A kind of preparation method of superfine high-activity low-sodium α-alumina powder

A technology of alumina powder and aluminum hydroxide, which is applied in the direction of alumina/aluminum hydroxide, can solve the problems of poor sintering activity, high sodium content, and uneven particle size of the powder, and achieve high powder activity and α The effect of high phase inversion rate and narrow particle size distribution

Active Publication Date: 2017-01-25
广西朗琨科技有限公司
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Problems solved by technology

[0003] The purpose of the present invention is to provide a method for preparing ultra-fine high-activity low-sodium α-alumina powder, which should be able to solve the problems of high sodium content in α-alumina, uneven particle size, and poor sintering activity.

Method used

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preparation example Construction

[0024] A method for preparing ultrafine high-activity low-sodium α-alumina powder, including industrial aluminum hydroxide, is characterized in that it also includes the following steps:

[0025] (1) Mix industrial aluminum hydroxide, dispersant and water and ball mill for 2-12 hours to obtain an aluminum hydroxide suspension with a solid phase volume fraction of 50-55%; the dispersant is ammonium citrate, ammonium polyacrylate One kind, accounting for 0.1%~1.5% of the mass of aluminum hydroxide powder;

[0026] (2) Add an acid solution to the aluminum hydroxide suspension for washing, suction filtration twice, rinse three times with deionized water, and dry to obtain aluminum hydroxide after desalination; wherein, the acid is hydrochloric acid, phosphoric acid, sulfuric acid One, the amount of acid added is 0.5~2% of the mass of aluminum hydroxide;

[0027] (3) Mix the aluminum hydroxide obtained in step (2) with the composite mineralizer, heat to 1300-1550°C at a heating ra...

Embodiment 1

[0031] 100 kg of industrial aluminum hydroxide, 0.5 kg of ammonium citrate and 42 kg of water were mixed and ball milled for 12 hours to prepare an aluminum hydroxide slurry with a solid phase volume fraction of 50%. Add 0.5 kg of hydrochloric acid to the aluminum hydroxide slurry to wash, suction filter twice, rinse with deionized water three times, and then dry it at 100°C for 24 hours to obtain desodiumized aluminum hydroxide. Mix the desodiumized aluminum hydroxide with 0.5 kg of boric acid and 0.5 kg of ammonium fluoride evenly, place the temperature in a high-temperature furnace to 1450 °C at 3 °C / min, and keep it for 3 hours to obtain low-sodium and high-activity α-oxidation Aluminum raw powder with a sodium content of 0.02%. The low-sodium high-activity α-alumina raw powder is put into a polyurethane ball mill tank for dry ball milling for 5 hours to obtain the particle size of the powder D 50 8μm low-sodium high-activity α-alumina micropowder. Mix α-alumina fine po...

Embodiment 2

[0033] 100 kg of aluminum hydroxide, 0.6 kg of ammonium polyacrylate and 42 kg of water were mixed and ball milled for 8 hours to prepare an aluminum hydroxide slurry with a solid phase volume fraction of 50%. Add 0.8 kg of sulfuric acid to the aluminum hydroxide slurry for washing, suction filtration twice, and rinse three times with deionized water, then place it at 100°C and dry for 24 hours to obtain aluminum hydroxide after desodination. The desodiumized aluminum hydroxide is uniformly mixed with 0.4 kg of boric acid and 0.8 kg of ammonium chloride, placed in a high-temperature furnace and raised to 1550 °C at 4 °C / min, and kept for 3 hours to obtain low-sodium and high-activity α-alumina Raw powder with a sodium content of 0.01%. Put low-sodium and high-activity α-alumina into a polyurethane ball mill tank for dry ball milling for 8 hours to obtain the particle size of the powder D 50 5μm low-sodium high-activity α-alumina micropowder. Mix low-sodium high-activity α-a...

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Abstract

The invention discloses a preparation method of superfine low-sodium alpha-alumina powder with high activity. Industrial aluminum hydroxide is taken as a raw material; alkali is removed and adsorbed by adding an acid; a compound mineralizer is added to calcine; the superfine low-sodium alpha-alumina powder with high activity, of which the mean grain size D50 is 0.2-1.0micron, is obtained by combining dry ball milling with wet ball milling; the sodium content is 0.01%-0.05%; and the content of the alpha phase is 97%-99%. The problems that the alpha-alumina is high in sodium content, uneven in grain size, poor in sintering activity and the like are solved, special requirements of high-performance ceramic, grinding and polishing materials and the like are met, and the method has the advantages of being simple in process, environmentally friendly, low in cost and the like, and is suitable for large-scale production.

Description

technical field [0001] The invention relates to the technical field of inorganic non-metallic mineral powders, in particular to a method for preparing ultrafine high-activity low-sodium α-alumina powders. Background technique [0002] α-alumina powder α-Al 2 o 3 With the advantages of high melting point, high hardness, good wear resistance and good physical and chemical stability, it is widely used in ceramics, refractory materials, abrasives, petrochemical and other industries. Powder particle size D 50 The ultra-fine low-sodium α-alumina powder less than 1.0μm is mainly used in various grinding and polishing, cutting tools and toughening precision alumina ceramics and various products produced by isostatic pressing. With the continuous development of science and technology, the physical and chemical indicators of ultra-fine low-sodium α-alumina are getting higher and higher. The existing α-alumina production is mainly obtained by high-temperature calcination of indust...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01F7/02
Inventor 许杰曹余良许华
Owner 广西朗琨科技有限公司
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