Method for removing sodium in preparation of high-purity alumina

A high-purity alumina and preparation process technology is applied in the field of high-purity material preparation, and achieves the effects of obvious sodium removal effect, simple use process and no pollution in use process

Active Publication Date: 2013-07-17
KUNMING METALLURGY INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, in the existing literature, the single pickling method can only remove sodium at a

Method used

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  • Method for removing sodium in preparation of high-purity alumina
  • Method for removing sodium in preparation of high-purity alumina

Examples

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Effect test

Embodiment 1

[0027] Take 1# aluminum hydroxide powder with an initial sodium content of 137ppm and grind it to ≤500μm for later use; wash the finely ground aluminum hydroxide powder with 45g / L hydrochloric acid in a constant temperature water bath at 50-55°C for 2-3 times to obtain pure Aluminum hydroxide; wash the purified aluminum hydroxide to pH7.0~7.5, dry and dehydrate at 300°C; add 10g / L ammonium chloride to the washed and dried aluminum hydroxide at 30~50 Stir and wash in a constant temperature water bath at ℃ for 2 to 3 times for secondary purification; wash the aluminum hydroxide after secondary purification with pure water at 30 to 50 ℃, dry and dehydrate at 300 ℃ after washing, and transform it into a fluffy ultra-low sodium Aluminum hydroxide, the sodium content is 9ppm after testing.

Embodiment 2

[0029] Take 2# aluminum hydroxide powder with an initial sodium content of 296ppm and grind it to ≤500μm for later use; wash the finely ground aluminum hydroxide powder with 35g / L hydrochloric acid in a constant temperature water bath at 50-55°C for 2-3 times to obtain pure Aluminum hydroxide; wash the purified aluminum hydroxide to pH 7.0-7.5, dry and dehydrate at 350°C; add 15g / L ammonium carbonate to the washed and dried aluminum hydroxide at 30-50°C Stir and wash in a constant temperature water bath for 2 to 3 times for secondary purification; wash the aluminum hydroxide after secondary purification with pure water at 30 to 50°C, dry and dehydrate at 500°C after washing, and transform it into a fluffy ultra-low sodium hydroxide Aluminum, tested sodium content is 8ppm.

Embodiment 3

[0031] Take 3# aluminum hydroxide powder with an initial sodium content of 327ppm and grind it to ≤500μm for later use; wash the finely ground aluminum hydroxide powder with 35g / L hydrochloric acid in a constant temperature water bath at 50-55°C for 2-3 times to obtain pure Aluminum hydroxide; wash the purified aluminum hydroxide to pH 7.0-7.5, dry and dehydrate at 500°C; add 15g / L ammonium carbonate to the washed and dried aluminum hydroxide at 30-50°C Stir and wash in a constant temperature water bath for 2 to 3 times for secondary purification; wash the aluminum hydroxide after secondary purification with pure water at 30 to 50°C, dry and dehydrate at 500°C after washing, and transform it into a fluffy ultra-low sodium hydroxide Aluminum, tested sodium content is 7ppm.

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Abstract

The invention discloses a method for removing sodium in a preparation of high-purity alumina. The method comprises the steps of purifying, secondary purifying, washing, drying, secondary washing and drying again. The method specifically comprises the following steps of: grinding aluminium hydroxide with high sodium content to be less than or equal to 500mu m, stirring and washing for 2-3 times in thermostatic water bath with temperature being 50-55 DEG C by utilizing a sodium removing agent I to obtain pure aluminium hydroxide; washing the purified pure aluminium hydroxide with water till pH value is 7.0-7.5, drying and dehydrating; adding a sodium removing agent II to the washed and dried aluminium hydroxide, and stirring and washing for 2-3 times in the thermostatic water bath with temperature being 30-50 DEG C; and washing the aluminium hydroxide which is purified for the second time by utilizing pure water with temperature being 30-50 DEG C, drying, dehydrating and transforming the washed aluminium hydroxide to fluffy ultralow sodium aluminium hydroxide. The method has the advantages of convenience, conciseness, no pollution and good sodium-removing effect.

Description

technical field [0001] The invention belongs to the technical field of high-purity substance preparation, and in particular relates to a method for removing sodium during the preparation of high-purity alumina. Background technique [0002] Sodium is considered to be one of the main impurities in the alumina production processes such as the Bayer method, sintering method, and combined method, and is one of the important indicators for the assessment of high-purity alumina grades. The sodium content in alumina mainly depends on the sodium in aluminum hydroxide. There are three main forms of sodium in aluminum hydroxide: ①adsorbed sodium, that is, sodium adsorbed on the surface of aluminum hydroxide and sodium wrapped in crystals, ②intergranular sodium, that is, during the decomposition and crystallization of aluminates, sodium replaces hydroxide The hydrogen atoms in aluminum are intercalated in the intercrystal and ③Crystalline sodium is Na formed during the decomposition a...

Claims

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Application Information

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IPC IPC(8): C01F7/46
Inventor 谢刚和晓才李怀仁余强魏可李永刚徐庆鑫刁微之闫森陈家辉崔涛陈加希杨大锦包崇军于站良
Owner KUNMING METALLURGY INST
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