Cationic aluminum-doped basic cobalt carbonate hexagonal prism and preparation method thereof

Abstract

The present invention discloses a cationic aluminum-doped basic cobalt carbonate hexagonal prism and a preparation method thereof. The preparation method comprises injecting a mixed solution of cobalt salt and aluminum salt, a cation-containing salt solution, and a second precipitant solution into a first precipitant solution by continuous feeding to obtain a mixed system; the mixed system is continuously reacted, and when the product grows to a desired length, the cationic aluminum-doped basic cobalt carbonate hexagonal prism is collected to obtain the cationic aluminum-doped basic cobalt carbonate hexagonal prism. The present invention does not require the addition of additional complexing agents and surfactants for regulation, but instead uses cations to regulate the morphology of basic cobalt carbonate under continuous feeding, successfully preparing basic cobalt carbonate hexagonal prisms. The reaction process is simple, with few control conditions and few exogenous additives, resulting in a product with high purity and strong repeatability, which is very suitable for industrial large-scale production. At the same time, based on the unique structure of the cationic aluminum-doped basic cobalt carbonate hexagonal prism, it has great potential application value.

Description

Technical Field

[0001] The present invention relates to the technical field of basic cobalt carbonate, and in particular to a cationic aluminum-doped basic cobalt carbonate hexagonal prism and a preparation method thereof. Background Art

[0002] Basic cobalt carbonate is an important inorganic compound with broad application prospects in multiple fields, making it a research hotspot in materials science. Industrially, it is a key precursor for the preparation of cobalt oxides and cobalt powders. Cobalt oxides are widely used in lithium-ion battery electrode materials, improving battery charge and discharge performance and cycle life, meeting the high-performance battery demands of modern electronic devices and electric vehicles. For example, in some high-end lithium-ion batteries, cobalt oxide electrodes prepared using basic cobalt carbonate can significantly increase the battery's energy density. In the ceramics and glass industries, basic cobalt carbonate can be used as a colorant, imparting a distinctive blue or blue-green color to products, enhancing their aesthetics and artistic value. It is commonly used in the manufacture of decorative ceramics and colored glass. In petroleum processing, basic cobalt carbonate serves as a new, environmentally friendly catalyst that can replace traditional cobalt nitrate, reducing nitrogen oxide emissions and thus reducing environmental pollution.

[0003] The morphology of basic cobalt carbonate has a great influence on its performance. At the same time, the preparation of basic cobalt carbonate faces the problem that the morphology and size are difficult to control. There are also some methods for preparing basic cobalt carbonate with regular shapes. For example, CN112331853A discloses a method for preparing spherical basic cobalt carbonate, and CN112777646A discloses a method for preparing sea urchin-shaped basic cobalt carbonate, but these methods usually require the use of a chelating agent or surfactant to regulate the structure. In addition, CN113522326A discloses a method for preparing nickel-doped basic cobalt carbonate for catalysts, and successfully prepared nickel-doped basic cobalt carbonate with a median particle size of 18-25 μm and a petal-shaped morphology on the surface.

[0004] Currently, the structure of basic cobalt carbonate is relatively simple, usually in the form of flakes, spherical shapes, and sea urchins. Hexagonal basic cobalt carbonate has been reported. Because different morphologies and element doping can significantly affect the performance of basic cobalt carbonate, it is necessary to provide a method for preparing doped hexagonal basic cobalt carbonate. Summary of the Invention

[0005] The purpose of the present invention is to adjust the morphology of basic cobalt carbonate by introducing cations without adding external complexing agents and surfactants, and to introduce aluminum element for doping in order to improve the applicability of basic cobalt carbonate.

[0006] In order to achieve the above object, the present invention provides a method for preparing cationic aluminum-doped basic cobalt carbonate hexagonal prisms, comprising:

[0007] Injecting a mixed solution of cobalt salt and aluminum salt, a cation-containing salt solution, and a second precipitant solution into the first precipitant solution in a continuous feeding manner to obtain a mixed system;

[0008] The mixed system continues to react, and when the product grows to a desired length, cationic aluminum-doped basic cobalt carbonate hexagonal prisms are collected.

[0009] It should be noted that the present invention does not strictly limit the types of cobalt salts and aluminum salts. For example, the cobalt salt can be at least one of cobalt chloride hexahydrate, cobalt sulfate heptahydrate, and cobalt nitrate hexahydrate; the aluminum salt can be at least one of aluminum nitrate nonahydrate, anhydrous aluminum chloride, and aluminum sulfate 18hydrate. The solvents for the mixed solution of the cobalt salt and aluminum salt, the cationic salt solution, the first precipitant solution, and the second precipitant solution are also not strictly limited. For example, they can be at least one of water, ethanol, and acetone, and are preferably water.

[0010] Furthermore, the concentration of the cationic salt in the cationic salt solution is 0.5-0.8 g / L;

[0011] The cationic element in the cation-containing salt is at least one element of Group I. The type of the cation-containing salt is not strictly limited and can be a halide salt of a Group I element, preferably at least one of sodium chloride, potassium chloride, sodium bromide, potassium bromide, etc., with sodium chloride being most preferred.

[0012] Furthermore, the concentrations of the cobalt salt and the aluminum salt in the mixed solution of the cobalt salt and the aluminum salt are 110-130 g / L and 0.8-0.9 g / L, respectively.

[0013] Further, the concentrations of the second precipitant solution and the first precipitant solution are 220-240 g / L and 40-50 g / L, respectively;

[0014] The precipitant includes at least one of a soluble carbonate and a soluble bicarbonate. The precipitants dissolved in the first precipitant solution and the second precipitant solution may be the same or different. However, for convenience in removing impurities, the precipitants are preferably of the same type. The precipitant may be at least one of sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, ammonium bicarbonate, and the like.

[0015] Furthermore, the feed rates of the mixed solution of cobalt salt and aluminum salt, the cation-containing salt solution, and the second precipitant solution are 250-300 L / h, 20-50 L / h, and 450-550 L / h, respectively.

[0016] Furthermore, the mixed system continues to react at a rotation speed of 180-220 rpm, a temperature of 40-50° C., and a pH value of 7.1-7.6.

[0017] Further, the collecting includes washing and drying;

[0018] The washing reduces the concentration of impurity ions in the washing liquid to less than 20 ppm;

[0019] The drying is carried out at 100-130°C.

[0020] Furthermore, the volume of the first precipitant solution is 3-5m 3 .

[0021] The present invention also provides a cationic aluminum-doped basic cobalt carbonate hexagonal prism, which is obtained by the above-mentioned preparation method.

[0022] The present invention also provides the use of the above-mentioned cationic aluminum-doped basic cobalt carbonate hexagonal prisms in catalysis, adsorption, pigments and fillers, and lithium battery materials.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] This method eliminates the need for additional complexing agents and surfactants for control. Instead, it uses cations to manipulate the morphology of basic cobalt carbonate under continuous feeding, successfully preparing cationic aluminum-doped basic cobalt carbonate hexagonal prisms. The simple reaction process, with few control conditions and minimal exogenous additives, results in a high-purity, highly reproducible product, making it ideal for large-scale industrial production. Furthermore, the unique structure of the cationic aluminum-doped basic cobalt carbonate hexagonal prisms holds great potential for application. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0026] Figure 1 A flow chart showing the method for preparing cationic aluminum-doped basic cobalt carbonate hexagonal prisms of Example 1 is shown;

[0027] Figure 2 The XRD patterns of the products of Example 1, Comparative Example 1, and Comparative Example 2 are shown;

[0028] Figure 3 The scanning electron microscope image of the product prepared in Example 1 is shown;

[0029] Figure 4 The scanning electron microscope image of the product prepared in Comparative Example 1 is shown;

[0030] Figure 5The scanning electron microscope image of the product prepared in Comparative Example 2 is shown. DETAILED DESCRIPTION

[0031] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to form one or more new numerical ranges, and these numerical ranges should be considered to be specifically disclosed in the present invention.

[0032] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the specific embodiments of the present invention and the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0033] Example 1

[0034] like Figure 1 As shown, a method for preparing cationic aluminum-doped basic cobalt carbonate hexagonal prisms comprises the following steps:

[0035] S1. Add 3.8m³ of bottom water to the reactor, and then add ammonium bicarbonate to obtain a first precipitant solution with a concentration of 45g / L; dissolve cobalt chloride hexahydrate and anhydrous aluminum chloride in water to prepare a mixed solution of cobalt salt and aluminum salt with a cobalt salt concentration of 120g / L and an aluminum salt concentration of 0.85g / L; dissolve sodium chloride in water to prepare a sodium chloride solution with a concentration of 0.6g / L; dissolve ammonium bicarbonate in water to prepare a second precipitant solution with an ammonium bicarbonate concentration of 230g / L;

[0036] S2, continuously injecting the mixed solution of cobalt salt and aluminum salt, sodium chloride solution, and second precipitant solution into the reactor containing the first precipitant solution at feed rates of 270 L / h, 35 L / h, and 500 L / h, respectively, to obtain a mixed system;

[0037] S3. The mixed system is continuously reacted at a speed of 200 rpm, a temperature of 42° C., and a pH value of 6.9. When the product grows to the desired length, stirring is stopped, the slurry is filtered to obtain a slurry, and then filtered and washed with water until the concentration of chloride ions and sodium ions in the water is less than 20 ppm. The insoluble matter is transferred to 120° C. and dried to obtain cationic aluminum-doped basic cobalt carbonate hexagonal prisms.

[0038] Example 2

[0039] The process is basically the same as Example 1, except that cobalt nitrate hexahydrate is used instead of cobalt chloride hexahydrate in step S1.

[0040] Example 3

[0041] The process is basically the same as Example 1, except that aluminum nitrate nonahydrate is used instead of anhydrous aluminum chloride in step S1.

[0042] Example 4

[0043] The process is basically the same as Example 1, except that sodium bromide is used instead of sodium chloride in step S1.

[0044] Example 5

[0045] The process is basically the same as Example 1, except that potassium chloride is used instead of sodium chloride in step S1.

[0046] Comparative Example 1

[0047] A method for preparing aluminum-doped basic cobalt carbonate comprises the following steps:

[0048] S1. Add 3.8 m³ of bottom water to the reactor, and then add ammonium bicarbonate to obtain a first precipitant solution with a concentration of 45 g / L; dissolve cobalt chloride hexahydrate and anhydrous aluminum chloride in water to prepare a mixed solution of cobalt salt and aluminum salt with a cobalt salt concentration of 120 g / L and an aluminum salt concentration of 0.85 g / L; dissolve ammonium bicarbonate in water to prepare a second precipitant solution with an ammonium bicarbonate concentration of 230 g / L;

[0049] S2, continuously injecting the mixed solution of cobalt salt and aluminum salt and the second precipitant solution into the reactor containing the first precipitant solution at feed rates of 270 L / h and 500 L / h, respectively, to obtain a mixed system;

[0050] S3. The mixed system is continuously reacted at a speed of 200 rpm, a temperature of 42° C., and a pH value of 6.9. When the product grows to the desired length, stirring is stopped, and the slurry is filtered to obtain a slurry, which is then filter-pressed and washed with water until the concentrations of chloride ions and sodium ions in the water are less than 20 ppm. The insoluble matter is then transferred to 120° C. for drying to obtain aluminum-doped basic cobalt carbonate.

[0051] Comparative Example 2

[0052] A method for preparing aluminum-doped cobalt carbonate comprises the following steps:

[0053] S1. Add 3.8 m³ of bottom water to the reactor, and then add ammonium bicarbonate to obtain a first precipitant solution with a concentration of 45 g / L; dissolve cobalt chloride hexahydrate and anhydrous aluminum chloride in water to prepare a mixed solution of cobalt salt and aluminum salt with a cobalt salt concentration of 120 g / L and an aluminum salt concentration of 0.85 g / L; dissolve ammonium bicarbonate in water to prepare a second precipitant solution with an ammonium bicarbonate concentration of 230 g / L;

[0054] S2, continuously injecting the mixed solution of cobalt salt and aluminum salt and the second precipitant solution into the reactor containing the first precipitant solution at feed rates of 270 L / h and 500 L / h, respectively, to obtain a mixed system;

[0055] S3. The mixed system is continuously reacted at a speed of 200 rpm, a temperature of 42° C., and a pH value of 7.1. When the product grows to the desired length, stirring is stopped, and the slurry is filtered to obtain a slurry, which is then press-filtered and washed with water until the concentrations of chloride ions and sodium ions in the water are less than 20 ppm. The insoluble matter is then transferred to 120° C. for drying to obtain aluminum-doped cobalt carbonate.

[0056] Comparative Example 3

[0057] The method is basically the same as Example 1, except that in step S3, the mixed system is continuously reacted at a rotation speed of 200 rpm, a temperature of 42° C., and a pH value of 7.1. In this comparative example, cationic aluminum-doped cobalt carbonate hexagonal prisms are prepared.

[0058] Test Case

[0059] The crystal forms of the products prepared in the examples and comparative examples were observed using XRD, and the results were as follows: Figure 2 As shown. Comparing with the standard card, it can be seen that Example 1, Comparative Example 1, and Comparative Example 2 successfully prepared sodium-doped basic cobalt carbonate, basic cobalt carbonate, and cobalt carbonate, respectively. This shows that sodium ions are doped into the basic cobalt carbonate structure in Example 1; Comparative Example 1 and Comparative Example 2, in which sodium ions are not introduced, illustrate that the pH of the reaction system must be strictly controlled during the preparation process. The pH values ​​of Comparative Example 1 and Comparative Example 2 are 6.9 and 7.1, respectively, which have a great influence on the type of product. It should be noted that Figure 2 The absence of aluminum is due to the low doping level. The XRD results of Comparative Example 3 are not shown here. Compared with Example 1, a diffraction peak of cobalt carbonate also appears, which indicates that the pH of the reaction system needs to be strictly controlled to avoid the introduction of cobalt carbonate impurities.

[0060] The morphology of the products prepared in the examples and comparative examples was observed using a scanning electron microscope. Figure 3 As can be seen from the graph, Example 1 successfully prepared basic cobalt carbonate hexagonal prisms with a uniform length of 3 μm, with some agglomeration. Figure 4As can be seen from the figure, the basic cobalt carbonate hexagonal prisms prepared in Comparative Example 2, in which no sodium chloride was introduced during the preparation process, exhibited clusters of uneven blocks. Figure 5 As can be seen from the figure, the morphology of cobalt carbonate prepared by increasing the pH of the reaction system is a spherical shape composed of tiny nanosheets. These results show that the introduction of cations is a key factor in regulating the basic cobalt carbonate. Cations can change the orientation of basic cobalt carbonate crystals, thereby preparing basic cobalt carbonate hexagonal prisms.

[0061] The products of Examples 2-5 were also observed, and their structures also exhibited hexagonal prisms, demonstrating the applicability of the preparation method of the present invention. Comparative Example 3 also exhibited hexagonal prisms, but it was aluminum-doped cobalt carbonate, further demonstrating that the introduction of cations is a key factor in regulating the formation of hexagonal prisms in basic cobalt carbonate, while pH is a key factor in inhibiting the transformation of basic cobalt carbonate into cobalt carbonate.

[0062] In summary, the present invention eliminates the need for additional complexing agents and surfactants for control. Instead, it uses cations to regulate the morphology of basic cobalt carbonate under continuous feeding, successfully preparing cationic aluminum-doped basic cobalt carbonate hexagonal prisms. The simple reaction process, with few control conditions and minimal exogenous additives, results in a high-purity and highly reproducible product, making it ideal for large-scale industrial production. Furthermore, the unique structure of the cationic aluminum-doped basic cobalt carbonate hexagonal prisms holds great potential for application.

[0063] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for preparing cationic aluminum-doped basic cobalt carbonate hexagonal prisms, characterized in that: include, Injecting a mixed solution of cobalt salt and aluminum salt, a cation-containing salt solution, and a second precipitant solution into the first precipitant solution in a continuous feeding manner to obtain a mixed system; The mixed system continues to react until the product grows to a desired length, and then is collected to obtain cationic aluminum-doped basic cobalt carbonate hexagonal prisms; The concentration of the cationic salt in the cationic salt solution is 0.5-0.8 g / L; The cationic element in the cation-containing salt is at least one of the first main group elements; The concentrations of the cobalt salt and the aluminum salt in the mixed solution of the cobalt salt and the aluminum salt are 110-130 g / L and 0.8-0.9 g / L, respectively; The concentrations of the second precipitant solution and the first precipitant solution are 220-240 g / L and 40-50 g / L, respectively; wherein the precipitant in the second precipitant solution and the first precipitant solution comprises at least one of a soluble carbonate and a soluble bicarbonate; The feed rates of the mixed solution of cobalt salt and aluminum salt, the cation salt solution, and the second precipitant solution are 250-300 L / h, 20-50 L / h, and 450-550 L / h, respectively; The mixed system continues to react at a rotation speed of 180-220 rpm, a temperature of 40-50° C., and a pH value of 7.1-7.

6.

2. The method for preparing cationic aluminum-doped basic cobalt carbonate hexagonal prisms according to claim 1, wherein: Said collecting comprises washing and drying; The washing reduces the concentration of impurity ions in the washing liquid to less than 20 ppm; The drying is carried out at 100-130°C.

3. The method for preparing cationic aluminum-doped basic cobalt carbonate hexagonal prisms according to claim 1 or 2, characterized in that: The volume of the first precipitant solution is 3-5m 3 .

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