Method for producing high intensity alumina from two extractive liquids in different consistencies

An alumina, high-strength technology, applied in the direction of alumina/hydroxide, etc., can solve the problems of easy breakage, high content of alumina fine particles, serious flying loss, etc.

Active Publication Date: 2008-07-02
GUIZHOU BRANCH CHINA ALUMINUM IND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The existing crystal seed decomposition process in my country uses a relatively high concentration of semen to add aluminum hydroxide seeds to maintain an initial decomposition temperature of about 60 degrees. After 40 to 60 hours, the final temperature reaches 45 to 50 degrees. The alumina produced has fine particle size and high strength. Poor (abrasion index over 30%), unable to meet the requirements of high-quality sandy alumina
This kind of alumina has a high content of fine particles, which is more easily broken during the transportation process, resulting in more fine particles, serious flying loss, and cannot meet the requirements
[0003] The application number is 200410049746. The patent adopts the production process of "high-temperature agglomeration, intermediate cooling, low-temperature growth, and medium solid content". Its purpose is to exert the agglomeration effect to reduce the content of fine particles in the product, but the relative supersaturation of high-concentration semen alumina is low , the agglomeration driving force is small, and the agglomeration effect is not necessarily obvious. Even if the content of -45μm in the product is controlled to a certain extent, the content of -20μm is difficult to meet the requirements of modern electrolysis technology

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0015] The volume ratio of low-concentration semen to high-concentration semen is 0.25:0.75, the concentration of alumina in low-concentration semen is 120 g / L, and the solid content is 60 g / L after adding fine crystal seeds. The initial temperature of decomposition is 81°C, and it drops to 78°C, then drop the temperature rapidly to 64°C, add high-concentration semen with an alumina content of 186.7 g / L, add coarse crystal seeds with a solid content of 500 g / L, and drop to the final temperature of 50°C after 44 hours, the semen caustic ratio 1.46. After the aluminum hydroxide product is roasted, the physical properties of the alumina are: the wear index is 15.2%, the content of the particle size is less than 20 μm is 0.5%, and the content of the particle size is less than 45 μm is 5.5%.

Embodiment 2

[0017] The volume ratio of low-concentration semen to high-concentration semen is 0.3:0.7, the concentration of aluminum oxide in low-concentration semen is 120 g / L, and the solid content is 80 g / L after adding fine crystal seeds. The initial temperature of decomposition is 80°C, and it drops to 77°C, then drop the temperature rapidly to 62°C, add high-concentration semen with an alumina content of 191.4 g / L, add coarse crystal seeds with a solid content of 480 g / L, and drop to the final temperature of 48°C after 44 hours, the semen caustic ratio 1.45. After the aluminum hydroxide product is roasted, the physical properties of the alumina are: the wear index is 14.5%, the content of the particle size is less than 20 μm is 0.4%, and the content of the particle size is less than 45 μm is 6.0%.

Embodiment 3

[0019] The volume ratio of low-concentration semen to high-concentration semen is 0.3:0.7, the concentration of alumina in low-concentration semen is 130 g / L, and the solid content is 100 g / L after adding fine crystal seeds. The initial temperature of decomposition is 82°C, and it drops to 79°C, then drop the temperature rapidly to 63°C, add high-concentration semen with an alumina content of 187.1 g / L, add coarse crystal seeds with a solid content of 600 g / L, and drop to the final temperature of 49°C after 44 hours, the semen caustic ratio 1.46. After the aluminum hydroxide product is roasted, the physical properties of the alumina are as follows: the wear index is 16.8%, the content of the particle size is less than 20 μm is 0.9%, and the content of the particle size is less than 45 μm is 7.0%.

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Abstract

This invention relates to a method for producing high-strength sand-like aluminum oxide with diasporite bauxite as the raw material. In this invention, a low-concentration refined solution and slurry prepared from aluminum hydroxide fine crystal seeds are efficiently agglomerated in the front part pool of the decomposition flow, and introduced into the back part of the decomposition flow together with a high-concentration refined solution and coarse crystal seeds. The concentrations of the two kinds of refined solution are 110-150 g / L and 170-220 g / l, respectively. The causticity ratios of the two kinds of refined solution are both 1.4-1.6. the volume ratio of the low-concentration and the high-concentration solution is (0.25) : 1. The method can guarantee the balance of the system grain sizes as well as improve the strength of the aluminum oxide product by controlling the concentration of the refined solution and the grain sizes of the fine crystal seeds.

Description

technical field [0001] The invention relates to a method for producing high-strength alumina from semen with two concentrations, which relates to a method for producing high-strength sandy alumina by using diaspore type bauxite as raw material and decomposing crystal seeds. Background technique [0002] At present, foreign sandy alumina production technologies mainly include the Alcoa method and the Alcoa method. Among them, the former effectively utilizes the mechanism of agglomeration and crystallization growth, and generally adopts higher decomposition initial temperature and lower seed crystal ratio conditions. The decomposition temperature of the aluminum method is low, the amount of seed crystals added is high, and the decomposition process is mainly a crystallization growth mechanism. In addition, the new Swiss aluminum method is an improved Alcoa method. These sandy alumina production technologies have great limitations in the sandy alumina production process using...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01F7/02
Inventor 白万全尹中林
Owner GUIZHOU BRANCH CHINA ALUMINUM IND
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