Ternary precursor and preparation method and application thereof

Abstract

The invention provides a ternary precursor and a preparation method and application thereof. The preparation method comprises the following steps: providing a nickel-cobalt-manganese aqueous solution, a nickel unit solution, a cobalt unit solution and a manganese unit solution after co-extraction, and determining a nickel-cobalt-manganese molar ratio in a target ternary precursor; providing an integrated burdening and feeding automatic control system, and inputting the total concentration of nickel, cobalt and manganese in the co-extracted nickel, cobalt and manganese water solution, the metal concentrations of nickel unit liquid, cobalt unit liquid and manganese unit liquid, the total feeding flow and the molar ratio of nickel, cobalt and manganese in the target ternary precursor into the integrated burdening and feeding automatic control system; feeding is started, the co-extracted nickel-cobalt-manganese aqueous solution, the nickel unit liquid, the cobalt unit liquid, the manganese unit liquid, the precipitant and the complexing agent are introduced into a reaction kettle for a co-precipitation reaction, and the ternary precursor is obtained. According to the method disclosed by the invention, proportioning and feeding procedures are combined, so that the cost is reduced, the synthesis of the ternary precursor in a target proportion is realized in one step, and the consistency of economy and precursor quality is improved.

Description

Technical Field

[0001] The present invention belongs to the field of metallurgy, and in particular relates to a ternary precursor and a preparation method and application thereof. Background Art

[0002] At present, the production of ternary precursors mostly uses nickel sulfate, cobalt sulfate, and manganese sulfate crystals or solutions as raw materials. Driven by the need to reduce costs and increase efficiency in the new energy industry, the market is severely involuted, and the pressure on precursor production costs continues to intensify. In order to break through the cost dilemma, co-extraction technology was proposed as an improvement plan. Compared with the nickel-cobalt-manganese step-by-step extraction technology, the cost of directly obtaining a nickel-cobalt-manganese mixed solution using co-extraction technology on the raw material side can be reduced by 30%-40%. However, the large-scale application of co-extraction technology faces technical constraints. Due to the different nickel-cobalt-manganese contents in different raw materials, the co-extraction technology cannot control the nickel-cobalt-manganese ratio of the final solution. Re-batch is required when producing precursors, and due to changes in the ratio, the batching difficulty increases compared to using three single raw materials, affecting the popularity of co-extraction raw materials.

[0003] Therefore, how to break through the technical bottleneck of uncontrollable co-extraction ratio and unbalanced coupling of multi-source material flow, realize precise proportion control of nickel, cobalt and manganese elements, reduce the processing cost of ternary precursors from the raw material end, and realize the generation of high-quality target products, is a technical problem that needs to be solved urgently. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a ternary precursor and its preparation method and application. The present invention takes an integrated batching and feeding automatic control system as the core, and by integrating the batching process and the feeding process, it realizes the efficient synthesis of the target ratio of the ternary precursor in one step, successfully breaking through the technical bottleneck of the uncontrollable ratio of the nickel-cobalt-manganese aqueous solution after co-extraction and the imbalance of the coupling of multi-source material flow, and realizes the real-time dynamic and precise control of the ratio of nickel-cobalt-manganese elements. It also greatly reduces the processing cost of raw materials, and the overall production cost of the raw material end is reduced by 20-30%. The prepared ternary precursor has high purity, which significantly improves the economic efficiency of the co-extraction technology and the consistency of the precursor quality.

[0005] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0006] In a first aspect, the present invention provides a method for preparing a ternary precursor, the preparation method comprising the following steps:

[0007] A nickel-cobalt-manganese aqueous solution, a nickel unit solution, a cobalt unit solution and a manganese unit solution are provided after co-extraction, and the molar ratio of nickel, cobalt and manganese in the target ternary precursor is determined.

[0008] An integrated batching and feeding automatic control system is provided, in which the following initial parameters are input: the total concentration of nickel, cobalt and manganese in the nickel, cobalt and manganese aqueous solution after co-extraction, the metal concentrations of the nickel unit liquid, the cobalt unit liquid and the manganese unit liquid, the total feed flow rate and the nickel, cobalt and manganese molar ratio in the target ternary precursor.

[0009] The feed is opened, and the nickel-cobalt-manganese aqueous solution after co-extraction, nickel unit liquid, cobalt unit liquid, manganese unit liquid, precipitant and complexing agent are introduced into the reactor to carry out co-precipitation reaction to obtain the ternary precursor.

[0010] The present invention takes an integrated batching and feeding automatic control system as its core, and realizes the efficient synthesis of a ternary precursor with a target ratio in one step by integrating the batching process and the feeding process. It successfully breaks through the technical bottleneck of the uncontrollable ratio of nickel, cobalt and manganese aqueous solutions after co-extraction and the imbalance of multi-source material flow coupling, realizes real-time dynamic and precise control of the ratio of nickel, cobalt and manganese elements, and greatly reduces the processing cost of raw materials. The overall production cost of the raw materials is reduced by 20-30%. The prepared ternary precursor has high purity, which significantly improves the economic efficiency of the co-extraction technology and the consistency of the precursor quality.

[0011] It should be noted that the metal concentrations of the nickel unit solution, the cobalt unit solution, and the manganese unit solution refer to the metal concentration of the nickel unit solution, the metal concentration of the cobalt unit solution, and the metal concentration of the manganese unit solution.

[0012] It should be noted that the present invention does not limit the preparation method of the nickel-cobalt-manganese aqueous solution after co-extraction. For example, the following method can be used:

[0013] Nickel, cobalt and manganese in the high-pressure acid leaching solution of laterite nickel ore are co-extracted to obtain an organic phase containing nickel, cobalt and manganese and a raffinate; the organic phase containing nickel, cobalt and manganese is stripped to obtain a strip solution containing nickel, cobalt and manganese, that is, the nickel-cobalt-manganese aqueous solution after co-extraction.

[0014] Preferably, the nickel unit solution is a soluble nickel salt solution, for example, nickel sulfate solution, nickel nitrate solution or nickel chloride solution.

[0015] Preferably, the cobalt unit solution is a soluble cobalt salt solution, for example, a cobalt sulfate solution, a cobalt nitrate solution, or a cobalt chloride solution.

[0016] Preferably, the manganese unit solution is a soluble manganese salt solution, for example, a manganese sulfate solution, a manganese nitrate solution or a manganese acetate solution.

[0017] Preferably, the total concentration of nickel, cobalt and manganese in the nickel, cobalt and manganese aqueous solution after co-extraction is 100-120 g / L, for example, 100 g / L, 110 g / L or 120 g / L.

[0018] Preferably, the nickel-cobalt-manganese aqueous solution after co-extraction comprises the following components in terms of mass concentration:

[0019] Nickel 30-120g / L, for example, it can be 30g / L, 50g / L, 70g / L, 90g / L, 100g / L or 120g / L, etc., cobalt 0-60g / L, for example, it can be 10g / L, 20g / L, 30g / L, 40g / L, 50g / L or 60g / L, etc., manganese 0-60g / L, for example, it can be 10g / L, 20g / L, 30g / L, 40g / L, 50g / L or 60g / L, etc.

[0020] Preferably, the metal concentrations in the nickel unit solution, the cobalt unit solution and the manganese unit solution are each independently 100-120 g / L, for example, 100 g / L, 110 g / L or 120 g / L.

[0021] Preferably, the total concentration of nickel, cobalt and manganese in the nickel-cobalt-manganese aqueous solution after co-extraction is the same as the metal concentrations in the nickel unit solution, the cobalt unit solution and the manganese unit solution.

[0022] In the present invention, the total concentration of nickel, cobalt and manganese in the nickel-cobalt-manganese aqueous solution after co-extraction is controlled to be the same as the metal concentrations in the nickel unit solution, the cobalt unit solution and the manganese unit solution, which helps to improve production efficiency and simplify the process.

[0023] Preferably, the total feed flow rate is 200-700 L / h, for example, it can be 200 L / h, 300 L / h, 400 L / h, 500 L / h, 600 L / h or 700 L / h.

[0024] Preferably, the integrated batching and feeding automatic control system includes a metal concentration calculation module, a multi-channel metering pump, and a dynamic flow monitoring and feedback module.

[0025] It should be noted that the metal concentration calculation module automatically calculates the feed flow rate of each solution based on the solution concentration, and the multi-channel metering pump can independently control the feed flow rate of different streams. The dynamic flow monitoring and feedback module monitors and corrects the pumping flow in real time to ensure that the element ratio dynamically meets the target.

[0026] In the present invention, the integrated batching and feeding automatic control system integrates the batching process and the feeding process. Before feeding, there is no need to deliberately control the amount of nickel unit liquid, cobalt unit liquid and manganese unit liquid added to the nickel-cobalt-manganese aqueous solution after co-extraction to adjust the target ratio of the ternary precursor. That is, the traditional pre-mixed liquid mode is abandoned. During the co-precipitation reaction feeding process, the flow rates of nickel, cobalt and manganese unit liquids and the nickel-cobalt-manganese aqueous solution after co-extraction are dynamically adjusted based on real-time feedback, thereby achieving the precise synthesis of the target ratio of the ternary precursor in one step, simplifying the production process, shortening the production cycle, and achieving high element ratio accuracy.

[0027] Preferably, the introduction method is a parallel flow addition method.

[0028] Preferably, the precipitant comprises liquid alkali and / or potassium hydroxide.

[0029] Preferably, the concentration of the liquid caustic soda is 30-40 wt%, for example, it can be 30 wt%, 32 wt%, 34 wt%, 36 wt%, 38 wt% or 40 wt%.

[0030] Preferably, the complexing agent includes any one of ammonia water, ammonium sulfate or EDTA (ethylenediaminetetraacetic acid), or a combination of at least two of them.

[0031] Preferably, the concentration of the ammonia water is 15-25 wt%, for example, 15 wt%, 17.5 wt%, 20 wt%, 22.5 wt% or 25 wt%.

[0032] Preferably, during the coprecipitation reaction, the ammonium concentration in the reaction system is 2-15 g / L, for example, 2 g / L, 5 g / L, 10 g / L or 15 g / L.

[0033] Preferably, the coprecipitation reaction temperature is 40-80°C, for example, 40°C, 50°C, 60°C, 70°C or 80°C.

[0034] Preferably, during the coprecipitation reaction, the pH value of the reaction system is 10-12, for example, 10, 10.5, 11, 11.5 or 12.

[0035] Preferably, the coprecipitation reaction is accompanied by stirring, and the stirring rate is 150-400 rpm, for example, 150 rpm, 200 rpm, 300 rpm or 400 rpm.

[0036] Preferably, the coprecipitation reaction is carried out in an inert atmosphere, for example, a nitrogen atmosphere.

[0037] Preferably, the termination criterion for the coprecipitation reaction is that the particle size D50 reaches 3-6 μm, for example, 3 μm, 3.5 μm, 4 μm, 4.5 μm, 5 μm or 6 μm.

[0038] Preferably, after the coprecipitation reaction is completed, the steps of washing, filtering, drying, mixing, screening, iron removal and packaging are sequentially performed.

[0039] In the present invention, mixing refers to the process of physically mixing dried precursor particles from different batches or within the same batch. The core purpose of mixing is to ensure the uniformity of chemical composition and physical properties of finished products from different batches.

[0040] Preferably, the doping metal solution is also introduced into the reaction kettle during the process of introducing the nickel-cobalt-manganese aqueous solution, nickel unit solution, cobalt unit solution, manganese unit solution, precipitant and complexing agent into the reaction kettle after the co-extraction.

[0041] Preferably, the metal concentration in the doped metal solution is 0.5-10 g / L, for example, it can be 0.5 g / L, 1 g / L, 2 g / L, 3 g / L, 4 g / L, 5 g / L, 6 g / L, 7 g / L, 8 g / L, 9 g / L or 10 g / L.

[0042] Preferably, the metal in the doped metal solution includes any one of aluminum, magnesium or zirconium, or a combination of at least two of them.

[0043] In the present invention, the doping of aluminum, magnesium and zirconium helps to improve the structural stability of the precursor and enhance the material properties.

[0044] Preferably, the amount of the doping metal solution introduced meets the following requirements: the doping amount of the doping metal is 0.1-5% of the total molar amount of nickel, cobalt and manganese in the target ternary precursor, for example, it can be 0.1%, 0.5%, 1%, 2%, 3%, 4% or 5%, etc.

[0045] The present invention uses an appropriate doping amount to achieve metal doping, which not only has a significant effect on improving material properties, which is far superior to too low or too high doping levels, but also has a limited increase in the cost of raw materials, meeting the needs of cost reduction and efficiency improvement.

[0046] In a second aspect, the present invention provides a ternary precursor, which is prepared using the preparation method described in the first aspect.

[0047] The chemical formula of the ternary precursor is Ni x Co y Mn z (OH)2, x>0, y>0, z>0, x+y+z=1. For example, the value of x can be, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8 or 0.9, the value of y can be, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8 or 0.9, and the value of z can be, for example, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8 or 0.9, etc.

[0048] In a third aspect, the present invention provides a cathode material, which is obtained by mixing and sintering the ternary precursor described in the second aspect with a lithium source. For example, the lithium source may be lithium carbonate.

[0049] In a fourth aspect, the present invention provides a lithium-ion battery, comprising the positive electrode material as described in the third aspect.

[0050] The numerical range described in the present invention includes not only the point values ​​listed above, but also any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0051] Compared with the prior art, the present invention has the following beneficial effects:

[0052] The present invention takes an integrated batching and feeding automatic control system as its core, and realizes the efficient synthesis of a ternary precursor with a target ratio in one step by integrating the batching process and the feeding process. It successfully breaks through the technical bottleneck of the uncontrollable ratio of nickel, cobalt and manganese aqueous solutions after co-extraction and the imbalance of multi-source material flow coupling, realizes real-time dynamic and precise control of the ratio of nickel, cobalt and manganese elements, and greatly reduces the processing cost of raw materials. The overall production cost of the raw materials is reduced by 20-30%. The prepared ternary precursor has high purity, which significantly improves the economic efficiency of the co-extraction technology and the consistency of the precursor quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 This is a process flow chart of the preparation method of the ternary precursor provided in Example 1 of the present invention. DETAILED DESCRIPTION

[0054] The technical solution of the present invention is further described below by way of specific embodiments. It should be understood by those skilled in the art that the embodiments are merely to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0055] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0056] Example 1

[0057] This embodiment provides a method for preparing a ternary precursor, and its process flow chart is as follows: Figure 1 As shown, the preparation method comprises the following steps:

[0058] (1) Providing a nickel-cobalt-manganese aqueous solution after co-extraction, a nickel unit liquid, a cobalt unit liquid and a manganese unit liquid, and determining the nickel-cobalt-manganese molar ratio in a target ternary precursor; the total concentration of nickel, cobalt and manganese in the nickel-cobalt-manganese aqueous solution after co-extraction is 100 g / L, and the nickel-cobalt-manganese aqueous solution after co-extraction comprises the following components in terms of mass concentration: 52 g / L nickel, 22 g / L cobalt and 26 g / L manganese; the metal concentration of the nickel unit liquid is 100 g / L, the metal concentration of the cobalt unit liquid is 100 g / L, and the metal concentration of the manganese unit liquid is 100 g / L; the nickel-cobalt-manganese molar ratio in the target ternary precursor is 60:20:20; the nickel unit liquid is a nickel sulfate solution, the cobalt unit liquid is a cobalt sulfate solution, and the manganese unit liquid is a manganese sulfate solution.

[0059] (2) providing an integrated batching and feeding automatic control system, wherein the following initial parameters are input into the integrated batching and feeding automatic control system: the total concentration of nickel, cobalt and manganese in the nickel-cobalt-manganese aqueous solution after co-extraction, the metal concentrations of the nickel unit liquid, the cobalt unit liquid and the manganese unit liquid, the total feed flow rate and the nickel-cobalt-manganese molar ratio in the target ternary precursor; wherein the total feed flow rate is 300 L / h; the integrated batching and feeding automatic control system includes a metal concentration calculation module, a multi-channel metering pump and a dynamic flow monitoring and feedback module.

[0060] (3) starting the feed, adding the nickel-cobalt-manganese aqueous solution after co-extraction, nickel unit liquid, cobalt unit liquid, manganese unit liquid, precipitant and complexing agent into a reactor in a nitrogen atmosphere in parallel to carry out a co-precipitation reaction, and stopping the feed reaction after the particle size D50 grows to 3.5 μm to obtain a ternary precursor slurry; the precipitant is a liquid alkali with a concentration of 32 wt%, and the complexing agent is ammonia water with a concentration of 20 wt%; during the co-precipitation reaction, the temperature is 50°C, the pH value of the reaction system is 11.8, the ammonium concentration in the reaction system is 6 g / L, and the co-precipitation reaction is accompanied by stirring at a rate of 400 rpm.

[0061] (4) Post-processing: washing, filtering, drying, mixing, screening, iron removal and packaging the ternary precursor slurry to obtain a ternary precursor finished product, i.e., NCM622 finished product.

[0062] Example 2

[0063] This embodiment provides a method for preparing a ternary precursor, the preparation method comprising the following steps:

[0064] (1) Providing a nickel-cobalt-manganese aqueous solution after co-extraction, a nickel unit liquid, a cobalt unit liquid and a manganese unit liquid, and determining the nickel-cobalt-manganese molar ratio in the target ternary precursor; the total concentration of nickel, cobalt and manganese in the nickel-cobalt-manganese aqueous solution after co-extraction is 110 g / L, and the nickel-cobalt-manganese aqueous solution after co-extraction comprises the following components in terms of mass concentration: 73 g / L nickel, 15 g / L cobalt and 22 g / L manganese; the metal concentration of the nickel unit liquid is 110 g / L, the metal concentration of the cobalt unit liquid is 110 g / L, and the metal concentration of the manganese unit liquid is 110 g / L; the nickel-cobalt-manganese molar ratio in the target ternary precursor is 80:10:10; the nickel unit liquid is a nickel sulfate solution, the cobalt unit liquid is a cobalt sulfate solution, and the manganese unit liquid is a manganese sulfate solution.

[0065] (2) providing an integrated batching and feeding automatic control system, wherein the following initial parameters are input into the integrated batching and feeding automatic control system: the total concentration of nickel, cobalt and manganese in the nickel-cobalt-manganese aqueous solution after co-extraction, the metal concentrations of the nickel unit liquid, the cobalt unit liquid and the manganese unit liquid, the total feed flow rate and the nickel-cobalt-manganese molar ratio in the target ternary precursor; wherein the total feed flow rate is 400 L / h; the integrated batching and feeding automatic control system includes a metal concentration calculation module, a multi-channel metering pump and a dynamic flow monitoring and feedback module.

[0066] (3) starting the feed, adding the nickel-cobalt-manganese aqueous solution after co-extraction, nickel unit liquid, cobalt unit liquid, manganese unit liquid, precipitant and complexing agent into a reactor in a nitrogen atmosphere in parallel to carry out a co-precipitation reaction, and stopping the feed reaction after the particle size D50 grows to 6 μm to obtain a ternary precursor slurry; the precipitant is a liquid alkali with a concentration of 30 wt%, and the complexing agent is ammonia water with a concentration of 15 wt%; during the co-precipitation reaction, the temperature is 40°C, the pH value of the reaction system is 10, the ammonium concentration in the reaction system is 3 g / L, and the co-precipitation reaction is accompanied by stirring at a rate of 200 rpm.

[0067] (4) Post-processing: washing, filtering, drying, mixing, screening, iron removal and packaging the ternary precursor slurry to obtain a ternary precursor finished product, i.e., NCM811 finished product.

[0068] Example 3

[0069] This embodiment provides a method for preparing a ternary precursor, the preparation method comprising the following steps:

[0070] (1) Providing a nickel-cobalt-manganese aqueous solution after co-extraction, a nickel unit liquid, a cobalt unit liquid and a manganese unit liquid, and determining the nickel-cobalt-manganese molar ratio in the target ternary precursor; the total concentration of nickel, cobalt and manganese in the nickel-cobalt-manganese aqueous solution after co-extraction is 120 g / L, and the nickel-cobalt-manganese aqueous solution after co-extraction comprises the following components in terms of mass concentration: 94 g / L nickel, 14 g / L cobalt and 12 g / L manganese; the metal concentration of the nickel unit liquid is 120 g / L, the metal concentration of the cobalt unit liquid is 120 g / L, and the metal concentration of the manganese unit liquid is 120 g / L; the nickel-cobalt-manganese molar ratio in the target ternary precursor is 80:10:10; the nickel unit liquid is a nickel sulfate solution, the cobalt unit liquid is a cobalt sulfate solution, and the manganese unit liquid is a manganese sulfate solution.

[0071] (2) providing an integrated batching and feeding automatic control system, wherein the following initial parameters are input into the integrated batching and feeding automatic control system: the total concentration of nickel, cobalt and manganese in the nickel-cobalt-manganese aqueous solution after co-extraction, the metal concentrations of the nickel unit liquid, the cobalt unit liquid and the manganese unit liquid, the total feed flow rate and the nickel-cobalt-manganese molar ratio in the target ternary precursor; wherein the total feed flow rate is 500 L / h; the integrated batching and feeding automatic control system includes a metal concentration calculation module, a multi-channel metering pump and a dynamic flow monitoring and feedback module.

[0072] (3) starting the feed, adding the nickel-cobalt-manganese aqueous solution after co-extraction, nickel unit liquid, cobalt unit liquid, manganese unit liquid, precipitant and complexing agent into a reactor in a nitrogen atmosphere in parallel to carry out a co-precipitation reaction, and stopping the feed reaction after the particle size D50 grows to 4 μm to obtain a ternary precursor slurry; the precipitant is a liquid alkali with a concentration of 40 wt%, and the complexing agent is ammonia water with a concentration of 25 wt%; during the co-precipitation reaction, the temperature is 80°C, the pH value of the reaction system is 12, the ammonium concentration in the reaction system is 8 g / L, and the co-precipitation reaction is accompanied by stirring at a rate of 300 rpm.

[0073] (4) Post-processing: washing, filtering, drying, mixing, screening, iron removal and packaging the ternary precursor slurry to obtain a ternary precursor finished product, i.e., NCM811 finished product.

[0074] Example 4

[0075] The difference between this embodiment and embodiment 1 is that the initial parameters input in step (2) also include a metal aluminum concentration of 2.5 g / L in the doped metal aluminum solution, and a molar fraction of 0.5% of the total molar amount of nickel, cobalt and manganese in the target ternary precursor.

[0076] The remaining methods and parameters remained the same as in Example 1.

[0077] Example 5

[0078] The difference between this embodiment and embodiment 1 is that the initial parameters input in step (2) also include a magnesium concentration of 2 g / L in the doped aluminum solution and a molar fraction of 1% of the total molar amount of nickel, cobalt and manganese in the target ternary precursor.

[0079] The remaining methods and parameters remained the same as in Example 1.

[0080] Example 6

[0081] The difference between this embodiment and embodiment 1 is that the initial parameters input in step (2) also include a magnesium concentration of 5 g / L in the doped aluminum solution and a molar fraction of 5% of the total molar amount of nickel, cobalt and manganese in the target ternary precursor.

[0082] The remaining methods and parameters remained the same as in Example 1.

[0083] Example 7

[0084] The difference between this embodiment and embodiment 1 is that the metal concentration of the nickel unit liquid in step (1) is 110 g / L, the metal concentration of the cobalt unit liquid is 110 g / L, and the metal concentration of the manganese unit liquid is 110 g / L, so that the total concentration of nickel, cobalt and manganese in the nickel-cobalt-manganese aqueous solution after co-extraction is different from the metal concentrations in the nickel unit liquid, cobalt unit liquid and manganese unit liquid.

[0085] The remaining methods and parameters remained the same as in Example 1.

[0086] Comparative Example 1

[0087] The difference between this comparative example and Example 1 is that no integrated automatic control system for batching and feeding is provided, that is, step (2) is not performed.

[0088] The remaining methods and parameters remained the same as in Example 1.

[0089] Comparative Example 2

[0090] This comparative example provides a method for preparing a ternary precursor, which comprises the following steps:

[0091] (1) Adding nickel sulfate, cobalt sulfate and manganese sulfate to the nickel-cobalt-manganese aqueous solution after co-extraction, adjusting the molar ratio of nickel, cobalt and manganese in the solution to 6:2:2, and preparing an NCM622 precursor solution.

[0092] (2) The NCM622 precursor solution, 32 wt% liquid caustic soda and 20 wt% ammonia water are introduced into a reactor in a nitrogen atmosphere for co-precipitation reaction to obtain a ternary precursor slurry; wherein, the flow rate of the NCM622 precursor solution is 300 L / h, the flow rate of the liquid caustic soda is 97 L / h, and the flow rate of the ammonia water is 38 L / h; during the co-precipitation reaction, the temperature is 50°C, the pH value of the reaction system is 11.8, and the ammonium concentration in the reaction system is 6 g / L; the co-precipitation reaction is accompanied by stirring at a rate of 400 rpm.

[0093] (3) The ternary precursor slurry is washed, filtered, dried, mixed, screened, deironed and packaged to obtain a ternary precursor finished product, i.e., NCM622 finished product.

[0094] Performance Testing

[0095] The element content of the finished ternary precursors prepared in the above examples and comparative examples was tested using the ICP-OES method.

[0096] The test results are shown in Table 1.

[0097] Table 1

[0098]

[0099] analyze:

[0100] As can be seen from Table 1, the present invention takes an integrated batching and feeding automatic control system as its core, and by integrating the batching process and the feeding process, it achieves the efficient synthesis of a ternary precursor with a target ratio in one step, successfully breaking through the technical bottleneck of the uncontrollable ratio of nickel, cobalt and manganese aqueous solution after co-extraction and the imbalance of multi-source material flow coupling, and realizes real-time dynamic and precise control of the ratio of nickel, cobalt and manganese elements. It also greatly reduces the processing cost of raw materials, and the overall production cost of the raw materials is reduced by 20-30%. The prepared ternary precursor has high purity, which significantly improves the economic efficiency of the co-extraction technology and the consistency of the precursor quality.

[0101] By comparing Example 1 with Examples 4-6, it can be seen that doping elements are also introduced during the preparation process, and the metal doping ratio is accurately controlled with the help of an integrated ingredient feeding automatic control system, which can significantly improve the performance and production efficiency of the ternary precursor, while also optimizing the technical and economic benefits.

[0102] By comparing Example 1 with Example 7, it can be seen that if the total concentration of nickel, cobalt and manganese in the nickel-cobalt-manganese aqueous solution after co-extraction in the initial stage is different from the metal concentrations in the nickel unit liquid, cobalt unit liquid and manganese unit liquid, it is not conducive to the stability of the total metal concentration, resulting in unstable matching with the liquid alkali flow rate, and the pH is not easy to stably control. When the pH is low, the nickel and cobalt precipitation is incomplete, deviates from the target ratio, and the precursor morphology is uneven.

[0103] From the comparison between Example 1 and Comparative Example 1, it can be seen that if the integrated automatic control system for feeding ingredients is not provided, that is, if step (2) is not performed, the ratio of the precursor and the ratio of the extract will be consistent, and the finished product will be unqualified.

[0104] By comparing Example 1 with Comparative Example 2, it can be seen that if the preparation of the ternary precursor is achieved by first mixing the ingredients and then feeding them, qualified precursor materials can be synthesized, but the extra step causes cost waste, and the control accuracy is not higher than that of direct feeding synthesis using the automatic control system of the present invention.

[0105] It should be noted that while the present invention illustrates the process method through the above-described embodiments, the present invention is not limited to the above-described process steps, and does not necessarily rely on the above-described process steps for implementation. Those skilled in the art will appreciate that any improvements to the present invention, equivalent replacements for the raw materials used, additions of auxiliary components, and selection of specific methods, etc., fall within the scope of protection and disclosure of the present invention.

Claims

1. A method for preparing a ternary precursor, characterized in that: The preparation method comprises the following steps: Providing a nickel-cobalt-manganese aqueous solution, a nickel unit solution, a cobalt unit solution, and a manganese unit solution after co-extraction, and determining the nickel-cobalt-manganese molar ratio in the target ternary precursor; An integrated automatic control system for batching and feeding is provided, into which the following initial parameters are input: the total concentration of nickel, cobalt and manganese in the nickel-cobalt-manganese aqueous solution after co-extraction, the metal concentrations of the nickel unit solution, the cobalt unit solution and the manganese unit solution, the total feed flow rate and the nickel-cobalt-manganese molar ratio in the target ternary precursor; The feed is opened, and the nickel-cobalt-manganese aqueous solution after co-extraction, nickel unit liquid, cobalt unit liquid, manganese unit liquid, precipitant and complexing agent are introduced into the reactor to carry out co-precipitation reaction to obtain the ternary precursor.

2. The preparation method according to claim 1, characterized in that The total concentration of nickel, cobalt and manganese in the nickel, cobalt and manganese aqueous solution after the co-extraction is 100-120 g / L; Preferably, the nickel-cobalt-manganese aqueous solution after co-extraction comprises the following components in terms of mass concentration: Nickel 30-120g / L, cobalt 0-60g / L, manganese 0-60g / L; Preferably, the metal concentrations in the nickel unit solution, the cobalt unit solution, and the manganese unit solution are each independently 100-120 g / L; Preferably, the total concentration of nickel, cobalt and manganese in the nickel-cobalt-manganese aqueous solution after co-extraction is the same as the metal concentration in the nickel unit solution, the cobalt unit solution and the manganese unit solution; Preferably, the total feed flow rate is 200-700 L / h.

3. The preparation method according to claim 1 or 2, characterized in that The integrated batching and feeding automatic control system includes a metal concentration calculation module, a multi-channel metering pump, and a dynamic flow monitoring and feedback module.

4. The preparation method according to any one of claims 1 to 3, characterized in that The method of introducing is a parallel flow addition method; Preferably, the precipitant comprises liquid alkali and / or potassium hydroxide; Preferably, the concentration of the liquid caustic soda is 30-40wt%; Preferably, the complexing agent comprises any one of ammonia, ammonium sulfate or EDTA, or a combination of at least two thereof; Preferably, the concentration of the ammonia water is 15-25wt%; Preferably, during the coprecipitation reaction, the ammonium concentration in the reaction system is 2-15 g / L.

5. The preparation method according to any one of claims 1 to 4, characterized in that The temperature of the coprecipitation reaction is 40-80°C; Preferably, during the coprecipitation reaction, the pH value of the reaction system is 10-12; Preferably, the coprecipitation reaction is accompanied by stirring at a rate of 150-400 rpm; Preferably, the coprecipitation reaction process is carried out in an inert atmosphere.

6. The preparation method according to any one of claims 1 to 5, characterized in that The termination criterion of the coprecipitation reaction is that the particle size D50 reaches 3-6 μm; Preferably, after the coprecipitation reaction is completed, the steps of washing, filtering, drying, mixing, screening, iron removal and packaging are sequentially performed.

7. The preparation method according to any one of claims 1 to 6, characterized in that The doping metal solution is also introduced into the reaction kettle during the process of introducing the nickel-cobalt-manganese aqueous solution, nickel unit solution, cobalt unit solution, manganese unit solution, precipitant and complexing agent into the reaction kettle after the co-extraction; Preferably, the metal concentration in the doped metal solution is 0.5-10 g / L; Preferably, the metal in the doped metal solution includes any one of aluminum, magnesium or zirconium, or a combination of at least two thereof; Preferably, the amount of the doping metal solution introduced meets the following requirement: the doping amount of the doping metal is 0.1-5% of the total molar amount of nickel, cobalt and manganese in the target ternary precursor.

8. A ternary precursor, characterized in that: The ternary precursor is prepared by the preparation method according to any one of claims 1 to 7; The chemical formula of the ternary precursor is Ni x Co y Mn z (OH)2, x>0, y≥0, z≥0, x+y+z=1.

9. A positive electrode material, characterized in that The positive electrode material is obtained by mixing and sintering the ternary precursor as claimed in claim 8 with a lithium source.

10. A lithium ion battery, characterized in that: The lithium-ion battery comprises the positive electrode material according to claim 9.

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