Wet detoxification method of hexavalent chromium contained alkali waste residues

A technology of wet detoxification and hexavalent chromium, applied in the direction of improving process efficiency, etc., can solve the problems of incomplete detoxification and high treatment cost

Inactive Publication Date: 2012-08-01
INST OF PROCESS ENG CHINESE ACAD OF SCI +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0012] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a method for wet detoxification of alka...

Method used

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  • Wet detoxification method of hexavalent chromium contained alkali waste residues
  • Wet detoxification method of hexavalent chromium contained alkali waste residues

Examples

Experimental program
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Effect test

Embodiment 1

[0067] Slurry the chromium-containing iron slag containing 0.125% of hexavalent chromium completely in the pulping tank, add a certain amount of sulfuric acid to adjust the pH to 8.65, and then add 20% of the theoretical amount of calcium lignosulfonate, and wait until the calcium lignosulfonate After completely dispersed, add ferrous ammonium sulfate 4 / 3 times the theoretical amount to reduce hexavalent chromium, the reduction time is 1h, the temperature is 75°C, the liquid-solid ratio is 5:1, and the chromium slag after complete reduction can be filtered Obtain qualified iron slag whose leaching toxicity meets the national environmental protection industry standard promulgated by the Ministry of Environmental Protection, and the leaching toxicity does not exceed the standard after being piled in the open air for 6 months.

Embodiment 2

[0069] Completely slurry the chromium slag containing 0.137% hexavalent chromium in the slurry tank, add a certain amount of CO 2 Adjust the pH to 9.43, and then add 50% of the theoretical amount of calcium lignosulfonate. After the calcium lignosulfonate is completely dispersed, add ferrous sulfate 5 / 3 times the theoretical amount to reduce hexavalent chromium. The reduction time is 2 hours. The temperature is 80°C, the liquid-solid ratio is 4:1, and the chromium slag after complete reduction can be filtered to obtain qualified chromium slag whose leaching toxicity meets the national environmental protection industry standard promulgated by the Ministry of Environmental Protection. The leaching toxicity does not exceed the standard after being stacked in the open air for 6 months. .

Embodiment 3

[0071] Slurry the chromium-containing iron slag containing 0.176% hexavalent chromium in the slurrying tank, the slurrying time is 1h, the slurrying temperature is 80°C, and the liquid-solid ratio is 5:1. After the slurrying is complete, filter and the filtrate Return to the system, add the reduced mother liquor and filter residue into the slurrying tank with a liquid-solid ratio of 4:1, re-slurry, and raise the temperature to keep the temperature at 80°C. After the slurry is complete, add a certain amount of CO 2 Adjust the pH to 9.13, and then add 40% of the theoretical amount of sodium lignosulfonate. After the sodium lignosulfonate is completely dispersed, add ferrous sulfate 5 / 3 times the theoretical amount to reduce hexavalent chromium. The reduction time is 2 hours. The fully reduced chromium slag can be filtered to obtain qualified chromium slag whose leaching toxicity meets the national environmental protection industry standard promulgated by the Ministry of Environme...

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Abstract

The invention belongs to the technical field of chromium chemical industry and chromium salt clean production, and in particular relates to a wet detoxification method of hexavalent chromium contained alkali waste residues. According to the method, the method comprises the following steps of: first, slurrying the chromium residues; and then adjusting the pH value of the slurry to 7-10; adding a stabilizing agent and a reducing agent to the completely slurried slurry at 20-150 DEG C; and reducing the hexavalent chromium to trivalent chromium, wherein the trivalent chromium can stably exist in the chromium residue for a long period. The leaching toxicity of the obtained chromium residue, which conforms to State Environmental Protection Industrial Standard issued by the Ministry of Environmental Protection, is less than 3 mg/L. Compared with the prior art, the wet detoxification method of the hexavalent chromium contained alkali waste residues, provided by the invention, has the advantages of simple process, less usage of the reducing agent, low cost, complete reduction of the hexavalent chromium, no rebound, low reducing reaction temperature, suitability for industrial production and better promotion and application prospect.

Description

technical field [0001] The invention relates to a wet detoxification method for waste slag containing hexavalent chromium, in particular to a wet detoxification method for chromium-containing slag discharged from a chromium salt production plant during the production of chromium salt. Background technique [0002] Chromium salt is an important inorganic chemical product and occupies an important position in the national economy. Its main production processes are calcium-containing roasting method, calcium-free roasting method, liquid phase oxidation method, etc. These methods will produce a certain amount of alkaline chromium-containing Waste slag-chromium slag, including chromium-containing waste slag produced by traditional roasting method and chromium-containing iron slag produced by liquid phase oxidation method. Chromium slag is the residue obtained after leaching with water, which contains a certain amount of soluble hexavalent chromium. Hexavalent chromium compounds ...

Claims

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Application Information

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IPC IPC(8): A62D3/37C22B7/04A62D101/43
CPCY02P10/20
Inventor 余志辉齐涛初景龙张懿王世君郭庆华骆克峻王锐
Owner INST OF PROCESS ENG CHINESE ACAD OF SCI
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