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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 high processing cost and incomplete detoxification

Inactive Publication Date: 2014-07-30
INST OF PROCESS ENG CHINESE ACAD OF SCI +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

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 alkaline chromium-containing waste residue, which solves the problems of high processing cost and incomplete detoxification in the existing wet reduction

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
Comparison scheme
Effect test

Embodiment 1

[0067] The chromium-containing iron slag containing 0.125% of hexavalent chromium is completely slurried in a slurry tank, a certain amount of sulfuric acid is added to adjust the pH to 8.65, and then 20% of the theoretical amount of calcium lignosulfonate is added. After completely dispersed, add 4 / 3 times the theoretical amount of ferrous ammonium sulfate to reduce hexavalent chromium, the reduction time is 1h, the temperature is 75℃, the liquid-solid ratio is 5:1, and the chromium residue after the reduction is completely filtered. Obtained the qualified iron slag whose leaching toxicity meets the national environmental protection industry standards promulgated by the Ministry of Environmental Protection, and the leaching toxicity does not exceed the standard when stored in the open for 6 months.

Embodiment 2

[0069] The chromium slag containing 0.137% of hexavalent chromium is completely slurried in a slurry tank, and a certain amount of CO is added 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 5 / 3 times the theoretical amount of ferrous sulfate to reduce hexavalent chromium. The reduction time is 2h. The temperature is 80℃, and the liquid-solid ratio is 4:1. The chromium residue after reduction can be filtered to obtain qualified chromium residue 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 when stored in the open for 6 months. .

Embodiment 3

[0071] The chromium-containing iron slag containing 0.176% of hexavalent chromium is slurried in a slurry tank. The slurrying time is 1h, the slurrying temperature is 80℃, and the liquid-to-solid ratio is 5:1. After the slurry is completed, filter and filtrate Return to the system, the reduced mother liquor and the filter residue are added to the slurry tank with a liquid-solid ratio of 4:1, re-slurry, and increase the temperature to keep the temperature at 80°C, and add a certain amount of CO after the slurry is completed 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 5 / 3 times the theoretical amount of ferrous sulfate to reduce hexavalent chromium. The reduction time is 2h. The reduced chromium residue can be filtered to obtain qualified chromium residue whose leaching toxicity meets the national environmental protection industry standards promulgated by the Ministry of E...

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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 residue containing hexavalent chromium, in particular to a wet detoxification method for chromium-containing residue 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 roasting method, calcium-free roasting method, liquid phase oxidation method, etc. These methods will produce a certain amount of alkaline chromium Waste slag-chromium slag, including chromium-containing waste slag produced by roasting method in the traditional sense and chromium-containing iron slag produced by liquid-phase oxidation method. Chromium residue is the residue obtained after immersion in water, which contains a certain amount of soluble hexavalent chromium. Hexavalent chromium compounds are ea...

Claims

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Application Information

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Patent Type & Authority Patents(China)
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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