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Dry process for detoxicating chromium slag

A process and technology for chromium slag, applied in the field of chromium slag dry detoxification technology and hazardous solid waste disposal, can solve the problems of easy yellowing and high temperature, and achieve the effects of no secondary pollution, overcoming yellowing and low process cost.

Inactive Publication Date: 2016-12-07
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

At present, high-temperature furnaces are generally used in China to dispose of chromium-containing wastes, but the temperature required for this process is relatively high, generally above 1300 ° C, and the slag is easy to turn yellow, so it needs to be further reduced with a reducing agent such as ferrous sulfate to ensure the final slag stability

Method used

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  • Dry process for detoxicating chromium slag

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Experimental program
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Effect test

Embodiment 1

[0023] According to the ratio in Table 1, mix alumina powder and light-burned magnesium powder and grind them together until the particle size is less than or equal to 3mm to make additives, mix the additives with chromium slag evenly, the alkalinity is 1.23, and put them into a vacuum tube furnace to control the reducibility The CO content of the gas is 80~90%, and it is reduced and roasted at 600°C for 30 minutes. The leaching toxicity of hexavalent chromium after the reaction is determined to be 0.130mg / kg, and the leaching toxicity of hexavalent chromium is determined to be 0.137mg after being placed under natural conditions for 3 months. / kg.

Embodiment 2

[0025] According to the ratio in Table 1, first mix alumina powder and anthracite powder, then add light-burned magnesium powder and mix them together, and then grind them together until the particle size is ≤ 3mm to make additives. Put it into a vacuum tube furnace, control the CO content of the reducing gas to 80~90%, reduce and roast at 800°C for 30 minutes, measure the leaching toxicity of hexavalent chromium after the reaction is 0.064mg / kg, and measure it after 3 months under natural conditions The leaching toxicity of hexavalent chromium is 0.067mg / kg.

Embodiment 3

[0027] According to the ratio in Table 1, first mix alumina powder and anthracite powder, then add light-burned magnesium powder and mix them together, and then grind them together until the particle size is ≤ 3mm to obtain additives. Mix the additives with chromium slag evenly. Put it into a vacuum tube furnace, control the CO content of the reducing gas to 80~90%, reduce and roast at 1000°C for 20 minutes, measure the leaching toxicity of hexavalent chromium after the reaction is 0.011mg / kg, and measure it after 3 months under natural conditions The leaching toxicity of hexavalent chromium is 0.015mg / kg.

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Abstract

The invention relates to a dry process for detoxicating chromium slag and belongs to the fields of dry chromium slag detoxication technology and treatment of harmful solid wastes. The process comprises the following steps: preparing additives by using 30-50 wt% of alumina powder with Al2O3 content of 96% or above, 30-50 wt% of caustic-burned magnesia powder at the grade of QM-95 or more and 0-40 wt% of anthracite culm, mixing and roasting with chromium slag, reducing hexavalent chromium in the chromium slag into trivalent chromium, and fixing the trivalent chromium at the normal temperature. According to the method, the component materials are commercial commodities, are low in manufacturing cost and small in doping amount in the dry chromium slag detoxication technology, the temperature needed in the dry detoxication process can be effectively reduced, formation of a final magnesium slag-containing spinel structure is promoted, the chromium slag can reach the standard when treated by a one-stage process, and the final slag does not become yellow.

Description

technical field [0001] The invention relates to a technique for dry detoxification of chromium slag, which belongs to the field of dry detoxification technology of chromium slag and disposal of harmful solid waste. Background technique [0002] Chromium slag is toxic due to the highly toxic and carcinogenic Cr(VI). Cr(Ⅵ) in chromium slag is leached out with rainwater and enters the surrounding rivers and soil, causing great harm to the environment and human health. Harmful hexavalent chromium in chromium slag exists in various states. In calcium silicate-calcium chromate solid solution and calcium aluminoferrate-calcium chromate solid solution, calcium chromate (CaCrO 4 ) exists in the crystal lattice of calcium silicate or calcium aluminoferrite, and belongs to acid-soluble Cr 6+ . To eliminate these two Cr 6+ , it is necessary to destroy the calcium silicate and calcium aluminoferrite crystal lattice, or dissociate hexavalent chromium at extremely high temperature, esp...

Claims

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Application Information

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IPC IPC(8): C04B35/44C04B35/622C04B35/64
CPCC04B35/44C04B35/622C04B35/62204C04B35/64C04B2235/652C04B2235/66C04B2235/3206C04B2235/3217C04B2235/422
Inventor 宁平何力为李彬
Owner KUNMING UNIV OF SCI & TECH
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