Preparation method of superfine low-sodium alpha-alumina powder with high activity

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: 2014-12-24
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 preparation method of ultra-fine, high-activity, low-sodium alpha-alumina powder, including industrial aluminum hydroxide, is characterized in that it further 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 and 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 to wash, filter twice, rinse with deionized water three times, and dry to obtain the aluminum hydroxide after sodium removal; where the acid is hydrochloric acid, phosphoric acid, and sulfuric acid. One type, the added amount of acid 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 it to 1300~1550°C at a hea...

Embodiment 1

[0031] 100 kg of industrial aluminum hydroxide, 0.5 kg of ammonium citrate and 42 kg of water were mixed, 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 for washing, suction filtration twice, and rinse with deionized water three times, and then dry it at 100° C. for 24 hours to obtain desodiumized aluminum hydroxide. The desodiumized aluminum hydroxide, 0.5 kg of boric acid and 0.5 kg of ammonium fluoride are uniformly mixed, and placed in a high temperature furnace at 3°C / min to 1450°C, and kept for 3 hours to obtain low sodium and high activity α-oxidation The original aluminum powder has a sodium content of 0.02%. Low-sodium and high-activity α-alumina raw powder is charged into a polyurethane ball milling tank for dry ball milling for 5 hours to obtain powder particle size D 50 It is 8μm low sodium and high activity α-alumina powder. Mix α-alumina p...

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 with deionized water three times, and then dry it at 100°C for 24 hours to obtain the desodiumized aluminum hydroxide 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 at 4°C / min to 1550°C, and kept for 3 hours to obtain low sodium and high activity α-alumina Original powder, the sodium content is 0.01%. Put low-sodium and high-activity α-alumina into a polyurethane ball milling tank for dry ball milling for 8 hours to obtain the powder particle size D 50 It is 5μm low sodium high activity α-alumina powder. Mix low-sodium high-activity α-alumina micropowder, ammon...

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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-metal mineral powders, in particular to a method for preparing ultrafine, high-activity, low-sodium alpha-alumina powder. Background technique [0002] α-Alumina powder α-Al 2 O 3 It has 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 industries and other industries. Powder particle size D 50 The ultra-fine low-sodium α-alumina powder less than 1.0μm is mainly used for various grinding and polishing, cutting tools, toughened precision alumina ceramics and various products produced by isostatic pressing. With the continuous development of science and technology, the physical and chemical indexes 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 Applications(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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