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CN-122010188-A - Synthesis process of small-particle-size basic cobalt carbonate

CN122010188ACN 122010188 ACN122010188 ACN 122010188ACN-122010188-A

Abstract

The invention discloses a synthesis process of small-particle-size basic cobalt carbonate in the technical field of inorganic functional materials, which is characterized in that surface-engineered gadolinium doped cerium oxide nano particles are firstly prepared as an inorganic modifier, and the modifier is prepared through the steps of coprecipitation, hydrothermal treatment, surface phosphorylation, reduction heat treatment and the like. In the synthesis of basic cobalt carbonate, the modifier is dispersed in water to form suspension, then cobalt sulfate and sodium bicarbonate solution are added in parallel flow under mild temperature to carry out precipitation reaction, the nucleation and growth process is regulated and controlled by precisely controlling the pH value of a reaction system, and finally the final product is obtained through the post-treatment of regulating the pH value of an end point, aging, separating, washing and drying by the sodium carbonate solution. The invention realizes the high-yield preparation of the basic cobalt carbonate with fine particle size, good sphericity and high purity under mild conditions through the synergistic effect of the unique inorganic modifier and the double precipitants, has simple process and is easy for industrial production.

Inventors

  • WANG LINGYUN
  • WANG XIAOPEI
  • CHEN JIANFENG

Assignees

  • 怀化炯诚新材料科技有限公司

Dates

Publication Date
20260512
Application Date
20260209

Claims (10)

  1. 1. The synthesis process of the small-particle-size basic cobalt carbonate is characterized by comprising the following steps of: S1, adding 800-1200 parts of deionized water into a reaction kettle in parts by weight, heating to 28-32 ℃, adding 0.5-1.5 parts of surface-engineered gadolinium-doped cerium oxide nano particles, and stirring at 28-32 ℃ to obtain a suspension; S2, adding 220-240 parts of cobalt sulfate aqueous solution and 95-110 parts of sodium bicarbonate aqueous solution into the suspension, adjusting the pH to 7.7-7.9, and continuously stirring to obtain a mixed solution; S3, adding 10-25 parts of sodium carbonate aqueous solution into the mixed solution, adjusting the pH to 8.1-8.3, and aging at 28-32 ℃ to obtain slurry; S4, centrifugally separating the slurry to obtain a filter cake, washing the filter cake with deionized water at 60-70 ℃ to obtain a washed filter cake, drying the washed filter cake at 110-130 ℃, and finally carrying out jet milling and sieving.
  2. 2. The process for synthesizing basic cobalt carbonate having a small particle diameter according to claim 1, wherein in the step S1, the stirring time is 40 to 60 minutes at 28 to 32 ℃.
  3. 3. The process for synthesizing small-particle-size basic cobalt carbonate according to claim 1, wherein in step S2, the stirring is continued for 2 to 4 hours.
  4. 4. The process for synthesizing basic cobalt carbonate of small particle size according to claim 1, wherein in step S3, the aging time is 1.5 to 2 hours at 28 to 32 ℃.
  5. 5. The process for synthesizing small particle size basic cobalt carbonate according to claim 1, wherein in step S4, the washed cake is dried at 110 to 130 ℃ for 24 to 48 hours.
  6. 6. The process for synthesizing small particle size basic cobalt carbonate according to any one of claims 1 to 5, wherein the preparing step of the surface-engineered gadolinium doped cerium oxide nanoparticles comprises: Mixing 75-85 parts by weight of aqueous solution containing cerium nitrate hexahydrate and 8-12 parts by weight of aqueous solution containing gadolinium nitrate hexahydrate, stirring to obtain mixed salt solution, adding the mixed salt solution and 15-25 parts by weight of aqueous ammonia solution into 58-62 ℃ deionized water under the protection of nitrogen and stirring to obtain slurry, transferring the slurry to a high-pressure reaction kettle, carrying out hydrothermal reaction at 178-182 ℃ to obtain a reaction mixture, cooling the reaction mixture, centrifugally collecting precipitate, and washing the precipitate with deionized water to obtain gadolinium-doped cerium-based hydrated oxide wet filter cakes; a2, dispersing gadolinium doped cerium-based hydrous oxide wet filter cake in an aqueous solution containing 5-15 parts of sodium pyrophosphate, and stirring at 78-82 ℃ to obtain a mixture; a3, placing the washed solid product in a tube furnace, and heating to 495-505 ℃ under the reducing atmosphere of hydrogen/argon to preserve heat; and A4, grinding the calcined solid product, dispersing in an ammonia water-ammonium chloride buffer solution with the pH of 7.8-8.2, carrying out ultrasonic treatment, and carrying out spray drying.
  7. 7. The process for synthesizing small-particle size basic cobalt carbonate according to claim 6, wherein in the step A1, the hydrothermal reaction time is 36-40h at 178-182 ℃.
  8. 8. The process for synthesizing small-particle size basic cobalt carbonate according to claim 6, wherein in the step A2, the stirring time is 12-14 hours at 78-82 ℃.
  9. 9. The process for synthesizing small-particle-size basic cobalt carbonate according to claim 6, wherein in the step A3, the temperature is raised to 495-505 ℃ and the heat preservation time is 2-4h.
  10. 10. The process for synthesizing small-particle-size basic cobalt carbonate according to claim 6, wherein in the step A4, the time of the ultrasonic treatment is 1-2 hours.

Description

Synthesis process of small-particle-size basic cobalt carbonate Technical Field The invention relates to the technical field of inorganic functional materials, in particular to a synthesis process of small-particle-size basic cobalt carbonate. Background Basic cobalt carbonate is used as an important inorganic cobalt salt and is a key precursor for preparing cobalt-based functional materials such as high-performance tricobalt tetraoxide, lithium cobaltate and the like. The physical and chemical properties, especially the particle size, distribution uniformity and microscopic morphology of the particles, directly determine the core indexes such as tap density, specific surface area, electrochemical performance and the like of the subsequently obtained functional material. Therefore, in various fields such as new energy batteries, high-end ceramic pigments, catalysts and the like, the market demand for basic cobalt carbonate products with small particle size, narrow distribution and regular morphology is increasing. The traditional basic cobalt carbonate preparation process generally adopts a direct double decomposition reaction of soluble cobalt salt (such as cobalt chloride and cobalt sulfate) and precipitants such as sodium carbonate or sodium bicarbonate. To control the product particle size, conventional technical routes often require slowing down the precipitation rate by forming intermediate complexes with the aid of organic complexing agents (e.g. ammonia, citrate) or complex processes requiring high temperature and pressure conditions, such as hydrothermal, solvothermal, etc. Although the method can influence the product morphology to a certain extent, the method inevitably introduces impurity ions which are difficult to thoroughly remove, increases the cost and difficulty of subsequent purification, has relatively harsh process conditions and higher energy consumption, and is not beneficial to large-scale green industrial production. However, achieving controllable preparation of small particle size basic cobalt carbonates under mild conditions independent of organic complexing agents remains a significant challenge. The core difficulty is that the generation of crystal nucleus and the growth rate of crystal are difficult to effectively coordinate in the precipitation reaction process. If fine particles are to be obtained, a high supersaturation degree is required to promote the instantaneous formation of a large number of crystal nuclei, but too high a reaction rate is extremely liable to cause uneven local concentration, causing agglomeration of particles or too wide particle size distribution. In addition, to ensure recovery of cobalt resources, the reaction endpoint requires sufficient alkalinity to completely precipitate cobalt ions, but this in turn accelerates the ostwald ripening process of the crystallites, leading to dissolution of small particles and redeposition on large particles, thereby coarsening the particle size. Some existing improved precipitation methods, such as attempting to control the feed rate, adjusting the stirring intensity or adopting a dual precipitant strategy, simplify the process, but under the condition of completely discarding the complexing agent, the fine control capability on the nano-scale of primary grains is still obviously insufficient, and the uniformity and the batch stability of the product are often unsatisfactory. Aiming at the defects in the prior art, the invention aims to provide a small-particle-size basic cobalt carbonate synthesis solution which is strong in innovation, simple in process and environment-friendly. The core concept of the invention is to introduce a surface engineering inorganic modifier which is formed by doping specific rare earth elements and modifying the surface by surface functionalization. In the synthesis process, the modifier is not a reactant, but is used as a directional control center of the crystallization process. In a mild normal-temperature reaction system, the modifier can effectively adsorb metal ions through the unique surface physical and chemical properties, and provide rich heterogeneous nucleation sites, so that the nucleation density is obviously increased, and the uniform formation of initial crystal nuclei is guided. Meanwhile, combining with a precipitant adding strategy of step-by-step accurate control, firstly utilizing sodium bicarbonate to realize preliminary precipitation of cobalt ions and locking of crystal nucleus size in a weak alkaline environment, and then using sodium carbonate to carry out final-point pH value fine adjustment so as to ensure complete precipitation of cobalt ions. The synergistic mechanism ensures that the whole process can stably and efficiently prepare the basic cobalt carbonate product with fine primary particles, good secondary sphericity and high cobalt recovery rate under the simple conditions of no need of any organic complexing agent and only conventional stirring and