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Method for recovering and treating chromium from waste chromium electrodeposition solution

A treatment method and electrodeposition technology, applied in the direction of electrolysis process, electrolysis components, cells, etc., to achieve the effect of fast speed and mild conditions

Inactive Publication Date: 2008-01-16
GUILIN UNIVERSITY OF TECHNOLOGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Obviously, these methods will face the difficult problem of the further processing of chromium sludge again
And use hydrazine hydrate to remove the Cr in the electrodeposited chromium waste liquid (VI) Reduced Cr (III) And made into Cr 2 (SO 4 ) 3 , the dual purpose of realizing the recovery and treatment of chromium in electrodeposited chromium waste liquid has not been reported yet

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0007] Take 25.00 mL of waste liquid, add 1.60 mL of concentrated sulfuric acid, mix well, heat to 30°C in a constant temperature heating stirrer, add 0.80 mL of hydrazine hydrate dropwise, and continue the reaction for 8 minutes to complete the reduction reaction. Then slowly add concentrated ammonia water to the reaction solution to completely precipitate trivalent chromium, then filter and wash the precipitate and dissolve it with an appropriate amount of concentrated sulfuric acid, evaporate and dry to obtain Cr 2 (SO 4 ) 3 Crystal, the recovery rate of chromium in the waste liquid is 95.2%.

Embodiment 2

[0009] Take 50.00 mL of waste liquid, add 2.80 mL of concentrated sulfuric acid, mix well, heat to 31°C in a constant temperature heating stirrer, add 2.00 mL of hydrazine hydrate dropwise, and continue the reaction for 10 minutes to complete the reduction reaction. Then slowly add concentrated ammonia water to the reaction solution to completely precipitate trivalent chromium, then filter and wash the precipitate and dissolve it with an appropriate amount of concentrated sulfuric acid, evaporate and dry to obtain Cr 2 (SO 4 ) 3 Crystal, the recovery rate of chromium in the waste liquid is 94.8%.

Embodiment 3

[0011] Take 100.00 mL of waste liquid, add 7.00 mL of concentrated sulfuric acid, mix well, heat to 32°C in a constant temperature heating stirrer, add 3.20 mL of hydrazine hydrate dropwise, and continue the reaction for 12 minutes to complete the reduction reaction. Then slowly add concentrated ammonia water to the reaction solution to completely precipitate trivalent chromium, then filter and wash the precipitate and dissolve it with an appropriate amount of concentrated sulfuric acid, evaporate and dry to obtain Cr 2 (SO 4 ) 3 Crystal, the recovery rate of chromium in the waste liquid is 96.6%.

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Abstract

The process of recovering chromium from waste electric deposition solution includes adding concentrated sulfuric acid and hydrazine hydrate in certain amount into waste electric deposition solution at 28-32 deg.c to reduce six-valent chromium into trivalent chromium; depositing trivalent chromium with concentrated ammonia water; filtering and washing the precipitate; adding sulfuric acid to dissolve the precipitate, evaporation and stoving to obtain Cr2(SO4)3 crystal. The process has chromium recovering rate over 95 %, and has mild condition, fast speed and no harmful gas produced.

Description

technical field [0001] The invention relates to a method for recovering and treating chromium in electrodeposited chromium waste liquid. Background technique [0002] The direct discharge of electrodeposited chromium waste liquid will cause very serious impact on the environment. The treatment of chromium waste liquid is a work that cannot be ignored. At present, the treatment methods for chromium waste liquid mainly include: biological treatment, chemical treatment, chromium sludge stabilization treatment, etc. The vast majority of these methods are to convert the chromium in the waste liquid into chromium sludge and deposit it, so as to reduce the chromium content in the waste liquid and achieve the purpose of waste liquid treatment. Obviously, these methods will face the difficult problem of the further treatment of chromium sludge again. And use hydrazine hydrate to remove the Cr in the electrodeposited chromium waste liquid (VI) Reduced Cr (III) And made into Cr 2...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C25D21/18C22B34/32
Inventor 钟福新韦东海陆晨梅蒋小友
Owner GUILIN UNIVERSITY OF TECHNOLOGY
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