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CN-117776238-B - Preparation method of spherical alumina powder with good dispersibility

CN117776238BCN 117776238 BCN117776238 BCN 117776238BCN-117776238-B

Abstract

A process for preparing the spherical alumina powder with high dispersivity includes such steps as dissolving aluminium nitrate nonahydrate and ammonium sulfate in deionized water, sequentially adding sodium hydroxide, polysiloxane-polyester sulfonate disperser and urea, stirring to obtain reaction solution, heating while stirring, filtering, washing, drying to obtain spherical alumina precursor, calcining, and cooling. The spherical alumina prepared by the method has smooth surface, good dispersibility, controllable particle diameter D50 of about 1-8 microns, easy acquisition of required raw materials, simple process, low requirements on production equipment and easy industrialization.

Inventors

  • Zou Haoying
  • PAN SHIJIAN
  • LI JIAHAO
  • LIU JIELI

Assignees

  • 广东金戈新材料股份有限公司

Dates

Publication Date
20260508
Application Date
20231226

Claims (8)

  1. 1. The preparation method of the spherical alumina powder with good dispersibility is characterized by comprising the following steps: (1) Aluminum nitrate nonahydrate and ammonium sulfate are dissolved in deionized water according to a proportion, and then a certain amount of sodium hydroxide, a certain amount of polysiloxane-polyester sulfonate dispersant and a certain amount of urea are sequentially added under the stirring condition to prepare a reaction solution; (2) The reaction solution is stirred at the stirring speed of 200-600r/min, the temperature is raised to 90-120 ℃ according to the heating rate of 0.8-2.0 ℃/min for reaction, the heat preservation time is 300-900min, and after the reaction is finished, the spherical alumina precursor is prepared by filtering, washing and drying; (3) Calcining the prepared spherical alumina precursor according to a certain calcining process, and cooling to obtain spherical alumina; Wherein the polysiloxane-polyester sulfonate dispersant has the structural formula: ; x is 25-35, y is 30-40, and z is 4-8.
  2. 2. The method for preparing a spherical alumina powder with good dispersibility according to claim 1, wherein the mass ratio of aluminum nitrate nonahydrate to ammonium sulfate in the step (1) is 10-3:1.
  3. 3. The method for producing a spherical alumina powder having good dispersibility according to claim 1, wherein the mass of sodium hydroxide in the step (1) is 1.6% to 6.4% of the mass of aluminum nitrate nonahydrate.
  4. 4. The method for preparing a spherical alumina powder with good dispersibility according to claim 1, wherein the polysiloxane-polyester sulfonate dispersant in the step (1) is added in an amount of 1.0% -4.0% of the sum of the mass of aluminum nitrate nonahydrate and the mass of ammonium sulfate.
  5. 5. The preparation method of the spherical alumina powder with good dispersibility according to claim 1, wherein the urea added in the step (1) is 160% -320% of the mass of the aluminum nitrate nonahydrate.
  6. 6. The method for preparing a spherical alumina powder with good dispersibility according to claim 1, wherein in the step (1), the stirring speed is 300-500r/min, the stirring time for adding sodium hydroxide is 20-40min, the stirring time for adding polysiloxane-polyester sulfonate dispersant is 20-40min, and the stirring time after adding urea is 20-40min.
  7. 7. The preparation method of the spherical alumina powder with good dispersibility according to claim 1, wherein the washing mode in the step (2) is that deionized water is used for washing 3-5 times, ethanol is used for washing 3-5 times, the drying temperature is 85-110 ℃, and the drying time is 20-24 hours.
  8. 8. The method for preparing a spherical alumina powder with good dispersibility according to claim 1, wherein the calcining process in the step (3) adopts a temperature rising rate of 5-10 ℃ per min to reach a calcining temperature of 600-1200 ℃, and the temperature is kept for 60-300min and then is cooled along with furnace cooling.

Description

Preparation method of spherical alumina powder with good dispersibility Technical Field The invention belongs to the technical field of inorganic powder, in particular relates to a preparation method of alumina powder, and particularly relates to a preparation method of spherical alumina powder with good dispersibility. Background In recent years, the global industry has rapidly developed, and the role of powder materials is increasingly prominent, wherein alumina powder is one of the most important powder materials in industrial production. Alumina powder has high heat conductivity and good chemical stability, such as high temperature resistance, high hardness, good insulativity and the like, so that the alumina is widely applied to various fields of electronics, machinery, ceramics, medicines, aerospace and the like, and has large market demand. Compared with the common alumina powder, the spherical alumina powder has the properties of regular shape, high bulk density, small specific surface area, good filling property, strong fluidity and the like, thereby having wider application scenes. Therefore, the preparation of spherical alumina powder has been one of the research hotspots in recent years. The preparation method of the spherical alumina comprises a high-temperature gas phase method, a template method, an aerosol decomposition method, a sol-gel method, a hydrothermal method, a ball dropping method, a homogeneous precipitation method, a ball milling method and the like, but the methods have defects. A method for preparing submicron spherical alumina powder by using thermal plasma as in CN110697746A, which uses carrier gas to convey aluminum powder and alumina into a thermal plasma reactor to gasify and deposit the aluminum powder and the alumina, thus preparing the spherical alumina powder. However, the preparation conditions required by the method are severe, the equipment is expensive, and periodic maintenance is required, so that the production cost is high. CN114408953A is ball milled to prepare spherical alpha-alumina, and the method carries out horizontal ball milling on the alpha-alumina and ball milled beads for 20-40h at the rotating speed of 350-500r/min to obtain spherical alpha-alumina. The preparation process of CN109911923A high-purity spherical aluminium hydroxide and alumina nanometer powder includes mixing aluminium alkoxide as material, hydrolyzing with mixed solution of surfactant, pH regulator, alcohol and high purity water, stirring to react, solid-liquid separation, drying to obtain aluminium hydroxide powder, and roasting to obtain alumina powder. The method has the advantages of simple equipment, convenient operation and easily obtained raw materials, but aluminum alkoxide has high price and high production cost, and simultaneously, the organic solvent generated in the reaction process also causes certain pollution to the environment. The homogeneous precipitation method is used as one of the common methods for preparing spherical alumina, the prepared powder has high purity and smooth surface, but the agglomeration phenomenon of the prepared powder product is serious, the particle size is difficult to regulate and control by technological parameters, and in order to overcome the existing problems, the technical scheme of the invention improves the traditional homogeneous precipitation method, and the prepared spherical alumina has smooth surface, good dispersibility and controllable particle size, and has the advantages of easily obtained raw materials, simple process, low production equipment requirement and easy industrialization. Disclosure of Invention In order to solve the problems of expensive equipment, high production cost, high agglomeration degree and the like in the existing method for preparing the spherical alumina powder. The invention provides a preparation method of spherical alumina powder with good dispersibility. The preparation method of the spherical alumina powder with good dispersibility comprises the following steps: (1) Aluminum nitrate nonahydrate and ammonium sulfate are dissolved in deionized water according to a proportion, and then a certain amount of sodium hydroxide, a certain amount of polysiloxane-polyester sulfonate dispersant and a certain amount of urea are sequentially added under the stirring condition to prepare a reaction solution; (2) Raising the temperature of the reaction solution to a certain temperature at a certain heating rate under the stirring condition to react, and filtering, washing and drying the reaction solution after the reaction is finished to obtain a spherical alumina precursor; (3) Calcining the prepared spherical alumina precursor according to a certain calcining process, and cooling to obtain spherical alumina; The structural formula of the polysiloxane-polyester sulfonate dispersant in the step (1) is as follows: x is 25-35, y is 30-40, and z is 4-8. The polysiloxane-polyester sulfonate dispersant in the step (1