Method for extracting alumina from high silicon bauxite

A high-silica bauxite and alumina technology, applied in chemical instruments and methods, aluminum compounds, inorganic chemistry, etc., can solve problems such as the deterioration of alumina economic effects, and achieve effective decomposition, low alkali circulation, and low energy consumption. Effect

Inactive Publication Date: 2006-07-26
CENT SOUTH UNIV
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Problems solved by technology

However, with the reduction of the ore's aluminum-silicon ratio, the economic effect of Bayer's production of alumina has deteriorated significantly. Therefore, it is required that the aluminum-silicon ratio (A / S) of Bayer's bauxite must be greater than 8

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  • Method for extracting alumina from high silicon bauxite
  • Method for extracting alumina from high silicon bauxite

Examples

Experimental program
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Effect test

Embodiment 1

[0022] Example 1. Bauxite containing Al 2 o 3 66.85%, SiO 2 8.01%, Fe 2 o 3 6.10%, CaO 0.80%, TiO 2 3.30%, burning reduction 13.97%, the main aluminum-containing mineral component is diaspore.

[0023] Add NaOH 93g in the stripping reactor, NaOH 2 O·Al 2 o 3 2.5H 2 O 27g, water 95ml, made into a simulated high-pressure water chemical eluate. Treat 100g of bauxite and add 4g of CaO. Discharge after elution at 175-186°C for 60 minutes. After the red mud was filtered, washed and dried, it was analyzed that Al 2 o 3 16.56%, SiO 2 13.06%, equivalent to a relative dissolution rate of 96.35%.

[0024] Add NaOH 100g to the dissolution reactor, NaOH 2 O·Al 2 o 3 2.5H 2 10g of O and 100ml of water were used to prepare a simulated solution (equivalent to the solution obtained by separating the crystallization of sodium aluminate hydrate after evaporation of the mother liquor). Then add 16g of CaO, treat the red mud obtained above at 260-270°C for 60 minutes, and ...

Embodiment 2

[0025] Example 2. Bauxite containing Al 2 o 3 45.61%, SiO 2 12.10%, Fe 2 o 3 44.83%, CaO 2.78%, TiO 2 2.71%, burning reduction 10.90%, the main aluminum-containing mineral composition is diaspore, and also contains part of diaspore.

[0026] Add NaOH 93g in the stripping reactor, NaOH 2 O·Al 2 o 3 2.5H 2 O 30g, water 90ml, dubbed into a simulated high-pressure water chemical eluate. Treat 100g of bauxite and add 10g of CaO. Discharge after 75 minutes of dissolution at 150-175°C. After the red mud was filtered, washed and dried, it was analyzed that Al 2 o 3 13.81%, SiO 2 13.06%, equivalent to a relative dissolution rate of 97.95%.

[0027] Add NaOH 100g to the dissolution reactor, NaOH 2 O·Al 2 o 3 2.5H 2O 10g, water 90ml, dubbed into a simulated solution (equivalent to the solution obtained by separating the crystallization of sodium aluminate hydrate after evaporation of the mother liquor). Then add 20g of CaO, treat the red mud obtained above at 275...

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Abstract

The invention relates to a technique to produce alumina with bauxite by alkaline method, which comprises: combining the symmetrical Bayer process at 100-250Deg and high-pressure hydrochemical method at 200-300Deg to treat directly high-silicon bauxite to extract alumina and treat red mud to recover Al2O3 combined by SiO2 and send obtained solution to the symmetrical Bayer process, respectively; hydrolyzing the generated calcium sodium silicate hydrate to recover the combined alkali; adding lime in any system by 1-3 times mole ratio as the SiO2. This invention can decompose the bauxite effectively with low alkali quantity and energy consumption, and fits to treat the diaspore, boehmite and aluminum trihydrate or the mixture.

Description

technical field [0001] The invention relates to the extraction of light metal aluminum in the field of hydrometallurgy, in particular to a process for producing alumina by treating bauxite with alkali. Background technique [0002] Processing bauxite to produce alumina by Bayer method has a series of advantages, such as simple process and convenient operation. However, with the reduction of the ore's aluminum-silicon ratio, the economic effect of Bayer's production of alumina is significantly worsened. Therefore, it is required that the aluminum-silicon ratio (A / S) of Bayer's bauxite must be greater than 8. [0003] The characteristic of my country's bauxite is that most of it belongs to the high-silicon diaspore type, and 80% of the bauxite has an aluminum-silicon ratio of 5-8, which cannot be treated economically by the Bayer process. [0004] Patent application 20041004691 proposes the "symmetrical Bayer process" for effective treatment of high-silicon bauxite. Unlike t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F7/20
Inventor 赵中伟
Owner CENT SOUTH UNIV
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