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A method for recycling mixed salt produced by waste acid treatment

A waste acid treatment and recycling technology, which is applied in chemical instruments and methods, filtration treatment, water/sewage treatment, etc., can solve the problems of poor quality of solid salt products and high treatment costs, and achieve low energy consumption and treatment costs. Dealing with costs, avoiding impact effects

Active Publication Date: 2020-12-08
NANJING UNIV YANCHENG ENVIRONMENTAL PROTECTION TECH & ENG RES INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0007] Aiming at the problems of high cost of industrial mixed salt treatment and poor quality of recovered solid salt products in the prior art, the present invention provides a method for recycling mixed salt produced by waste acid treatment

Method used

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  • A method for recycling mixed salt produced by waste acid treatment

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Experimental program
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Effect test

Embodiment 1

[0042] A chemical waste acid was neutralized to obtain 12,000 tons / year of solid mixed salt, of which sodium sulfate was about 32%, sodium chloride was about 55%, and the organic matter content was 1250mg / kg.

[0043] Select n-hexane as the extractant, mix it with mixed salt, ultrasonically extract the organic impurities in the mixed salt, and centrifuge after extraction to obtain solid salt residue and extract. During the extraction, the amount of n-hexane was 0.8mL / g, the ultrasonic power was 200w, and the single extraction time was 10min. After repeated extraction for 3 times, the content of organic matter in the salt residue was 680mg / kg.

[0044] Dry the solid salt residue obtained by solid-liquid separation after extraction at 70°C for 60 minutes to remove the residual extractant in the solid salt residue, and dissolve the dried solid salt residue in water to prepare a 310g / L salt solution. Add precipitant sodium hydroxide and sodium carbonate and flocculant sodium polya...

Embodiment 2

[0049] The basic content of this embodiment is the same as that of Embodiment 1, except that this embodiment selects dichloroethane as the extraction agent. Mix it with mixed salt, ultrasonically extract the organic impurities in the mixed salt, and centrifuge after extraction to obtain solid salt residue and extract. During the extraction, the amount of dichloroethane was 1.2mL / g, the ultrasonic power was 300w, and the extraction time was 30min. The content of organic matter in the salt residue after ultrasonic extraction was 565mg / kg.

[0050] Dry the solid salt residue obtained by solid-liquid separation after extraction at 90°C for 100 minutes to remove the residual extractant in the solid salt residue, and dissolve the dried solid salt residue in water to prepare a 280g / L salt solution , add precipitant sodium hydroxide and sodium carbonate and flocculant sodium polyacrylate to remove calcium and magnesium ions, and filter to remove insoluble matter to obtain liquid A.

...

Embodiment 3

[0055] The basic content of this embodiment is the same as that of Embodiment 1, except that this embodiment selects dichloroethane-acetone as the extractant. Mix it with mixed salt, ultrasonically extract the organic impurities in the mixed salt, and centrifuge after extraction to obtain solid salt residue and extract. During the extraction, the dosage of dichloroethane-acetone was 1.5mL / g, the ultrasonic power was 400w, and the single extraction time was 15min. After repeated extraction twice, the content of organic matter in the salt residue was 410mg / kg.

[0056] Dry the solid salt residue obtained by solid-liquid separation after extraction at 80°C for 120 minutes to remove the residual extractant in the solid salt residue, and dissolve the dried solid salt residue in water to prepare a 260g / L salt solution and put it into Add precipitant sodium hydroxide and sodium carbonate and flocculant sodium polyacrylate to remove calcium and magnesium ions, and filter to remove ins...

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Abstract

The invention discloses a method for recycling a mixed salt produced after waste acid treatment, and belongs to the field of recycling of solid mixed salts. The method of the invention comprises the following steps: performing ultrasonic extraction on the mixed salt by using an extractant to remove organic impurities in the mixed salt; dissolving the extracted mixed salt to prepare a salt solution, and adding a precipitating agent and a flocculating agent to remove hardness; performing adsorbing and oxidizing treatment to further remove organic impurities in the salt solution; freeze-crystallizing the treated salt solution to obtain a sodium sulfate decahydrate solid and a frozen mother liquid; and carrying out evaporative crystallization on the frozen mother liquid to obtain a sodium chloride solid. The method of the invention has the characteristics of reasonable process, economical property, high efficiency, stability in running, maximum recycling of inorganic salts, avoiding of theoccupation of land resources by waste salt landfill, and reduction of the processing cost of enterprises.

Description

technical field [0001] The invention belongs to the field of recycling solid mixed salt, and more specifically relates to a method for recycling mixed salt produced by waste acid treatment. Background technique [0002] China is a big country in the world for the production and use of industrial acids. There are many acid-using and acid-consuming industries, such as nitration, sulfonation, esterification, halogenation, and alkylation of organic matter, as well as the production of fine chemical products, steel pickling, battery production, petroleum refining, Chemical fiber production and other industries will produce waste acid. The types of waste acid mainly include simple waste acid (such as waste sulfuric acid and waste hydrochloric acid) and mixed acids (including nitric acid, hydrofluoric acid, phosphoric acid, hydrochloric acid, sulfuric acid, etc.). Generally speaking, medium and high-concentration elemental waste acids (concentration of waste sulfuric acid > 20%,...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C02F9/10C01D5/16C01D3/14C02F101/30
CPCC01D3/14C01D5/16C02F1/001C02F1/04C02F1/28C02F1/283C02F1/32C02F1/42C02F1/52C02F1/66C02F1/722C02F1/725C02F9/00C02F2101/30
Inventor 陈利芳仇鑫王炼周腾腾朱强戴建军李爱民
Owner NANJING UNIV YANCHENG ENVIRONMENTAL PROTECTION TECH & ENG RES INST
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