 1g / L, 1.5g / L, 2.0g / L, 3.0g / L, 5g / L, or about 8g / L.

[0134] Mn 70-110g / L. For example, it can be specifically about 90g / L, 100g / L, 101g / L, 102g / L, 104g / L, 105g / L, 106g / L, 107g / L, 108g / L, or about 109g / L.

[0135] Therefore, the impurity removal method obtains a manganese-containing solution with high purity.

[0136] According to some embodiments of the present application, the ratio of manganese in the HBL116 mixed extraction liquid to the manganese in the nickel sulfate raw solution, i.e., the recovery rate of manganese, is ≥99.9%. For example, it can be specifically about 99.99% or about 99.999%. That is, it has basically reached 100% recovery.

[0137] According to some embodiments of the present application, in step S6, the water phase used in back extraction is 0.5-1.5 mol / L sulfuric acid. For example, it can be about 1 mol / L sulfuric acid. If the acid concentration is too low, back extraction cannot be effectively achieved, and the indicators of the P204 second washing solution are difficult to meet. If the acid concentration is too high, it will affect the reuse of the HBL116 organic phase to some extent.

[0138] According to some embodiments of the present application, in step S6, the number of stages of back extraction is 4-6 stages; for example, it can be 5 stages.

[0139] According to some embodiments of the present application, in step S6, the O / A value of back extraction is 3-5:1. For example, it can be about 4:1.

[0140] According to some embodiments of the present application, the equilibrium pH of back extraction is ≤1.

[0141] In actual production, the output of the P204 second washing solution needs to be controlled to be less than or equal to the actual demand in step S7. Otherwise, the nickel and cobalt content in the calcium-manganese back extraction phase should be adjusted to adjust the nickel and cobalt content in the HBL116 mixed extraction post-phase; specifically, the adjustment method of the nickel and cobalt content in the calcium-manganese back extraction phase can be dilution by 1-2 mol / L sulfuric acid.

[0142] According to some embodiments of the present application, in step S6, the P204 second washing solution meets the following indicators:

[0143] Ni 0-10 g / L; for example, it can be about 1 g / L, 1.5 g / L, 2 g / L, 5 g / L, or about 8 g / L;

[0144] Co 5-20 g / L; for example, it can be about 7 g / L, 8 g / L, 9 g / L, 9.5 g / L, 10 g / L, 12 g / L, or about 15 g / L;

[0145] Mn 0-25 g / L; for example, it can be about 5 g / L, 10 g / L, 15 g / L, 17 g / L, 18 g / L, 19 g / L, or about 20 g / L.

[0146] According to some embodiments of the present application, in step S6, it further includes washing copper and zinc and washing chlorine in sequence to reuse the HBL116 blank phase.

[0147] According to some embodiments of the present application, in step S7, the washing solution used in the first washing is 1-2 mol / L sulfuric acid aqueous solution. The specific concentration can be about 1 mol / L, 1.5 mol / L, or about 2 mol / L.

[0148] According to some embodiments of the present application, in step S7, the washing method is countercurrent washing.

[0149] According to some embodiments of the present application, in step S7, the number of washing stages is 1-4 stages. For example, it can be 2 stages or 3 stages.

[0150] According to some embodiments of the present application, in step S7, the O / A value of the washing is 10-50:1. For example, it can be about 15:1, 20:1, 25:1, 30:1, 35:1 or about 40:1.

[0151] Through the washing in step S7, more than 80% of the total amount of nickel and cobalt in the P204 loaded organic phase can be removed.

[0152] According to some embodiments of the present application, in step S7, the washing of the P204 second washing solution is countercurrent washing.

[0153] According to some embodiments of the present application, in step S7, the number of washing stages of the P204 second washing solution is 1-3 stages. For example, it can be 2 stages.

[0154] According to some embodiments of the present application, in step S7, the O / A ratio of the washing of the P204 second washing solution is 15-30:1. For example, it can be about 20:1 or about 25:1.

[0155] According to some embodiments of the present application, in step S7, the washing mechanism of the P204 second washing solution is as follows:

[0156] Mn 2+ +CoA2 / NiA2=Co 2+ / Ni 2+ +MnA2;

[0157] MnA2+Ca 2+ =CaA2+Mn 2+ ;

[0158] Wherein A2 represents the P204 extractant.

[0159] In step S7, the washing of the P204 second washing solution can remove most of the nickel and cobalt in the phase after the first washing of P204 by controlling the flow rate (O / A value) of the P204 second washing solution. The principle is that the manganese ions in the P204 second washing solution replace the nickel and cobalt ions therein, but do not replace the calcium ions, thereby reducing the washing of calcium ions into the aqueous phase, and further preventing calcium crystallization. Further, the two washings in step S7 can remove more than 90% of the nickel and cobalt in the P204 loaded organic phase.

[0160] According to some embodiments of the present application, the impurity removal method further comprises collecting the nickel sulfate solution crude product in step S7 and refluxing it to step S1, and mixing it with the nickel sulfate stock solution, and then extracting it with the P204 organic phase of nickel soap. In this way, the yield of nickel and cobalt can be further improved.

[0161] According to some embodiments of the present application, in step S7, the aqueous phase used for stripping is 3.5-4.5 mol / L hydrochloric acid aqueous solution. For example, it can be about 4 mol / L.

[0162] According to some embodiments of the present application, in step S7, the O / A value of the stripping is 20-30:1. For example, it can be about 25:1.

[0163] According to some embodiments of the present application, in step S7, the stripping is performed for 5-7 stages. For example, it can be 6 stages.

[0164] According to some embodiments of the present application, in step S7, the equilibrium pH of the stripping is 2-2.5.

[0165] According to some embodiments of the present application, in step S7, the calcium-manganese stripping phase satisfies the following indexes:

[0166] Ni 0-2 g / L; for example, it can be about 0.1 g / L, 0.12 g / L, 0.2 g / L, 0.5 g / L, 1 g / L, 1.1 g / L, 1.2 g / L, 1.3 g / L, 1.5 g / L, or about 1.8 g / L.

[0167] Co 0-5 g / L; for example, it can be about 0.5 g / L, 1 g / L, 2 g / L, 3 g / L, or about 4 g / L;

[0168] Mn 80-110 g / L; for example, it can be about 85 g / L, 90 g / L, 95 g / L, 100 g / L, 103 g / L, or about 105 g / L.

[0169] Ca 0-10 g / L. For example, it can be about 1 g / L, 2 g / L, 3 g / L, 4 g / L, 5 g / L, 6 g / L, 7 g / L, 8 g / L, or about 9 g / L.

[0170] According to some embodiments of the present application, the impurity removal method further comprises sequentially washing iron and chlorine from the P204 blank phase and reapplying it. In this way, the total amount of extractant used in the recycling process of the impurity removal method can be saved, and the cost of reagents can be saved.

[0171] According to embodiments of the second aspect of the present application, the application of the impurity removal method in lithium battery recycling is provided.

[0172] Since the lithium battery recycling adopts all the technical solutions of the impurity removal methods of the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments.

[0173] According to some embodiments of the present invention, the lithium battery recycling includes the following steps performed sequentially:

[0174] Disassembling and sorting lithium batteries to obtain positive electrode sheets;

[0175] Separate the positive current collector and the positive electrode dressing from the positive electrode sheet;

[0176] The positive electrode dressing is dissolved and impregnated to obtain a lithium battery positive electrode material leachate;

[0177] The method described above is used to separate and recover valuable metal elements such as nickel, cobalt, and manganese from the leachate of the lithium battery cathode material.

[0178] According to an embodiment of a third aspect of the present invention, an application of the aforementioned impurity removal method in the wet extraction of nickel ore is provided.

[0179] Since the wet extraction of nickel ore adopts all the technical solutions of the impurity removal methods of the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments.

[0180] According to some embodiments of the present invention, the wet extraction of nickel ore includes the following steps:

[0181] Leaching nickel ore to obtain nickel ore leachate;

[0182] The nickel ore leaching solution is purified using the aforementioned purification method to obtain a nickel-containing product.

[0183] Unless otherwise specified, the term "about" in this invention actually means that the error is allowed to be within ±2%, for example, about 100 is actually 100 ± 2% × 100.

[0184] Unless otherwise specified, "between" in this invention includes the number itself, for example, "between 2 and 3" includes the endpoint values ​​2 and 3.

[0185] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. Attached Figure Description

[0186] The above and / or additional aspects and advantages of the present invention will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0187] Figure 1 This is a schematic flowchart of the impurity removal method provided in an embodiment of the present invention. Detailed Implementation

[0188] The concept and technical effects of the present application will be described clearly and completely in combination with the embodiments, so that the purpose, features and effects of the present application can be fully understood. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments of the present application, other embodiments obtained by those skilled in the art without creative labor are within the protection scope of the present application.

[0189] In the description of the present application, the description of the terms “one embodiment”, “some embodiments”, “illustrative embodiment”, “example”, “specific example” or “some examples” means that the specific features, structures, materials or characteristics described in combination with the embodiment or example are contained in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0190] Embodiment 1

[0191] Reference Figure 1 According to the flow of the present application, a method for removing impurities from a nickel sulfate raw solution is provided, Figure 1 In the present application, the solid line box is the organic phase, the dashed line box is the aqueous phase, the underlined part is the product produced by the impurity removal method, and the part without any mark is the process name. The arrow indicates the material and flow direction.

[0192] The specific steps of the impurity removal method provided in the present application are as follows:

[0193] S1. Preparation of P204 organic phase of nickel soap:

[0194] Mix P204 and sulfonated kerosene at a volume ratio of 25:75 to obtain P204 organic phase;

[0195] Mix the P204 organic phase and 32wt% sodium hydroxide aqueous solution to prepare sodium soap, and the saponification rate is 30%.

[0196] Convert the P204 organic phase of sodium soap into nickel soap by mixing with 75g / L nickel sulfate solution to obtain the P204 organic phase of nickel soap. During the conversion of nickel soap, all sodium soap can be converted into nickel soap, i.e. the saponification rate of nickel soap is also 30%. The same operation is used for other conversion of nickel soap.

[0197] Extraction: 1000mL of nickel sulfate raw solution is mixed with the P204 organic phase of nickel soap for countercurrent extraction, and the P204 raffinate phase and P204 loaded organic phase are obtained by phase separation. The O / A ratio of countercurrent extraction in this step is 2.5:1; the extraction stage is 11 stages; and the process maintains the equilibrium pH of 3.5-4.

[0198] The indexes of the original solution used in this example are shown in Table 1. Some results of the P204 raffinate phase obtained are as follows:

[0199] Mn 0.009g / L;

[0200] Ca 0.001g / L.

[0201] S2. Preparation of composite extractant of nickel soap:

[0202] After mixing C272 and P507 in a volume ratio of 1:1.5, the composite extractant is obtained by mixing with diluent sulfonated kerosene, wherein the volume percentage of sulfonated kerosene is 75%.

[0203] The composite extractant is first saponified with 32% sodium hydroxide aqueous solution to obtain a composite extractant of sodium soap with a saponification rate of 40%;

[0204] Then, the composite extractant of sodium soap is mixed with a 75g / L nickel sulfate solution to perform nickel soap conversion to obtain a composite extractant of nickel soap.

[0205] Extraction: The P204 raffinate phase obtained in step S1 is extracted with the composite extractant of nickel soap, and the composite extractant loaded organic phase and the composite extractant raffinate phase are obtained by phase separation; wherein, after removing oil from the composite extractant raffinate phase using activated carbon, a battery-grade nickel sulfate solution is obtained, and the specific components are shown in Table 1.

[0206] The extraction in this step has an O / A value of 2:1 and 10 stages of extraction, and the equilibrium pH is greater than or equal to 5.

[0207] S3. Washing of nickel in the composite extractant loaded organic phase:

[0208] The composite extractant loaded organic phase obtained in step S2 is washed with 1mol / L aqueous sulfuric acid solution to obtain a composite extractant after nickel washing phase and a nickel washing solution; wherein the nickel washing solution is returned to step S2 and mixed with the P204 raffinate phase;

[0209] During the nickel washing process, the washing has 7 stages; and the O / A value is 10:1.

[0210] Washing of magnesium in the composite extractant loaded organic phase:

[0211] The composite extractant after nickel washing phase is washed with 2mol / L aqueous sulfuric acid solution to obtain a magnesium washing solution and a composite extractant after magnesium washing phase; the magnesium washing has 14 stages, and the O / A value is 9:1. The indexes of the magnesium washing solution obtained are as follows:

[0212]

[0213] The composite extractant after magnesium washing phase is further stripped with 4mol / L aqueous sulfuric acid solution to obtain a crude cobalt sulfate solution with the following parameters:

[0214]

[0215] The number of back-extraction stages is 6, the O / A value is 25:1, and the equilibrium pH is 2-2.5.

[0216] The crude cobalt sulfate solution is further extracted with the same extractant as the P204 organic phase after sodium soap in step S1 (8 stages, O / A value of 1:1, and equilibrium pH of 2-2.5), to obtain a cobalt sulfate solution and a calcium-manganese loaded phase; the cobalt sulfate solution is deoiled with activated carbon to obtain a battery-grade cobalt sulfate solution (the specific parameters are shown in Table 1), and the calcium-manganese loaded phase is back-extracted (back-extraction agent: 4 mol / L hydrochloric acid aqueous solution; O / A value: 10:1, and equilibrium pH≤2.5) to obtain a calcium-manganese solution and a reusable P204 organic phase. The calcium-manganese solution is recycled to step S5 for extraction with the HBL116 loaded organic phase to fully utilize the nickel and cobalt resources therein (see step S5 for details).

[0217] S4. Preparation of sodium soap HBL116 organic phase:

[0218] The HBL116 and the diluent sulfonated kerosene are mixed at a volume ratio of 45:55 to obtain the HBL116 organic phase;

[0219] The above HBL116 organic phase is treated with a 32wt% sodium hydroxide aqueous solution to obtain a sodium soap HBL116 organic phase with a saponification rate of 30%.

[0220] Extraction and separation of cobalt and magnesium: the above sodium soap HBL116 organic phase is mixed with the magnesium washing liquid obtained in step S3 for countercurrent extraction; an HBL116 loaded organic phase and an HBL116 raffinate phase are obtained; the HBL116 raffinate phase is actually a sodium-containing magnesium sulfate solution, and the specific components are shown in Table 1.

[0221] In this step, the number of extraction stages is selected to be 5, the O / A ratio is selected to be 2:1, and the extraction equilibrium pH is 2-3.

[0222] S5. Sulfur washing:

[0223] The HBL116 loaded organic phase obtained in step S4 is washed with pure water in countercurrent for 2 stages (O / A value of 30:1 for each stage) to obtain a pure HBL116 loaded organic phase;

[0224] Extraction and separation of cobalt and manganese:

[0225] The P204 loaded organic phase is mixed with the HBL116 loaded organic phase (countercurrent mixing extraction) to obtain HBL116 mixing post-extraction liquid and HBL116 mixing post-extraction phase; wherein the HBL116 mixing post-extraction liquid is actually a manganese calcium chloride solution, and the specific components are shown in Table 1.

[0226] The number of stages of the mixing extraction in this example is 4, the O / A ratio is 5:1, and the equilibrium pH value is 2-3.

[0227] S6. The HBL116 mixing post-extraction phase is back-extracted to obtain P204 second washing liquid (for step S7) and HBL116 blank phase;

[0228] The aqueous phase used for back-extraction is 1 mol / L sulfuric acid aqueous solution; the number of stages is 5, the O / A value is 4:1, and the equilibrium pH is ≤1.

[0229] The parameters of the obtained P204 second washing liquid are as follows:

[0230] Ni 1.47g / L;

[0231] Co 9.455g / L;

[0232] Mn 17.26g / L.

[0233] The HBL116 blank phase is repeatedly used after washing copper and zinc and washing chlorine.

[0234] S7. The P204 loaded organic phase is washed once to obtain P204 first washing post-extraction phase and crude nickel sulfate solution;

[0235] The first washing is countercurrent washing with 1 mol / L sulfuric acid, the washing number of stages is 4, and the washing ratio (O / A value) is 26:1.

[0236] The P204 first washing post-extraction phase is washed with P204 second washing liquid (self-prepared second washing liquid for the first week cycle) to obtain P204 second washing post-extraction phase and crude nickel sulfate solution;

[0237] The second washing is 3-stage countercurrent washing, the washing ratio (O / A value) is 21:1, and the self-prepared second washing liquid has the following indexes: Ni: 1.47, Co: 9.45, and Mn: 17.25, unit: g / L.

[0238] The crude nickel sulfate solution obtained by the two washings in this example is recycled to step S1, mixed with the original nickel sulfate solution, and subjected to subsequent operations.

[0239] The P204 secondary washing phase is back-extracted with 4 mol / L hydrochloric acid to obtain a calcium-manganese back-extraction phase (used in step S5) and a P204 blank phase. In this case, the O / A value of the back-extraction is 25:1, the number of stages is 6, and the equilibrium pH is 2-2.5; the parameters of the obtained calcium-manganese back-extraction phase are as follows:

[0240]

[0241] The P204 blank phase is repeatedly used after washing iron and chlorine.

[0242] In this example, the operation of washing chlorine is 2-stage pure water countercurrent washing.

[0243] Example 2

[0244] This example provides a method for removing impurities from a nickel sulfate stock solution, and the specific steps are as follows:

[0245] S1. Preparation of P204 organic phase of nickel soap:

[0246] Mix P204 and sulfonated kerosene at a volume ratio of 25:75 to obtain P204 organic phase;

[0247] Mix the P204 organic phase with 32 wt% sodium hydroxide aqueous solution to prepare sodium soap, and the saponification rate is 30%.

[0248] Perform nickel transfer soap with the P204 organic phase of sodium soap and 75 g / L nickel sulfate solution to obtain the P204 organic phase of nickel soap.

[0249] Extraction: 1000 mL of nickel sulfate stock solution is mixed with the P204 organic phase of nickel soap to perform countercurrent extraction, and the P204 raffinate phase and the P204 loaded organic phase are obtained by phase separation. The O / A ratio of countercurrent extraction in this step is 4:1; the extraction stage number is 11; and the process maintains an equilibrium pH of 3.5-4.

[0250] The indicators of the stock solution used in this example are shown in Table 1. Some results of the obtained P204 raffinate phase are as follows:

[0251] Mn 0.01 g / L;

[0252] Ca 0.0008 g / L.

[0253] S2. Preparation of composite extractant of nickel soap:

[0254] Mix C272 and P507 at a volume ratio of 1:1.5, then mix with diluent sulfonated kerosene to obtain a composite extractant; the volume percentage of sulfonated kerosene is 75%.

[0255] First, saponify the composite extractant with 32% sodium hydroxide aqueous solution to obtain a sodium soap composite extractant with a saponification rate of 40%;

[0256] The composite extractant of the sodium soap is then mixed with 75 g / L nickel sulfate solution to perform a nickel transfer soap, to obtain a composite extractant of the nickel soap.

[0257] Extraction: the P204 raffinate phase obtained in step S1 is extracted with the composite extractant of the nickel soap, and phase separation is performed to obtain a composite extractant loaded organic phase and a composite extractant raffinate phase; wherein the composite extractant raffinate phase is deoiled with activated carbon to obtain a battery-grade nickel sulfate solution, and the specific components are shown in Table 1.

[0258] The O / A value of the extraction in this step is 1.5:1, and the extraction series is 10 stages, and the equilibrium pH is greater than or equal to 5.

[0259] S3. Washing of the nickel in the composite extractant loaded organic phase:

[0260] The composite extractant loaded organic phase obtained in step S2 is washed with 1 mol / L aqueous sulfuric acid solution to obtain a composite extractant washed nickel phase and a nickel washing solution; wherein the nickel washing solution is returned to step S2 and mixed with the P204 raffinate phase.

[0261] During the washing of the nickel, the washing series is 7 stages, and the O / A value is 9:1.

[0262] Washing of the magnesium in the composite extractant loaded organic phase:

[0263] The composite extractant washed nickel phase is washed with 2 mol / L aqueous sulfuric acid solution to obtain a magnesium washing solution and a composite extractant washed magnesium phase.

[0264] The washing series of the magnesium is 14 stages, and the O / A value is 8:1. The indexes of the obtained magnesium washing solution are as follows:

[0265]

[0266] The composite extractant washed magnesium phase is continuously stripped with 4 mol / L aqueous sulfuric acid solution to obtain a crude cobalt sulfate solution with the following parameters:

[0267]

[0268] The stripping series is 6 stages, the O / A value is 23:1, and the equilibrium pH is 2-2.5.

[0269] The above-mentioned crude cobalt sulfate solution is continuously extracted with the same extractant as the P204 organic phase after sodium soap in step S1 (8 stages, O / A value of 1:1, equilibrium pH of 2-2.5), to obtain a cobalt sulfate solution and a calcium-manganese loaded phase; the cobalt sulfate solution is deoiled with activated carbon to obtain a battery-grade cobalt sulfate solution (specific parameters are shown in Table 1), and the calcium-manganese loaded phase is stripped (stripping agent: 4 mol / L hydrochloric acid aqueous solution; O / A value of 10:1, equilibrium pH ≤2.5) to obtain a calcium-manganese solution and a reusable P204 organic phase. The calcium-manganese solution is recycled to step S5 for extraction with the HBL116 loaded organic phase to fully utilize the nickel and cobalt resources therein (see step S5 for details).

[0270] S4. Preparation of sodium soap HBL116 organic phase:

[0271] The HBL116 and the diluent sulfonated kerosene are mixed in a volume ratio of 45:55 to obtain the HBL116 organic phase;

[0272] The above-mentioned HBL116 organic phase is treated with a 32wt% sodium hydroxide aqueous solution to obtain a sodium soap HBL116 organic phase with a saponification rate of 30%.

[0273] Extraction and separation of cobalt and magnesium: the above-mentioned sodium soap HBL116 organic phase is mixed with the magnesium washing solution obtained in step S3 in countercurrent extraction; HBL116 loaded organic phase and HBL116 raffinate phase are obtained; the HBL116 raffinate phase is actually a sodium-containing magnesium sulfate solution, and its specific composition is shown in Table 1.

[0274] In this step, the number of extraction stages is selected to be 5, the O / A ratio is selected to be 3:1, and the extraction equilibrium pH is 2-3.

[0275] S5. Washing sulfur:

[0276] The HBL116 loaded organic phase obtained in step S4 is washed with pure water in countercurrent 2 stages (O / A value of 30:1 per stage) to obtain a pure HBL116 loaded organic phase;

[0277] Extraction and separation of cobalt and manganese:

[0278] The calcium-manganese stripping phase (from step S7, which will be described in detail in step S7) and / or the calcium-manganese solution obtained in step S3 is mixed with the pure HBL116 loaded organic phase for extraction (countercurrent mixing extraction) to obtain HBL116 mixed post-extraction liquid and HBL116 mixed post-extraction phase; the HBL116 mixed post-extraction liquid is actually a calcium-manganese chloride solution, and its specific composition is shown in Table 1.

[0279] The number of stages for this example mixed extraction is 4, the O / A ratio is 5:1, and the equilibrium pH value is 2-3.

[0280] S6. The P204 second washing liquid (for step S7) and the HBL116 blank phase are obtained by mixing the P204 loaded organic phase after back extraction and the HBL116 blank phase;

[0281] The water phase used for back extraction is 1 mol / L sulfuric acid aqueous solution; the number of stages is 5, the O / A value is 3:1, and the equilibrium pH is ≤1.

[0282] The parameters of the obtained P204 second washing liquid are as follows:

[0283] Ni 1.13 g / L;

[0284] Co 7.2 g / L;

[0285] Mn 19.69 g / L.

[0286] The HBL116 blank phase is repeatedly used after washing copper and zinc and washing chlorine.

[0287] S7. The P204 loaded organic phase is washed once to obtain the P204 first washing liquid and the crude nickel sulfate solution;

[0288] The first washing is countercurrent washing with 1 mol / L sulfuric acid, the number of washing stages is 4, and the washing ratio (O / A value) is 27:1.

[0289] The P204 first washing liquid is washed with the P204 second washing liquid (the second washing liquid configured by itself is used in the first week) to obtain the P204 second washing liquid and the crude nickel sulfate solution;

[0290] The second washing is 3-stage countercurrent washing, the washing ratio (O / A value) is 24:1, and the index of the self-prepared second washing liquid is Ni: 1.13, Co: 7.2, and Mn: 19.69, unit: g / L.

[0291] The crude nickel sulfate solution obtained by the two washings in this example is recycled to step S1, mixed with the original nickel sulfate solution, and subjected to subsequent operations.

[0292] The P204 second washing liquid is back extracted with 4 mol / L hydrochloric acid to obtain the calcium-manganese back extraction phase (for step S5) and the P204 blank phase. The O / A value of the back extraction is 25:1, the number of stages is 6, and the equilibrium pH is 2-2.5. The parameters of the obtained calcium-manganese back extraction phase are as follows:

[0293]

[0294] The P204 blank phase is repeatedly used after washing iron and washing chlorine.

[0295] In this example, the operation of washing chlorine is 2-stage pure water countercurrent washing.

[0296] Comparative Example 1

[0297] The example provides a method for removing impurities from a nickel sulfate raw solution, which is different from the embodiment 1 in that:

[0298] In the step S7, the P204 second washing solution (self-prepared second washing solution for the first cycle) is replaced by a 1 mol / L sulfuric acid aqueous solution.

[0299] Meanwhile, the P204 second washing solution obtained in the step S6 is directly introduced into the step S1, mixed with the nickel sulfate raw solution, and extracted by the P204 organic phase of the nickel soap.

[0300] Comparative example 2

[0301] The example provides a method for removing impurities from a nickel sulfate raw solution, which is different from the embodiment 2 in that:

[0302] The steps S4-S6 are not included. That is, no cycle is performed, and thus the magnesium washing solution produced in the step S3, the calcium-manganese stripping phase produced in the step S7, and the calcium-manganese solution produced in the step S3 are directly discharged from the system; the second washing in the step S7 is performed by using a self-prepared second washing solution (the indexes are Ni: 1.13, Co: 7.2, and Mn: 19.69, units: g / L).

[0303] Test example

[0304] The examples 1-2 and the comparative examples 1-2 are tested for the components of the nickel sulfate raw solution and the produced cobalt sulfate solution, nickel sulfate solution, sodium-containing magnesium sulfate solution, and calcium-manganese chloride solution, and the recovery rates of several target metals are calculated. Specifically, the concentration test method is ICP-OES. The test results are shown in Table 1.

[0305] Table 1: Partial results of the examples and comparative examples

[0306]

[0307]

[0308] In Table 1, the blank indicates that the content is too low, below the detection limit, or the calculation result is almost equal to 0.

[0309] According to the above results, the method for removing impurities provided by the present application can obtain high-purity nickel and cobalt products, and at the same time, high-purity manganese and magnesium products, and the recovery rates of the above metals are all >99.9%. Further, the method for removing impurities provided by the present application does not have obvious calcium crystallization problems during the cycle operation, and the process is relatively simple.

[0310] Comparing Example 1 and Comparative Example 1, under the condition that the extraction conditions of each step of the HBL116 organic phase remain unchanged, the Co content in the calcium manganese chloride solution increases, and a large amount of calcium crystals appear in the production line. This indicates that when sulfuric acid is used as a secondary washing agent, the appearance of calcium crystals in the production line affects the impurity removal method, especially the operation of the washing section. The amount of cobalt in the P204 loaded organic phase entering the back-extraction section increases, resulting in an increase in the cobalt concentration in the back-extracted calcium manganese back-extraction phase. With the HBL116 extraction conditions unchanged, the cobalt concentration in the extracted calcium manganese chloride solution increases. As a result, the metal yield of cobalt is lower than that in Example 1, and the calcium crystals further affect the process operation. It can be seen that in the impurity removal method provided by the present invention, there is a synergistic effect between the extraction of the HBL116 organic phase (and subsequent processing stage) and the extraction of the P204 organic phase (and subsequent processing stage). More precisely, it is a cyclic process between steps S5 and S7, which significantly improves the recovery efficiency and purity of nickel and cobalt, and also reduces the difficulty of process operation. The binding strength of P204 extractant and metal ions is ranked (extraction priority): Fe > Zn > Ca > Al > Cu > Mn > Mg > Ni > Co. Manganese in the second washing solution of P204 can replace nickel and cobalt, meaning the resulting crude nickel sulfate solution can be recycled, improving the nickel yield. Furthermore, manganese in this invention forms a closed-loop process, combining washing and metal recovery. Using a nickel-cobalt-containing manganese sulfate solution (P204 second washing solution) as the washing agent is irreplaceable.

[0311] Comparing Example 1 and Comparative Example 2, without the HBL116 organic phase extraction process and its auxiliary processes (steps S4 to S6), as shown in Table 1, cobalt and nickel are directly lost in the magnesium washing solution and calcium chloride manganese solution, with a cobalt recovery rate of 89.12%. It can be seen that the present invention can directly increase the cobalt recovery rate by about 10% and the nickel recovery rate by 0.1% by setting the HBL116 organic phase extraction process. In the example, the addition of steps S4 to S6 can achieve nickel and cobalt metal recovery on the one hand, and slow down calcium crystallization in the production line on the other hand, which is beneficial to production.

[0312] It should be noted that this invention has found that calcium will crystallize in the aqueous phase if both calcium and manganese concentrations are low; however, if the manganese content is high and the calcium content is low, crystallization may not occur. The role of the second washing liquid P204 in this invention is twofold: firstly, it can utilize the manganese in the calcium-manganese back-extraction phase obtained from P204 back-extraction to alleviate calcium crystallization; secondly, it can replace part of the washing acid while recovering nickel and cobalt, thus achieving the effect of washing nickel and cobalt.

[0313] In summary, the impurity removal method provided by this invention can significantly improve the yield and purity of metals such as nickel, cobalt, and manganese in the liquid phase, while avoiding the problem of calcium crystallization in the production line. Due to these advantages, this impurity removal method is expected to find wide application in lithium battery recycling and nickel ore extraction.

[0314] The embodiments of the present application are described in detail above with reference to the drawings, but the present application is not limited to the above-described embodiments, and various changes can be made within the knowledge of those skilled in the art without departing from the spirit of the present application. Furthermore, the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

Claims

1. A method for removing impurities from nickel sulfate stock solution, characterized in that, The nickel sulfate stock solution contains Ni 2+ Co 2+ Mn 2+ Mg 2 + and Ca 2+ ; The impurity removal method includes the following steps: S1. Extract the nickel sulfate stock solution with the P204 organic phase of nickel soap; to obtain a P204 supported organic phase and a P204 raffinate phase; S2. Extract the P204 raffinate phase with a nickel soap composite extractant to obtain a composite extractant-supported organic phase and a composite extractant raffinate phase; the composite extractant includes C272 and P507; S3. The organic phase supported by the composite extractant is washed with nickel to obtain the nickel-washed phase of the composite extractant and the nickel washing solution; The nickel-washed phase of the composite extractant is then washed with magnesium to obtain a magnesium washing solution and a magnesium-washed phase of the composite extractant. S4. Extract the magnesium washing solution with the HBL116 organic phase of sodium soap to obtain the HBL116 supported organic phase and the HBL116 raffinate phase; S5. The calcium-manganese back-extraction phase and the HBL116-supported organic phase are mixed and extracted to obtain the HBL116 mixed extraction liquid and the HBL116 mixed extraction phase; the O / A ratio of the mixed extraction is 3~10:1; S6. Back-extract the HBL116 mixed extraction phase to obtain P204 second washing solution and HBL116 blank phase; S7. The P204-supported organic phase is washed once to obtain the P204 phase after one wash and crude nickel sulfate solution. The P204 phase after the first washing is washed with the second washing solution to obtain the P204 phase after the second washing and crude nickel sulfate solution. After back-extracting the P204 phase and washing it twice, the calcium-manganese back-extracted phase and the P204 blank phase are obtained.

2. The impurity removal method according to claim 1, characterized in that, The preparation method further includes back-extracting the composite extractant to wash the magnesium phase to obtain a blank phase of the composite extractant and a crude cobalt sulfate solution; and / or, the preparation method further includes extracting the crude cobalt sulfate solution with P204 to obtain a cobalt sulfate solution and a calcium-manganese supported phase.

3. The impurity removal method according to claim 1 or 2, characterized in that, In step S3, the washing solution used for washing nickel is a 1-2 mol / L sulfuric acid aqueous solution; and / or, in step S3, the washing solution used for washing magnesium is a 2-2.5 mol / L sulfuric acid aqueous solution.

4. The impurity removal method according to claim 1 or 2, characterized in that, In step S3, the magnesium washing solution meets the following criteria: Ni 0~5g / L; Co 0~27g / L; Mg 10~25g / L.

5. The impurity removal method according to claim 1 or 2, characterized in that, In step S4, the equilibrium pH of the extraction is 2-3; and / or, in step S4, the O / A ratio of the extraction is 1-5:

1.

6. The impurity removal method according to claim 1 or 2, characterized in that, In step S5, the HBL116 mixed extraction solution meets the following criteria: Ni≤0.005g / L; Co ≤ 0.005 g / L; Ca 0~10g / L; Mn 70~110g / L.

7. The method for removing impurities according to claim 1 or 2, characterized in that, In step S6, the second washing liquid P204 meets the following criteria: Ni 0~10g / L; Co5~20g / L; Mn 0~25g / L.

8. The method for removing impurities according to claim 1 or 2, characterized in that, In step S7, the calcium-manganese back-extraction phase meets the following criteria: Ni 0~2g / L; Co 0~5g / L; Mn 80~110g / L; Ca 0~10g / L.

9. The application of the impurity removal method as described in any one of claims 1 to 8 in lithium battery recycling.

10. The application of the impurity removal method as described in any one of claims 1 to 8 in the wet extraction of nickel ore.

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