Method for detoxicating chromic slag with reductive gas

A technology of chromium slag and gas, which is applied in the field of detoxification of chromium slag by using reducing gas, can solve the problems of hexavalent chromium pollution, easy yellowing of chromium slag, inability to completely restore hexavalent chromium, etc., and achieve no secondary pollution Effect

Inactive Publication Date: 2008-12-10
SICHUAN YINHE CHEM
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  • Summary
  • Abstract
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  • Claims
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Problems solved by technology

Due to the defects in the process of the above two methods, the reduction conditions are not good, and the reducing agent is insufficient, the hexavalent chromium cannot be completely reduced, and the reduced chromium slag is easy to turn yellow, causing pollution to the hexavalent chromium

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 2

[0019] Embodiment 2: utilize reductive oxidation to carry out the method for detoxifying chromium slag according to the following steps:

[0020] A. Dry the chromium slag and pulverize it to 200 mesh;

[0021] B. Add the chromium slag into the sealed thermal vibrating fluidized bed and heat it to 500°C;

[0022] C. Pass nitrogen to drive away oxygen;

[0023] D. Pass gas into the vibrating fluidized bed and keep it inflated for 10 minutes;

[0024] E. Cool in a semi-closed silo filled with reducing gas;

[0025] F, discharge, process the water gas in the chromium slag.

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PUM

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Abstract

The invention relates to a method for detoxicating chromium slag. In the invention, when the temperature of the chromium slag ranging from 350 DEG C to 750 DEG C is reached by heating, a reducing gas is pumped into the chromium slag for more than five seconds; at last the chromium slag is cooled. In the method, a redox reaction is carried out by utilizing the reducibility of the reducing gas and the oxidizability of hexavalent chromium in the chromium slag at a high temperature so as to reduce the hexavalent chromium into trivalent chromium or chromium with lower valent so that the toxicity of the water-soluble and the acid-soluble hexavalent chromium can be removed from the chromium slag. The method can completely remove the hexavalent chromium from the chromium slag. The detoxicated chromium slag can be used for cement blending material or other purposes without causing secondary pollution.

Description

(1) Technical field [0001] The invention is a method for detoxifying chromium slag, especially a method for converting hexavalent chromium in chromium slag into trivalent chromium or lower compound chromium by using reducing gas, so as to detoxify the water-soluble hexavalent chromium in chromium slag. and the toxicity of acid-soluble hexavalent chromium. (2) Background technology [0002] Most of the current chromium salt production is roasted with calcareous fillers, such as dolomite, limestone, chromite, soda ash and some chromium slag mixed powder. 2 to 2.5 tons of slag. Since chromium slag contains hexavalent chromium, up to 2 to 3% (calculated as chromium trioxide), and chromium slag contains water-insoluble calcium chromate, which is a carcinogen, so a large amount of chromium slag is discarded or utilized, such as If the toxins (water-soluble hexavalent chromium and water-insoluble calcium chromate) are not removed, it will cause great threat and damage to human be...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): A62D3/37A62D101/08A62D101/43
Inventor 李先荣张国庆秦龙
Owner SICHUAN YINHE CHEM
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