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Method for recycling waste sulfuric acid in chlor-alkali industry

A technology for chlor-alkali industry and waste sulfuric acid, which is applied in the direction of alkali metal sulfite/sulfite, chemical instruments and methods, alkali metal compounds, etc., and can solve the problems of limited improvement effect, low economic benefit, and poor operability, etc. problems, achieve the effect of simple operation, simple and feasible process, and eliminate risks

Pending Publication Date: 2020-06-19
CHENGDU HUARONG CHEM CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although these methods can improve the quality of industrial waste sulfuric acid and have certain significance for environmental protection, the improvement effect is limited, the operability is not strong, and the economic benefit is not high

Method used

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  • Method for recycling waste sulfuric acid in chlor-alkali industry

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Comparison scheme
Effect test

Embodiment 1

[0035] A method for recycling waste sulfuric acid in the chlor-alkali industry, comprising the following steps:

[0036] (1) at 6.3m 3 Add deionized water into the enamel reaction kettle, turn on the stirrer, then weigh the chlor-alkali industrial waste sulfuric acid (76.5%), slowly add it into the reaction kettle through a diaphragm pump, and then slowly add potassium hydroxide solution (30%) under stirring , the percentage by weight of the added chlor-alkali industrial waste sulfuric acid, deionized water, and potassium hydroxide solution is 25.05%, 2.33% and 72.62%. After adding, a mixed solution is formed and a white precipitate is separated out. The pH of the mixed solution is controlled at 6.5. The reaction process The chlorine gas removed in the process is transported to the alkali washing tower by the induced draft fan, and is absorbed by caustic soda to generate sodium hypochlorite;

[0037] (2) Add deionized water to the neutralization kettle, make the product in st...

Embodiment 2

[0041] A method for recycling waste sulfuric acid in the chlor-alkali industry, comprising the following steps:

[0042] (1) at 6.3m 3 Add deionized water into the enamel reaction kettle, turn on the agitator, then weigh the chlor-alkali industrial waste sulfuric acid (76.5%), slowly add it into the reaction kettle through a diaphragm pump, and then slowly add potassium hydroxide solution (48%) under stirring , the percentage by weight of the added chlor-alkali industrial waste sulfuric acid, deionized water, and potassium hydroxide solution is 33.25%, 6.5% and 60.25%. After adding, a mixed solution is formed and a white precipitate is separated out. The pH of the mixed solution is controlled at 6.5. The reaction process The chlorine gas removed in the process is transported to the alkali washing tower by the induced draft fan, and is absorbed by caustic soda to generate sodium hypochlorite;

[0043] (2) Add deionized water to the neutralization kettle, make the product in st...

Embodiment 3

[0047] A method for recycling waste sulfuric acid in the chlor-alkali industry, comprising the following steps:

[0048] (1) at 6.3m 3 Add deionized water into the enamel reaction kettle, turn on the agitator, then weigh the chlor-alkali industrial waste sulfuric acid (75.1%), slowly add it into the reaction kettle through a diaphragm pump, and then slowly add potassium hydroxide solution (30%) under stirring , the percentage by weight of the added chlor-alkali industrial waste sulfuric acid, deionized water, and potassium hydroxide solution is 25.44%, 1.85% and 72.71%. After adding, a mixed solution is formed and a white precipitate is separated out, and the pH of the mixed solution is controlled at 7. The reaction process The chlorine gas removed in the process is transported to the alkali washing tower by the induced draft fan, and is absorbed by caustic soda to generate sodium hypochlorite;

[0049] (2) Add deionized water to the neutralization kettle, make the product in...

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Abstract

The invention belongs to the field of chemical engineering, and particularly relates to a chlor-alkali industrial waste sulfuric acid recycling method, which mainly comprises the following steps: adding pure water into a neutralization kettle, slowly adding waste sulfuric acid, adding an alkaline solution, and controlling the pH value at 6.5-7 at the reaction endpoint; continuously adding pure water into the neutralization kettle to prepare a solution with a certain concentration, continuously introducing steam into a jacket in the process, and keeping the temperature of the solution at 95-100DEG C; and filtering the solution by a precision filter, conveying the solution to an MVR crystallizer, carrying out evaporative crystallization, conveying the solution to a thickener, thickening, centrifuging, and drying to obtain the chemical reagent potassium sulfate. The treatment process is simple, feasible and convenient to operate, free chlorine dissolved in waste sulfuric acid is removedby utilizing heat generated by the neutralization reaction, energy can be saved, byproducts with high economic value are obtained, and the treatment process has important significance for environmental protection, and has good economic benefits and social benefits.

Description

technical field [0001] The invention belongs to the field of chemical industry, and in particular relates to a method for recycling waste sulfuric acid in the chlor-alkali industry. Background technique [0002] In the production process of chlor-alkali products, the chlorine gas produced by electrolysis is washed and purified, cooled to remove water, and then further absorbed and dried with 98% concentrated sulfuric acid (GBT534-2014), so that the moisture in the chlorine gas is reduced to below 50ppm, and then enters the chlorine gas liquefaction station , while the chlorine gas is drying, the water absorption concentration of concentrated sulfuric acid is reduced to 75-80%, and the water content is about 20-25%. Because chlorine gas has a certain solubility in water, there is a trace amount of free chlorine in dilute sulfuric acid, which is about 1000~2000PPm, with toxicity and strong oxidizing properties, its application in chemical production is limited, which forms haz...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01D5/00
CPCC01D5/00
Inventor 冯冬娅欧阳腾颜学伦刘杨
Owner CHENGDU HUARONG CHEM CO LTD