Process for preparing ultrafine aluminum hydroxide by seed crystal precipitation method

A technology of ultra-fine aluminum hydroxide and aluminum hydroxide, which is applied in the preparation of alkali metal aluminate/alumina/aluminum hydroxide, can solve the problems of large gaps, non-universal production equipment and processes, and increased overall costs. Achieve the effect of low cost, excellent performance and good crystallinity

Active Publication Date: 2015-06-03
BEIJING SUN SILVER SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In the factories that adopt the Bayer method to prepare aluminum hydroxide, due to the large gap between the seed crystal preparation method and the main product process, the production equipment and process are not universal, which increases the overall cost of production, and there is room for improvement

Method used

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  • Process for preparing ultrafine aluminum hydroxide by seed crystal precipitation method
  • Process for preparing ultrafine aluminum hydroxide by seed crystal precipitation method
  • Process for preparing ultrafine aluminum hydroxide by seed crystal precipitation method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0031] At a temperature of 100°C, coarse alumina ore is dissolved in concentrated alkali solution with a mass concentration of 25% to prepare a concentrated metaaluminate saturated solution. The concentrated solution and distilled water were quickly mixed in a ratio of 3:1 in a stator-rotor reactor at a temperature of 40° C., and the stator-rotor speed was 300 rpm. The mixed reaction solution went through a crystallization process of 120 h under continuous stirring. The solid product obtained by filtering and separating the crystallized reaction liquid is washed with process water for 3 to 4 times, and dried at 100° C. for 24 hours to obtain crystal seeds for preparing ultrafine aluminum hydroxide. After the filtrate is evaporated to recover the process water, the concentrated liquid is redissolved and circulated.

[0032] The obtained aluminum hydroxide seed crystals carry out XRD characterization, see specification attached figure 2 .

Embodiment 2

[0034] At a temperature of 200°C, coarse alumina ore is dissolved in concentrated alkali solution with a mass concentration of 40% to prepare a concentrated metaaluminate saturated solution. The concentrated solution and distilled water were quickly mixed at a ratio of 1:4 in a stator-rotor reactor at a temperature of 90° C., and the stator-rotor speed was 3000 rpm. The mixed reaction solution went through a crystallization process for 12 h under continuous stirring. The solid product obtained by filtering and separating the crystallized reaction liquid is washed 3 to 4 times with process water, and dried at 120° C. for 24 hours to obtain crystal seeds for preparing ultrafine aluminum hydroxide. After the filtrate is evaporated to recover the process water, the concentrated liquid is redissolved and circulated.

[0035] Preparation example of ultrafine aluminum hydroxide

Embodiment 3

[0037] At a temperature of 100°C, crude aluminum hydroxide is dissolved in concentrated alkali solution with a mass concentration of 25% to prepare a concentrated metaaluminate saturated solution. The seed crystal prepared in Example 1 and the process water were formulated into a seed crystal slurry, and the concentrated metaaluminate saturated solution and the seed crystal slurry were quickly mixed in a ratio of 3:1 in a stator-rotor reactor at a temperature of 40°C, and fixed - The rotor speed is 3000rpm. The mixed reaction solution was circulated in the stator-rotor reactor for 40h to carry out crystallization. The solid product obtained by filtering and separating the crystallized reaction liquid is washed with process water, and then dried at 100° C. for 24 hours to obtain an ultrafine aluminum hydroxide product. The filtrate is used to evaporate and recover process water to prepare seed crystal slurry, and the concentrated filtrate is reused to dissolve crude aluminum h...

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Abstract

The invention provides a process for preparing ultrafine aluminum hydroxide. Alumina crude ore or crude aluminum hydroxide is dissolved in alkali lye so that a meta-aluminate solution is prepared, and the meta-aluminate solution and seed slurry are mixed and crystallize in a stator-rotor reactor so that the ultrafine aluminum hydroxide is prepared. The process has a low production cost and no pollution. The ultrafine aluminum hydroxide has good performances and can be used as an industrial additive and a fire retardant.

Description

technical field [0001] The invention relates to a production process of superfine aluminum hydroxide material, which is characterized in that a stator-rotor reaction device is used as a core crystallization reactor, and is a clean production process with low cost and no pollution. Background technique [0002] Aluminum hydroxide is the largest and most widely used inorganic flame retardant additive. As a flame retardant, aluminum hydroxide can not only be flame retardant, but also prevent smoke, no dripping, and no toxic gas. Therefore, it has been widely used and its usage is increasing year by year. Often used in thermosetting plastics, thermoplastics, synthetic rubber, coatings and building materials industries for flame retardancy. [0003] The particle size of aluminum hydroxide directly affects its flame retardancy and filling property. Increasing the surface area of ​​aluminum hydroxide particles will increase the water vapor pressure on the surface of the particle...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F7/14
Inventor 宋云华刘欣陈建铭魏玉胜李璐
Owner BEIJING SUN SILVER SCI & TECH
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