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Method for recycling waste sulfuric acid and waste hydrochloric acid mixed solution after acid-leaching of steel

A technology of mixed liquid and waste sulfuric acid, which is applied in the field of water treatment, can solve problems such as waste of resources, and achieve the effects of recycling, low equipment cost, and reduced consumption

Inactive Publication Date: 2017-12-29
CENT RES INST OF BUILDING & CONSTR CO LTD MCC GRP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0003] The technical problem to be solved by the present invention is to provide a method for recycling waste sulfuric acid and waste hydrochloric acid mixture after acid leaching of steel materials, which overcomes the problem that the waste acid produced by acid leaching in the prior art is all passed the neutralization precipitation method, and then reaches the standard Emissions, defects caused by waste of resources

Method used

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  • Method for recycling waste sulfuric acid and waste hydrochloric acid mixed solution after acid-leaching of steel

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Effect test

Embodiment 1

[0034] The method for recycling waste sulfuric acid and waste hydrochloric acid mixed liquor after steel pickling in the embodiment of the present invention comprises the following steps:

[0035] 1) Preliminarily filter the mixture of waste sulfuric acid and waste hydrochloric acid with an acid-resistant glass fiber membrane to filter out solid impurities above 1um in the mixture, and detect the concentrations of sulfuric acid and hydrochloric acid in the mixture.

[0036] 2) The concentration of sulfuric acid in the mixed solution after step 1) is 4.2%; then add oxalic acid and slowly heat to 30° C. to make the mixed solution fully react with oxalic acid for 20 minutes; the added amount of oxalic acid is sulfuric acid and hydrochloric acid 1.5 times the molar weight.

[0037] 3), the mixed solution after the reaction in step 2) is heated in the circulating heating ax, and the gas is discharged from the gas outlet provided on the circulating heating ax and collected; the hydr...

Embodiment 2

[0042]The method for recycling waste sulfuric acid and waste hydrochloric acid mixed liquor after steel pickling in the embodiment of the present invention comprises the following steps:

[0043] 1) Preliminarily filter the mixture of waste sulfuric acid and waste hydrochloric acid with an acid-resistant glass fiber membrane to remove solid impurities above 1um in the mixture, and detect the concentrations of sulfuric acid and hydrochloric acid in the mixture;

[0044] 2) The concentration of sulfuric acid in the mixed solution after step 1) is 3.5%; then add oxalic acid and slowly heat to 45° C. to make the mixed solution fully react with oxalic acid for 50 minutes; the amount of oxalic acid added is sulfuric acid and twice the molar mass of hydrochloric acid.

[0045] 3), the mixed solution after the reaction in step 2) is heated in the circulating heating ax, and the gas is discharged from the gas outlet provided on the circulating heating ax and collected; the hydrogen chl...

Embodiment 3

[0050] The method for recycling waste sulfuric acid and waste hydrochloric acid mixed liquor after steel pickling in the embodiment of the present invention comprises the following steps:

[0051] 1) Preliminarily filter the mixture of waste sulfuric acid and waste hydrochloric acid with an acid-resistant glass fiber membrane to remove solid impurities above 1um in the mixture, and detect the concentrations of sulfuric acid and hydrochloric acid in the mixture;

[0052] 2) The concentration of sulfuric acid in the mixed solution after step 1) is 4.3%; then add oxalic acid and slowly heat to 35° C. to make the mixed solution fully react with oxalic acid for 40 minutes; the added amount of oxalic acid is sulfuric acid and hydrochloric acid 3 times the molar mass.

[0053] 3), the mixed solution after the reaction in step 2) is heated in the circulating heating ax, and the gas is discharged from the gas outlet provided on the circulating heating ax and collected; the hydrogen chl...

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Abstract

The invention relates to a method for recycling waste sulfuric acid and waste hydrochloric acid mixed solution after acid-leaching of steel. The method comprises the following steps: primarily filtering the waste sulfuric acid and waste hydrochloric acid mixed solution to remove solid impurities exceeding 1 micron from the mixed solution; then adding oxalic acid to enable full reaction of the mixed solution and oxalic acid; heating the reacted mixed solution through a circular heating kettle; exhausting hydrogen chloride through a gas outlet in the circular heating kettle, and collecting hydrogen chloride; cooling the processed mixed solution; stirring; cooling until room temperature is reached; adding absolute ethyl alcohol; uniformly mixing; cooling and crystallizing; and filtering to obtain an iron oxal crystalline and filtrate. According to the method, ferrous chloride and ferrous sulfate are converted into iron oxal through oxalic acid, thus hydrochloric acid and sulfuric acid can be completely transferred into the acid leaching process again in order to be recycled, and as a result, the dosage of hydrochloric acid and sulfuric acid of an acid leaching enterprise can be decreased; zero emission is completely achieved; the iron resource is recycled; and moreover, environmental pollution is not caused.

Description

technical field [0001] The invention relates to a method for recycling waste acid after acid leaching of steel, in particular to a method for recycling waste sulfuric acid and waste hydrochloric acid mixture after acid leaching of steel, so as to realize recycling and utilization of waste acid and realize zero discharge , belongs to the technical field of water treatment. Background technique [0002] Steel materials and original blanks that require surface plating and spraying generally need to be pickled to remove oxides on their surfaces. Iron and steel enterprises mostly use sulfuric acid and hydrochloric acid for the pickling process. my country's steel output has exceeded 100 million tons, and every 10,000 tons of steel is pickled once, with an average of 20,000 tons of pickling wastewater and 600 tons of waste acid. The amount of acid is large. In order to save storage space, enterprises will produce a large amount of mixed waste acid. At present, this pickling waste...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23G1/36
CPCC23G1/36
Inventor 王纪元吕尚霖陈昕郭继飞刘鹏翔李亚赵英杰
Owner CENT RES INST OF BUILDING & CONSTR CO LTD MCC GRP
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