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Zero discharge and chromium recovery method for iron and steel industry chromium-containing wastewater

A technology of chromium wastewater and zero discharge, applied in chemical instruments and methods, general water supply saving, metallurgical wastewater treatment, etc., can solve the problems of increasing the environmental and economic benefits of enterprises, and achieve the reduction of sludge hazardous waste and good environmental protection benefits And economic benefits, the effect of small footprint

Inactive Publication Date: 2020-10-09
武汉钢铁有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide a method for zero discharge of chromium-containing wastewater in the iron and steel industry and a method for recovering chromium. By this method, the clean production level of the steel rolling process in the iron and steel industry is improved. On the one hand, zero discharge of chromium wastewater is realized, and on the other hand, chromium resources are recovered for ceramic The main pigment of the paint, so as to completely solve the problem of secondary pollution of chromium, avoid environmental risks, and increase the environmental and economic benefits of the enterprise

Method used

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  • Zero discharge and chromium recovery method for iron and steel industry chromium-containing wastewater
  • Zero discharge and chromium recovery method for iron and steel industry chromium-containing wastewater
  • Zero discharge and chromium recovery method for iron and steel industry chromium-containing wastewater

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0055] refer to figure 1 The flow chart of the zero discharge of chromium-containing wastewater in the iron and steel industry and the chromium recovery method shown in the following process:

[0056] Add PAC (polyaluminum chloride) and PAM (polyacrylamide) to the wastewater regulating tank for the chromium-containing wastewater from the iron and steel rolling process. The mass percentage of PAC is 3wt%, and the mass percentage of PAM is 2wt%. The coagulation condition is : The stirring speed is 50r / min, the dosage of PAC and PAM is 8mg / L and 1.5mg / L respectively, and the hydraulic retention time is 45min. Pumped to the sludge settling tank, after a certain amount is accumulated, the sludge is dehydrated and sent to sintering for disposal;

[0057] The chromium-containing wastewater is sent to the multi-media filter for pretreatment after passing through the wastewater conditioning tank, to remove suspended solids, colloids, turbidity, bacteria, microorganisms, viruses, etc. ...

Embodiment 2

[0068] refer to figure 1 The flow chart of the zero discharge of chromium-containing wastewater in the iron and steel industry and the chromium recovery method shown in the following process:

[0069] Add PAC (polyaluminum chloride) and PAM (polyacrylamide) to the wastewater regulating tank for the chromium-containing wastewater from the iron and steel rolling process. The mass percentage of PAC is 3wt%, and the mass percentage of PAM is 2wt%. The coagulation condition is : The stirring speed is 50r / min, the dosage of PAC and PAM is 12mg / L and 1mg / L respectively, and the hydraulic retention time is 60min. Sent to the sludge sedimentation tank, after accumulating a certain amount, send it to sintering disposal through sludge dehydration;

[0070] The chromium-containing wastewater is sent to the multi-media filter for pretreatment after passing through the wastewater conditioning tank, to remove suspended solids, colloids, turbidity, bacteria, microorganisms, viruses, etc. lar...

Embodiment 3

[0082] refer to figure 1 The flow chart of the zero discharge of chromium-containing wastewater in the iron and steel industry and the chromium recovery method shown in the following process:

[0083] Add PAC (polyaluminum chloride) and PAM (polyacrylamide) to the wastewater regulating tank for the chromium-containing wastewater from the iron and steel rolling process. The mass percentage of PAC is 3wt%, and the mass percentage of PAM is 2wt%. The coagulation condition is : The stirring speed is 50r / min, the dosage of PAC and PAM is 15mg / L and 0.5mg / L respectively, and the hydraulic retention time is 30min. Pumped to the sludge settling tank, after a certain amount is accumulated, the sludge is dehydrated and sent to sintering for disposal;

[0084] The chromium-containing wastewater is sent to the multi-media filter for pretreatment after passing through the wastewater conditioning tank, to remove suspended solids, colloids, turbidity, bacteria, microorganisms, viruses, etc....

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Abstract

The invention relates to a zero discharge and chromium recovery method for iron and steel industry chromium-containing wastewater. The method includes: sending chromium-containing wastewater generatedin a steel rolling process into a wastewater regulating tank for pretreatment, adding a flocculant into the wastewater regulating tank for precipitation, and discharging sludge for sintering treatment; sending supernatant wastewater in the wastewater regulating tank sequentially into a multi-medium filter and a security filter for filtration treatment, and then sequentially enabling the treated wastewater to enter a micro-filtration membrane assembly for filtration and a reverse osmosis membrane assembly for desalination, recycling the produced water desalinated by the reverse osmosis membrane assembly to a circulating water system to replace new water or soft water, and sending reverse osmosis concentrated water into a reduction tank for reduction and detoxification; feeding a Cr(OH)3-containing suspension into a spray evaporation system after detoxification, and carrying out spray drying to generate a Cr(OH)3 crude product; putting the Cr(OH)3 crude product into a calcining furnace,and performing calcining at 1050DEG C-1150DEG C to obtain a chrome green crude product. The method has the beneficial effects that: the occupied area is small, the operation is stable, and zero discharge of wastewater and recycling of chromium resources are realized.

Description

technical field [0001] The invention relates to the technical field of chromium-containing wastewater treatment, in particular to a method for zero discharge of chromium-containing wastewater and chromium recovery in the iron and steel industry. Background technique [0002] The chromium-containing wastewater in the steel rolling process (cold rolling, silicon steel) mainly comes from part of the high-priced chromium solution splashed when the steel plate surface is passivated with a high-priced chromium-containing compound (such as chromic acid) and the wastewater generated by washing the ground. The water-soluble Cr contained in 6+ Very toxic, carcinogenic, often with CrO 4 2- and Cr 2 o 7 2- It exists in various forms, and it is difficult to handle and dispose of it. [0003] At present, conventional treatment technologies include physical methods (adsorption, membrane method, ion exchange method), chemical methods (precipitation, reduction), physical chemical metho...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C02F9/04C02F9/10C01G37/02C02F101/22C02F103/16
CPCC02F9/00C01G37/02C02F2103/16C02F2101/22C02F1/5281C02F2001/007C02F1/001C02F2301/08C02F1/441C02F1/444C02F1/70C02F2303/04C02F1/5236C02F1/56C02F1/04C01P2006/80Y02A20/131Y02P20/129
Inventor 张垒舒纯俞琴王丽娜刘璞刘尚超付本全卢丽君
Owner 武汉钢铁有限公司
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