Method for producing aluminium oxide by middle-low grade alumyte

A technology for low-grade bauxite and alumina, applied in aluminate/alumina/aluminum hydroxide purification, chemical instruments and methods, alumina/aluminum hydroxide, etc. Realize industrialization, solution is difficult to obtain and other problems, to achieve the effect of improving utilization rate, reducing the amount of red mud, and easy operation

Active Publication Date: 2008-01-30
中铝郑州有色金属研究院有限公司
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Problems solved by technology

There are some problems in the above-mentioned production process, such as the alumina recovery rate of the beneficiation Bayer method and the lime Bayer method is low; although the series method can improve the utilization rate of resources, there is still a sintering method, and the energy consumption is still relatively large
Bayer hydration method and hydrothermal method can increase the recovery rate of alumina and reduce alkali consumption and energy consumption. They have great advantages in processing low- and medium-grade bauxite, but there is a high α K Solutions difficult to obtain, high alpha K It is difficult to decompose the solution, or use the method of aluminum precipitation, and there are many problems such as aluminum precipitation slag, which cannot be effectively recycled, so it is difficult to realize industrialization

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  • Method for producing aluminium oxide by middle-low grade alumyte

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Effect test

Embodiment 1

[0021] The aluminum-silicon ratio A / S of bauxite is 3, the dissolution temperature of the Bayer method is 250°C, and the caustic alkali concentration of the circulating lye is N k is 230g / L, a K It is 3.0, and the dealuminated slag produced in the regeneration process of circulating alkaline solution is used as the stripping additive with Bayer process red mud wet method, and the stripping time is 90min, and the stripping liquid a K The aluminum-silicon ratio of the dissolved red mud is 1.48, and the ratio A / S of the dissolved red mud is 1.5; the temperature of the Bayer red mud wet treatment is 290°C, the concentration of the circulating lye is 30g / L, the calcium-silicon ratio of the total lime added is 1.0, and the dissolution time is 20min. The aluminum-silicon ratio A / S of red mud is 0.5, and the sodium-silicon ratio N / S is 0.10.

Embodiment 2

[0023] The aluminum-silicon ratio A / S of bauxite is 4, the Bayer process dissolution temperature is 260°C, and the caustic alkali concentration Nk of the circulating lye is 230g / L, a K is 3.0, the dissolution time is 60min, and the dissolution liquid a k The aluminum-silicon ratio of the dissolved red mud is 1.50, and the ratio A / S of the dissolved red mud is 1.4; the temperature of the Bayer red mud wet treatment is 260°C, the concentration of the circulating lye is 90g / L, the calcium-silicon ratio of the total lime addition is 1.2, and the dissolution time is 90min. The aluminum-silicon ratio A / S of red mud is 0.60, and the sodium-silicon ratio N / S is 0.15.

Embodiment 3

[0025] The aluminum-silicon ratio A / S of bauxite is 5, the Bayer process dissolution temperature is 270°C, and the caustic alkali concentration Nk of the circulating lye is 230g / L, a K is 3.0, the dissolution time is 60min, and the dissolution liquid a K The aluminum-silicon ratio of the dissolved red mud is 1.50, the ratio A / S of the leached red mud is 1.30; the temperature of the Bayer red mud wet treatment is 250°C, the concentration of the circulating lye is 130g / L, the calcium-silicon ratio of the total lime addition is 1.4, and the dissolution time is 80min. The aluminum-silicon ratio A / S of red mud is 0.65, and the sodium-silicon ratio N / S is 0.18.

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Abstract

A method to produce aluminum oxide with middle-low bauxite relates to a method to produce aluminum oxide with middle-low bauxite by the means of Bayer-method. The invention is characterized in that: during the Bayer-method process, digestion process is to add dealuminization slag instead of lime as additive in middle-low bauxite to do Bayer process digestion; after digestion and backward washing of red mud, the red mud is mixed with recycle alkaline liquor, the lime is added, the digestion reaction is done, the red mud is separated from the slurry and discharged outside, the solution part obtained oppositely washes with Bayer-method, is sent to Bayer-method system to supplement alkali after digesting the red mud, the lime is added partly and is reacted, then, dealuminization slag and recycle alkaline liquor that goes through Bayer-method red mud wet treatment are gotten and dealuminization slag calcium aluminate hydrate instead of lime is added into the Bayer process digestion. The method of the invention belongs to all wet treatment, has simple process, low energy consumption, low alkali consumption and high recovery rate of aluminum oxide and is suitable for treating Chinese bauxite that is mainly middle-low bauxite; besides, the resource utilization is high, the amount of discharged red mud is low and the red mud is easy to be utilized comprehensively.

Description

technical field [0001] The invention discloses a method for producing alumina from middle and low grade bauxite, which relates to a method for producing alumina by processing middle and low grade bauxite by Bayer method. technical background [0002] my country's bauxite resources are mostly high-alumina, high-silicon, low-iron, and medium-grade diaspore-type bauxite, and the bauxite with an aluminum-silicon ratio of 4 to 6 accounts for more than 60%. The production of alumina mainly adopts the hybrid method, which has high energy consumption and complicated process. In order to reduce alkali consumption, energy consumption and more effective use of bauxite resources, new production processes such as beneficiation Bayer method, lime Bayer method, and series method have been gradually developed and applied. There are some problems in the above-mentioned production process, such as the alumina recovery rate of the beneficiation Bayer method and the lime Bayer method is low; a...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F7/02C01F7/0633C01F7/47
CPCC01F7/0633C01F7/47
Inventor 顾松青尹中林李新华刘祥民武国宝
Owner 中铝郑州有色金属研究院有限公司
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