Method for performing dealkalization on Bayer process red mud by using fluorgypsum

A technology of Bayer red mud and fluorogypsum, which is applied in chemical instruments and methods, sludge treatment, water/sludge/sewage treatment, etc., can solve the problems of complex operation, long dealkalization time, and high cost of dealkalization, and achieve The process is simple, the cost is low, and the effect that is difficult to handle is solved

Inactive Publication Date: 2013-11-27
HENAN POLYTECHNIC UNIV
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  • Summary
  • Abstract
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  • Claims
  • Application Information

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Problems solved by technology

Using the suspension carbonization dealkalization method of the invention, the alkali removal rate in red mud can reach mor

Method used

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  • Method for performing dealkalization on Bayer process red mud by using fluorgypsum

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Experimental program
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Effect test

Embodiment 1

[0033] The alkali content of Bayer red mud is 4.66%, the particle size is 180um, and the liquid-solid ratio is 8 to make red mud slurry, add 35% fluorine gypsum gypsum, and conduct steam dealkalization reaction in the high-pressure reactor. The reaction temperature was 90° C., the reaction pressure was 1.2 MPa, and the mixture was stirred for 90 minutes at a stirring speed of 200 rpm. After the red mud slurry is filtered, washed and dried, the content of alkali in the sintered red mud is analyzed to be 0.96%.

Embodiment 2

[0035] The alkali content of Bayer red mud is 4.28%, the particle size is 200um, and the liquid-solid ratio (ml / g) is 9 to prepare red mud slurry, add 40% fluorine gypsum, and heat in a high-pressure reactor by feeding steam dealkalization reaction. The reaction temperature was 100° C., the reaction pressure was 1.6 MPa, and the stirring rate was 180 rpm for 90 min. After the red mud slurry was filtered, washed and dried, the content of alkali in the red mud by the sintering method was analyzed to be 0.86%.

Embodiment 3

[0037] The alkali content of Bayer red mud is 6.28%, the particle size is 180um, and the liquid-solid ratio is 8.5 to make red mud slurry, add 35% fluorine gypsum, and carry out heating dealkalization reaction by passing steam into the reaction vessel. The reaction temperature is 70° C., the reaction pressure is 1.0 MPa, and the stirring rate is 180 rpm for 80 min. After the red mud slurry is filtered, washed and dried, the content of alkali in the sintered red mud is analyzed to be 0.96%.

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Abstract

The invention discloses a method for performing dealkalization on bayer process red mud by using fluorgypsum. The method comprises the following steps: step 1, adding crushed fluorgypsum in red mud slurry produced in a bayer process technological process proportionally, wherein the mass fraction of the fluorgypsum is 35-50 percent, and the liquid-solid ratio of the red mud slurry is 5 to 10; step 2, stirring the mixture in a reaction vessel, and pressurizing and heating the mixture for 40-120 minutes, wherein the mixing speed is 100-200 rpm, the pressure is 1.0-1.6 MPa, and the reaction temperature is 40-100 DEG C; step 3, filtering out liquid reactant, namely completing the dealkalization process. The method has the characteristics that the process is simple, the cost is low, the dealkalization rate is high, and the dealkalized red mud can be recycled, so that not only is the environment pollution caused by red mud and the fluorgypsum avoided to create good social benefits, but also an excellent economic effect is provided.

Description

technical field [0001] The invention relates to a red mud dealkalization method, in particular to a method for dealkalizing the Bayer process red mud by using fluorogypsum. Background technique [0002] Bayer process red mud is the waste slag produced after alumina is extracted from bauxite by Bayer process. In the process of alumina production, 0.8-1.5 tons of solid waste will be produced for every ton of industrial alumina produced --- red mud. Dam building and stockpiling is a commonly used disposal method at home and abroad. However, due to its high alkali content and large quantity, stockpiling red mud not only takes up a lot of land, but also causes serious pollution to the surrounding water body and atmosphere. Red mud contains a lot of alkali, with a pH value of 10.30-11.88, and a pH value of 12.1-13.0 of its leachate, which exceeds the "Nonferrous Metal Industry Solid Waste Pollution Control Standard", so red mud belongs to strong alkaline soil. Due to the high a...

Claims

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Application Information

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IPC IPC(8): C02F11/00
Inventor 李小雷王红亮曹新鑫胡强胡美华何小芳王利英李尚升宿太超
Owner HENAN POLYTECHNIC UNIV
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