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Preparation method of high-purity boehmite and high-purity aluminum oxide

A technology of boehmite and boehmite, which is applied in the field of preparation of high-purity boehmite and high-purity alumina, can solve the problems of high content, difficult to continue to improve the purity, and affect the application, and achieve high purity, The effect of low price and stable product quality

Inactive Publication Date: 2019-11-15
中铝山东有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Although this type of method synthesizes high-purity boehmite and high-purity alumina, it is an alkaline process and needs to use sodium aluminate solution to obtain boehmite, and the obtained boehmite or alumina The sodium, silicon, and gallium content of the product is high, and it is difficult to continue to improve the purity. The limitation of the purity index affects its application in many fields

Method used

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  • Preparation method of high-purity boehmite and high-purity aluminum oxide
  • Preparation method of high-purity boehmite and high-purity aluminum oxide

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preparation example Construction

[0022] The first aspect of the present invention provides a method for preparing high-purity boehmite, the steps comprising:

[0023] S1. Acid-dissolving: acid-dissolving industrial aluminum hydroxide to obtain aluminum salt solution;

[0024] S2, crystallization and purification: crystallization and purification of the aluminum salt solution obtained in step S1 to obtain high-purity aluminum salt;

[0025] S3. Pre-precipitation and impurity removal: add a pre-precipitant to the aqueous solution of the high-purity aluminum salt to form a colloidal precipitation, and separate the solid and liquid to obtain a high-purity aluminum salt solution; the pre-precipitant includes one of ammonia water, ammonium carbonate or ammonium bicarbonate species or several;

[0026] S4. Chemical homogeneous precipitation: react the high-purity aluminum salt solution obtained in step S3 with a precipitant, control the reaction temperature to 85-99° C., and the pH of the reaction end point to 5.5-...

Embodiment 1

[0044]In this example, industrial aluminum hydroxide is dissolved in sulfuric acid to obtain an aluminum sulfate solution, and high-purity aluminum sulfate is obtained by two crystallization purifications. A certain amount of ammonium carbonate is added to form a highly active flocculent colloid for impurity removal, and high-purity sulfuric acid is obtained after solid-liquid separation. aluminum solution. Precipitate reaction between urea and high-purity aluminum sulfate solution to obtain amorphous alumina hydrate, obtain high-purity boehmite through hydrothermal treatment, and obtain high-purity alumina after roasting. Specific steps are as follows:

[0045] (1) Acid-soluble industrial aluminum hydrogen: configure sulfuric acid with a concentration of 30%, heat and dissolve industrial aluminum hydroxide under stirring conditions, and obtain aluminum sulfate solution after dilution and filtration. In order to ensure the complete consumption of sulfuric acid, control the exc...

Embodiment 2

[0055] In this example, industrial aluminum hydroxide is dissolved in nitric acid to obtain aluminum nitrate solution, and high-purity aluminum nitrate is obtained by two crystallization purifications, and a certain amount of ammonia water is added to form highly active floc colloid for impurity removal, and high-purity aluminum nitrate is obtained after solid-liquid separation solution. Precipitation reaction between urea and high-purity aluminum nitrate solution to obtain amorphous alumina hydrate, high-purity boehmite after hydrothermal treatment, and high-purity alumina after roasting. Specific steps are as follows:

[0056] (1) Acid-soluble industrial aluminum hydroxide: prepare nitric acid with a concentration of 30% to heat and dissolve industrial aluminum hydroxide, and obtain an aluminum nitrate solution after dilution and filtration.

[0057] (2) Twice crystallization and purification: cooling the aluminum nitrate solution to 20°C, filtering to obtain primary crysta...

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Abstract

The invention provides a preparation method of high-purity boehmite and high-purity aluminum oxide. The method comprises the following steps: heating and dissolving industrial aluminum hydroxide by using analytically-pure sulfuric acid or nitric acid to obtain an aluminum sulfate or aluminum nitrate solution, respectively; carrying out cooling crystallizing twice for purifying to obtain a high-purity aluminum salt; adding a certain amount of a precipitant such as ammonia water or ammonium carbonate or ammonium bicarbonate, carrying out pre-precipitating to form a high-activity colloid, furtherremoving impurities, and carrying out solid-liquid separation to obtain a high-purity aluminum salt solution; carrying out a precipitation reaction on the high-purity aluminum salt solution and urea,carrying out filtering and carrying out washing to obtain an amorphous aluminum oxide hydrate; and carrying out hydrothermal treatment to obtain the high-purity boehmite, and roasting the boehmite toobtain the high-purity aluminum oxide. The purity of the prepared high-purity boehmite and high-purity aluminum oxide is greater than 99.99%, and the sum of the content of metal elements except an aluminum element and the content of a silicon element is not higher than 0.001%.

Description

technical field [0001] The invention belongs to the technical field of alumina refining, in particular to a preparation method of high-purity boehmite and high-purity alumina. Background technique [0002] High-purity alumina, whose purity is generally higher than 99.99%, is widely used in catalyst supports, sapphire, ruby, functional ceramics and other fields. High-purity boehmite is an important precursor for the preparation of high-purity alumina. Except for the boehmite phase, the content of other impurities generally does not exceed 0.001%. At present, the most widely used method for large-scale production of boehmite is the direct hydrothermal method of aluminum hydroxide, which uses aluminum hydroxide as raw material and water as the medium, and generates hydrothermally at a temperature above 160°C in an autoclave boehmite monohydrate. The method has a simple production process and low cost, but its purity is directly determined by the aluminum hydroxide raw materia...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F7/02C01F7/34C01F7/66C01F7/74C01F7/44
CPCC01F7/021C01F7/34C01F7/441C01F7/66C01F7/748C01P2006/80
Inventor 杜善国杨丛林李凡司恒刚周波张卫东姚毅
Owner 中铝山东有限公司
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