Preparation method of high-whiteness aluminum hydroxide

By employing a multi-stage purification process using polyacrylamide composite adsorbents, lime slurry, and hydrogen peroxide, organic and inorganic impurities in the Bayer process are synergistically removed, solving the problem of low whiteness in aluminum hydroxide and enabling the industrial production of high-whiteness products and enhancing market competitiveness.

CN122166805APending Publication Date: 2026-06-09CHALCO SHANDONG CO LTD
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Patent Information

Application Number
CN202610502977.6
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2026-04-16
Publication Date
2026-06-09

AI Technical Summary

Technical Problem

Existing technologies are insufficient to effectively remove organic and inorganic impurities from the Bayer process for producing alumina, resulting in low whiteness of aluminum hydroxide, which affects its value in high-end applications and market competitiveness.

Method used

A multi-stage purification process is employed, using polyacrylamide composite adsorbents for adsorption and decarbonization, lime slurry for co-precipitation and impurity removal, and hydrogen peroxide for strong oxidation and degradation. This process synergistically removes large molecular organic matter such as humic acid and inorganic impurities such as iron and titanium, ensuring a clean environment during the aluminum hydroxide crystallization process.

Benefits of technology

It significantly improves the whiteness of aluminum hydroxide to over 85% and reduces the sodium oxide content to below 0.20%, meeting the needs of high-end applications, expanding the product's market competitiveness, and enabling convenient and economical industrial implementation.

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Abstract

The invention provides a preparation method of high-whiteness aluminum hydroxide, and belongs to the field of aluminum oxide production. The method comprises the following steps: adding a polyacrylamide composite adsorbent into a sodium aluminate diluent from a Bayer process dissolution process, and carrying out adsorption decarburization treatment on the sodium aluminate diluent to obtain a first purified solution; lime milk is added into the first purified liquid, so that the first purified liquid is subjected to co-precipitation impurity removal treatment, and second purified liquid is obtained through solid-liquid separation; hydrogen peroxide is added into the second purified liquid, so that residual organic matter in the second purified liquid is subjected to strong oxidative degradation treatment, and third purified liquid is obtained; performing seed decomposition on the third purified liquid to obtain slurry; and carrying out solid-liquid separation on the slurry, and washing a filter cake to obtain a high-whiteness aluminum hydroxide product. By constructing an adsorption-precipitation-oxidation three-stage synergistic purification system, classified, segmented and targeted removal of organic and inorganic impurities is realized, so that the Bayer process high-whiteness aluminum hydroxide preparation method capable of synergistically removing various impurities is developed.
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