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

Abstract

The invention discloses a cationic aluminum-doped basic cobalt carbonate hexagonal prism and a preparation method thereof.The preparation method comprises the steps that a mixed solution of cobalt salt and aluminum salt, a cation-containing salt solution and a second precipitant solution are injected into a first precipitant solution in a continuous feeding mode, and a mixed system is obtained; and continuously reacting the mixed system, and collecting to obtain the cationic aluminum-doped basic cobalt carbonate hexagonal prism when the product grows to the required length. According to the method, additional complexing agents and surfactants do not need to be added for regulation, the morphology of the basic cobalt carbonate is regulated through cations under continuous feeding, the basic cobalt carbonate hexagonal prism is successfully prepared, the reaction process is simple, control conditions are few, exogenous additives are few, the product purity is high, repeatability is high, and the method is suitable for industrial production. The method is very suitable for industrial large-scale production. Meanwhile, based on the unique structure of the cationic aluminum-doped basic cobalt carbonate hexagonal prism, the cationic aluminum-doped basic cobalt carbonate hexagonal prism has very potential application value.

Description

Technical Field

[0001] The 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 many fields, making it one of the research hotspots in the field of materials science. In industry, it is a key precursor for the preparation of cobalt oxide and cobalt powder. Cobalt oxide is widely used in lithium-ion battery electrode materials, which can improve the battery's charge and discharge performance and cycle life, and meet the needs of modern electronic devices and electric vehicles for high-performance batteries. For example, in some high-end lithium-ion batteries, cobalt oxide electrodes prepared using basic cobalt carbonate can significantly improve the battery's energy density. In the ceramic and glass industries, basic cobalt carbonate can be used as a colorant to give the product a unique blue or blue-green color, enhance its aesthetics and artistic value, and is often used in the manufacture of decorative ceramics and colored glass. In petroleum processing, basic cobalt carbonate, as a new environmentally friendly catalyst, can replace traditional cobalt nitrate, reduce nitrogen oxide emissions, and thus reduce environmental pollution.

[0003] The morphology of basic cobalt carbonate has a great influence on its performance, and 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 shape, such as 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 chelating agents or surfactants to regulate the structure. In addition, CN113522326A discloses a method for preparing nickel-doped basic cobalt carbonate for catalysts, and successfully prepares nickel-doped basic cobalt carbonate with a median particle size of 18-25μm and a petal-shaped morphology on the surface.

[0004] At present, the structure of basic cobalt carbonate is relatively simple, usually in the form of flakes, spherical shapes and sea urchins, and hexagonal basic cobalt carbonate has been reported. Different morphologies and element doping will have a significant impact on the performance of basic cobalt carbonate, so it is necessary to provide a preparation method for 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 elements 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: 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, and when the product grows to a desired length, cationic aluminum-doped basic cobalt carbonate hexagonal prisms are obtained by collection.

[0007] It should be noted that the present invention does not need to 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, cobalt nitrate hexahydrate, etc.; the aluminum salt can be at least one of aluminum nitrate nonahydrate, anhydrous aluminum chloride, aluminum sulfate 18hydrate, etc. The solvents for the mixed solution of the cobalt salt and the aluminum salt, the cation salt solution, the first precipitant solution, and the second precipitant solution also do not need to be strictly limited. For example, they can be at least one of water, ethanol, acetone, etc., preferably water.

[0008] Further, 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 elements of the first main group. The type of the cation-containing salt does not need to be strictly limited, and can be a halide salt of the first main group element, preferably at least one of sodium chloride, potassium chloride, sodium bromide, potassium bromide, etc., and most preferably sodium chloride.

[0009] 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.

[0010] Further, 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 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 the convenience of removing impurities, the types of precipitants are preferably controlled to be the same, and the precipitant may be at least one of sodium carbonate, sodium bicarbonate, potassium carbonate, potassium bicarbonate, ammonium bicarbonate, etc.

[0011] 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.

[0012] Further, 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.

[0013] Further, the collecting includes 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.

[0014] Furthermore, the volume of the first precipitant solution is 3-5m 3 .

[0015] The present invention also provides a cationic aluminum-doped basic cobalt carbonate hexagonal prism, which is obtained by the above-mentioned preparation method.

[0016] The present invention also provides the use of the above-mentioned cationic aluminum-doped basic cobalt carbonate hexagonal prisms in catalysis, adsorption, color filler, and lithium battery materials.

[0017] Compared with the prior art, the present invention has the following beneficial effects: The present invention does not need to add additional complexing agents and surfactants for regulation, but uses cations to regulate the morphology of basic cobalt carbonate under continuous feeding, and successfully prepares cationic aluminum-doped basic cobalt carbonate hexagonal prisms. The reaction process is simple, with few control conditions and few exogenous additives, so that the product has high purity and strong repeatability, which is very suitable for industrial large-scale production. At the same time, based on the unique structure of cationic aluminum-doped basic cobalt carbonate hexagonal prisms, it has great potential application value. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. 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 creative work.

[0019] Figure 1 A flow chart showing the method for preparing cationic aluminum-doped basic cobalt carbonate hexagonal prisms of Example 1 is shown; Figure 2 The XRD patterns of the products of Example 1, Comparative Example 1 and Comparative Example 2 are shown; Figure 3 The scanning electron microscope image of the product prepared in Example 1 is shown; Figure 4 The scanning electron microscope image of the product prepared in Comparative Example 1 is shown; Figure 5 The scanning electron microscope image of the product prepared in Comparative Example 2 is shown. DETAILED DESCRIPTION

[0020] The endpoints and any values ​​of the ranges disclosed in the present invention 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 endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be regarded as specifically disclosed in the present invention.

[0021] The following will be combined with the specific embodiments of the present invention and the drawings of the specification to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments 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 creative work are within the scope of protection of the present invention.

[0022] Example 1 like Figure 1 As shown, a method for preparing cationic aluminum-doped basic cobalt carbonate hexagonal prisms comprises the following steps: 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; S2, continuously injecting the mixed solution of cobalt salt and aluminum salt, sodium chloride solution, and the 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; S3. The mixed system is continuously reacted at a rotation speed of 200 rpm, a temperature of 42° C., and a pH value of 6.9. When the product grows to a desired length, stirring is stopped, and 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. for drying to obtain cationic aluminum-doped basic cobalt carbonate hexagonal prisms.

[0023] Example 2 The method is basically the same as Example 1, except that cobalt nitrate hexahydrate is used instead of cobalt chloride hexahydrate in step S1.

[0024] Example 3 The method is basically the same as Example 1, except that aluminum nitrate nonahydrate is used in step S1 instead of anhydrous aluminum chloride.

[0025] Example 4 The method is basically the same as Example 1, except that sodium bromide is used instead of sodium chloride in step S1.

[0026] Example 5 The method is basically the same as Example 1, except that potassium chloride is used instead of sodium chloride in step S1.

[0027] Comparative Example 1 A method for preparing aluminum-doped basic cobalt carbonate comprises the following steps: 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 ammonium bicarbonate in water to prepare a second precipitant solution with an ammonium bicarbonate concentration of 230g / L; 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; S3. The mixed system is continuously reacted at a rotation speed of 200 rpm, a temperature of 42° C., and a pH value of 6.9. When the product grows to a desired length, stirring is stopped, and the slurry is filtered and then pressed 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. for drying to obtain aluminum-doped basic cobalt carbonate.

[0028] Comparative Example 2 A method for preparing aluminum-doped cobalt carbonate comprises the following steps: 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 ammonium bicarbonate in water to prepare a second precipitant solution with an ammonium bicarbonate concentration of 230g / L; 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; 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. When the product grows to a desired length, stirring is stopped, and the slurry is filtered to obtain a slurry, which is then pressed 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 then transferred to 120° C. for drying to obtain aluminum-doped cobalt carbonate.

[0029] Comparative Example 3 The method is basically the same as Example 1, except that in step 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. In this comparative example, cationic aluminum-doped cobalt carbonate hexagonal prisms are prepared.

[0030] Test Case The crystal forms of the products prepared in the examples and comparative examples were observed by XRD. Figure 2 As shown. By 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 without the introduction of sodium ions show 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 impact on the type of product. It should be noted that Figure 2 The aluminum element does not appear in the reaction mixture because the doping amount is low. The XRD results of Comparative Example 3 are not shown here. Compared with Example 1, the 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.

[0031] 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 figure, Example 1 successfully prepared basic cobalt carbonate hexagonal prisms with a uniform length of 3 μm, with some agglomeration. Figure 4 It can be seen that the basic cobalt carbonate hexagonal prisms prepared in Comparative Example 2, in which no sodium chloride was introduced during the preparation process, present a cluster of uneven blocks. Figure 5 It can be seen that the morphology of cobalt carbonate prepared by increasing the pH of the reaction system is a spherical shape formed by the accumulation of tiny nanosheets. These results show that the introduction of cations is a key factor in regulating basic cobalt carbonate. Cations can change the orientation of basic cobalt carbonate crystals, thereby preparing basic cobalt carbonate hexagonal prisms.

[0032] The products of Examples 2 to 5 were also observed, and the structures also showed hexagonal prisms, which illustrates the applicability of the preparation method of the present invention. Comparative Example 3 also showed hexagonal prisms, but it was aluminum-doped cobalt carbonate, which further showed that the introduction of cations was the key factor in regulating the formation of hexagonal prisms of basic cobalt carbonate, and the pH value was the key factor in inhibiting the transformation of basic cobalt carbonate into cobalt carbonate.

[0033] In summary, the present invention does not need to add additional complexing agents and surfactants for regulation, but uses cations to regulate the morphology of basic cobalt carbonate under continuous feeding, and successfully prepares cationic aluminum-doped basic cobalt carbonate hexagonal prisms. The reaction process is simple, the control conditions are few, and the exogenous additives are few, so that the product purity is high and the repeatability is strong, which is very suitable for industrial large-scale production. At the same time, based on the unique structure of cationic aluminum-doped basic cobalt carbonate hexagonal prisms, it has great potential application value.

[0034] 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, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to 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 protection scope 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, and when the product grows to a desired length, cationic aluminum-doped basic cobalt carbonate hexagonal prisms are obtained by collection.

2. The method for preparing cationic aluminum-doped basic cobalt carbonate hexagonal prisms according to claim 1, characterized in that: 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.

3. The method for preparing cationic aluminum-doped basic cobalt carbonate hexagonal prisms according to claim 1, characterized in that: 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.

4. The method for preparing cationic aluminum-doped basic cobalt carbonate hexagonal prisms according to claim 1, characterized in that: 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 includes at least one of a soluble carbonate and a soluble bicarbonate.

5. The method for preparing cationic aluminum-doped basic cobalt carbonate hexagonal prisms according to claim 1, characterized in that: 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.

6. The method for preparing cationic aluminum-doped basic cobalt carbonate hexagonal prisms according to claim 1, characterized in that: The mixed system continued 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.

7. The method for preparing cationic aluminum-doped basic cobalt carbonate hexagonal prisms according to claim 1, characterized in that: 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.

8. The method for preparing cationic aluminum-doped basic cobalt carbonate hexagonal prisms according to any one of claims 1 to 7, characterized in that: The volume of the first precipitant solution is 3-5m 3 .

9. A cationic aluminum-doped basic cobalt carbonate hexagonal prism, characterized in that: The method is obtained by the preparation method according to any one of claims 1 to 8.

10. Use of the cationic aluminum-doped basic cobalt carbonate hexagonal prisms as claimed in claim 9 in catalysis, adsorption, pigments and fillers, and lithium battery materials.

Images