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Method for extracting and recovering chromium from cold-rolled chrome sludge

A technology of chromium mud and solution, applied in the field of solid waste recycling, can solve the problems of high extraction cost, high processing cost, pollution, etc., and achieve the effect of improving chromium recovery rate, saving disposal cost, and increasing added value

Inactive Publication Date: 2017-03-29
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

This kind of cold-rolled chromium sludge has a large amount of sludge and serious pollution. In the metallurgical industry, it is treated as hazardous waste and handed over to companies with corresponding qualifications for treatment. There is a problem of high treatment costs.
[0003] At present, the main method of cold-rolled chrome sludge disposal is high-temperature roasting method. Glass beads or calcium carbonate and other additives are added to cold-rolled chrome sludge to make samples, and then the samples are roasted at high temperature to precipitate chromium. There are following problems: 1) the chromium recovery rate is generally about 50%, and the sludge chromium content after treatment is still very high, and the harmless treatment of cold-rolled chrome sludge is not thorough enough; 2) this high-temperature roasting method has high energy consumption, The high extraction cost is the bottleneck of its commercialization

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0024] The components and weight percentages of cold-rolled chrome mud are as follows: 50% Cr(OH) 3 , 30% Ca(OH) 2 , 10% water, 10% non-reactive metal compounds.

[0025] 1) Weigh 50g of cold-rolled chrome sludge and place it in 1L of concentrated hydrochloric acid with a concentration of 30% by weight, stir for 40min and then let it stand for 2h, then filter to remove the precipitate therein, and the filtered solution is for subsequent use;

[0026] 2) Add 5g Zn powder to the solution obtained in step 1), stir the solution, and under the action of Zn powder, trace inactive metals such as Cu Pb in the cold-rolled chromium mud are precipitated, and after standing for 40min, the solution is filtered to remove impurities , the filtered solution is for subsequent use;

[0027] 3) Add 1mol / L NaOH to the solution obtained in step 2), adjust the pH value to 7.5, and then bubble CO into the solution 2 Gas and slowly heated, the solution began to become turbid, until the turbidity o...

Embodiment 2

[0031] Components and weight percentages thereof of cold-rolled chromium mud are as follows: 40% Cr(OH) 3 , 30% Ca(OH) 2 , 20% of water, 10% of non-reactive metal compounds.

[0032] 1) Weigh 50g of cold-rolled chrome sludge and place it in 1L of concentrated hydrochloric acid with a concentration of 20% by weight, stir for 60min and then let it stand for 2h, then filter to remove the precipitate therein, and the filtered solution is for subsequent use;

[0033] 2) Add 3g Zn powder to the solution obtained in step 1), stir the solution, and under the action of Zn powder, trace inactive metals such as Cu Pb in the cold-rolled chromium mud are precipitated, and after standing for 40min, the solution is filtered to remove impurities , the filtered solution is for subsequent use;

[0034] 3) Add 1mol / L NaOH to the solution obtained in step 2), adjust the pH value to 8, and then bubble CO into the solution 2 Gas and slowly heated, the solution began to become turbid, until the t...

Embodiment 3

[0038] Components and weight percentages thereof of cold-rolled chrome mud are as follows: 60% Cr(OH) 3 , 25% Ca(OH) 2 , 10% water, 5 inactive metal compounds.

[0039] 1) Weigh 50g of cold-rolled chrome sludge and place it in 1L of concentrated hydrochloric acid with a concentration of 37% by weight, stir for 50min and then let it stand for 2.5h, then filter to remove the precipitate therein, and the filtered solution is set aside;

[0040] 2) Add 2g Zn powder to the solution obtained in step 1), stir the solution, under the action of Zn powder, trace inactive metals such as Cu Pb in the cold-rolled chromium mud are precipitated, and after standing for 40min, the solution is filtered to remove impurities , the filtered solution is for subsequent use;

[0041] 3) Add 0.8mol / L NaOH to the solution obtained in step 2), adjust the pH value to 7, and then bubble CO into the solution 2 Gas and slowly heated, the solution began to become turbid, until the turbidity of the solutio...

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Abstract

The invention discloses a method for extracting and recovering chromium from cold rolling chromium sludge. The method comprises the following steps: 1), soaking cold rolling chromium sludge in concentrated hydrochloric acid 20-37% in weight percentage, stirring for mixing, so as to enable Cr elements in cold rolling chromium sludge to exist in the form of chromium (iii), then leaving to stand and filtering out insoluble solid matters to obtain a solution I; 2), adding Zn powder to the solution I, fully separating out non-active metal deposition, filtering out deposition to obtain a solution II; 3), regulating the pH value of the solution II to be 7-8, introducing CO2, heating to enable Zinc (ii) and Ca (ii) to precipitate in the form of ZnCO3.3Zn(OH)2 and CaCO3, and enable Cr elements in the solution II to exist in the form of CrCl3, leaving to stand to filter out precipitate to obtain the solution III for standby application; 4), regulating the pH value of the solution III to be 8-9, heating to enable CrCl3 in the solution III to be hydrolyzed to form CrOCl precipitate, the formed CrOCl precipitate is the chromium product. According to the method for extracting and recovering chromium from cold rolling chromium sludge, the recovery rate of chromium from the cold rolling chromium sludge can reach 95% or above, the recovery rate of chromium is greatly improved, innocent treatment on cold rolling chromium sludge is fully realized, the energy consumption is reduced, and the chromium recovery additional value is increased.

Description

technical field [0001] The invention relates to solid waste recycling technology, in particular to a method for extracting and recovering chromium from cold-rolled chrome sludge. Background technique [0002] With the continuous expansion of the production capacity of cold-rolled automobile sheets, the discharge of cold-rolled chromium-containing wastewater in the steel industry has also increased year by year. Correspondingly, a large amount of cold-rolled chromium sludge will be generated during the treatment of cold-rolled chromium-containing wastewater. This kind of cold-rolled chromium sludge has a large amount of sludge and serious pollution. It is treated as hazardous waste in the metallurgical industry and handed over to companies with corresponding qualifications for treatment, which has the problem of high treatment costs. [0003] At present, the main method of cold-rolled chromium sludge disposal is high-temperature roasting method, adding glass beads or calcium ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C02F11/00C22B7/00
CPCY02P10/20
Inventor 刘尚超薛改凤张垒王丽娜刘璞付本全周泳康凌晨卢丽君
Owner 武汉钢铁有限公司
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