Method for extracting nickel sulfate from nickel-containing solution and nickel sulfate

Abstract

The invention provides a method for extracting nickel sulfate from a nickel-containing solution and nickel sulfate, and relates to the technical field of waste battery recovery. The method for extracting nickel sulfate from the nickel-containing solution comprises the following steps: sequentially carrying out evaporation treatment and cooling crystallization on the nickel-containing solution, and then carrying out first solid-liquid separation to obtain a first nickel sulfate crystal and condensate water; wherein the temperature of the evaporation treatment is 70-100 DEG C, and the evaporation ratio is 50-80%; washing the first nickel sulfate crystal by using a nickel sulfate solution, and then carrying out second solid-liquid separation to obtain a second nickel sulfate crystal and a washed solution; wherein the volume ratio of the nickel sulfate solution to the nickel-containing solution is 3%-30%, and by means of the method, the production cost is effectively reduced, and the production process is shortened.

Description

Technical Field

[0001] The present application relates to the technical field of waste battery recycling, and in particular to a method for extracting nickel sulfate from a nickel-containing solution and nickel sulfate. Background Art

[0002] With the rapid development of new energy vehicles and energy storage technology, the demand for battery materials is growing. Wet recycling of metals from waste batteries can provide a stable supply of raw materials for the new energy industry. In the wet recycling process of ternary batteries, the nickel leaching solution obtained by recovering and extracting nickel ions from waste ternary cathode materials contains a certain concentration of impurity ions, such as Li + 、Na + Mg 2+ , Ca 2+ In order to obtain qualified battery-grade nickel sulfate products, the nickel leaching solution needs to be deeply treated to recover valuable metals and remove impurities to achieve the high purity standards required for battery manufacturing. The commonly used method at this stage is mainly the extraction method, which has a long nickel extraction stage. Although the nickel extraction rate in the nickel leaching solution is high, the nickel sulfate solution still contains a small amount of Li after extraction. + 、Na + Mg 2+ and Ca 2+ , further processing is required to obtain qualified battery-grade nickel sulfate products, and the extractant has a greater impact on the environment, is costly, and has a longer process, making it difficult to extract battery-grade nickel sulfate from the nickel leachate efficiently and at a low cost. Summary of the invention

[0003] The main purpose of the present application is to provide a method for extracting nickel sulfate from a nickel-containing solution and nickel sulfate, so as to solve the problems of high cost and long process in the existing process of extracting battery-grade nickel sulfate from nickel leaching solution.

[0004] In order to achieve the above object, the first aspect of the present application provides a method for extracting nickel sulfate from a nickel-containing solution, comprising:

[0005] S1, sequentially subjecting the nickel-containing solution to evaporation treatment and cooling crystallization, and then performing a first solid-liquid separation to obtain first nickel sulfate crystals and condensed water;

[0006] The evaporation temperature is 70°C to 100°C, and the evaporation ratio is 50% to 80%.

[0007] S2, washing the first nickel sulfate crystals with a nickel sulfate solution, and then performing a second solid-liquid separation to obtain second nickel sulfate crystals and a washed liquid;

[0008] The volume ratio of the nickel sulfate solution to the nickel-containing solution is 3% to 30%.

[0009] Further, the mass concentration of nickel in the nickel sulfate solution is 60 g / L to 150 g / L, and preferably, the mass concentration of nickel in the nickel-containing solution is 60 g / L to 130 g / L; and / or,

[0010] The nickel-containing solution includes lithium element, and the mass concentration of lithium element is 0.2g / L to 5g / L; and / or,

[0011] The nickel-containing solution includes sodium element, and the mass concentration of the sodium element is 0.2g / L to 5g / L; and / or,

[0012] The nickel-containing solution includes magnesium, and the mass concentration of magnesium is 10ppm to 100ppm; and / or,

[0013] The nickel-containing solution includes calcium element, and the mass concentration of the calcium element is 10ppm to 100ppm.

[0014] Furthermore, the nickel-containing solution also includes cobalt element, and the mass concentration of the cobalt element is 50ppm to 200ppm; and / or,

[0015] The nickel-containing solution also includes manganese, and the mass concentration of manganese is 10ppm to 200ppm; and / or,

[0016] The nickel-containing solution also includes potassium, and the mass concentration of potassium is 10ppm to 250ppm; and / or,

[0017] The nickel-containing solution also includes silicon, and the mass concentration of silicon is 50ppm to 100ppm; and / or,

[0018] The nickel-containing solution also includes aluminum element, and the mass concentration of the aluminum element is 5ppm to 50ppm.

[0019] Furthermore, the method for preparing the nickel-containing solution comprises:

[0020] The waste battery positive electrode material is mixed with sulfuric acid for acid leaching to obtain an acid leaching solution; the acid leaching solution is subjected to iron and aluminum removal treatment to obtain an iron and aluminum removal solution; the iron and aluminum removal solution is mixed with a first extractant for a first extraction to obtain a first raffinate; the first raffinate is mixed with a second extractant for a second extraction to obtain a second raffinate; the second raffinate is mixed with a third extractant for a third extraction to obtain a third raffinate; the third raffinate is mixed with a fourth extractant for a fourth extraction to obtain a nickel-containing solution;

[0021] Among them, the first extractant is C272, the second extractant is P204, the third extractant is P507, and the fourth extractant is C272.

[0022] Further, the temperature of cooling crystallization is 20°C to 35°C, and the rotation speed is 100rpm to 500rpm; and / or,

[0023] The washing process is agitation washing and / or spray washing;

[0024] Preferably, the washing treatment is carried out at a temperature of 20°C to 50°C and for a time of 10 min to 60 min.

[0025] Further, the rotation speed of the first solid-liquid separation is 400 rpm to 1000 rpm, and the time is 5 min to 60 min; and / or,

[0026] The rotation speed of the second solid-liquid separation is 400 rpm to 1000 rpm, and the time is 5 min to 60 min.

[0027] Furthermore, the method further comprises: S3, drying the second nickel sulfate crystals to obtain nickel sulfate. Preferably, the nickel sulfate solution is formed by mixing nickel sulfate and water, and the volume ratio of the nickel sulfate solution to the nickel-containing solution is 3% to 10%.

[0028] Furthermore, the recovery rate of nickel sulfate is 60% to 90%.

[0029] The second aspect of the present application provides nickel sulfate, which is prepared by the method provided by the first aspect.

[0030] Furthermore, the purity of nickel sulfate is ≥99.5%, and the moisture content is ≤0.5%.

[0031] By applying the technical solution of the present application, the evaporation, cooling crystallization, washing and drying processes are precisely controlled, and the impurity ions are removed to the maximum extent at a suitable evaporation ratio and washing ratio, thereby effectively improving the purity and recovery rate of nickel sulfate and reducing the interference of impurity elements. The present application does not require a nickel extraction process to extract qualified battery-grade nickel sulfate products from the nickel leachate, thereby effectively reducing production costs and shortening the production process. DETAILED DESCRIPTION

[0032] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below in conjunction with the embodiments.

[0033] As described in the background technology, the existing process of extracting battery-grade nickel sulfate from nickel leaching solution has the problems of high cost and long process. In order to solve the above technical problems, the present application provides a method for extracting nickel sulfate from a nickel-containing solution, comprising:

[0034] S1, sequentially subjecting the nickel-containing solution to evaporation treatment and cooling crystallization, and then performing a first solid-liquid separation to obtain first nickel sulfate crystals and condensed water;

[0035] The evaporation temperature is 70°C to 100°C, and the evaporation ratio is 50% to 80%.

[0036] S2, washing the first nickel sulfate crystals with a nickel sulfate solution, and then performing a second solid-liquid separation to obtain second nickel sulfate crystals and a washed liquid;

[0037] The volume ratio of the nickel sulfate solution to the nickel-containing solution is 3% to 30%.

[0038] In S1, the nickel-containing solution is evaporated at a temperature of 70°C to 100°C, the purpose of which is to concentrate the nickel element in the solution and promote the crystallization of nickel sulfate. The evaporation ratio is set to 50% to 80%, which means that 50% to 80% of the volume of water in the nickel-containing solution is evaporated during the evaporation process, thereby greatly increasing the concentration of nickel sulfate in the solution. This process helps to separate metal ions from non-metallic impurities because the solubility of nickel sulfate decreases during the evaporation and concentration process, prompting it to precipitate in the form of crystals. After the evaporation is completed, the further growth of nickel sulfate crystals is promoted by cooling, and then the first solid-liquid separation is performed to obtain the first nickel sulfate crystals and the separated condensed water and mother liquor.

[0039] The temperature of the evaporation treatment is 70° C. to 100° C., for example, 70° C., 75° C., 80° C., 85° C., 90° C., 95° C., 100° C., or any two thereof. The evaporation ratio is 50% to 80%, for example, 50%, 55%, 60%, 65%, 70%, 75%, 80%, or any two thereof.

[0040] After the first solid-liquid separation, some impurity ions usually remain on the surface of the nickel sulfate crystals. In order to further purify the crystals, in S2, a nickel sulfate solution is used for washing. The volume ratio of the nickel sulfate solution to the nickel-containing solution (also referred to as the washing ratio) is 3% to 30%. A higher washing liquid concentration and an appropriate washing ratio help to more effectively remove the impurity ions on the surface of the crystals, while avoiding the reverse dissolution of the nickel sulfate crystals and the loss of the product due to the low washing liquid concentration. After washing, a second solid-liquid separation is performed to obtain a purer second nickel sulfate crystal and a washed liquid, which contains washed impurity ions.

[0041] This application gradually improves the purity of nickel sulfate through evaporation treatment, cooling crystallization, washing and other steps, and finally obtains a nickel sulfate product suitable for battery manufacturing. Parameter control of the evaporation and washing steps is crucial for removing impurities and improving product purity, while the drying step ensures the stability and appropriate moisture content of the final product, meeting the strict standards for battery-grade nickel sulfate. Compared with traditional extraction methods, this method has the advantages of simple operation, low cost and less environmental impact, and is suitable for resource recovery of waste batteries and preparation of battery-grade nickel sulfate.

[0042] The nickel-containing solution of the present application can be a solution obtained by acid leaching a nickel-containing material, and the nickel-containing material can be nickel-containing positive electrode powder or black powder in waste batteries. By utilizing the method of the present application, waste batteries can be recycled.

[0043] In some embodiments, the mass concentration of nickel in the nickel sulfate solution is 60 g / L to 150 g / L, such as 60 g / L, 70 g / L, 80 g / L, 90 g / L, 100 g / L, 110 g / L, 120 g / L, 130 g / L, 140 g / L, 150 g / L, or any two thereof. The volume ratio of the nickel sulfate solution to the nickel-containing solution is 3% to 30%, such as 3%, 5%, 10%, 15%, 20%, 25%, 30%, or any two thereof. In some preferred embodiments, the mass concentration of nickel in the nickel-containing solution is 60g / L to 130g / L; and / or, the nickel-containing solution includes lithium, and the mass concentration of lithium is 0.2g / L to 5g / L; and / or, the nickel-containing solution includes sodium, and the mass concentration of sodium is 0.2g / L to 5g / L; and / or, the nickel-containing solution includes magnesium, and the mass concentration of magnesium is 10ppm to 100ppm; and / or, the nickel-containing solution includes calcium, and the mass concentration of calcium is 10ppm to 100ppm. The present application is particularly suitable for nickel-containing solutions having the above-mentioned specific concentration range. After treatment, battery-grade nickel sulfate with high purity and low impurity content can be obtained, and the battery-grade nickel sulfate can be used to manufacture high-performance lithium-ion batteries.

[0044] Wherein, the mass concentration of nickel in the nickel-containing solution is 60g / L to 130g / L, for example, 60g / L, 70g / L, 80g / L, 90g / L, 100g / L, 110g / L, 120g / L, 130g / L or a range consisting of any two thereof. The mass concentration of lithium in the nickel-containing solution is 0.2g / L to 5g / L, for example, 0.2g / L, 0.5g / L, 1g / L, 2g / L, 3g / L, 4g / L, 5g / L or a range consisting of any two thereof. The mass concentration of sodium in the nickel-containing solution is 0.2g / L to 5g / L, for example, 0.2g / L, 0.5g / L, 1g / L, 2g / L, 3g / L, 4g / L, 5g / L or a range consisting of any two thereof. The mass concentration of magnesium in the nickel-containing solution is 10ppm to 100ppm, for example, 10ppm, 20ppm, 30ppm, 40ppm, 50ppm, 60ppm, 70ppm, 80ppm, 90ppm, 100ppm or a range consisting of any two thereof. The mass concentration of calcium in the nickel-containing solution is 10ppm to 100ppm, for example, 10ppm, 20ppm, 30ppm, 40ppm, 50ppm, 60ppm, 70ppm, 80ppm, 90ppm, 100ppm or a range consisting of any two thereof.

[0045] In some embodiments, the nickel-containing solution also includes cobalt, and the mass concentration of the cobalt element is 50ppm to 200ppm; and / or, the nickel-containing solution also includes manganese, and the mass concentration of the manganese element is 10ppm to 200ppm; and / or, the nickel-containing solution also includes potassium, and the mass concentration of the potassium element is 10ppm to 250ppm; and / or, the nickel-containing solution also includes silicon, and the mass concentration of the silicon element is 50ppm to 100ppm; and / or, the nickel-containing solution also includes aluminum, and the mass concentration of the aluminum element is 5ppm to 50ppm. The presence of these trace elements can be effectively removed after the treatment of this application, ensuring the high quality of the final product, battery-grade nickel sulfate.

[0046] The nickel-containing solution also includes cobalt, and the mass concentration of cobalt is 50ppm~200ppm, for example, 50ppm, 60ppm, 70ppm, 80ppm, 90ppm, 100ppm, 120ppm, 140ppm, 160ppm, 180ppm, 200ppm or the range composed of any two thereof. The nickel-containing solution also includes manganese, and the mass concentration of manganese is 10ppm~200ppm, for example, 10ppm, 20ppm, 30ppm, 40ppm, 50ppm, 80ppm, 100ppm or the range composed of any two thereof. The nickel-containing solution also includes potassium, and the mass concentration of potassium is 10ppm~250ppm, for example, 10ppm, 50ppm, 100ppm, 150ppm, 200ppm, 250ppm or the range composed of any two thereof. The nickel-containing solution also includes silicon, and the mass concentration of silicon is 50ppm to 100ppm, such as 50ppm, 60ppm, 70ppm, 80ppm, 90ppm, 100ppm or any two thereof. The nickel-containing solution also includes aluminum, and the mass concentration of aluminum is 5ppm to 50ppm, such as 5ppm, 10ppm, 20ppm, 30ppm, 40ppm, 50ppm or any two thereof.

[0047] In some embodiments, the method for preparing a nickel-containing solution comprises:

[0048] The waste battery positive electrode material is mixed with sulfuric acid for acid leaching to obtain an acid leaching solution; the acid leaching solution is subjected to iron and aluminum removal treatment to obtain an iron and aluminum removal solution; the iron and aluminum removal solution is mixed with a first extractant for a first extraction to obtain a first raffinate; the first raffinate is mixed with a second extractant for a second extraction to obtain a second raffinate; the second raffinate is mixed with a third extractant for a third extraction to obtain a third raffinate; the third raffinate is mixed with a fourth extractant for a fourth extraction to obtain a nickel-containing solution;

[0049] The first extractant is C272, the second extractant is P204, the third extractant is P507, and the fourth extractant is C272. Specifically, through the above extraction process, impurities such as manganese, cobalt, and magnesium in the positive electrode material of the waste battery are removed.

[0050] In some embodiments, the temperature of cooling crystallization is 20° C. to 35° C., and the rotation speed is 100 rpm to 500 rpm. By limiting the conditions of cooling crystallization, the formation of nickel sulfate crystals can be effectively promoted, and the purity and recovery rate of nickel sulfate crystals can be improved.

[0051] In some embodiments, the washing treatment is stirring washing and / or spray washing; by limiting the washing treatment method, impurities on the crystal surface can be effectively removed and the purity of nickel sulfate can be improved. In some embodiments, the washing treatment temperature is 20°C to 50°C, for example, 20°C, 30°C, 40°C, 50°C or a range consisting of any two thereof, and the time is 10min to 60min, for example, 10min, 20min, 30min, 40min, 50min, 60min or a range consisting of any two thereof.

[0052] When the washing treatment is stirring washing, the first nickel sulfate crystals are mixed with a washing liquid (nickel sulfate solution) and stirred so that the washing liquid fully contacts the surface of the nickel sulfate crystals to remove impurity ions adsorbed on the surface; after the stirring washing is completed, a second solid-liquid separation is performed to obtain a purer second nickel sulfate crystal and a washed liquid.

[0053] When the washing treatment is spray washing, the first nickel sulfate crystals are placed in a washing device, and the washing liquid (nickel sulfate solution) is evenly sprayed on the surface of the first nickel sulfate crystals by spraying or rinsing; after the rinsing is completed, a second solid-liquid separation is performed to obtain purer second nickel sulfate crystals and washed liquid.

[0054] In some embodiments, the first solid-liquid separation has a rotation speed of 400 rpm to 1000 rpm and a time of 5 min to 60 min; and / or, the second solid-liquid separation has a rotation speed of 400 rpm to 1000 rpm and a time of 5 min to 60 min. By limiting the conditions of the first solid-liquid separation and the second solid-liquid separation to meet the above requirements, high-purity nickel sulfate crystals can be effectively separated, the interference of impurities can be reduced, and it is helpful to manufacture high-purity battery-grade nickel sulfate.

[0055] Wherein, the rotation speed of the first solid-liquid separation is 400rpm~1000rpm, for example, 400rpm, 500rpm, 1000rpm or the range of any two thereof, and the time is 5min~60min, for example, 5min, 10min, 20min, 30min, 40min, 50min, 60min or the range of any two thereof. The rotation speed of the second solid-liquid separation is 400rpm~1000rpm, for example, 400rpm, 500rpm, 1000rpm or the range of any two thereof, and the time is 5min~60min, for example, 5min, 10min, 20min, 30min, 40min, 50min, 60min or the range of any two thereof. By limiting the rotation speed within the above range, it is avoided that the rotation speed is too low and the separation effect is poor, and the rotation speed is too high and the large-scale industrial equipment is difficult to bear.

[0056] In some embodiments, the process further includes: S3, drying the second nickel sulfate crystals to obtain nickel sulfate. In S3, the washed second nickel sulfate crystals are dried to remove moisture from the surface and inside of the crystals to ensure that the moisture content of the final product meets the standard of battery-grade nickel sulfate. The drying process can prevent the decomposition of the crystal water of the nickel sulfate crystals due to high temperature by precisely controlling the temperature and time, while ensuring that the moisture is completely evaporated to obtain a dry battery-grade nickel sulfate product.

[0057] In some embodiments, the nickel sulfate solution is formed by mixing nickel sulfate and water. By selecting battery-grade nickel sulfate to prepare the nickel sulfate solution, the washing effect can be ensured. The volume ratio of the nickel sulfate solution to the nickel-containing solution is 3% to 10%, for example, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10% or a range consisting of any two of them. By further limiting the volume ratio of the nickel sulfate solution to the nickel-containing solution to 3% to 10%, the purity and recovery rate of the battery-grade nickel sulfate can be further improved.

[0058] In some embodiments, the recovery rate of battery-grade nickel sulfate is 60% to 90%, indicating that the method provided in the present application can achieve a high recovery rate, which not only realizes efficient utilization of resources, but also reduces production costs and improves economic benefits.

[0059] The second aspect of the present application provides nickel sulfate, which is prepared by the method provided by the first aspect.

[0060] Since the nickel sulfate is prepared by the above method, it has the advantage of high purity, reaches the standard of battery-grade nickel sulfate, and can be directly used in the manufacture of high-performance lithium-ion batteries.

[0061] In some embodiments, the purity of nickel sulfate is ≥99.5% and the moisture content is ≤0.5%.

[0062] The present application is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in the present application.

[0063] Example 1

[0064] The nickel-containing solution of this embodiment has a Ni element mass concentration of 69.04 g / L, a Li element mass concentration of 0.31 g / L, a Na element mass concentration of 4.16 g / L, a Mn element mass concentration of 120 ppm, a Mg element mass concentration of 24 ppm, and a Ca element mass concentration of 20 ppm.

[0065] The method of extracting battery-grade nickel sulfate from a nickel-containing solution in this embodiment comprises:

[0066] S1. Pour 2L of nickel-containing solution into a rotary evaporator, evaporate at 90°C, and control the evaporation ratio to 70%; after the evaporation is completed, stir and cool to crystallize at room temperature at a stirring speed of 400rpm, and after cooling to room temperature, perform solid-liquid separation to obtain crude nickel sulfate crystals;

[0067] S2, using nickel sulfate product as raw material, preparing nickel sulfate solution, controlling the mass concentration of Ni element to be 140g / L; using the nickel sulfate solution as washing liquid, stirring and washing crude nickel sulfate crystals at a washing ratio of 10% (i.e., the volume ratio of washing liquid to nickel-containing solution is 10%), the stirring and washing temperature is 30°C, the time is 30min, to obtain nickel sulfate slurry; performing solid-liquid separation on the nickel sulfate slurry obtained by stirring and washing, to obtain nickel sulfate solid and washed liquid;

[0068] S3, drying the nickel sulfate solid to obtain a nickel sulfate product.

[0069] The nickel sulfate product obtained in Example 1 meets the battery-grade nickel sulfate standard, and the mass proportion of the nickel sulfate product in the nickel-containing solution is 85.84%.

[0070] Example 2

[0071] The nickel-containing solution used in this embodiment has a Ni element mass concentration of 69.04 g / L, a Li element mass concentration of 0.31 g / L, a Na element mass concentration of 4.16 g / L, a Co element mass concentration of 100 ppm, a Mg element mass concentration of 24 ppm, and a Ca element mass concentration of 20 ppm.

[0072] The method of extracting battery-grade nickel sulfate from a nickel-containing solution in this embodiment comprises:

[0073] S1. Pour 2L of nickel-containing solution into a rotary evaporator, evaporate at 90°C, and control the evaporation ratio to 70%; after the evaporation is completed, stir and cool to crystallize at room temperature at a stirring speed of 400rpm, and after cooling to room temperature, perform solid-liquid separation to obtain crude nickel sulfate crystals;

[0074] S2. Using nickel sulfate product as raw material, prepare nickel sulfate solution, and control the mass concentration of Ni element to be 140 g / L; using the nickel sulfate solution as washing liquid, spray washing crude nickel sulfate crystals according to a washing ratio of 10% (i.e., the volume ratio of washing liquid to nickel-containing solution is 10%), the spray washing temperature is 30° C., and the time is 30 min to obtain nickel sulfate slurry; the nickel sulfate slurry obtained by spray washing is subjected to solid-liquid separation to obtain nickel sulfate solid and washed liquid;

[0075] S3, drying the nickel sulfate solid to obtain a nickel sulfate product.

[0076] Under the conditions of Example 2, the obtained nickel sulfate product meets the battery-grade nickel sulfate standard, and the proportion of the nickel sulfate product in the nickel sulfate stock solution is 86.02%.

[0077] Example 3

[0078] The nickel-containing solution of this embodiment has a Ni element mass concentration of 69.04 g / L, a Li element mass concentration of 0.31 g / L, a Na element mass concentration of 4.16 g / L, a K element mass concentration of 250 ppm, a Mg element mass concentration of 12 ppm, and a Ca element mass concentration of 10 ppm.

[0079] The method of extracting battery-grade nickel sulfate from a nickel-containing solution in this embodiment comprises:

[0080] S1. Pour 2L of nickel-containing solution into a rotary evaporator, evaporate at 90°C, and control the evaporation ratio to 70%; after the evaporation is completed, stir and cool to crystallize at room temperature at a stirring speed of 400rpm, and after cooling to room temperature, perform solid-liquid separation to obtain crude nickel sulfate crystals;

[0081] S2. Using nickel sulfate product as raw material, prepare nickel sulfate solution, and control the mass concentration of Ni element to be 140 g / L; using the nickel sulfate solution as washing liquid, spray washing crude nickel sulfate crystals according to a washing ratio of 5% (i.e., the volume ratio of washing liquid to nickel-containing solution is 5%), the spray washing temperature is 30° C., and the time is 30 min to obtain nickel sulfate slurry; the nickel sulfate slurry obtained by spray washing is subjected to solid-liquid separation to obtain nickel sulfate solid and washed liquid;

[0082] S3, drying the nickel sulfate solid to obtain a nickel sulfate product.

[0083] Under the conditions of Example 3, the obtained nickel sulfate product meets the battery-grade nickel sulfate standard, and the proportion of the nickel sulfate product in the nickel sulfate stock solution is 86.11%.

[0084] Example 4

[0085] The nickel-containing solution of this embodiment has a Ni element mass concentration of 69.04 g / L, a Li element mass concentration of 0.31 g / L, a Na element mass concentration of 4.16 g / L, a Mg element mass concentration of 24 ppm, and a Ca element mass concentration of 20 ppm.

[0086] The method of extracting battery-grade nickel sulfate from a nickel-containing solution in this embodiment comprises:

[0087] S1. Pour 2L of nickel-containing solution into a rotary evaporator, evaporate at 90°C, and control the evaporation ratio to 60%; after the evaporation is completed, stir and cool to crystallize at room temperature at a stirring speed of 400rpm, and after cooling to room temperature, perform solid-liquid separation to obtain crude nickel sulfate crystals;

[0088] S2. Using nickel sulfate product as raw material, prepare nickel sulfate solution, and control the mass concentration of Ni element to be 140 g / L; using the nickel sulfate solution as washing liquid, spray washing the crude nickel sulfate crystals at a washing ratio of 5% (i.e., the volume ratio of the washing liquid to the nickel-containing solution is 5%); the spray washing temperature is 30° C., and the time is 30 min to obtain nickel sulfate slurry; the nickel sulfate slurry obtained by spray washing is subjected to solid-liquid separation to obtain nickel sulfate solid and washed liquid;

[0089] S3, drying the nickel sulfate solid to obtain a nickel sulfate product.

[0090] Under the conditions of Example 3, the obtained nickel sulfate product meets the battery-grade nickel sulfate standard, and the proportion of the nickel sulfate product in the nickel sulfate stock solution is 64.78%.

[0091] Example 5

[0092] The nickel-containing solution of this embodiment has a Ni element mass concentration of 125.48 g / L, a Li element mass concentration of 1.25 g / L, a Na element mass concentration of 0.36 g / L, a Si element mass concentration of 80 ppm, a Mg element mass concentration of 25 ppm, and a Ca element mass concentration of 18 ppm.

[0093] The method of extracting battery-grade nickel sulfate from a nickel-containing solution in this embodiment comprises:

[0094] S1. Pour 2L of nickel-containing solution into a rotary evaporator, evaporate at 80°C, and control the evaporation ratio to 60%; after the evaporation is completed, stir and cool to crystallize at room temperature at a stirring speed of 400rpm, and after cooling to room temperature, perform solid-liquid separation to obtain crude nickel sulfate crystals;

[0095] S2. Using nickel sulfate product as raw material, prepare nickel sulfate solution, and control the mass concentration of Ni element to be 140 g / L; using the nickel sulfate solution as washing liquid, spray washing crude nickel sulfate crystals according to a washing ratio of 5% (i.e., the volume ratio of washing liquid to nickel-containing solution is 5%), the spray washing temperature is 30° C., and the time is 30 min to obtain nickel sulfate slurry; the nickel sulfate slurry obtained by stirring and washing is subjected to solid-liquid separation to obtain nickel sulfate solid and washed liquid;

[0096] S3, drying the nickel sulfate solid to obtain a nickel sulfate product.

[0097] Example 6

[0098] The nickel-containing solution in this embodiment has a Ni element mass concentration of 122.6 g / L, a Li element mass concentration of 4.71 g / L, a Na element mass concentration of 0.36 g / L, a Co element mass concentration of 100 ppm, a Mn element mass concentration of 120 ppm, a K element mass concentration of 250 ppm, a Si element mass concentration of 80 ppm, a Mg element mass concentration of 27 ppm, a Ca element mass concentration of 22 ppm, and an Al element mass concentration of 5 ppm.

[0099] The method of extracting battery-grade nickel sulfate from a nickel-containing solution in this embodiment comprises:

[0100] S1. Pour 2L of nickel-containing solution into a rotary evaporator, evaporate at 90°C, and control the evaporation ratio to 60%; after the evaporation is completed, stir and cool to crystallize at room temperature at a stirring speed of 400rpm, and after cooling to room temperature, perform solid-liquid separation to obtain crude nickel sulfate crystals;

[0101] S2, using nickel sulfate product as raw material, preparing nickel sulfate solution, controlling the mass concentration of Ni element to 65g / L; using the nickel sulfate solution as washing liquid, stirring and washing crude nickel sulfate crystals at a washing ratio of 10% (i.e., the volume ratio of washing liquid to nickel-containing solution is 10%), the stirring and washing temperature is 30°C, the time is 15min, to obtain nickel sulfate slurry; performing solid-liquid separation on the nickel sulfate slurry obtained by stirring and washing, to obtain nickel sulfate solid and washed liquid;

[0102] S3, drying the nickel sulfate solid to obtain a nickel sulfate product.

[0103] Example 7

[0104] The nickel-containing solution of this embodiment has a Ni element mass concentration of 125.48 g / L, a Li element mass concentration of 1.25 g / L, a Na element mass concentration of 0.36 g / L, a Mg element mass concentration of 25 ppm, and a Ca element mass concentration of 18 ppm.

[0105] The method of extracting battery-grade nickel sulfate from a nickel-containing solution in this embodiment comprises:

[0106] S1. Pour 2L of nickel-containing solution into a rotary evaporator, evaporate at 80°C, and control the evaporation ratio to 60%; after the evaporation is completed, stir and cool to crystallize at room temperature at a stirring speed of 400rpm, and after cooling to room temperature, perform solid-liquid separation to obtain crude nickel sulfate crystals;

[0107] S2, using nickel sulfate product as raw material, preparing nickel sulfate solution, controlling the mass concentration of Ni element to be 140g / L; using the nickel sulfate solution as washing liquid, stirring and washing crude nickel sulfate crystals at a washing ratio of 3% (i.e., the volume ratio of washing liquid to nickel-containing solution is 3%), the stirring and washing temperature is 30°C, the time is 30min, to obtain nickel sulfate slurry; performing solid-liquid separation on the nickel sulfate slurry obtained by stirring and washing, to obtain nickel sulfate solid and washed liquid;

[0108] S3, drying the nickel sulfate solid to obtain a nickel sulfate product.

[0109] Comparative Example 1

[0110] The nickel-containing solution of this comparative example has a Ni element mass concentration of 69.04 g / L, a Li element mass concentration of 0.31 g / L, a Na element mass concentration of 4.16 g / L, a Mn element mass concentration of 120 ppm, a Mg element mass concentration of 24 ppm, and a Ca element mass concentration of 20 ppm.

[0111] The method for extracting battery-grade nickel sulfate from a nickel-containing solution in this comparative example comprises:

[0112] S1. Pour 2L of nickel-containing solution into a rotary evaporator, evaporate at 90°C, and control the evaporation ratio to 45%; after the evaporation is completed, stir and cool to crystallize at room temperature at a stirring speed of 400rpm, and cool to room temperature to perform solid-liquid separation to obtain crude nickel sulfate crystals;

[0113] S2, using nickel sulfate product as raw material, preparing nickel sulfate solution, controlling the mass concentration of Ni element to be 140g / L; using the nickel sulfate solution as washing liquid, stirring and washing crude nickel sulfate crystals at a washing ratio of 10% (i.e., the volume ratio of washing liquid to nickel-containing solution is 10%), the stirring and washing temperature is 30°C, the time is 30min, to obtain nickel sulfate slurry; performing solid-liquid separation on the nickel sulfate slurry obtained by stirring and washing, to obtain nickel sulfate solid and washed liquid;

[0114] S3, drying the nickel sulfate solid to obtain a nickel sulfate product.

[0115] In the comparative example, nickel sulfate did not crystallize after evaporation crystallization.

[0116] Comparative Example 2

[0117] The nickel-containing solution of this comparative example has a Ni element mass concentration of 125.48 g / L, a Li element mass concentration of 1.25 g / L, a Na element mass concentration of 0.36 g / L, a Co element mass concentration of 100 ppm, a Mg element mass concentration of 25 ppm, and a Ca element mass concentration of 18 ppm.

[0118] The method for extracting battery-grade nickel sulfate from a nickel-containing solution in this comparative example comprises:

[0119] S1. Pour 2L of nickel-containing solution into a rotary evaporator, evaporate at 90°C, and control the evaporation ratio to 60%; after the evaporation is completed, stir and cool to crystallize at room temperature at a stirring speed of 400rpm, and after cooling to room temperature, perform solid-liquid separation to obtain crude nickel sulfate crystals;

[0120] S2. Using nickel sulfate product as raw material, prepare nickel sulfate solution, and control the mass concentration of Ni element to be 140 g / L; using the nickel sulfate solution as washing liquid, spray washing crude nickel sulfate crystals according to a washing ratio of 2% (i.e., the volume ratio of washing liquid to nickel-containing solution is 2%), the spray washing temperature is 30° C., and the time is 30 min to obtain nickel sulfate slurry; the nickel sulfate slurry obtained by spray washing is subjected to solid-liquid separation to obtain nickel sulfate solid and washed liquid;

[0121] S3, drying the nickel sulfate solid to obtain a nickel sulfate product.

[0122] Comparative Example 3

[0123] The nickel-containing solution of this comparative example has a Ni element mass concentration of 69.04 g / L, a Li element mass concentration of 0.31 g / L, a Na element mass concentration of 4.16 g / L, a K element mass concentration of 250 ppm, a Mg element mass concentration of 24 ppm, and a Ca element mass concentration of 20 ppm.

[0124] The method of extracting battery-grade nickel sulfate from a nickel-containing solution in this embodiment comprises:

[0125] S1. Pour 2L of nickel-containing solution into a rotary evaporator, evaporate at 60°C, and control the evaporation ratio to 82%; after the evaporation is completed, stir and cool to crystallize at room temperature at a stirring speed of 400rpm, and after cooling to room temperature, perform solid-liquid separation to obtain crude nickel sulfate crystals;

[0126] S2. Using nickel sulfate product as raw material, prepare nickel sulfate solution, and control the mass concentration of Ni element to be 140 g / L; using the nickel sulfate solution as washing liquid, spray washing the crude nickel sulfate crystals according to a washing ratio of 20% (i.e., the volume ratio of the washing liquid to the nickel-containing solution is 20%); the spray washing temperature is 30° C. and the time is 30 min to obtain nickel sulfate slurry; the nickel sulfate slurry obtained by spray washing is subjected to solid-liquid separation to obtain nickel sulfate solid and washed liquid;

[0127] S3, drying the nickel sulfate solid to obtain a nickel sulfate product.

[0128] Comparative Example 4

[0129] The nickel-containing solution of this comparative example has a Ni element mass concentration of 69.04 g / L, a Li element mass concentration of 0.31 g / L, a Na element mass concentration of 4.16 g / L, a Mg element mass concentration of 24 ppm, and a Ca element mass concentration of 20 ppm.

[0130] The method of extracting battery-grade nickel sulfate from a nickel-containing solution in this embodiment comprises:

[0131] S1. Pour 2L of nickel-containing solution into a rotary evaporator, evaporate at 90°C, and control the evaporation ratio to 85%; after the evaporation is completed, stir and cool to crystallize at room temperature at a stirring speed of 400rpm, and cool to room temperature to perform solid-liquid separation to obtain crude nickel sulfate crystals;

[0132] S2, using nickel sulfate product as raw material, preparing nickel sulfate solution, controlling the mass concentration of Ni element to be 140g / L; using the nickel sulfate solution as washing liquid, stirring and washing crude nickel sulfate crystals at a washing ratio of 20% (i.e., the volume ratio of washing liquid to nickel-containing solution is 20%), the stirring and washing temperature is 30°C, the time is 30min, to obtain nickel sulfate slurry; performing solid-liquid separation on the nickel sulfate slurry obtained by stirring and washing, to obtain nickel sulfate solid and washed liquid;

[0133] S3, drying the nickel sulfate solid to obtain a nickel sulfate product.

[0134] In Comparative Example 4, nickel sulfate over-crystallized after evaporation crystallization, and impurities could not be separated in the liquid-solid separation.

[0135] Comparative Example 5

[0136] The nickel-containing solution of this comparative example has a Ni element mass concentration of 125.48 g / L, a Li element mass concentration of 1.25 g / L, a Na element mass concentration of 0.36 g / L, a Si element mass concentration of 80 ppm, a Mg element mass concentration of 25 ppm, and a Ca element mass concentration of 18 ppm.

[0137] The method for extracting battery-grade nickel sulfate from a nickel-containing solution in this comparative example comprises:

[0138] S1. Pour 2L of nickel-containing solution into a rotary evaporator, evaporate at 90°C, and control the evaporation ratio to 35%; after the evaporation is completed, stir and cool to crystallize at room temperature at a stirring speed of 400rpm, and cool to room temperature to perform solid-liquid separation to obtain crude nickel sulfate crystals;

[0139] S2. Using nickel sulfate product as raw material, prepare nickel sulfate solution, and control the mass concentration of Ni element to be 140 g / L; using the nickel sulfate solution as washing liquid, spray washing crude nickel sulfate crystals according to a washing ratio of 5% (i.e., the volume ratio of washing liquid to nickel-containing solution is 5%), the spray washing temperature is 30° C., and the time is 30 min to obtain nickel sulfate slurry; the nickel sulfate slurry obtained by spray washing is subjected to solid-liquid separation to obtain nickel sulfate solid and washed liquid;

[0140] S3, drying the nickel sulfate solid to obtain a nickel sulfate product.

[0141] Comparative Example 6

[0142] The nickel-containing solution of this comparative example has a Ni element mass concentration of 125.48 g / L, a Li element mass concentration of 1.25 g / L, a Na element mass concentration of 0.36 g / L, a Mg element mass concentration of 25 ppm, and a Ca element mass concentration of 18 ppm.

[0143] The method for extracting battery-grade nickel sulfate from a nickel-containing solution in this comparative example comprises:

[0144] S1. Pour 2L of nickel-containing solution into a rotary evaporator, evaporate at 90°C, and control the evaporation ratio to 60%; after the evaporation is completed, stir and cool to crystallize at room temperature at a stirring speed of 400rpm, and after cooling to room temperature, perform solid-liquid separation to obtain crude nickel sulfate crystals;

[0145] S2, using nickel sulfate product as raw material, preparing nickel sulfate solution, controlling the mass concentration of Ni element to be 45g / L; using the nickel sulfate solution as washing liquid, stirring and washing crude nickel sulfate crystals at a washing ratio of 10% (i.e., the volume ratio of washing liquid to nickel-containing solution is 10%), the stirring and washing temperature is 30°C, the time is 30min, to obtain nickel sulfate slurry; performing solid-liquid separation on the nickel sulfate slurry obtained by stirring and washing, to obtain nickel sulfate solid and washed liquid;

[0146] S3, drying the nickel sulfate solid to obtain a nickel sulfate product.

[0147] Test example

[0148] 1. Purity of nickel sulfate products

[0149] The Ni content in the nickel sulfate product is determined by EDTA titration method, and the contents of other elements are determined by ICP emission spectrometry. The requirements are Ni ≥ 22%, Co ≤ 0.02%, Li, Mn, Si ≤ 0.001%, Na ≤ 0.01%, Mg ≤ 0.002%, Ca ≤ 0.0005%. If the above requirements are met, it is qualified, otherwise it is unqualified.

[0150] 2. Yield of nickel sulfate product

[0151] The yield of the nickel sulfate product is calculated according to the yield of the nickel sulfate product = the mass of the nickel sulfate product / the mass of the nickel recovery liquid × 100%.

[0152] The test results are shown in Table 1.

[0153] Table 1

[0154]

[0155]

[0156] According to Table 1, the present application obtains qualified battery-grade nickel sulfate by controlling the appropriate evaporation ratio and washing ratio. The present application omits the extraction process, directly evaporates and crystallizes the nickel recovery liquid, controls the appropriate evaporation ratio by the difference in solubility of nickel sulfate and other impurity ions, precipitates nickel sulfate in the form of crystals, prevents the impurity ions from eutectic precipitation with nickel sulfate, and the impurity ions adsorbed on the surface of the nickel sulfate crystal enter the washing liquid through washing, thereby obtaining battery-grade nickel sulfate, effectively reducing production costs and shortening the process flow.

[0157] By comparing Examples 1-7 with Comparative Examples 1 and 3-5, it can be seen that by controlling the appropriate evaporation temperature and the appropriate evaporation ratio, nickel sulfate crystallization is facilitated, and the growth process of nickel sulfate crystals is prevented from encapsulating Li + 、Na + , Ca 2+ Mg 2+ 、Co 2+ , Mn 2+ , K + 、Si 4+ Impurity ions such as nickel sulfate are removed to ensure the growth of pure nickel sulfate crystals; in Comparative Examples 1 and 5, due to the low evaporation ratio, nickel sulfate does not crystallize or the amount of crystallization is small, and the economic benefit is insufficient; in Comparative Examples 3-4, due to the high evaporation ratio, impurity ions and nickel sulfate co-crystallize even under extreme conditions, and the nickel sulfate crystals cannot be washed to standard.

[0158] By comparing Examples 1-7 with Comparative Examples 2 and 6, it can be seen that, on the basis of satisfying the appropriate evaporation ratio, due to the low washing ratio (<3%) of Comparative Example 2, a small amount of washing liquid cannot take away enough impurity ions adsorbed on the surface of the product, and the product cannot be washed to standard; due to the low concentration of the nickel sulfate solution in the washing liquid of Comparative Example 6, or when the elution ratio is high, the nickel sulfate product is reversely dissolved during the washing process, and the economic benefits are insufficient. Compared with the extraction process, the present application directly omits the nickel extraction and reverse extraction steps, greatly reduces the production cost, shortens the process flow, is simple to operate, and has strong feasibility.

[0159] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those described herein, for example.

[0160] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for extracting nickel sulfate from a nickel-containing solution, characterized in that: include: S1, sequentially subjecting the nickel-containing solution to evaporation treatment and cooling crystallization, and then performing a first solid-liquid separation to obtain first nickel sulfate crystals and condensed water; Wherein, the temperature of the evaporation treatment is 70°C to 100°C, and the evaporation ratio is 50% to 80%; S2, washing the first nickel sulfate crystals with a nickel sulfate solution, and then performing a second solid-liquid separation to obtain second nickel sulfate crystals and a washed liquid; Wherein, the volume ratio of the nickel sulfate solution to the nickel-containing solution is 3% to 30%.

2. The method according to claim 1, characterized in that The mass concentration of nickel element in the nickel sulfate solution is 60g / L to 150g / L; Preferably, the mass concentration of nickel element in the nickel-containing solution is 60 g / L to 130 g / L; and / or, The nickel-containing solution includes lithium element, and the mass concentration of the lithium element is 0.2 g / L to 5 g / L; and / or, The nickel-containing solution includes sodium element, and the mass concentration of the sodium element is 0.2 g / L to 5 g / L; and / or, The nickel-containing solution includes magnesium element, and the mass concentration of the magnesium element is 10ppm to 100ppm; and / or, The nickel-containing solution includes calcium element, and the mass concentration of the calcium element is 10ppm to 100ppm.

3. The method according to claim 1 or 2, characterized in that: The nickel-containing solution also includes cobalt element, and the mass concentration of the cobalt element is 50ppm to 200ppm; and / or, The nickel-containing solution also includes manganese, and the mass concentration of the manganese is 10ppm to 200ppm; and / or, The nickel-containing solution further includes potassium, and the mass concentration of the potassium is 10ppm to 250ppm; and / or, The nickel-containing solution also includes silicon, and the mass concentration of the silicon is 50ppm to 100ppm; and / or, The nickel-containing solution also includes aluminum element, and the mass concentration of the aluminum element is 5ppm to 50ppm.

4. The method according to any one of claims 1 to 3, characterized in that The method for preparing the nickel-containing solution comprises: mixing the waste battery positive electrode material with sulfuric acid for acid leaching to obtain an acid leaching solution; performing iron and aluminum removal treatment on the acid leaching solution to obtain an iron and aluminum removal solution; mixing the iron and aluminum removal solution with a first extractant for a first extraction to obtain a first raffinate; mixing the first raffinate with a second extractant for a second extraction to obtain a second raffinate; mixing the second raffinate with a third extractant for a third extraction to obtain a third raffinate; mixing the third raffinate with a fourth extractant for a fourth extraction to obtain a nickel-containing solution; Among them, the first extractant is C272, the second extractant is P204, the third extractant is P507, and the fourth extractant is C272.

5. The method according to any one of claims 1 to 4, characterized in that The cooling crystallization temperature is 20°C to 35°C, and the rotation speed is 100rpm to 500rpm; and / or, The washing process is stirring washing and / or spray washing; Preferably, the washing treatment is carried out at a temperature of 20°C to 50°C and for a time of 10 min to 60 min.

6. The method according to any one of claims 1 to 5, characterized in that The first solid-liquid separation has a rotation speed of 400 rpm to 1000 rpm and a time of 5 min to 60 min; and / or, The second solid-liquid separation has a rotation speed of 400 rpm to 1000 rpm and a time of 5 min to 60 min.

7. The method according to any one of claims 1 to 6, characterized in that Also includes: S3, drying the second nickel sulfate crystals to obtain the nickel sulfate; Preferably, the nickel sulfate solution is formed by mixing the nickel sulfate and water, and the volume ratio of the nickel sulfate solution to the nickel-containing solution is 3% to 10%.

8. The method according to any one of claims 1 to 7, characterized in that The recovery rate of the nickel sulfate is 60% to 90%.

9. A nickel sulfate, characterized in that Prepared by the method according to any one of claims 1 to 8.

10. Nickel sulfate according to claim 9, characterized in that The purity of the nickel sulfate is ≥99.5%, and the moisture content is ≤0.5%.

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