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a use of co 2 Method for dealing with bayer process red mud dealkalization in combination with waste acid

A Bayer process red mud and combined treatment technology is applied in the treatment field of Bayer process red mud dealkalization, which can solve the problems of low absorption rate and long time, and achieve the effect of great economic value.

Active Publication Date: 2016-09-28
CHINA UNIV OF GEOSCIENCES (BEIJING)
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

According to relevant literature, the effect of red mud on CO 2 The absorption rate is low, and this method takes a long time for dealkalization of high-alkaline red mud

Method used

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Examples

Experimental program
Comparison scheme
Effect test

example 1

[0019] The first step is to crush the red mud. After grinding, the particle size of the red mud is 160 mesh, and mix it with water. The weight ratio of Bayer red mud to water is 1:10; CO2 is introduced into the Bayer red mud 2 Carry out acidification reaction to obtain solid-liquid mixture (1); Pass into CO 2 The flow rate is 1L / min, the reaction temperature is 80°C, and the time is 0.5h; the second step is to add waste hydrochloric acid with a mass concentration of 20% to the solid-liquid mixture (1) obtained in the first step of acidification reaction, Bayer method The mass ratio of red mud to the added waste hydrochloric acid is 4:1, the reaction temperature is 80°C, and the time is 2 hours to obtain a solid-liquid mixture (2); in the third step, the solid-liquid mixture (2) obtained after the second step is pumped Separation by filtration and separation of treated residues for recovery of aluminum and iron. The alkali content in the low-alkali red mud was detected by conv...

example 2

[0021] The first step is to crush the red mud. After grinding, the particle size of the red mud is 160 mesh, and mix it with water. The weight ratio of Bayer red mud to water is 1:9; CO2 is introduced into the Bayer red mud 2 Carry out acidification reaction to obtain solid-liquid mixture (1); Pass into CO 2 The flow rate is 1L / min, the reaction temperature is 60°C, and the time is 1h; the second step is to add waste hydrochloric acid with a mass concentration of 20% to the solid-liquid mixture (1) obtained in the first step of acidification reaction, and the Bayer process The mass ratio of mud to the added waste hydrochloric acid is 3:1, the reaction temperature is 60°C, and the time is 1h to obtain a solid-liquid mixture (2); in the third step, the solid-liquid mixture (2) obtained after the second step is suction filtered Separation, the residue after separation is used for recycling aluminum and iron. The alkali content in the low-alkali red mud was detected by convention...

example 3

[0023] The first step is to crush the red mud. After grinding, the particle size of the red mud is 180 mesh, and mix it with water. The weight ratio of the Bayer process red mud to water is 1:8; CO2 is introduced into the Bayer process red mud 2 Carry out acidification reaction to obtain solid-liquid mixture (1); Pass into CO 2 The flow rate is 0.8L / min, the reaction temperature is 70°C, and the time is 1.5h; the second step is to add waste hydrochloric acid with a mass concentration of 20% to the solid-liquid mixture (1) obtained in the first step acidification reaction, Bayer The mass ratio of French red mud to the added waste hydrochloric acid is 3:1, the reaction temperature is 60°C, and the time is 1h to obtain a solid-liquid mixture (2); the third step, the solid-liquid mixture (2) obtained after the second step treatment Separation by suction filtration, the residue after separation and treatment is used for recovery of aluminum and iron. The alkali content in the low-...

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Abstract

The invention discloses a method for dealkalizing Bayer process red mud by using CO2 and waste acid in a combined way. The method comprises the following steps: smashing the Bayer process red mud, and mixing the smashed Bayer process red mud with water in the weight ratio of 1:(3-10); grinding the red mud till the granularity is 160-200 meshes to form a solid-liquid mixture, and introducing CO2 into the Bayer process red mud for performing an acidification reaction at the temperature of 60-80 DEG C for 0.5-2 hours, wherein the CO2 is introduced at the flow of 0.2-1L / min; adding 20 percent by mass waste hydrochloric acid into the solid-liquid mixture obtained in the first step for reacting at the temperature of 60-80 DEG C for 0.5-2 hours to obtain a solid-liquid mixture, wherein the mass ratio of the Bayer process red mud to the added waste hydrochloric acid is (2-4):1; and performing suction filtration separation on the obtained solid-liquid mixture, and separating treated residues to recover aluminum and iron. Through adoption of the method for treating the Bayer process red mud, a solution is provided for the application of the red mud to building materials.

Description

technical field [0001] The invention relates to a treatment method for dealkalization of red mud by the Bayer process, and belongs to the technical field of comprehensive utilization of resources. Background technique [0002] my country is a big producer of alumina, and the Bayer process red mud is the waste in the production process of alumina production according to the Bayer process route. For every ton of alumina produced, 1.0-1.4 tons of red mud will be produced by-product. At present, my country's alumina production is about 30 million tons of red mud. [0003] At present, the comprehensive utilization rate of red mud in my country is relatively low. As my country's alumina production increases year by year and the grade of bauxite gradually decreases, the stockpiles of red mud will continue to increase. The comprehensive utilization of red mud is still a worldwide problem, and the red mud is mainly disposed of by stockpiling and covering soil in the world. At pre...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C02F11/00
CPCC02F11/00
Inventor 张以河吕凤柱王新珂陆荣荣胡攀
Owner CHINA UNIV OF GEOSCIENCES (BEIJING)
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