Preparation method of aluminium hydroxide micro powder

A technology of aluminum hydroxide and aluminum hydroxide gel, which is applied in the preparation of alkali metal aluminate/aluminum oxide/aluminum hydroxide, etc., which can solve the problems of imperfect crystal form development, low dehydration temperature and difficulty in satisfying micro-powder products, etc. problems, to achieve the effect of perfect crystal form development, complete crystal phase transformation, and perfect crystallization

Active Publication Date: 2008-08-20
GUIZHOU BRANCH CHINA ALUMINUM IND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The patent No. 00130250.7 "Preparation of Ultrafine Aluminum Hydroxide Process by Species Method" patent describes the preparation process of the above two methods. At present, the aluminum hydroxide micropowder β-Al(OH ) 3 % content is between 15% and 25%, the micropowder product crystal form is not perfect, the stability is poor, and the dehydration temperature is low; it is difficult to meet the requirements of β-Al(OH) 3 % around 5% of the market demand for high-grade flame retardants

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0021] 1. Preparation of seeds:

[0022] a After the sodium aluminate solution is cooled by a plate heat exchanger, it is diluted until the concentration of alumina is 20g / l, α K : 1.35, the temperature is controlled at 50°C, and CO is quickly passed into the carbon tank 2 gas, the decomposition time is controlled at 30 minutes, and the decomposition pH is controlled at 7-9 to obtain amorphous alumina gel.

[0023] b Add the prepared gel slurry and the filtered sodium aluminate solution cooled to 50-55°C into the seed preparation tank synchronously, and the amount added is based on the alumina content in the sodium aluminate solution: the alumina content in the gel seeds = 2 : 1, then control the temperature to be 50~60 DEG C, stir and decompose for 6 hours, make it reach the equilibrium concentration of alumina, then raise the temperature to 70 DEG C, keep the temperature for 10 hours, promptly complete the pseudo-boehmite through β-Al( Oh) 3 Then to α-Al(OH) 3 The comple...

Embodiment 2

[0027] 1. Preparation of seeds:

[0028] a After the sodium aluminate solution is cooled by a plate heat exchanger, it is diluted until the concentration of alumina is 60g / l, α K : 1.6, the temperature is controlled at 30°C, and CO is quickly passed into the carbon tank 2 gas, the decomposition time is controlled at 10 minutes, the decomposition pH is controlled at 7-9, and amorphous alumina gel is obtained.

[0029] b Add the prepared gel slurry and the filtered sodium aluminate solution cooled to 50-55°C into the seed preparation tank synchronously, and the amount added is based on the alumina content in the sodium aluminate solution: the alumina content in the gel seed=2 : 1, then control the temperature to be 50~60 DEG C, stir and decompose for 6 hours, make it reach the equilibrium concentration of alumina, then raise the temperature to 80 DEG C, keep warm for 3 hours, promptly complete the pseudo-boehmite through β-Al( Oh) 3 Then to α-Al(OH) 3 The complete transforma...

Embodiment 3

[0033] 1. Preparation of seeds:

[0034] a After the sodium aluminate solution is cooled by a plate heat exchanger, it is diluted until the concentration of alumina is 20g / l, α K : 1.35, the temperature is controlled at 30°C, and the aluminum sulfate solution diluted to 8% is quickly added, the pH is controlled at 7-9, and stirred for 10 minutes to obtain an amorphous alumina gel.

[0035] b Add the prepared gel slurry and the filtered sodium aluminate solution cooled to 50-55°C into the seed preparation tank synchronously. : 1, then control the temperature to be 50°C, stir and decompose for 6 hours to make it reach the equilibrium concentration of alumina, then raise the temperature to 80°C, and keep it warm for 10 hours to complete the process of pseudoboehmite through β-Al(OH) 3 Then to α-Al(OH) 3 The complete transformation process, the β-Al(OH) of the prepared micropowder seeds 3 % content is zero, and the preparation of aluminum hydroxide ultrafine powder slurry with ...

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Abstract

The present invention relates to technological process of producing fine aluminum hydroxide powder as fire retardant stuffing, and is especially technological process of producing fine aluminum hydroxide powder with high crystallization degree. The gel seed prepared with sodium aluminate solution through CO2 introducing carbon process and with sodium aluminate solution through aluminum sulfate neutralization process is converted via a special process into fine pure alpha-aluminum hydroxide powder without beta-aluminum hydroxide. The fine pure alpha-aluminum hydroxide powder is coated, modified and stoved to obtain submicron level pure alpha-aluminum hydroxide powder. Or, the completely converted fine powder slurry is added into sodium aluminate solution directly or after being concentrated and further decomposed to obtain fine aluminum hydroxide powder with excellent fire retarding performance.

Description

technical field [0001] The invention discloses a preparation method of aluminum hydroxide micropowder, which relates to a production process method of aluminum hydroxide micropowder used as a flame-retardant filler, in particular a process method for improving the crystal perfection of aluminum hydroxide micropowder. Background technique [0002] In the aluminum hydroxide market, the ultra-fine aluminum hydroxide flame retardant filler has three functions of flame retardancy, smoke elimination and filling because of its extremely fine particles, and there is no secondary pollution when burning, so it is used in advanced composite materials such as plastics and rubber. Adding this product in the middle not only makes the product have the effect of flame retardant and smoke suppression, but also enhances the performance of anti-leakage, arc resistance and wear resistance. It is widely used as filler in thermoplastic materials, rubber, paper, paint and other industries. At pre...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01F7/14
Inventor 刘国艳霍登伟邢国冯晓明刘轶巍刘春利石宝利付延军
Owner GUIZHOU BRANCH CHINA ALUMINUM IND
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