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Alkali-compensating method in process of aluminium oxide

A process and alumina technology, which is applied in the preparation of alkali metal aluminate/alumina/aluminum hydroxide, etc., can solve the problems of low decomposition rate and reduce alumina yield, so as to improve the decomposition rate and shorten the decomposition rate. time, reducing the effect of low decomposition rate

Inactive Publication Date: 2005-01-26
GUIZHOU BRANCH CHINA ALUMINUM IND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the low decomposition rate of the Bayer process, the alumina output rate of the system is reduced

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0023] In the mixed method, the concentration of total alkali in the mother liquor and semen of the sintering method is Na 2 O is calculated as 60g / l, and CaO is added to the mother liquor of the sintering method for causticizing reaction. The final carbon separation mother liquor is added to the Bayer method seed separation mother liquor, and is evaporated and concentrated together with it, and is used for the Bayer method to dissolve the next batch of ores, thereby achieving the purpose of alkali supplementation. The carbon decomposition rate of the controlled sintering method semen is 90%, and the decomposition time is 3 hours.

Embodiment 2

[0025] In the mixed method, the total alkali concentration of the sintering method carbon separation mother liquor is Na 2 O is calculated as 150g / l, and CaO is added to the mother liquor of the carbon fraction of the sintering method for causticizing reaction. The amount of CaO added is 270g / l, and causticizing reaction is carried out at 80°C. The final carbon separation mother liquor is added to the Bayer method seed separation mother liquor, and is evaporated and concentrated together with it, and is used for the Bayer method to dissolve the next batch of ores, thereby achieving the purpose of alkali supplementation. The carbon decomposition rate of the controlled sintering method semen is 85%, and the decomposition time is 4 hours.

Embodiment 3

[0027] In the mixed method, the total alkali concentration of the sintering method carbon separation mother liquor is Na 2 O is calculated as 100g / l, and CaO is added to the mother liquor of the sintering method for causticizing reaction. The final carbon separation mother liquor is added to the Bayer method seed separation mother liquor, and is evaporated and concentrated together with it, and is used for the Bayer method to dissolve the next batch of ores, thereby achieving the purpose of alkali supplementation. The carbon decomposition rate of semen by the controlled sintering method is 86%, and the decomposition time is 3.5 hours.

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Abstract

The invention relates to a method for supplementing alkali in the alumina production process by using mixed joint method for compensating alkali loss in Bayer process system. It is characterized by that CaO is added to the carbon component mother liquor in sintering method to make causticization reaction, the peralkali concentration of carbon component mother liquor of sintering method in 60g / l-150g / l by Na2O, the addition amount of CaO is 50%-200% of chemometrics, causticizatino reaction temp. is 80 deg.C-100 deg.C, and the causticization time is 1-3 hr. Said method can change the sodium carbonate in the carbon component mother liquor into caustic sodium NaOH, after the causticization reaction the sodium carbonate component in the solution is equal to seed component mother liquor.

Description

Technical field [0001] The invention relates to a method for supplementing alkali in the production process of alumina, which relates to a method for supplementing the loss of alkali in the Bayer process system in the production process of alumina by a hybrid method. Background technique [0002] At present, when producing alumina by alkaline method, NaOH or Na 2 CO 3 Bauxite is processed so that the alumina in the ore becomes water-soluble sodium aluminate. Impurities such as iron and titanium in the ore and most of the silicon are turned into insoluble compounds, and the insoluble compounds are separated from the solution, washed and discarded or comprehensively treated. The pure sodium aluminate solution is decomposed to precipitate aluminum hydroxide, and after separation, washing and calcination, the alumina product can be obtained. The decomposed mother liquor is recycled to process the next batch of aluminum ore. [0003] Alkali production of alumina includes Baye...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01F7/04
Inventor 杨巧芳赵清杰李晓萍
Owner GUIZHOU BRANCH CHINA ALUMINUM IND