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Red mud dealkalization method

A red mud and dealkalization technology, which is applied in chemical instruments and methods, sludge treatment, water/sludge/sewage treatment, etc., can solve the problems of high dealkalization cost, cumbersome operation, and long dealkalization time, and achieve dealkalization The alkali time is shortened, the removal effect is good, and the operation is simple

Active Publication Date: 2009-05-06
中国长城铝业有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Under normal pressure conditions, the red mud is dealkalized by using activated calcium oxide, and the alkali content in the red mud is reduced to less than 1% after dealkalization. Complicated and costly for dealkalization

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] Embodiment one: a kind of method of dealkalization of red mud

[0030] The method comprises a dilute sulfuric acid dealkalization process and a calcium oxide dealkalization process under pressurized conditions, and its detailed steps are as follows:

[0031] a. Dilute sulfuric acid dealkalization: first analyze the alkali content in the red mud, prepare it into a slurry, the solid content of the slurry is 50%, import the prepared slurry into a fast grinder for grinding, and then grind it according to the alkali content The required concentration is 8% sulfuric acid slowly added in the slurry, the addition of the sulfuric acid is according to the chemical reaction 2K + +2Na + +2SO 4 2- =Na 2 SO 4 +K 2 SO 4 1.3 times the amount of sulfuric acid required, the particle size of the red mud after grinding for 45 minutes is less than 10 microns, filter and wash the ground red mud to obtain a filter cake, and analyze the alkali content in the obtained filter cake by conv...

Embodiment 2

[0033] Embodiment two: basically the same as embodiment one, the similarity is no longer described, and the difference is:

[0034] The concentration of dilute sulfuric acid in step a is 6%, and its add-on is according to chemical reaction 2K + +2Na + +2SO 4 2- =Na 2 SO 4 +K 2 SO 4 2 times of the required amount of sulfuric acid, the solid content of the prepared slurry is 45%, and the time for importing into the fast grinder for grinding is 50 minutes;

[0035] The amount of calcium oxide added in the step b is 4 times of the amount of calcium oxide required according to the chemical reaction KNaR+CaO=KNaO+CaR, the solid content of the slurry is 60%, and the reaction temperature in the autoclave is 120°C. The time is 20 minutes, and the obtained filter cake is dried with a drum dryer at a drying temperature of 150°C.

Embodiment 3

[0036] Embodiment three: basically the same as embodiment one, the similarity is no longer described, and the difference is:

[0037] The concentration of dilute sulfuric acid in step a is 9%, and its addition is according to chemical reaction 2K + +2Na + +2SO 4 2- =Na 2 SO 4 +K 2 SO 4 0.5 times of the required amount of sulfuric acid, the solid content of the prepared slurry is 30%, and the time for importing into the fast grinder for grinding is 30 minutes;

[0038] The amount of calcium oxide added in step b is 6 times the amount of calcium oxide required according to the chemical reaction KNaR+CaO=KNaO+CaR, the solid content of the slurry is 35%, and the reaction temperature in the autoclave is 150°C. The time is 5 minutes, and the obtained filter cake is dried under the condition of 180°C by airflow drying method.

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PUM

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Abstract

The invention discloses a dealkalization method for red mud. The method comprises a dilute sulphuric acid dealkalization step and a pressure calcium oxide dealkalization step. Red mud is prepared into slurry and introduced into a grinder to be ground; according to the content of alkaline in the red mud, the slurry is slowly added with required dilute sulphuric acid to be ground, filtered and washed to obtain a filter cake and the content of alkaline in the filter cake is analyzed; according to the analyzed content of alkaline in the filter cake, the filter cake is added with calcium oxide and uniformly mixed to be introduced to a high pressure reaction kettle and heated for reaction, and after reaction, the mixture is cooled, filtered and washed; and the obtained filter cake is dried and content of alkaline in the dried filter cake is analyzed. The invention can use only the pressure calcium oxide method to carry out dealkalization of the red mud. Red mud subjected to dealalization treatment of the method has low alkaline content and can be used more in fields such as concrete production, high quality brick and transformed brickproduction. The method solves the problem of the red mud of severe pollution and achieves remarkable economic and social benefits.

Description

1. Technical field: [0001] The present invention relates to a method for treating red mud, which is solid powdery waste discharged during the production process of alumina smelting industry, in particular to a combined method of using dilute sulfuric acid-pressurized calcium oxide and its pressurized calcium oxide method to treat red mud. The method of dealkalization of mud. 2. Background technology: [0002] Red mud is a solid powdery waste discharged during the production process of alumina smelting industry. Because of the high iron content of bauxite, the appearance color of this kind of waste is similar to red soil, so it is named. Red mud is mainly composed of fine-grained mud and coarse-grained sand, and its chemical composition varies with the origin of bauxite and the production method of alumina. The main mineral composition of red mud produced in the domestic alumina smelting industry is dicalcium silicate, hydrated garnet, and diaspore, followed by tricalcium al...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F11/00
Inventor 吴一峰李晓东李慧萍孙志昂王胜兰霍本龙王霄楠张子亮杨勇孙文祥王东升
Owner 中国长城铝业有限公司
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