Improved method for producing aluminium oxide by medium-low-grade bauxite

A low-grade bauxite and alumina technology, applied in the direction of alumina/hydroxide, etc., can solve problems such as complex process, not optimal lime addition, and no explanation of the relationship, so as to simplify the process and achieve better economic benefits Good, the effect of increasing the dissolution temperature

Active Publication Date: 2012-10-10
河南华慧有色工程设计有限公司 +1
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Problems solved by technology

high alpha k Solution reverse washing Bayer process red mud will increase the molecular ratio of the red mud dissolution system, but the process is complicated and there is still room for optimization
The technological conditions of the Bayer dissolution process in this patent are: the aluminum-silicon ratio A / S of the middle and low-grade bauxite is 3-9, and the amount of dealumination slag added is 5-15% of the added bauxite in terms of CaO. % is added, the amount of lime added is not optimal, and there is still a large room for optimization; in addition, the patent does not explain the relationship between the lime used for Bayer process dissolution and the lime used for red mud dissolution. When the total amount of lime added is constant, how better

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  • Improved method for producing aluminium oxide by medium-low-grade bauxite

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Experimental program
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Effect test

Embodiment 1

[0018] The aluminum-silicon ratio A / S of bauxite is 3, the dissolution temperature of the Bayer method is 145°C, and the caustic alkali concentration of circulating lye is N k 140g / 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 dissolved red mud is 1.48, the ratio A / S of dissolved red mud is 1.5; the Bayer process red mud wet treatment temperature is 180°C, the concentration of circulating lye is 190g / L, the calcium-silicon ratio of the total lime addition is 1.6, and the Bayer process part accounts for 20 %, wet treatment of red mud accounts for 80%, the dissolution time is 120min, the aluminum-silicon ratio A / S of the dissolved red mud is 0.5, and the sodium-silicon ratio N / S is 0.08.

Embodiment 2

[0020] The aluminum-silicon ratio A / S of bauxite is 4, the dissolution temperature of the Bayer method is 100°C, and the caustic alkali concentration of the circulating lye is N k is 230g / L, a K 3.0, dissolution time 240min, 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 Bayer method red mud wet treatment temperature is 160°C, the concentration of the circulating lye is 190g / L, the calcium-silicon ratio of the total lime addition is 1.2, and the Bayer method part accounts for 10 %, the wet treatment of red mud accounts for 90%, the dissolution time is 150min, the aluminum-silicon ratio A / S of the dissolved red mud is 0.60, and the sodium-silicon ratio N / S is 0.10.

Embodiment 3

[0022] The aluminum-silicon ratio A / S of bauxite is 5, the dissolution temperature of the Bayer method is 145°C, and the caustic alkali concentration of the circulating lye is N k 180g / L, a K is 3.0, the dissolution time is 30min, and the dissolution liquid a K The aluminum-silicon ratio of dissolved red mud is 1.50, the ratio A / S of dissolved red mud is 1.30; the Bayer process red mud wet treatment temperature is 200°C, the concentration of circulating lye is 160g / L, the calcium-silicon ratio of the total lime addition is 1.8, and the Bayer process part accounts for 20 %, wet treatment of red mud accounts for 80%, the dissolution time is 80min, the aluminum-silicon ratio A / S of the dissolved red mud is 0.65, and the sodium-silicon ratio N / S is 0.04.

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Abstract

The invention relates to an improved method for producing aluminium oxide by medium-low-grade bauxite, which is characterized in that the production process comprises two-time dissolution processes, i.e. (1) dealuminizing slag is added into the bauxite for carrying out Bayer-process dissolution, and carrying out Bayer-process production of the aluminium oxide; and (2) adding Bayer-process dissolved red mud obtained in the step (1) into alkali liquor, carrying out wet-process dissolution treatment, recovering alkali and aluminium oxide in the Bayer-process red mud. In the method disclosed by the invention, the process of the Bayer process mainly recovers the aluminium oxide in the bauxite, and a wet-process red mud treatment system mainly recovers alkali in the Bayer-process red mud. Dissolved liquor obtained in the Bayer-process part is diluted and purified to remove seed crystal for decomposition, lime is added into the dissolved liquor by wet-process treatment of the Bayer-process red mud to dealuminize, the obtained high-molecular-proportion dealuminized mother liquor is then used for dissolving the Bayer-process red mud, solid-phase dealuminizing slag replacing the lime is added into a Bayer-process system. In the method disclosed by the invention, the process is simple, the energy consumption is low, alkali consumption is low, the recovery ratio of the aluminium oxide is high, the method is suitable for treating the medium-low-grade bauxite mainly in China, the resource utilization ratio is high, the discharged red mud amount is less, and the red mud is easy to be utilized comprehensively.

Description

technical field [0001] An improved method for producing alumina from middle and low-grade bauxite relates to a method for Bayer red mud wet treatment and dissolution in the process of producing alumina from middle and low-grade bauxite. Background technique [0002] my country's bauxite resources are mostly high-alumina, high-silicon, low-iron, and low-to-medium grade diaspore-type bauxite. Alumina is mainly produced by the hybrid method with 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. However, there are still some problems in the above-mentioned production processes, such as the low alumina recovery rate of the beneficiation Bayer process and the lime Bayer process; although the resource utilization rate of the series process is...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C01F7/02
Inventor 尹中林李新华樊大林武国宝车洪生顾松青
Owner 河南华慧有色工程设计有限公司
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