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Method for treating electroplating chromium-containing wastewater

A treatment method and technology for chromium wastewater, applied in the fields of metallurgical wastewater treatment, water/sewage multi-stage treatment, reductive water/sewage treatment, etc. Simple process steps and high removal rate

Inactive Publication Date: 2017-03-08
HUNAN HENGYANG XINLI CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The present invention aims to solve the problems of strict process conditions, unfavorable practical operation, high treatment cost and low treatment efficiency of the prior art chromium-containing wastewater treatment method, and provides a process with simple process steps, strong operability and wide applicability. Chromium-containing wastewater treatment method with high efficiency, low treatment cost and high chromium removal rate

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0017] A method for treating chromium-containing wastewater, the main steps of which are as follows: adding a reducing agent into chromium-containing wastewater at a temperature of 50°C, the volume of chromium-containing wastewater is 1 liter, the total mass concentration of chromium in the chromium-containing wastewater is 100 mg / L, and each liter contains Add 10g of reducing agent to the chromium wastewater, stir continuously for 30min, and add appropriate amount of lime, let it settle, filter, and adjust the pH of the filtrate to neutral before discharging. The reducing agent is composed of the following components in mass percentage: sodium thiosulfate 40 %, ascorbic acid 10%, oxalic acid 10%, glucose 8%, starch 12%, ferrous sulfate 20%.

[0018] The filtrate in this example is determined to contain 0.083 mg / L of chromium, and the removal rate of chromium reaches 99.89%.

Embodiment 2

[0020] A method for treating chromium-containing wastewater, the main steps of which are as follows: adding a treatment agent into chromium-containing wastewater at a temperature of 30°C, the volume of chromium-containing wastewater is 1 liter, the total mass concentration of chromium in the chromium-containing wastewater is 10 mg / L, and each liter contains Add 5g of treatment agent to the chromium wastewater, stir continuously for 10min, and add an appropriate amount of lime, let it settle, filter, and adjust the pH of the filtrate to neutral before discharging. The reducing agent is composed of the following components in mass percentage: sodium thiosulfate 30 %, ascorbic acid 10%, oxalic acid 15%, glucose 8%, starch 12%, ferrous sulfate 25%.

[0021] The filtrate in this example is determined to contain 0.0081 mg / L of chromium, and the removal rate of chromium reaches 99.91%.

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Abstract

The invention relates to treatment methods for electroplating wastewater and particularly relates to a method for treating electroplating chromium-containing wastewater. The method comprises the following steps: (1) adding a reducer into the chromium-containing wastewater; (2) carrying out continuous stirring, and adding lime or sodium hydroxide into the mixture; and (3) then, carrying out standing precipitation for 10 to 30 minutes, carrying out filtration, adjusting the pH of the filtrate to be neutral, and then, carrying out draining, wherein the reducer contains the ingredients in percentage by weight: 20% to 80% of sodium thiosulfate, 2% to 20% of ascorbic acid, 2% to 20% of oxalic acid, 2% to 10% of glucose, 2% to 20% of starch and 10% to 60% of ferrous sulfate. By adopting the method disclosed by the invention, sexavalent chromium is reduced to trivalent chromium through electron acceptance, a linkage reduction process is formed in the participation of ferric ions, and the sexavalent chromium is effectively reduced in a weak acid medium, so that energy is saved, the processing steps are simple, and the popularization prospect is good.

Description

technical field [0001] The invention relates to the technical field of electroplating wastewater treatment, in particular to a method for treating chromium-containing wastewater. Background technique [0002] In the metallurgical industry, electroplating, tanning, paint, photography and other industries, a large amount of chromium-containing wastewater is discharged every day. The chromium in the chromium-containing wastewater mainly exists in the form of hexavalent (Cr6+) and trivalent (Cr3+). If these chromium-containing wastewater If the wastewater is discharged directly without treatment, it will cause great harm to the environment. At present, the main treatment methods of chromium-containing wastewater are: chemical reduction method, electrochemical method, ion exchange method, activated carbon adsorption method and liquid membrane method. Although the above methods have their own advantages, they also have the disadvantages of complicated treatment process, low effic...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F9/04C02F1/70C02F103/16C02F101/22
Inventor 刘建周双宝帅留芳
Owner HUNAN HENGYANG XINLI CHEM
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