A cobalt carbonate product, its preparation method and application

Abstract

The application discloses a kind of cobalt carbonate product and its preparation method and application, belong to cobalt carbonate material technical field.It is prepared and includes: adding cobalt salt solution and ammonium bicarbonate solution or ammonium carbonate solution to bottom liquid for seed synthesis, then carry out crystal nucleus growth;The value of inhibiting agglomeration index A in seed synthesis stage is 3~21.5, the value of nucleation driving index N is 3~7.5;A=(ω 2 ×T×t) / (C×Q), N=[(45-|T-45|)×C0×V0] / (C×Q×t).By controlling the value of A and N in the above range, it can be ensured that the whole seed synthesis stage is maintained in a moderate and stable supersaturation environment, so that the nucleation process can be continued, smooth and synchronized, and the prepared seed has excellent monodispersity. As a template for epitaxial growth, a high-quality cobalt carbonate product with high sphericity, narrow particle size distribution, regular morphology and good product consistency can be efficiently and stably obtained.

Description

Technical Field

[0001] This invention relates to the field of cobalt carbonate materials technology, and more specifically, to a cobalt carbonate product, its preparation method, and its application. Background Technology

[0002] In the field of lithium-ion battery cathode materials, lithium cobalt oxide (LiCoO2) has become a key material in high-end consumer electronics due to its high compaction density and stable electrochemical performance. The electrochemical performance of lithium cobalt oxide is highly dependent on the physical properties of its precursor, cobalt tetroxide (CTO), and the morphology and uniformity of CTO are determined by the microstructure of spherical cobalt carbonate (which yields CTO after calcination). Therefore, preparing cobalt carbonate with high sphericity and narrow particle size distribution is beneficial for improving the energy density, cycle life, and safety of lithium cobalt oxide cathode materials.

[0003] Currently, the industry mainly prepares spherical cobalt carbonate using the liquid-phase co-precipitation method, which typically includes two stages: "seed crystal synthesis" and "nucleus growth." Current methods suffer from large fluctuations and poor consistency in seed crystal particle size distribution between batches. Since "seed crystal synthesis" is the starting point of the entire preparation process, the dispersion uniformity of the product directly determines the sphericity and particle size distribution of the final secondary particles. Therefore, there is an urgent need to develop a method that can effectively ensure batch-to-batch consistency of seed crystals and a narrower particle size distribution.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a cobalt carbonate product, its preparation method, and its application, in order to solve or improve the above-mentioned technical problems.

[0006] This invention can be implemented as follows: In a first aspect, the present invention provides a method for preparing cobalt carbonate, comprising the following steps: adding either an ammonium bicarbonate solution or an ammonium carbonate solution and a cobalt salt solution to a base solution to perform seed crystal synthesis, followed by nucleus growth; The inhibition index for agglomeration in the seed crystal synthesis stage is A, and the nucleation driving index is N. The value of A is 3~21.5, and the value of N is 3~7.5. Where, A=(ω 2 ×T×t) / (C×Q), N=[(45-|T-45|)×C0×V0] / (C×Q×t); ω is the stirring speed for seed crystal synthesis, in r / s; T is the reaction temperature for seed crystal synthesis, in ℃; t is the feeding time of the cobalt salt solution, in h; C is the concentration of the cobalt salt solution, in mol / L; Q is the volume of the cobalt salt solution added, in L; C0 is the concentration of ammonium bicarbonate or ammonium carbonate in the base solution, in mol / L; V0 is the volume of the base solution, in L.

[0007] In an optional implementation, the value of A is 4.5 to 15; and / or, the value of N is 3.0 to 7.5.

[0008] In an optional implementation, the value of A is 4.9 to 12; and / or, the value of N is 5.2 to 6.2.

[0009] In an optional embodiment, the seed crystal synthesis stage has at least one of the following characteristics: Feature 1: ω is 3r / s~4.5r / s; Feature 2: T is 40℃~48℃; Feature 3: t is 2.5h~3.0h; Feature 4: C is 1.8 mol / L~2.3 mol / L; Feature 5: Q is 50L~100L; Feature 6: C0 is 0.4 mol / L to 1.2 mol / L; Feature 7: V0 is 50L~100L.

[0010] In an optional embodiment, the average particle size of the cobalt carbonate seeds obtained after seed synthesis is 3.5 μm to 4.2 μm; And / or, the particle size distribution value of the cobalt carbonate seed crystals obtained after the seed crystal synthesis is ≤0.86, preferably ≤0.8.

[0011] In an optional embodiment, the crystal nuclei are grown at a pH of 7.0 to 8.0 and a temperature of 40°C to 45°C.

[0012] In an optional embodiment, the average particle size of the cobalt carbonate particles obtained after the crystal nucleation is 15 μm to 20 μm, preferably 16 μm to 17 μm; And / or, the particle size distribution value of the cobalt carbonate particles obtained after the crystal nucleation is completed is ≤0.4, preferably 0.30~0.33.

[0013] Secondly, the present invention provides a cobalt carbonate product, which is prepared by any of the preparation methods described in the foregoing embodiments.

[0014] Thirdly, the present invention provides cobalt tetroxide, which is prepared from the cobalt carbonate product of the aforementioned embodiments.

[0015] Fourthly, the present invention provides a lithium cobalt oxide, which is synthesized from cobalt tetroxide as described in the foregoing embodiments.

[0016] Fifthly, the present invention provides a battery in which the active material comprises lithium cobalt oxide as described in the foregoing embodiments.

[0017] The beneficial effects of this invention include: This invention creatively constructs a dual-index model capable of controlling the kinetics and thermodynamics of the crystallization process, namely, an agglomeration suppression index A and a nucleation driving index N. This dual-index model integrates the previously disparate process parameters of the seed crystal synthesis stage into two comprehensive control indicators with clear physicochemical significance. By coordinating and controlling the specific values ​​of the A and N indices within an optimal window, the crystallization process can be precisely regulated from both kinetic and thermodynamic dimensions, ensuring that the system maintains a moderate and stable supersaturation environment throughout the entire seed crystal synthesis stage. Under this environment, the nucleation process proceeds continuously, smoothly, and synchronously, thereby achieving the instantaneous and uniform formation of a large number of crystal nuclei at the microscale and subsequent uniform growth. The resulting seed crystals exhibit excellent monodispersity. Using these as templates for epitaxial growth, cobalt carbonate products with high sphericity, narrow particle size distribution, and regular morphology can be obtained efficiently and stably, improving product consistency and leading to downstream products with superior performance. Attached Figure Description

[0018] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a SEM image of the cobalt carbonate seeds obtained in the seed synthesis stage of Example 1; Figure 2 SEM image of cobalt carbonate seeds obtained in the seed synthesis stage of Comparative Example 1; Figure 3 The image shows a SEM image of the cobalt carbonate seed crystals obtained during the seed crystal synthesis stage in Comparative Example 2. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased commercially.

[0021] The cobalt carbonate product, its preparation method, and its applications provided by this invention will be described in detail below.

[0022] The method for preparing cobalt carbonate provided by the present invention includes the following steps: adding either ammonium bicarbonate solution or ammonium carbonate solution and cobalt salt solution to the base solution to synthesize crystal seeds, followed by crystal nucleus growth; The inhibition index for agglomeration in the seed crystal synthesis stage is A, and the nucleation driving index is N. The value of A is 3~21.5, and the value of N is 3~7.5. Where, A=(ω 2 ×T×t) / (C×Q), N=[(45-|T-45|)×C0×V0] / (C×Q×t); ω is the stirring speed for seed crystal synthesis, in r / s; T is the reaction temperature for seed crystal synthesis, in ℃; t is the feeding time of the cobalt salt solution, in h; C is the concentration of the cobalt salt solution, in mol / L; Q is the volume of the cobalt salt solution added, in L; C0 is the concentration of ammonium bicarbonate or ammonium carbonate in the base solution, in mol / L; V0 is the volume of the base solution, in L.

[0023] In some optional embodiments, the value of A can be 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, or 21.5, or other values ​​within the range of 3 to 21.5. In some more typical embodiments, the value of A can be 4.5 to 15; in some even more typical embodiments, the value of A can be 4.9 to 12.

[0024] In some alternative implementations, the value of N can be 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, or 7.5, or other values ​​within the range of 3 to 7.5. In some more typical implementations, the value of N can be 3.0 to 7.5; in some even more typical implementations, the value of N can be 5.2 to 6.2.

[0025] It should be noted that in traditional processes, parameters such as stirring speed, synthesis temperature, and cobalt salt solution concentration involved in the seed crystal synthesis stage are independently controlled. This invention creatively proposes that the quality of seed crystal formation is fundamentally subject to the dynamic balance between two competing processes: suppressing agglomeration and driving nucleation. Therefore, this invention creatively constructs a dual-index model capable of controlling the kinetics and thermodynamics of the crystallization process, namely, the agglomeration suppression index A and the nucleation driving index N. The agglomeration suppression index A is used to quantify the balance between the shear dispersion capability of the mechanical stirring input and the solid phase generation load of the system; the nucleation driving index N is used to quantify the effective reaction driving force after temperature window correction. Furthermore, the aforementioned kinetic balance can only be achieved when the values ​​of both the agglomeration suppression index A and the nucleation driving index N are within their respective specific ranges, thereby stably obtaining seed crystals with excellent monodispersity.

[0026] Specifically, the numerator of the anti-agglomeration index A represents the total effective shear impulse related to the stirring shear force. The introduction of the temperature term objectively reflects the correction of the system viscosity and mixing efficiency by temperature. The denominator represents the total amount of cobalt ions participating in the reaction, i.e., the solid phase load that needs to be dispersed. Therefore, the physical meaning of the value of A is the temperature-corrected shear intensity obtained per unit reactant, which can characterize the competition between dispersion and agglomeration. When the value of A is too low (less than 3), it indicates that the dispersion motive force is insufficient to overcome the agglomeration tendency between particles; when the value of A is too high (greater than 21.5), it means that the shear is too intense, which easily produces a large number of metastable microcrystal nuclei, whose extremely high specific surface area and surface energy can induce secondary agglomeration.

[0027] The nucleation driving index N is constructed considering the thermodynamic and kinetic coupling effects of the reaction. Its numerator introduces a temperature efficiency factor centered at 45°C, which cleverly characterizes the dual influence of reaction temperature on the nucleation process: on the one hand, increased temperature enhances molecular kinetic energy and the reaction rate constant; on the other hand, excessively high temperatures accelerate the decomposition of ammonium bicarbonate or ammonium carbonate, leading to a decrease in the effective reactant concentration. The formula for calculating the nucleation driving index N allows it to reflect the "net" nucleation driving force, rather than simply the concentration or temperature effect. The denominator of the nucleation driving index N combines the total reactant amount and the feeding time, reflecting the time-averaged rate of reactant supply. Therefore, the value of N directly represents the effective reactant molar ratio per unit time after optimization of the temperature window, i.e., the net nucleation driving force. By controlling the value of N within a reasonable range, it is possible to effectively avoid slow nucleation and Ostwald ripening caused by insufficient driving force (e.g., N less than 3), while preventing explosive, non-uniform nucleation caused by excessive driving force (e.g., N greater than 7.5).

[0028] In some optional embodiments, ω can be 3r / s to 4.5r / s, such as 3r / s, 3.5r / s, 4r / s, or 4.5r / s, or other values ​​within the range of 3r / s to 4.5r / s. If ω is less than 3r / s, it is not conducive to the uniform dispersion of reactants. After the cobalt salt solution is added, it cannot mix rapidly with the base liquid, resulting in excessively high local supersaturation and triggering explosive non-uniform nucleation. At the same time, insufficient shear force cannot effectively suppress the agglomeration tendency of the formed crystal nuclei, resulting in a wide particle size distribution and irregular morphology of the final product. If ω is greater than 4.5r / s, the shear force is too strong, which easily breaks the crystal nuclei into excessively fine microcrystals. These microcrystals have a large specific surface area and high surface energy, which exacerbates the secondary agglomeration between particles. At the same time, excessively strong turbulence may interfere with the orderly growth of crystal nuclei, resulting in a wider particle size distribution. In some more typical embodiments, ω can be 3r / s to 4r / s.

[0029] In some optional embodiments, T can be 40℃~48℃, such as 40℃, 42℃, 45℃, or 48℃, or other values ​​within the range of 40℃~48℃. If T is less than 40℃, it is not conducive to the establishment of nucleation driving force. When the temperature is too low, the molecular kinetic energy is insufficient, the reaction rate is slow, the nucleation process is delayed, resulting in fewer crystal nuclei, larger sizes, and easy Ostwald ripening, which widens the particle size distribution. If T is greater than 48℃, it is not conducive to maintaining the effective nucleation driving force. When the temperature is too high, the decomposition of ammonium bicarbonate is intensified, the effective carbonate concentration decreases, and the net nucleation driving force decreases; at the same time, the excessively high reaction rate may lead to explosive nucleation, asynchronous crystal nucleus formation, and uneven morphology and dispersed particle size of the final product. In some more typical embodiments, T can be 44℃~48℃.

[0030] In some optional embodiments, t can be 2.5h to 3h, such as 2.5h, 2.7h, or 3h, or other values ​​within the range of 2.5h to 3h. If t is shorter than 2.5h, it is not conducive to the gradual control of supersaturation. Too short a feeding time means that the cobalt salt solution is injected rapidly, causing a sudden spike in local cobalt ion concentration, a sharp increase in supersaturation, triggering explosive and uneven nucleation, resulting in an excessive number of crystal nuclei that form asynchronously, ultimately leading to a wider particle size distribution. If t is longer than 3h, it is not conducive to maintaining the nucleation driving force. Too long a feeding time leads to a low reactant supply rate, the system remains in a low supersaturation state for a long time, insufficient nucleation motive force, a small number of crystal nuclei generated, and the formed crystal nuclei are prone to Ostwald ripening, with small particles dissolving and large particles growing, also resulting in a wider particle size distribution. In some more typical embodiments, t can be 2.5h to 2.6h.

[0031] In some optional embodiments, C can be 1.8 mol / L to 2.3 mol / L, such as 1.8 mol / L, 2 mol / L, or 2.3 mol / L, or other values ​​within the range of 1.8 mol / L to 2.3 mol / L. If C is less than 1.8 mol / L, it is not conducive to the establishment of effective nucleation driving force. When the cobalt salt concentration is too low, the number of cobalt ions per unit volume is insufficient, resulting in low supersaturation when reacting with the underlying ammonium bicarbonate or ammonium carbonate solution, insufficient nucleation motive force, few crystal nuclei generated, and easy Ostwald ripening, leading to larger seed crystal size and wider particle size distribution. If C is greater than 2.3 mol / L, it is not conducive to the gradual control of supersaturation. When the cobalt salt concentration is too high, the local supersaturation increases sharply at the moment of contact between cobalt ions and carbonate ions, triggering explosive non-uniform nucleation, asynchronous crystal nuclei formation, and at the same time, the viscosity of the high-concentration system increases, making mixing and dispersion more difficult, easily causing agglomeration, and the final product has irregular morphology and wide particle size distribution. In some typical implementations, C can be 2.0 mol / L to 2.1 mol / L.

[0032] In some optional implementations, Q can be 50L~100L, such as 50L, 60L, 70L, 80L, 90L, or 100L, or other values ​​within the range of 50L~100L. If Q is less than 50L, it is not conducive to the stable control of the reaction system. When the volume of the cobalt salt solution is too small, the total amount of reactants is insufficient, the number of seed crystals generated is small, and the concentration fluctuates greatly during the feeding process. The system has weak buffering capacity and is easily affected by local disturbances, making it difficult to form a uniform and sufficient crystal nucleus group. If Q is greater than 100L, it is not conducive to maintaining the mixing and dispersion efficiency. When the volume of the cobalt salt solution is too large, the ratio with the bottom liquid volume is unbalanced, the total volume of the reaction system exceeds the effective range of stirring, the mixing uniformity decreases, and supersaturation accumulation easily occurs in local areas, leading to uneven nucleation.

[0033] In some optional embodiments, CO can be 0.4 mol / L to 1.2 mol / L, such as 0.4 mol / L, 0.5 mol / L, 0.6 mol / L, 0.8 mol / L, 1 mol / L, 1.1 mol / L, or 1.2 mol / L, or other values ​​within the range of 0.4 mol / L to 1.2 mol / L. If CO is less than 0.4 mol / L, it is not conducive to the effective establishment of nucleation driving force. When the concentration of the base solution is too low, the total amount of carbonate provided by ammonium bicarbonate or ammonium carbonate is insufficient, resulting in low supersaturation when reacting with cobalt salt, insufficient nucleation motive force, few crystal nuclei generated and slow formation, easy Ostwald ripening, leading to larger seed crystal size and wider grain size distribution; if CO is greater than 1.2 mol / L, it is not conducive to the gradual control of supersaturation. When the base solution concentration is too high, the initial carbonate concentration is too large, and the local supersaturation increases sharply upon the addition of cobalt salt, triggering explosive and heterogeneous nucleation. Simultaneously, the high concentration of the base solution may exacerbate the decomposition side reactions of ammonium bicarbonate or ammonium carbonate, affecting the stability of the reaction system and ultimately leading to asynchronous crystal nucleus formation and irregular product morphology. In some typical embodiments, CO can be 0.6 mol / L to 0.8 mol / L.

[0034] In some optional embodiments, V0 can be 50L~100L, such as 50L, 60L, 70L, 80L, 90L, or 100L, or other values ​​within the range of 50L~100L. If V0 is less than 50L, it is not conducive to the buffering and stability of the reaction system. If the bottom liquid volume is too small, the dilution buffering capacity for the added cobalt salt is insufficient, the local concentration of cobalt ions rises sharply at the moment of injection, and the supersaturation is difficult to control smoothly, which easily leads to explosive and uneven nucleation; at the same time, if the bottom liquid volume is too small, the stirring blades cannot be fully wetted, the mixing effect decreases, and it affects the uniform formation of crystal nuclei; if V0 is greater than 100L, it is not conducive to maintaining the mixing and dispersion efficiency. If the bottom liquid volume is too large, the ratio of the bottom liquid volume to the cobalt salt solution volume is unbalanced, the effective reaction volume in the reactor exceeds the optimal range of stirring, the local uneven mixing is easy to form a concentration gradient; at the same time, the excessive bottom liquid volume will dilute the reactant concentration, reduce the nucleation driving force, resulting in insufficient crystal nuclei and affecting the particle size distribution of the final product.

[0035] In some optional embodiments, the average particle size of the cobalt carbonate seeds obtained after seed synthesis is 3.5 μm to 4.2 μm, such as 3.5 μm, 3.7 μm, 4.0 μm or 4.2 μm, or other values ​​in the range of 3.5 μm to 4.2 μm.

[0036] In some optional embodiments, the particle size distribution value of the cobalt carbonate seed crystals obtained after seed crystal synthesis is ≤0.86. In some more typical embodiments, the particle size distribution value of the cobalt carbonate seed crystals obtained after seed crystal synthesis is ≤0.8, such as 0.74~0.78.

[0037] Building upon the above, the dual-exponential model provided by this invention integrates the previously fragmented process parameters of the seed crystal synthesis stage into two comprehensive control indicators with clear physicochemical significance, thereby elevating seed crystal preparation from an empirical operation to a predictable and reproducible scientific process. By synergistically controlling the values ​​of the A-index and N-index within an optimal window, the crystallization process can be precisely regulated from both kinetic and thermodynamic dimensions, ensuring that the system maintains a moderate and stable supersaturation environment throughout the entire seed crystal synthesis stage. Under this environment, the nucleation process proceeds continuously, smoothly, and synchronously, achieving the instantaneous and uniform formation of a large number of crystal nuclei at the microscale and subsequent uniform growth. The resulting seed crystals exhibit excellent monodispersity. Using these as templates for epitaxial growth, cobalt carbonate products with high sphericity, narrow particle size distribution, and regular morphology can be obtained efficiently and stably, improving product consistency. Therefore, this invention, through the dual-exponential synergistic control model, solves the technical bottlenecks in cobalt carbonate synthesis caused by uncontrollable seed crystal preparation and large fluctuations in product morphology and particle size distribution.

[0038] Furthermore, in this invention, crystal nucleus growth can be carried out under conditions of pH 7.0~8.0 and temperature 35℃~45℃.

[0039] The pH value for crystal nucleus growth can be 7.0, 7.2, 7.5, 7.8, or 8.0, or other values ​​within the range of 7.0 to 8.0. The pH value for crystal nucleus growth can be stably controlled by adjusting the flow rate of the ammonium bicarbonate solution.

[0040] The temperature for crystal nucleus growth can be 35℃, 38℃, 40℃, 42℃ or 45℃, or other values ​​within the range of 35℃ to 45℃.

[0041] During the crystal growth process, once the reactor is full, the concentrator is turned on to concentrate the growth, filter out the mother liquor, and continue to react in the reactor to finally obtain cobalt carbonate particles.

[0042] In some optional embodiments, the average particle size of the cobalt carbonate particles obtained after nucleation growth can be 15 μm to 20 μm, such as 15 μm, 16 μm, 17 μm, 18 μm, 19 μm, or 20 μm, or other values ​​within the range of 15 μm to 20 μm. In some more typical embodiments, the average particle size of the cobalt carbonate particles obtained after nucleation growth can be 16 μm to 17 μm.

[0043] In some optional embodiments, the particle size distribution span of the cobalt carbonate particles obtained after nucleation growth is ≤0.4. In some more typical embodiments, the particle size distribution span of the cobalt carbonate particles obtained after nucleation growth is 0.30~0.33.

[0044] Furthermore, the cobalt carbonate particles obtained after the crystal nucleus growth is completed are washed and dried.

[0045] The washing process can be carried out using pure water, and can be repeated 3 to 5 times.

[0046] Drying can be carried out at 100℃~120℃ (e.g., 100℃, 110℃ or 120℃) for 8h~12h (e.g., 8h, 10h or 12h).

[0047] Accordingly, the present invention provides a cobalt carbonate product, which is prepared by the above-described preparation method.

[0048] In addition, the present invention also provides cobalt tetroxide, which is prepared from the above-mentioned cobalt carbonate product.

[0049] In some alternative embodiments, cobalt tetroxide can be obtained by calcining cobalt carbonate products.

[0050] In addition, the present invention also provides a lithium cobalt oxide, which is synthesized from the above-mentioned cobalt tetroxide.

[0051] In some alternative implementations, lithium cobalt oxide can be synthesized from cobalt tetroxide and a lithium source.

[0052] In addition, the present invention also provides a battery in which the active material includes the aforementioned lithium cobalt oxide.

[0053] The features and performance of the present invention will be further described in detail below with reference to embodiments.

[0054] Example 1 This embodiment provides a cobalt carbonate product, the preparation method of which includes: S1: Seed Synthesis Stage A 70L solution of 0.6mol / L ammonium bicarbonate was added to a 600L reactor as a base solution. The reactor temperature was controlled at 44℃, and the stirring speed was set to 3r / s. After the temperature stabilized, a cobalt salt solution and supplementary ammonium bicarbonate solution were added simultaneously. The cobalt salt solution was cobalt chloride solution, with a total volume of 70L, a concentration of 2.0mol / L, and a feeding time of 2.5h. The total molar amount of supplementary ammonium bicarbonate was 2.2 times the molar amount of cobalt salt. After the reaction, cobalt carbonate seed crystals with an average particle size of approximately 3.8μm and a particle size distribution Span value of 0.74 were obtained.

[0055] S2: Crystal nucleus growth stage (i.e., seed epitaxial growth stage) The pH of the seed slurry obtained above was adjusted to 7.5 by adjusting the flow rate of ammonium bicarbonate solution, and the reaction temperature was controlled at 40℃. After the reactor was full, the thickener was turned on for concentrated growth. Part of the mother liquor was filtered out, and the concentrated slurry continued to react, finally obtaining spherical cobalt carbonate particles with an average particle size of about 16μm and a particle size distribution Span value of 0.30.

[0056] S3: Post-processing stage The obtained cobalt carbonate particles were washed four times with pure water and dried at 110°C for 10 hours to obtain battery-grade spherical cobalt carbonate product.

[0057] Example 2 This embodiment provides a cobalt carbonate product, the preparation method of which includes: S1: Seed Synthesis Stage An 80L solution of 0.8mol / L ammonium bicarbonate was added to a 600L reactor as a base solution. The reactor temperature was controlled at 48℃, and the stirring speed was set to 4r / s. After the temperature stabilized, a cobalt salt solution and supplementary ammonium bicarbonate solution were added simultaneously. The cobalt salt solution was cobalt chloride solution, with a total volume of 80L, a concentration of 2.1mol / L, and a feeding time of 2.6h. The total molar amount of supplementary ammonium bicarbonate was 2.3 times the molar amount of cobalt salt. After the reaction, cobalt carbonate seed crystals with an average particle size of approximately 4.1μm and a particle size distribution Span value of 0.78 were obtained.

[0058] S2: Same as S2 in Example 1, spherical cobalt carbonate particles with an average particle size of about 17 μm and a particle size distribution Span value of 0.30 were finally obtained.

[0059] S3: Same as S3 in Example 1.

[0060] Example 3 This embodiment provides a cobalt carbonate product, the preparation method of which includes: S1: Seed Synthesis Stage A 50L solution of 0.6mol / L ammonium bicarbonate was added to a 600L reactor as a base solution. The reactor temperature was controlled at 44℃, and the stirring speed was set to 3r / s. After the temperature stabilized, a cobalt salt solution and supplementary ammonium bicarbonate solution were added simultaneously. The cobalt salt solution was cobalt chloride solution, with a total volume of 50L, a concentration of 2.0mol / L, and a feeding time of 2.5h. The total molar amount of supplementary ammonium bicarbonate was 2.2 times the molar amount of cobalt salt. After the reaction, cobalt carbonate seed crystals with an average particle size of approximately 3.9μm and a particle size distribution Span value of 0.76 were obtained.

[0061] S2: Same as S2 in Example 1.

[0062] S3: Same as S3 in Example 1.

[0063] Example 4 This embodiment provides a cobalt carbonate product, the preparation method of which includes: S1: Seed Synthesis Stage 100 L of a 0.6 mol / L ammonium bicarbonate solution was added to a 600 L reactor as the base solution. The reactor temperature was controlled at 44 °C, and the stirring speed was set to 3 r / s. After the temperature stabilized, the cobalt salt solution and the replenished ammonium bicarbonate solution were added simultaneously. The cobalt salt solution was a cobalt chloride solution, with a total volume of 100 L, a concentration of 2.0 mol / L, and a feeding time of 2.5 h. The total molar amount of the replenished ammonium bicarbonate was 2.2 times the molar amount of the cobalt salt. After the reaction, cobalt carbonate seed crystals with an average particle size of approximately 4.0 μm and a particle size distribution Span value of 0.78 were obtained.

[0064] S2: Same as S2 in Example 1.

[0065] S3: Same as S3 in Example 1.

[0066] Example 5 This embodiment provides a cobalt carbonate product, the preparation method of which includes: S1: Seed Synthesis Stage 70 L of a 0.6 mol / L ammonium bicarbonate solution was added to a 600 L reactor as the base solution. The reactor temperature was controlled at 45 °C, and the stirring speed was set to 4.5 r / s. After the temperature stabilized, the cobalt salt solution and supplementary ammonium bicarbonate solution were added simultaneously. The cobalt salt solution was a cobalt chloride solution, with a total volume of 60 L, a concentration of 1.8 mol / L, and a feeding time of 2.5 h. The total molar amount of supplementary ammonium bicarbonate was 2.2 times the molar amount of cobalt salt. After the reaction, cobalt carbonate seed crystals with an average particle size of approximately 3.5 μm and a particle size distribution Span value of 0.84 were obtained.

[0067] S2: Same as S2 in Example 1.

[0068] S3: Same as S3 in Example 1.

[0069] Example 6 This embodiment provides a cobalt carbonate product, the preparation method of which includes: S1: Seed Synthesis Stage 70 L of a 0.7 mol / L ammonium bicarbonate solution was added to a 600 L reactor as the base solution. The reactor temperature was controlled at 40 °C, and the stirring speed was set to 3 r / s. After the temperature stabilized, the cobalt salt solution and supplementary ammonium bicarbonate solution were added simultaneously. The cobalt salt solution was a cobalt chloride solution, with a total volume of 80 L, a concentration of 2.5 mol / L, and a feeding time of 3.0 h. The total molar amount of supplementary ammonium bicarbonate was 2.2 times the molar amount of cobalt salt. After the reaction, cobalt carbonate seed crystals with an average particle size of approximately 4.2 μm and a particle size distribution Span value of 0.86 were obtained.

[0070] S2: Same as S2 in Example 1.

[0071] S3: Same as S3 in Example 1.

[0072] Example 7 This embodiment provides a cobalt carbonate product, the preparation method of which includes: S1: Seed Synthesis Stage 80 L of a 0.9 mol / L ammonium bicarbonate solution was added to a 600 L reactor as the base solution. The reactor temperature was controlled at 48 °C, and the stirring speed was set to 3 r / s. After the temperature stabilized, the cobalt salt solution and supplementary ammonium bicarbonate solution were added simultaneously. The cobalt salt solution was a cobalt chloride solution, with a total volume of 80 L, a concentration of 2.2 mol / L, and a feeding time of 2.5 h. The total molar amount of supplementary ammonium bicarbonate was 2.2 times the molar amount of cobalt salt. After the reaction, cobalt carbonate seed crystals with an average particle size of approximately 3.7 μm and a particle size distribution Span value of 0.81 were obtained.

[0073] S2: Same as S2 in Example 1.

[0074] S3: Same as S3 in Example 1.

[0075] Example 8 This embodiment provides a cobalt carbonate product, the preparation method of which includes: S1: Seed Synthesis Stage A 70L solution of 0.4mol / L ammonium bicarbonate was added to a 600L reactor as a base solution. The reactor temperature was controlled at 44℃, and the stirring speed was set to 3r / s. After the temperature stabilized, a cobalt salt solution and supplementary ammonium bicarbonate solution were added simultaneously. The cobalt salt solution was cobalt chloride solution, with a total volume of 70L, a concentration of 1.8mol / L, and a feeding time of 2.5h. The total molar amount of supplementary ammonium bicarbonate was 2.2 times the molar amount of cobalt salt. After the reaction, cobalt carbonate seed crystals with an average particle size of approximately 3.6μm and a particle size distribution Span value of 0.83 were obtained.

[0076] S2: Same as S2 in Example 1.

[0077] S3: Same as S3 in Example 1.

[0078] Example 9 This embodiment provides a cobalt carbonate product, the preparation method of which includes: S1: Seed Synthesis Stage An 80L solution of 1.2mol / L ammonium bicarbonate was added to a 600L reactor as a base solution. The reactor temperature was controlled at 48℃, and the stirring speed was set to 3r / s. After the temperature stabilized, a cobalt salt solution and supplementary ammonium bicarbonate solution were added simultaneously. The cobalt salt solution was cobalt chloride solution, with a total volume of 80L, a concentration of 2.3mol / L, and a feeding time of 3.0h. The total molar amount of supplementary ammonium bicarbonate was 2.2 times the molar amount of cobalt salt. After the reaction, cobalt carbonate seed crystals with an average particle size of approximately 4.2μm and a particle size distribution Span value of 0.85 were obtained.

[0079] S2: Same as S2 in Example 1.

[0080] S3: Same as S3 in Example 1.

[0081] Comparative Example 1 This comparative example provides a cobalt carbonate product, the preparation method of which includes: S1: Seed Synthesis Stage 100 L of a 0.1 mol / L ammonium bicarbonate solution was added to a 600 L reactor as the base solution. The reactor temperature was controlled at 50 °C, and the stirring speed was set to 1 r / s. After the temperature stabilized, the cobalt salt solution and the replenished ammonium bicarbonate solution were added simultaneously. The cobalt salt solution was a cobalt chloride solution, with a total volume of 100 L, a concentration of 2.2 mol / L, and a feeding time of 3.0 h. The total molar amount of ammonium bicarbonate added was 2.0 times the molar amount of cobalt salt. After the reaction, cobalt carbonate seed crystals with an average particle size of approximately 5.0 μm and a particle size distribution Span value of 1.02 were obtained.

[0082] S2: Same as S2 in Example 1.

[0083] S3: Same as S3 in Example 1.

[0084] Comparative Example 2 This comparative example provides a cobalt carbonate product, the preparation method of which includes: S1: Seed Synthesis Stage 50 L of a 1.5 mol / L ammonium bicarbonate solution was added to a 600 L reactor as the base solution. The reactor temperature was controlled at 35 °C, and the stirring speed was set to 8 r / s. After the temperature stabilized, the cobalt salt solution and supplementary ammonium bicarbonate solution were added simultaneously. The cobalt salt solution was a cobalt chloride solution, with a total volume of 50 L, a concentration of 1.5 mol / L, and a feeding time of 2.1 h. The total molar amount of supplementary ammonium bicarbonate was 2.5 times the molar amount of cobalt salt. After the reaction, cobalt carbonate seed crystals with an average particle size of approximately 2.5 μm and a particle size distribution Span value of 0.95 were obtained.

[0085] S2: Same as S2 in Example 1.

[0086] S3: Same as S3 in Example 1.

[0087] Comparative Example 3 This comparative example provides a cobalt carbonate product, the preparation method of which includes: S1: Seed Synthesis Stage A 70L solution of 0.4mol / L ammonium bicarbonate was added to a 600L reactor as a base solution. The reactor temperature was controlled at 38℃, and the stirring speed was set to 3r / s. After the temperature stabilized, a cobalt salt solution and supplementary ammonium bicarbonate solution were added simultaneously. The cobalt salt solution was cobalt chloride solution, with a total volume of 70L, a concentration of 2.2mol / L, and a feeding time of 3.0h. The total molar amount of supplementary ammonium bicarbonate was 2.0 times the molar amount of cobalt salt. After the reaction, cobalt carbonate seed crystals with an average particle size of approximately 4.5μm and a particle size distribution Span value of 0.96 were obtained.

[0088] S2: Same as S2 in Example 1.

[0089] S3: Same as S3 in Example 1.

[0090] Comparative Example 4 This comparative example provides a cobalt carbonate product, the preparation method of which includes: S1: Seed Synthesis Stage An 80L solution of 1.2mol / L ammonium bicarbonate was added to a 600L reactor as a base solution. The reactor temperature was controlled at 52℃, and the stirring speed was set to 3r / s. After the temperature stabilized, a cobalt salt solution and supplementary ammonium bicarbonate solution were added simultaneously. The cobalt salt solution was cobalt chloride solution, with a total volume of 80L, a concentration of 2.0mol / L, and a feeding time of 2.5h. The total molar amount of supplementary ammonium bicarbonate was 2.2 times the molar amount of cobalt salt. After the reaction, cobalt carbonate seed crystals with an average particle size of approximately 3.3μm and a particle size distribution Span value of 0.98 were obtained.

[0091] S2: Same as S2 in Example 1.

[0092] S3: Same as S3 in Example 1.

[0093] Comparative Example 5 This comparative example provides a cobalt carbonate product, the preparation method of which includes: S1: Seed Synthesis Stage A 70L solution of 0.6mol / L ammonium bicarbonate was added to a 600L reactor as a base solution. The reactor temperature was controlled at 44℃, and the stirring speed was set to 1.5r / s. After the temperature stabilized, a cobalt salt solution and supplementary ammonium bicarbonate solution were added simultaneously. The cobalt salt solution was cobalt chloride solution, with a total volume of 70L, a concentration of 2.0mol / L, and a feeding time of 2.5h. The total molar amount of supplementary ammonium bicarbonate was 2.2 times the molar amount of cobalt salt. After the reaction, cobalt carbonate seed crystals with an average particle size of approximately 4.8μm and a particle size distribution Span value of 0.97 were obtained.

[0094] S2: Same as S2 in Example 1.

[0095] S3: Same as S3 in Example 1.

[0096] Comparative Example 6 This comparative example provides a cobalt carbonate product, the preparation method of which includes: S1: Seed Synthesis Stage 70 L of a 0.5 mol / L ammonium bicarbonate solution was added to a 600 L reactor as the base solution. The reactor temperature was controlled at 48 °C, and the stirring speed was set to 5.5 r / s. After the temperature stabilized, the cobalt salt solution and supplementary ammonium bicarbonate solution were added simultaneously. The cobalt salt solution was a cobalt chloride solution, with a total volume of 60 L, a concentration of 2.0 mol / L, and a feeding time of 2.2 h. The total molar amount of supplementary ammonium bicarbonate was 2.2 times the molar amount of cobalt salt. After the reaction, cobalt carbonate seed crystals with an average particle size of approximately 2.8 μm and a particle size distribution Span value of 0.94 were obtained.

[0097] S2: Same as S2 in Example 1.

[0098] S3: Same as S3 in Example 1.

[0099] Test case The morphology and size of the seed crystals and cobalt carbonate particles obtained in Examples 1-9 and Comparative Examples 1-6 were compared, and the results are shown in Table 1. Figures 1 to 3 As shown.

[0100] The morphology was observed using a scanning electron microscope; the average particle size was obtained by Malvern 3000 testing; and the span value was calculated according to the formula (D90-D10) / D50.

[0101] Table 1 Comparison Results

[0102] As can be seen from Table 1: Compared with Example 1 (e.g.) Figure 1Compared to the example shown), the values ​​of A and N in Comparative Example 1 are much lower than 3, resulting in insufficient dispersion ability and nucleation driving force, making it impossible to achieve uniform nucleation (as shown). Figure 2 (as shown) Compared to Example 1, the value of A in Comparative Example 2 is much higher than 21.5, and the value of N is much higher than 7.5, indicating that excessive shearing and excessively strong reaction kinetics disrupted the nucleation-dispersion balance, leading to seed agglomeration (e.g., Figure 3 (As shown).

[0103] Furthermore, in Examples 1-9, A and N both satisfy the range of A being 3-21.5 and N being 3-7.5, respectively, resulting in superior morphology and size of the obtained seed crystals and cobalt carbonate particles; while in Comparative Examples 3-6, at least one of A and N does not satisfy the range of A being 3-21.5 and N being 3-7.5, resulting in inferior morphology and size of the obtained seed crystals and cobalt carbonate particles.

[0104] The results of the above embodiments and comparative examples fully demonstrate that the present invention, by synergistically controlling the agglomeration inhibition index A and the nucleation driving index N within a specific range, is a necessary and sufficient condition for obtaining uniform, high-quality cobalt carbonate seed crystals. Deviation from this control range will directly lead to a deterioration in product performance.

[0105] In summary, by controlling the agglomeration inhibition index A to 3~21.5 and the nucleation driving index N to 3~7.5 during the seed synthesis stage, this invention ensures that the system maintains a moderate and stable supersaturation environment throughout the entire seed synthesis stage. This allows the nucleation process to proceed continuously, smoothly, and synchronously, resulting in seed crystals with excellent monodispersity. Using these seed crystals as templates for epitaxial growth, cobalt carbonate products with high sphericity, narrow particle size distribution, regular morphology, and good product consistency can be obtained efficiently and stably, leading to downstream products with superior performance.

[0106] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing cobalt carbonate, characterized in that, Includes the following steps: Seed crystals were synthesized by adding either ammonium bicarbonate solution or ammonium carbonate solution and cobalt salt solution to the substrate, followed by nucleus growth. The inhibition index for agglomeration in the seed crystal synthesis stage is A, and the nucleation driving index is N. The value of A is 3~21.5, and the value of N is 3~7.

5. Where, A=(ω 2 ×T×t) / (C×Q), N=[(45-|T-45|)×C0×V0] / (C×Q×t); ω is the stirring speed for seed crystal synthesis, in r / s; T is the reaction temperature for seed crystal synthesis, in ℃; t is the feeding time of the cobalt salt solution, in h; C is the concentration of the cobalt salt solution, in mol / L; Q is the volume of the cobalt salt solution added, in L; C0 is the concentration of ammonium bicarbonate or ammonium carbonate in the base solution, in mol / L; V0 is the volume of the base solution, in L.

2. The preparation method according to claim 1, characterized in that, The value of A is 4.5 to 15; and / or, the value of N is 3.0 to 7.5; Preferably, the value of A is 4.9 to 12; and / or, the value of N is 5.2 to 6.

2.

3. The preparation method according to claim 1 or 2, characterized in that, The seed crystal synthesis stage has at least one of the following characteristics: Feature 1: ω is 3r / s~4.5r / s; Feature 2: T is 40℃~48℃; Feature 3: t is 2.5h~3.0h; Feature 4: C is 1.8 mol / L~2.3 mol / L; Feature 5: Q is 50L~100L; Feature 6: C0 is 0.4 mol / L to 1.2 mol / L; Feature 7: V0 is 50L~100L.

4. The preparation method according to claim 1, characterized in that, The average particle size of the cobalt carbonate seeds obtained after seed synthesis was 3.5 μm to 4.2 μm. And / or, the particle size distribution value of the cobalt carbonate seed crystals obtained after the seed crystal synthesis is ≤0.86, preferably ≤0.

8.

5. The preparation method according to claim 1, characterized in that, Crystal nuclei were grown at a pH of 7.0–8.0 and a temperature of 35°C–45°C.

6. The preparation method according to claim 1, characterized in that, The average particle size of the cobalt carbonate particles obtained after the crystal nucleus growth is 15 μm to 20 μm, preferably 16 μm to 17 μm; And / or, the particle size distribution value of the cobalt carbonate particles obtained after the crystal nucleation is completed is ≤0.4, preferably 0.30~0.

33.

7. A cobalt carbonate product, characterized in that, It is prepared by the preparation method according to any one of claims 1 to 6.

8. A cobalt tetroxide, characterized in that, The cobalt tetroxide is prepared from the cobalt carbonate product according to claim 7.

9. A lithium cobalt oxide, characterized in that, The lithium cobalt oxide is synthesized from cobalt tetroxide as described in claim 8.

10. A battery, characterized in that, The active material in the battery includes lithium cobalt oxide as described in claim 9.

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