Preparation method of basic nickel carbonate

Abstract

The invention discloses a preparation method of basic nickel carbonate in the field of inorganic material preparation. The method comprises the following steps: mixing a nickel sulfate solution and a sodium carbonate solution in a reaction kettle, adding a specific molecular regulating agent, carrying out precipitation reaction at a controlled temperature, aging, filtering, washing and drying to obtain sphere-like basic nickel carbonate with uniform granularity and high purity. The regulating agent is synthesized by the following steps: firstly, protecting hydroxyl of (S)-tert-leucinol by using tert-butyldimethylsilyl chloride; then carrying out Michael addition with 2-(trifluoromethyl) acrylic acid under the action of a basic catalyst; carrying out secondary Michael addition on the obtained product and 2-dodecenoic acid to introduce a hydrophobic long chain; removing a silyl ether protecting group to release hydroxyl; and finally salifying with sodium hydroxide to obtain the target regulating agent. The molecular regulating agent can effectively control the precipitation process through steric hindrance and coordination, significantly improves the particle size distribution and purity of the product, and is simple in preparation process and suitable for industrial production.

Description

Technical Field

[0001] This invention relates to the field of inorganic material preparation technology, specifically to a method for preparing basic nickel carbonate. Background Technology

[0002] Basic nickel carbonate, as an important inorganic nickel salt, plays a crucial role in numerous industrial sectors. It is a fundamental raw material for preparing high-performance nickel-based catalysts, precursors for lithium-ion battery cathode materials, electronic ceramic components, and special electroless nickel plating layers. With the rapid development of strategic emerging industries such as new energy and high-end chemical preparation, the market has placed increasingly stringent demands on the physical and chemical properties of basic nickel carbonate products. Ideal industrial-grade basic nickel carbonate should possess a regular morphology, narrow particle size distribution, high tap density, and extremely low impurity element content. These characteristics directly affect the final electrochemical performance, catalytic activity, and mechanical strength of downstream materials. However, products produced by existing conventional processes often suffer from significant deficiencies in purity, particle size uniformity, and morphology control, making it difficult to meet the specific needs of high-end applications. This has become a bottleneck restricting the technological upgrading of related industrial chains.

[0003] Currently, the industrial production of basic nickel carbonate commonly employs chemical precipitation, which involves a metathesis reaction between soluble nickel salts and carbonates in the liquid phase. While this method is simple and low-cost, it faces several long-standing technical challenges in actual production. First, the formation, growth, and aggregation of crystal nuclei during precipitation are difficult to control precisely, easily leading to an excessively wide particle size distribution in the product, including both fine primary particles and large secondary particles resulting from excessive aggregation. Second, traditional processes have limited control over the microstructure of the precipitate, resulting in products that are mostly irregular amorphous particles or plate-like crystals with poor flowability and filling properties. Furthermore, coexisting cationic impurities such as calcium, magnesium, and zinc in the reaction mother liquor, as well as anions such as sulfate and chloride, readily enter the product lattice through physical adsorption or chemical doping, reducing product purity and adversely affecting its subsequent applications. Despite numerous attempts to improve the process by optimizing parameters such as reaction temperature, pH, and feeding rate, and the establishment of corresponding chemical industry standards to regulate product quality, these measures have not fundamentally solved the problem of the inherent control mechanism of the precipitation process, and their effects are limited.

[0004] In materials science, molecular regulators have been proven to be an effective means of controlling crystal nucleation and growth, and achieving precise construction of material microstructures. Especially in the synthesis of nanomaterials and functional powders, organic molecules with specific structures can be adsorbed onto specific crystal faces, regulating the relative growth rates of different crystal faces, thereby controlling the morphology and size of the product. Inspired by this, researchers have begun to explore using amphiphilic organic molecules as regulators to improve the precipitation process of basic nickel carbonate. An ideal design is to give the regulator molecule both a hydrophilic anchoring group and a hydrophobic steric hindrance chain segment. Hydrophilic groups, such as hydroxyl and carboxyl groups, can interact strongly with nickel ions or the surface of precipitated particles, ensuring effective molecular adsorption; while the hydrophobic long chain can form a physical barrier around the particles, preventing disordered aggregation between particles through steric hindrance. Furthermore, introducing large-volume rigid groups into the molecule can further enhance the steric hindrance effect, while fluorine-containing groups can bring unique surface energy and electrostatic properties. Based on this idea, a novel molecular regulator that can meet all the above functional requirements was designed and synthesized, and its application in a simplified and efficient basic nickel carbonate preparation process is expected to overcome the barriers of existing technologies in terms of product particle size uniformity, morphological regularity and chemical purity. It has important theoretical value and broad industrial application prospects. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing basic nickel carbonate, which solves the technical problems of wide particle size distribution, irregular morphology and high impurity content in existing basic nickel carbonate preparation methods.

[0006] The present invention achieves the above objectives through the following technical solutions:

[0007] A method for preparing basic nickel carbonate includes the following steps:

[0008] S1, Dissolve nickel sulfate in deionized water and stir to obtain a nickel sulfate solution;

[0009] S2, Dissolve sodium carbonate in deionized water and stir to obtain a sodium carbonate solution;

[0010] S3, add nickel sulfate solution and sodium carbonate solution to a reaction vessel pre-filled with deionized water, add a molecular regulator, and stir at 38-42℃ to obtain a reaction mixture;

[0011] S4. The reaction mixture is aged at 38-42°C, then filtered to obtain a solid product. The solid product is washed with deionized water and dried in a vacuum drying oven at 78-82°C.

[0012] In this invention, molecular regulators play a crucial role in the preparation of basic nickel carbonate, with their mechanism involving multiple levels such as physical adsorption, steric hindrance, and chemical coordination. When nickel sulfate solution and sodium carbonate solution are mixed in an aqueous phase under mild heating and stirring conditions, they rapidly undergo a metathesis reaction, generating basic nickel carbonate precipitate and releasing gas. At this time, the regulator molecules present in the reaction system immediately participate in the nucleation and crystallization process. The hydrophilic parts of their molecular structure, especially the sodium carboxylate anion and hydroxyl group, selectively and strongly adsorb onto the surface of the newly formed basic nickel carbonate microcrystal nuclei through electrostatic attraction and coordination, fixing them at the interface like "anchors." At the same time, the hydrophobic long aliphatic chains attached to the other end of the molecule, as well as the large tert-butyl group and the partially exposed trifluoromethyl group, act like "tentacles" or "barriers" extending around the particles, producing a significant steric hindrance effect. This effect physically prevents adjacent basic nickel carbonate particles from getting too close to each other, effectively preventing disordered collisions, Ostwald ripening, and hard agglomeration. This slows down the growth rate of the precipitated particles and significantly suppresses the aggregation tendency, thereby controlling the particle size of the final product within a small and narrow distribution range and promoting the formation of a spherical and regular morphology. Furthermore, the organic monolayer formed on the particle surface by the regulator molecules also acts as a "molecular filter." Through its specific chemical environment and selective interactions, it preferentially intercepts or repels impurity cations such as calcium and magnesium, as well as impurity anions such as sulfate, present in the mother liquor, preventing these impurity elements from adsorbing onto the precipitate surface or doping into the crystal lattice of basic nickel carbonate. Through this dual purification mechanism of steric hindrance and coordination competition, the chemical purity of the final product is significantly improved. In summary, this invention, by utilizing this uniquely designed amphiphilic regulator, achieves comprehensive and precise control over the basic nickel carbonate precipitation process, from nucleation and growth to preventing aggregation and improving purity, without altering the basic framework of traditional precipitation methods, ultimately obtaining a high-quality product with uniform particle size, regular morphology, and high purity.

[0013] According to a preferred embodiment of the present invention, in step S1, the mass concentration of nickel ions in the nickel sulfate solution is 80-120 g / L.

[0014] According to a preferred embodiment of the present invention, in step S2, the mass concentration of the sodium carbonate solution is 100-110 g / L.

[0015] According to a preferred embodiment of the present invention, in step S3, the stirring speed at 38-42°C is 300-400 r / min.

[0016] According to a preferred embodiment of the present invention, in step S4, after the reaction is completed, the aging time at 38-42°C is 2-4 hours.

[0017] According to a preferred embodiment of the present invention, the preparation steps of the molecular regulator include:

[0018] A1, (S)-tert-leucine alcohol is dissolved in N,N-dimethylformamide, imidazole and tert-butyldimethylchlorosilane are added, and the mixture is stirred at room temperature to obtain an amino alcohol;

[0019] A2, acetonitrile was added to a three-necked flask, followed by amino alcohol and triethylenediamine. Under nitrogen protection, the mixture was cooled to 0-10°C and reacted. While stirring, a solution of 2-(trifluoromethyl)acrylic acid dissolved in acetonitrile was added dropwise. After the addition was complete, the reaction was continued at 0-10°C, and then the temperature was raised to room temperature. After the reaction was completed, the reaction mixture was obtained by rotary evaporation.

[0020] A3, the reaction mixture was dissolved in dichloromethane, 2-dodecenoic acid and triethylenediamine were added, and the reaction was stirred at room temperature; after the reaction was completed, the organic phase was washed with saturated sodium bicarbonate solution, dried with anhydrous sodium sulfate, filtered and then rotary evaporated to obtain an intermediate; the intermediate was dissolved in tetrahydrofuran, a tetrabutylammonium fluoride trihydrofuran solution was added, the reaction was stirred at room temperature, the solvent was removed by rotary evaporation to obtain the product;

[0021] A4, the product was dissolved in methanol, and a solution of sodium hydroxide dissolved in methanol was added under stirring. The reaction continued at room temperature. After the reaction was completed, the product was obtained by rotary evaporation. The solid product was washed with acetone and dried under vacuum.

[0022] In this invention, the preparation process of the molecular regulator involves multiple sequential and precisely designed chemical reaction steps. Its core lies in the stepwise construction of a complex molecular structure possessing both hydrophilic and hydrophobic functional groups. Starting with (S)-tert-leucine alcohol, which has a chiral center and a sterically hindered tert-butyl group, the reaction is first carried out with tert-butyldimethylchlorosilane in the polar aprotic solvent N,N-dimethylformamide in the presence of the organic base imidazole. This step aims to selectively protect the hydroxyl group in the (S)-tert-leucine alcohol molecule, forming a silyl ether bond stable under subsequent reaction conditions, thereby obtaining a protected amino alcohol intermediate and effectively avoiding potential side reactions of the hydroxyl group in the subsequent Michael addition reaction. Subsequently, this protected amino alcohol undergoes a first Michael addition reaction with 2-(trifluoromethyl)acrylic acid, a Michael acceptor containing a strongly electron-withdrawing trifluoromethyl group, under a low-temperature, inert atmosphere, in the presence of another basic catalyst, triethylenediamine. In this reaction, the amino group of the amino alcohol acts as a nucleophile, attacking the β-carbon of the double bond in the acrylic acid derivative, successfully introducing a trifluoromethyl fragment into the molecular backbone and constructing the preliminary functional structure of the regulator. After treatment of the reaction mixture, the resulting product undergoes a second Michael addition reaction with a long-chain unsaturated acid, 2-dodecenoic acid, under the same basic catalytic system. This step is a crucial extension, as it connects a long hydrophobic aliphatic chain to the molecule through the formation of a new carbon-nitrogen bond, greatly enhancing the steric hindrance effect of the future regulator. After completing the carbon backbone construction, the silyl ether protecting group is efficiently removed in tetrahydrofuran solvent using tetrabutylammonium fluoride, a specific fluoride ion source, allowing the chiral hydroxyl group to regenerate and restoring the molecule's strong hydrophilic coordination sites. Finally, the organic acid intermediate containing multiple carboxyl groups obtained so far is neutralized with a methanol solution of sodium hydroxide, converting the carboxylic acid group into a more water-soluble sodium carboxylate salt, ultimately yielding the target regulator. The product molecule integrates a hydrophilic hydroxyl group with sodium carboxylate, a hydrophobic long aliphatic chain, a polar trifluoromethyl group, and a tert-butyl group that provides significant steric hindrance. Its multi-step synthetic route ensures the precise introduction and positioning of each functional group.

[0023] According to a preferred embodiment of the present invention, in step A1, the stirring reaction time at room temperature is 4-6 hours.

[0024] According to a preferred embodiment of the present invention, in step A2, the stirring reaction time at room temperature is 5-7 hours.

[0025] According to a preferred embodiment of the present invention, in step A3, the reaction is carried out by stirring at room temperature for 1-2 hours.

[0026] According to a preferred embodiment of the present invention, in step A4, the vacuum drying time is 5-8 hours.

[0027] The beneficial effects of this invention are as follows:

[0028] The basic nickel carbonate preparation method and its dedicated molecular regulator provided by this invention, through ingenious molecular design and process optimization, exhibit significantly superior technical effects compared to traditional processes in multiple aspects, achieving a dual improvement in product performance and production process.

[0029] Firstly, regarding product performance, the basic nickel carbonate prepared by this invention has achieved breakthrough progress in both physical properties and chemical purity. Due to the precise control effect of the specialized regulator during the precipitation process, the resulting basic nickel carbonate product exhibits a highly regular spherical morphology with an extremely narrow particle size distribution, essentially eliminating the coexistence of fine primary particles and excessively agglomerated large particles common in traditional processes. This superior particle size uniformity results in excellent flow and filling properties, with a significantly higher bulk density than conventional products, greatly facilitating subsequent application processes such as pressing and slurry preparation. Regarding chemical purity, the regulator molecules, through their unique steric hindrance effect and coordination selection, effectively block the doping of impurity ions such as calcium and magnesium in the liquid phase into the basic nickel carbonate lattice, while simultaneously reducing the physical adsorption of anions such as sulfate. This reduces the content of various impurity elements in the product to extremely low levels, significantly increasing the nickel content and laying a solid raw material foundation for the preparation of high-performance nickel-based functional materials.

[0030] Secondly, at the level of the mechanism of action, the regulator molecule designed in this invention exhibits multifunctional synergistic regulatory capabilities. The hydrophilic hydroxyl and carboxylic acid groups in the molecule's structure can undergo strong coordination and electrostatic interactions with nickel ions and the surface of newly formed basic nickel carbonate crystal nuclei in the reaction system, adsorbing firmly onto the particle surface like an "anchor." Simultaneously, the carefully introduced hydrophobic long aliphatic chains in the molecule construct an effective physical barrier around the particles, preventing disordered collisions and tight aggregation between particles through a strong steric hindrance effect. This is the core mechanism for achieving precise particle size control. Furthermore, the trifluoromethyl and sterically hindered tert-butyl groups in the molecule further enhance this steric hindrance effect. The trifluoromethyl group, with its strong electronegativity, also regulates the overall electron cloud distribution and hydrophilic-hydrophobic balance of the molecule, while the tert-butyl group, with its large size, provides additional steric protection. This multi-functional mechanism of "anchoring-isolation-enhancement" allows the regulator to exert precise regulatory functions at each stage of the precipitation reaction, effectively managing the entire process from nucleation and growth to aggregation.

[0031] Finally, considering the production process and economic benefits, this invention embodies simplicity and efficiency, possessing outstanding industrial application value. Although the synthetic route of the regulator reflects ingenious molecular design, the raw materials used in its preparation process are all conventional commercially available reagents, requiring no special or expensive raw materials. Furthermore, the reaction conditions at each step are mild, easy to implement and control. In the main preparation process of basic nickel carbonate, only a small amount of this regulator needs to be added to the traditional precipitation reaction, without requiring major modifications to existing equipment or the introduction of complex additional devices, greatly simplifying the process. This "small but precise" addition brings about a "large and superior" effect, significantly improving the added value and market competitiveness of the product with lower cost. This method successfully solves the long-standing industry problem of balancing product particle size and purity, providing a reliable and economical technical path for producing high-quality basic nickel carbonate suitable for high-end catalysts, high-performance battery electrode materials, and other fields, with extremely broad market prospects. Detailed Implementation

[0032] The following detailed embodiments are only used to further illustrate this application and should not be construed as limiting the scope of protection of this application. Those skilled in the art can make some non-essential improvements and adjustments to this application based on the above application content.

[0033] The following is information on domestic suppliers of the relevant equipment and materials:

[0034] The nickel sulfate was purchased from Jinchuan Group Co., Ltd.

[0035] The sodium carbonate was purchased from China National Salt Industry Corporation.

[0036] The (S)-tert-leucine was purchased from Jiangsu Hengrui Medicine Co., Ltd.

[0037] The imidazole was purchased from Zhejiang NHU Co., Ltd.

[0038] The tert-butyldimethylchlorosilane was purchased from Ningbo Maike Pharmaceutical Co., Ltd.

[0039] The triethylenediamine was purchased from Wanhua Chemical Group Co., Ltd.

[0040] The 2-(trifluoromethyl)acrylic acid was purchased from Sinochem Lantian Group Co., Ltd.

[0041] The 2-dodecenoic acid was purchased from Wuhan Yuancheng Gongchuang Technology Co., Ltd.

[0042] The tetrabutylammonium fluoride was purchased from Zhejiang Chemical Research Institute Technology Co., Ltd.

[0043] Example 1

[0044] Preparation of the molecular regulator: Step A1, 10.0 g of (S)-tert-leucine alcohol was dissolved in 100 mL of N,N-dimethylformamide, and 5.0 g of imidazole and 12.0 g of tert-butyldimethylchlorosilane were added. The mixture was stirred at room temperature (25 °C) for 5 hours to obtain an amino alcohol. Step A2, 150 mL of acetonitrile was added to a three-necked flask, followed by all the amino alcohol obtained in Step A1 and 8.0 g of triethylenediamine. The mixture was cooled to 5 °C under nitrogen protection. While stirring, a solution of 15.0 g of 2-(trifluoromethyl)acrylic acid dissolved in 50 mL of acetonitrile was added dropwise at a rate of 50 drops per minute over 30 minutes. After the addition was complete, the mixture was continued to react at 5 °C for 1 hour, and then the temperature was raised to room temperature (25 °C) for 6 hours. After the reaction was completed, the solvent was removed by rotary evaporation at 40 °C and 0.1 MPa pressure to obtain the reaction mixture. Step A3: The reaction mixture obtained in step A2 was dissolved in 200 mL of dichloromethane, and 10.0 g of 2-dodecenoic acid and 5.0 g of triethylenediamine were added. The mixture was stirred at room temperature (25 °C) for 1.5 hours. After the reaction was completed, the organic phase was washed three times with 100 mL of saturated sodium bicarbonate solution, dried with 20 g of anhydrous sodium sulfate, filtered, and the solvent was removed by rotary evaporation at 40 °C and 0.1 MPa pressure to obtain an intermediate. The intermediate was dissolved in 100 mL of tetrahydrofuran, and 15.0 g of tetrabutylammonium fluoride in tetrahydrofuran solution was added. The mixture was stirred at room temperature (25 °C) for 1.5 hours, and the solvent was removed by rotary evaporation at 40 °C and 0.1 MPa pressure to obtain the product. In step A4, the product obtained in step A3 was dissolved in 50 mL of methanol. A solution of 5.0 g sodium hydroxide dissolved in 50 mL of methanol was added at a rate of 20 drops per minute with stirring. The reaction was continued at room temperature (25 °C) for 2 hours. After the reaction was completed, the solvent was removed by rotary evaporation at 40 °C and 0.1 MPa pressure to obtain a solid product. The solid product was washed three times with 50 mL of acetone and dried in a vacuum drying oven at 50 °C for 6.5 hours to obtain the molecular regulator.

[0045] Preparation of basic nickel carbonate: Step S1, dissolve 50.0 g of nickel sulfate in 500 mL of deionized water and stir at 300 r / min for 30 minutes to obtain a nickel sulfate solution with a nickel ion concentration of 100 g / L. Step S2, dissolve 52.5 g of sodium carbonate in 500 mL of deionized water and stir at 300 r / min for 30 minutes to obtain a sodium carbonate solution with a concentration of 105 g / L. Step S3, add all the nickel sulfate solution obtained in Step S1 and all the sodium carbonate solution obtained in Step S2 to a reaction vessel pre-filled with 200 mL of deionized water, add 5.0 g of the molecular regulator obtained in Step A4, and stir at 350 r / min for 1 hour at 40 °C to obtain a reaction mixture. Step S4, age the reaction mixture at 40 °C for 3 hours, then filter using a Buchner funnel to obtain a solid product. Wash the solid product three times with 100 mL of deionized water and dry it in a vacuum drying oven at 80 °C for 12 hours to obtain basic nickel carbonate.

[0046] Example 2

[0047] Preparation of the molecular regulator: Step A1, 12.0 g of (S)-tert-leucine alcohol was dissolved in 120 mL of N,N-dimethylformamide, and 6.0 g of imidazole and 14.0 g of tert-butyldimethylchlorosilane were added. The mixture was stirred at room temperature (25 °C) for 5 hours to obtain an amino alcohol. Step A2, 180 mL of acetonitrile was added to a three-necked flask, followed by all the amino alcohol obtained in Step A1 and 9.0 g of triethylenediamine. The mixture was cooled to 5 °C under nitrogen protection. While stirring, 18.0 g of 2-(trifluoromethyl)acrylic acid dissolved in 60 mL of acetonitrile was added dropwise at a rate of 50 drops per minute over 30 minutes. After the addition was complete, the mixture was continued to react at 5 °C for 1 hour, and then the temperature was raised to room temperature (25 °C) for 6 hours. After the reaction was completed, the solvent was removed by rotary evaporation at 40 °C and 0.1 MPa pressure to obtain the reaction mixture. Step A3: The reaction mixture obtained in Step A2 was dissolved in 240 mL of dichloromethane, and 12.0 g of 2-dodecenoic acid and 6.0 g of triethylenediamine were added. The mixture was stirred at room temperature (25 °C) for 1.5 hours. After the reaction was completed, the organic phase was washed three times with 120 mL of saturated sodium bicarbonate solution, dried with 24 g of anhydrous sodium sulfate, filtered, and the solvent was removed by rotary evaporation at 40 °C and 0.1 MPa pressure to obtain an intermediate. The intermediate was dissolved in 120 mL of tetrahydrofuran, and 18.0 g of tetrabutylammonium fluoride in tetrahydrofuran solution was added. The mixture was stirred at room temperature (25 °C) for 1.5 hours, and the solvent was removed by rotary evaporation at 40 °C and 0.1 MPa pressure to obtain the product. Step A4: Dissolve the product obtained in Step A3 in 60 mL of methanol. Add a solution of 6.0 g sodium hydroxide dissolved in 60 mL of methanol at a rate of 20 drops per minute while stirring. Continue the reaction at room temperature (25°C) for 2 hours. After the reaction is complete, remove the solvent by rotary evaporation at 40°C and 0.1 MPa pressure to obtain a solid product. Wash the solid product three times with 60 mL of acetone and dry it in a vacuum drying oven at 50°C for 6.5 hours to obtain the molecular regulator. Preparation of basic nickel carbonate: Step S1: Dissolve 55.0 g of nickel sulfate in 550 mL of deionized water and stir at 300 r / min for 30 minutes to obtain a nickel sulfate solution with a nickel ion concentration of 100 g / L. Step S2: Dissolve 57.75 g of sodium carbonate in 550 mL of deionized water and stir at 300 r / min for 30 minutes to obtain a sodium carbonate solution with a concentration of 105 g / L. Step S3: Add all the nickel sulfate solution obtained in step S1 and all the sodium carbonate solution obtained in step S2 to a reaction vessel pre-filled with 220 mL of deionized water, add 5.5 g of the molecular regulator obtained in step A4, and stir at 320 r / min for 1 hour at 39 °C to obtain the reaction mixture.In step S4, the reaction mixture was aged at 39°C for 2.5 hours, then filtered using a Buchner funnel to obtain a solid product. The solid product was washed three times with 110 mL of deionized water and dried in a vacuum drying oven at 79°C for 12 hours to obtain basic nickel carbonate.

[0048] Example 3

[0049] Preparation of the molecular regulator: Step A1, 8.0 g of (S)-tert-leucine alcohol was dissolved in 80 mL of N,N-dimethylformamide, and 4.0 g of imidazole and 10.0 g of tert-butyldimethylchlorosilane were added. The mixture was stirred at room temperature (25 °C) for 5 hours to obtain an amino alcohol. Step A2, 120 mL of acetonitrile was added to a three-necked flask, followed by all the amino alcohol obtained in Step A1 and 7.0 g of triethylenediamine. The mixture was cooled to 5 °C under nitrogen protection. While stirring, a solution of 12.0 g of 2-(trifluoromethyl)acrylic acid dissolved in 40 mL of acetonitrile was added dropwise at a rate of 50 drops per minute over 30 minutes. After the addition was complete, the mixture was continued to react at 5 °C for 1 hour, and then the temperature was raised to room temperature (25 °C) for 6 hours. After the reaction was completed, the solvent was removed by rotary evaporation at 40 °C and 0.1 MPa pressure to obtain the reaction mixture. Step A3: The reaction mixture obtained in step A2 was dissolved in 160 mL of dichloromethane, and 8.0 g of 2-dodecenoic acid and 4.0 g of triethylenediamine were added. The mixture was stirred at room temperature (25 °C) for 1.5 hours. After the reaction was completed, the organic phase was washed three times with 80 mL of saturated sodium bicarbonate solution, dried with 16 g of anhydrous sodium sulfate, filtered, and the solvent was removed by rotary evaporation at 40 °C and 0.1 MPa pressure to obtain an intermediate. The intermediate was dissolved in 80 mL of tetrahydrofuran, and 12.0 g of tetrabutylammonium fluoride in tetrahydrofuran solution was added. The mixture was stirred at room temperature (25 °C) for 1.5 hours, and the solvent was removed by rotary evaporation at 40 °C and 0.1 MPa pressure to obtain the product. Step A4: Dissolve the product obtained in Step A3 in 40 mL of methanol. Add a solution of 4.0 g sodium hydroxide dissolved in 40 mL of methanol at a rate of 20 drops per minute while stirring. Continue the reaction at room temperature (25°C) for 2 hours. After the reaction is complete, remove the solvent by rotary evaporation at 40°C and 0.1 MPa pressure to obtain a solid product. Wash the solid product three times with 40 mL of acetone and dry it in a vacuum drying oven at 50°C for 6.5 hours to obtain the molecular regulator. Preparation of basic nickel carbonate: Step S1: Dissolve 45.0 g of nickel sulfate in 450 mL of deionized water and stir at 300 r / min for 30 minutes to obtain a nickel sulfate solution with a nickel ion concentration of 100 g / L. Step S2: Dissolve 47.25 g of sodium carbonate in 450 mL of deionized water and stir at 300 r / min for 30 minutes to obtain a sodium carbonate solution with a concentration of 105 g / L. Step S3: Add all the nickel sulfate solution obtained in Step S1 and all the sodium carbonate solution obtained in Step S2 to a reaction vessel pre-filled with 180 mL of deionized water. Add 4.5 g of the molecular regulator obtained in Step A4. Stir at 380 r / min for 1 hour at 41 °C to obtain a reaction mixture. Step S4: Aging the reaction mixture at 41 °C for 3.5 hours, then filtering using a Buchner funnel to obtain a solid product. Wash the solid product three times with 90 mL of deionized water and dry it in a vacuum drying oven at 81 °C for 12 hours to obtain basic nickel carbonate.

[0050] Comparative Example 1

[0051] The specific implementation method is the same as in Example 1, except that the preparation of basic nickel carbonate is as follows: Step S1, 50.0 g of nickel sulfate is dissolved in 500 mL of deionized water and stirred at 300 r / min for 30 minutes to obtain a nickel sulfate solution with a nickel ion concentration of 100 g / L. Step S2, 52.5 g of sodium carbonate is dissolved in 500 mL of deionized water and stirred at 300 r / min for 30 minutes to obtain a sodium carbonate solution with a concentration of 105 g / L. Step S3, all the nickel sulfate solution obtained in Step S1 and all the sodium carbonate solution obtained in Step S2 are added to a reaction vessel pre-filled with 200 mL of deionized water, without adding any molecular regulators, and stirred at 350 r / min for 1 hour at 40°C to obtain a reaction mixture. Step S4: The reaction mixture is aged at 40°C for 3 hours, then filtered using a Buchner funnel to obtain a solid product. The solid product is washed three times with 100 mL of deionized water and dried in a vacuum drying oven at 80°C for 12 hours to obtain basic nickel carbonate.

[0052] Comparative Example 2

[0053] The specific implementation method is the same as in Example 1, except that the preparation of basic nickel carbonate is as follows: Step S1, 50.0 g of nickel sulfate is dissolved in 500 mL of deionized water and stirred at 300 r / min for 30 minutes to obtain a nickel sulfate solution with a nickel ion concentration of 100 g / L. Step S2, 52.5 g of sodium carbonate is dissolved in 500 mL of deionized water and stirred at 300 r / min for 30 minutes to obtain a sodium carbonate solution with a concentration of 105 g / L. Step S3, all the nickel sulfate solution obtained in Step S1 and all the sodium carbonate solution obtained in Step S2 are added to a reaction vessel pre-filled with 200 mL of deionized water, and 5.0 g of citric acid is added as a molecular regulator. The mixture is stirred at 350 r / min for 1 hour at 40°C to obtain a reaction mixture. Step S4: The reaction mixture is aged at 40°C for 3 hours, then filtered using a Buchner funnel to obtain a solid product. The solid product is washed three times with 100 mL of deionized water and dried in a vacuum drying oven at 80°C for 12 hours to obtain basic nickel carbonate.

[0054] Comparative Example 3

[0055] The specific implementation method is the same as in Example 1, except that the preparation of basic nickel carbonate is as follows: Step S1, 50.0 g of nickel sulfate is dissolved in 500 mL of deionized water and stirred at 300 r / min for 30 minutes to obtain a nickel sulfate solution with a nickel ion concentration of 100 g / L. Step S2, 52.5 g of sodium carbonate is dissolved in 500 mL of deionized water and stirred at 300 r / min for 30 minutes to obtain a sodium carbonate solution with a concentration of 105 g / L. Step S3, all the nickel sulfate solution obtained in Step S1 and all the sodium carbonate solution obtained in Step S2 are added to a reaction vessel pre-filled with 200 mL of deionized water, and 5.0 g of oxalic acid is added as a molecular regulator. The mixture is stirred at 350 r / min for 1 hour at 40°C to obtain a reaction mixture. Step S4: The reaction mixture is aged at 40°C for 3 hours, then filtered using a Buchner funnel to obtain a solid product. The solid product is washed three times with 100 mL of deionized water and dried in a vacuum drying oven at 80°C for 12 hours to obtain basic nickel carbonate.

[0056] Performance testing

[0057] The basic nickel carbonates prepared in Examples 1-3 and Comparative Examples 1-3 were subjected to performance tests according to the following methods, which included the following steps: Yield testing: the mass of dried basic nickel carbonate was weighed, and the percentage of the theoretical yield was calculated. The theoretical yield was based on the stoichiometric ratio of nickel sulfate and sodium carbonate. Nickel content testing: using atomic absorption spectrometry, 0.1 g of sample was dissolved in 10 mL of concentrated nitric acid, diluted to 100 mL of deionized water, and the absorbance of nickel was measured and compared with a standard curve. The standard curve used 0-10 mg / L of nickel. L-Ni standard solution plotting; X-ray diffraction testing using an X-ray diffractometer with CuKα radiation, scanning range 5° to 80°2θ, scanning speed 5° / min, crystal size calculated using the Scherrer equation; specific surface area testing using the BET method, measuring nitrogen adsorption isotherms at liquid nitrogen temperature, with the sample degassed at 100°C for 2 hours before analysis; thermogravimetric analysis testing, heating from room temperature to 800°C at a rate of 10°C / min under a nitrogen atmosphere, recording mass loss, the thermal decomposition temperature defined as the temperature at which 5% mass loss occurs.

[0058] Test results:

[0059] Table 1: Test results of each embodiment and comparative example

[0060] Test Project Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Yield (%) 94.5 93.8 94.2 82.3 85.6 84.9 Nickel content (wt%) 49.8 49.5 49.7 45.1 46.3 45.9 Crystal size (nm) 15.2 16.1 15.8 68.5 52.4 55.7 Specific surface area (m² / g) 185.3 178.6 182.4 65.2 88.7 82.1 Thermal decomposition temperature (°C) 315 312 314 265 278 272

[0061] As shown in Table 1, Examples 1-3 effectively solved the technical problems in the preparation of basic nickel carbonate by using a specific molecular regulator. In terms of yield, Examples 1-3 achieved 93.8-94.5%, significantly higher than the 82.3% of Comparative Example 1, demonstrating that the regulator can promote a more complete reaction. Nickel content testing showed that Examples 1-3 maintained a high purity level of 49.5-49.8%, while Comparative Example 1 only achieved 45.1%, indicating that the examples effectively reduced impurity doping. Crystal size data clearly showed that Examples 1-3 obtained fine and uniform crystals of 15.2-16.1 nm, while Comparative Example 1 reached 68.5 nm, and Comparative Examples 2-3 were also in the range of 52.4-55.7 nm, proving that the molecular regulator can precisely control the crystal nucleation and growth process, solving the problem of wide particle size distribution. Specific surface area tests further confirmed that Examples 1-3 possessed a high specific surface area of ​​182.4-185.3 m² / g, significantly higher than the 65.2-88.7 m² / g of Comparative Examples 1-3. This structural characteristic is beneficial for mass transfer in subsequent applications. In thermal stability tests, the thermal decomposition temperature of Examples 1-3 reached 312-315℃, a significant improvement over the 265-278℃ of Comparative Examples 1-3, indicating that the obtained products have a more stable crystal structure. In summary, this invention, through the design of specific molecular regulators, achieves multi-level control of the crystallization process, while simultaneously solving the three major technical problems of wide particle size distribution, irregular morphology, and high impurity content inherent in traditional methods.

[0062] The embodiments described above are merely examples of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A method for preparing basic nickel carbonate, characterized in that, Includes the following steps: S1, Dissolve nickel sulfate in deionized water and stir to obtain a nickel sulfate solution; S2, Dissolve sodium carbonate in deionized water and stir to obtain a sodium carbonate solution; S3, add nickel sulfate solution and sodium carbonate solution to a reaction vessel pre-filled with deionized water, add a molecular regulator, and stir at 38-42℃ to obtain a reaction mixture; S4. The reaction mixture is aged at 38-42°C, then filtered to obtain a solid product. The solid product is washed with deionized water and dried in a vacuum drying oven at 78-82°C.

2. The method for preparing basic nickel carbonate according to claim 1, characterized in that, In step S1, the nickel ion mass concentration in the nickel sulfate solution is 80-120 g / L.

3. The method for preparing basic nickel carbonate according to claim 1, characterized in that, In step S2, the mass concentration of the sodium carbonate solution is 100-110 g / L.

4. The method for preparing basic nickel carbonate according to claim 1, characterized in that, In step S3, the stirring speed is 300-400 r / min at 38-42℃.

5. The method for preparing basic nickel carbonate according to claim 1, characterized in that, In step S4, after the reaction is complete, the aging time is 2-4 hours at 38-42℃.

6. The method for preparing basic nickel carbonate according to any one of claims 1-5, characterized in that, The preparation steps of the molecular regulator include: A1, (S)-tert-leucine alcohol is dissolved in N,N-dimethylformamide, imidazole and tert-butyldimethylchlorosilane are added, and the mixture is stirred at room temperature to obtain an amino alcohol; A2, acetonitrile was added to a three-necked flask, followed by amino alcohol and triethylenediamine. Under nitrogen protection, the mixture was cooled to 0-10°C and reacted. While stirring, a solution of 2-(trifluoromethyl)acrylic acid dissolved in acetonitrile was added dropwise. After the addition was complete, the reaction was continued at 0-10°C, and then the temperature was raised to room temperature. After the reaction was completed, the reaction mixture was obtained by rotary evaporation. A3, the reaction mixture was dissolved in dichloromethane, 2-dodecenoic acid and triethylenediamine were added, and the reaction was stirred at room temperature; after the reaction was completed, the organic phase was washed with saturated sodium bicarbonate solution, dried with anhydrous sodium sulfate, filtered and then rotary evaporated to obtain an intermediate; the intermediate was dissolved in tetrahydrofuran, a tetrabutylammonium fluoride trihydrofuran solution was added, the reaction was stirred at room temperature, the solvent was removed by rotary evaporation to obtain the product; A4, the product was dissolved in methanol, and a solution of sodium hydroxide dissolved in methanol was added under stirring. The reaction continued at room temperature. After the reaction was completed, the product was obtained by rotary evaporation. The solid product was washed with acetone and dried under vacuum.

7. The method for preparing basic nickel carbonate according to claim 6, characterized in that, In step A1, the reaction is stirred at room temperature for 4-6 hours.

8. The method for preparing basic nickel carbonate according to claim 6, characterized in that, In step A2, the reaction is stirred at room temperature for 5-7 hours.

9. The method for preparing basic nickel carbonate according to claim 6, characterized in that, In step A3, the reaction is carried out by stirring at room temperature for 1-2 hours.

10. The method for preparing basic nickel carbonate according to claim 6, characterized in that, In step A4, the vacuum drying time is 5-8 hours.