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A kind of dechroming method of organic reduction hexavalent chromium alkaline waste liquid

A hexavalent chromium and organic technology, applied in the field of chromium chemical industry and chromium salt clean production, can solve the problems of incomplete detoxification and high treatment cost, and achieve the effects of increasing comprehensive economic benefits, avoiding accumulation, and expanding the scope of production

Active Publication Date: 2019-07-23
INST OF PROCESS ENG CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] The purpose of the present invention is to provide a method for the treatment of organic reduction hexavalent chromium alkaline waste liquid in view of the deficiencies in the above-mentioned process, so as to solve the high processing cost of the existing difficult-to-handle organic reduction hexavalent chromium alkaline liquid wet reduction. , the problem of incomplete detoxification

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] The slurry obtained from the crystallization solution obtained from the potassium-based liquid-phase oxidation and starch reduction was selected, which contained 2.34 g / L of Cr(VI) and a pH of 10.00. The slurry was completely slurried, and Cr(VI) was added at a temperature of 40°C. VI) Completely reduce the hydrazine hydrate to 1.2 times the theoretical amount of Cr(III). After stirring for 30 minutes, add a certain amount of cationic polyacrylamide flocculant so that the concentration in the solution is 10 mg / L. The feed liquid is in a state of slow stirring, the temperature is 40°C, and the flocculation time is 3 hours. After the flocculation is complete, the solid-liquid separation is carried out, and the total chromium content in the obtained feed liquid is 0.48mg / L.

Embodiment 2

[0026] Select the filtrate obtained from the solid-liquid separation of the crystal solution obtained from the potassium-based liquid-phase oxidation through starch reduction, wherein the Cr(VI) content is 3.76g / L, and potassium hydroxide is added to adjust the pH to 11.79, and it is completely slurried. At a temperature of 60°C, add hydrazine hydrate that completely reduces Cr(VI) to 1.8 times the theoretical amount of Cr(III). After stirring for 20 minutes, add a certain amount of anionic polyacrylamide flocculant to make the concentration in the solution When flocculating, keep the feed liquid in a slow stirring state, the temperature is 60°C, the flocculation time is 4h, and the solid-liquid separation is carried out after the flocculation is complete, and the total chromium content in the obtained feed liquid is 0.32mg / L.

Embodiment 3

[0028] Select the slurry obtained from the sodium-based liquid-phase oxidation and reduce the sucrose to obtain a Cr(VI) content of 1.44g / L, add sodium carbonate to adjust the pH to 10.50, and completely slurry, at room temperature 25 ° C Add hydrazine hydrate that completely reduces Cr(VI) to 2.0 times the theoretical amount of Cr(III), and after stirring for 30 minutes, add a certain amount of hydrolyzed polyacrylamide flocculant so that the concentration in the solution is 6mg / L, keep the feed liquid in a slow stirring state during flocculation, the temperature is 40°C, the flocculation time is 5h, and the solid-liquid separation is carried out after the flocculation is complete, and the total chromium content in the obtained feed liquid is 0.41mg / L.

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Abstract

The invention belongs to the technical field of chromium chemical engineering and chromium salt cleaning production and relates to a dechroming method of an organic reduced hexavalent chromium alkaline waste liquid. The dechroming method comprises adjusting pH of an organic reduced hexavalent chromium alkaline waste liquid to 10-14, adding a certain amount of a reducer into the waste liquid at the room temperature to 90 DEG C, after complete reduction, adding a certain amount of a flocculating agent into the liquid, after flocculation, carrying out solid-liquid separation to obtain a material liquid with chrome content less than 3mg / L, and using the dechromed liquid for preparation of a carbonate product satisfying the national standards. The dechroming method is free of an acidifying agent, has simple processes, widens a liquid phase organic reduced hexavalent chromium production range and improves integrated economic benefits.

Description

technical field [0001] The invention belongs to the technical field of chromium chemical industry and clean production of chromium salts. Specifically, the invention relates to a method for dechroming alkaline waste liquid of organic reduction of hexavalent chromium, especially for the production of chromium oxide by organic reduction of hexavalent chromium under alkaline conditions. Dechromation of the resulting reduction mother liquor. Background technique [0002] Chromium salt is an important inorganic chemical product and occupies an important position in the national economy. The existing chromium oxide production process has high energy consumption and poor product quality. A new process for the production of chromium oxide by organic liquid phase reduction has more development prospects. However, due to the liquid-phase reduction reaction of organic matter, a large amount of oxidized derivatives of organic matter, a large amount of carbonate, bicarbonate, high pH val...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C02F9/04C02F101/22
Inventor 余志辉曲景奎齐涛李玉杰魏广叶李永利
Owner INST OF PROCESS ENG CHINESE ACAD OF SCI