Method for carbon dioxide suspension dealkalization of red mud for alumina plant

A technology of alumina and red mud, which is applied in cement production, solid waste removal, etc., can solve the problems that restrict the comprehensive utilization of resources, and achieve the effects of simple operation, high dealkalization rate and high alkali purity

Inactive Publication Date: 2010-12-29
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, due to the high content of alkali in red mud, its comprehensive utilization of resources is restricted.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0018] The red mud produced by the sintering method is used as the raw material. The chemical composition and phase composition of the red mud are shown in Table 1.

[0019] Table 1 Chemical composition and phase composition (%) of red mud

[0020] Alumina production method

[0021] First, the red mud was calcined in a muffle furnace at 600° C. for 5 hours, and then crushed and ground through an 80-mesh sieve. Put the pretreated red mud in the dealkalization reactor, add water quantitatively according to the liquid-solid ratio of 10:1, fully stir and mix to form a slurry, and at a temperature of 60°C, pass CO2 at a gas rate of 4m / s 2 The gas-liquid-solid three-phase dealkalization reaction was carried out for 1.5 hours, and the clarified liquid and solid residue were centrifuged. After dealkalization, the dealkalization rate of red mud can reach 85%, and the alkali content in red mud (as Na 2 O meter) is reduced to below 0.3%, fully meets the requirement as the bas...

Embodiment 2

[0023] The red mud produced by the combined method is used as the raw material. The chemical composition and phase composition of the red mud are shown in Table 1.

[0024] Table 2 Chemical composition and phase composition (%) of red mud

[0025] Alumina production method

[0026] First, the red mud was calcined in a muffle furnace at 400° C. for 5 hours, and then crushed and ground through a 150-mesh sieve. Put the pretreated red mud in the dealkalization reactor, add water quantitatively according to the liquid-solid ratio of 5:1, fully stir and mix to form a slurry, and at a temperature of 40°C, pass CO2 at a gas rate of 3m / s 2 The gas-liquid-solid three-phase dealkalization reaction was carried out for 1 hour, and the clarified liquid and solid residue were centrifuged. After dealkalization, the dealkalization rate of red mud can reach 75%, and the alkali content in red mud (as Na 2 O meter) is reduced to below 0.75%, fully meets the requirement as the base ma...

Embodiment 3

[0028] The red mud produced by the Bayer process was used as the raw material. The chemical composition and phase composition of the red mud are shown in Table 1.

[0029] Table 3 Chemical composition and phase composition (%) of red mud

[0030] Alumina production method

[0031] First, the red mud was calcined in a muffle furnace at 700° C. for 3 hours, and then crushed and ground through a 70-mesh sieve. Put the pretreated red mud in the dealkalization reactor, add water quantitatively according to the liquid-solid ratio of 5:1, fully stir and mix to form a slurry, and at a temperature of 40°C, pass CO2 at a gas velocity of 3.5m / s 2 The gas-liquid-solid three-phase dealkalization reaction was carried out for 2 hours, and the clarified liquid and solid residue were centrifuged. After dealkalization, the dealkalization rate of red mud can reach 93%, and the alkali content in red mud (as Na 2 O meter) is reduced to below 0.4%, fully meets the requirement as the bas...

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Abstract

The invention relates to a dealkalization reutilization method of red mud which is a waste material produced by an alumina plant, which belongs to the technical field of chemical industry and environmental protection. The process comprises the following steps: (1) firstly baking the red mud in a muffle furnace, removing crystallization water in the red mud, and further smashing and grinding the red mud into powder; (2) placing the red mud powder after pretreatment in a dealkalization reactor, adding water, fully stirring and mixing into slurry; (3) introducing CO2 into the slurry-like red mud, and carrying out gas-liquid-solid three-phase dealkalization reaction; and (4) carrying out centrifugal separation on clarifying solution and solid residue after the reaction is finished and obtaining the red mud after the dealkalization. The method can realize the sustainable comprehensive reutilization of the waste; compared with the traditional quicklime dealkalization process, the CO2 suspension process has the advantages of simple operation, high dealkalization rate, high alkali purity of the obtained product, no emission of the wastes and the like; and the whole process can realize the closed loop circulation, and the reaction process does not produce the pollution of three wastes, thereby belonging to a green, environment-friendly and clean production process.

Description

technical field [0001] The invention relates to a method for dealkalization and reuse of production waste red mud in an alumina plant, and belongs to the technical fields of chemical industry and environmental protection. Background technique [0002] With the development of the aluminum industry, the amount of red mud discharged from the production of alumina is increasing. At present, the world produces about 50 million tons of red mud every year, and my country's red mud discharge is about 15 million tons per year. per ton of Al produced 2 o 3 Will produce 0.6 ~ 1.2 tons of red mud slag. Such a large amount of red mud is stored by wet or dry methods, which not only pollutes water sources and takes up a lot of land, but also many available components in red mud cannot be rationally utilized, resulting in secondary waste of resources. It is imminent to study the comprehensive utilization of red mud. [0003] In order to effectively utilize red mud and realize the reuse ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B09B3/00C04B7/147
CPCY02P40/10
Inventor 宁平王学谦
Owner KUNMING UNIV OF SCI & TECH
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