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Method for recycling residues of sodium dithionite

A technology of sodium hydrosulfite and residue, which is applied in the direction of thiosulfate/dithionite/polythionate, etc., can solve problems such as environmental pollution and waste of resources, and achieve reduction in production costs, energy consumption and material consumption, and good The effect of economic and social benefits

Inactive Publication Date: 2013-04-24
HUBEI YIHUA CHEMICAL INDUSTRY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

In traditional production, the residues are only incinerated and discharged directly, which wastes resources and pollutes the environment

Method used

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  • Method for recycling residues of sodium dithionite
  • Method for recycling residues of sodium dithionite

Examples

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Embodiment 1

[0024] A method for recovering and reusing sodium hydrosulfite residue, comprising the following steps:

[0025] 1) Put the residue into the incinerator for incineration at 700-900°C to remove the organic salts;

[0026] 2) Send the residue of the material to the reactor in a stirring state, and heat it to boiling; then add sulfur with 5% weight of the residue, continue heating at 90-100°C, and stir for 1 hour;

[0027] 3) Put the solution obtained in step 2) into the oxidation reactor, and oxidize it with air at 70-80°C until the reaction solution changes from brownish-yellow or yellow to white, and the pH value is 7-8, which is regarded as the oxidation end point ;

[0028] 4) The reaction solution after oxidation is vacuum evaporated, decolorized by activated carbon, pressure filtered, cooled, crystallized, centrifuged and sieved to obtain industrial-grade sodium thiosulfate product (big soda); the mother liquor after crystallization and separation is returned to the oxida...

Embodiment 2

[0031] A method for recovering and reusing sodium hydrosulfite residue, comprising the following steps:

[0032] 1) Put the residue into the incinerator for incineration at 700-800°C to remove the organic salts;

[0033] 2) Send the material residue to the reactor under stirring state, heat to boiling; then add 8% sulfur by weight of the residue, continue heating at 90-100°C, and stir for 2 hours;

[0034] 3) Put the solution obtained in step 2) into the oxidation reactor, and oxidize it with air at 70-80°C until the reaction solution changes from brownish-yellow or yellow to white, and the pH value is 7-8, which is regarded as the oxidation end point ;

[0035] 4) The reaction solution after oxidation is vacuum evaporated, decolorized by activated carbon, pressure filtered, cooled, crystallized, centrifuged and sieved to obtain industrial-grade sodium thiosulfate product (big soda); the mother liquor after crystallization and separation is returned to the oxidation reaction ...

Embodiment 3

[0037] A method for recovering and reusing sodium hydrosulfite residue, comprising the following steps:

[0038] 1) Put the residue into the incinerator for incineration at 800-900°C to remove the organic salts;

[0039] 2) Send the material residue to the reactor under stirring state, heat to boiling; then add sulfur with 12% weight of the residue, continue heating at 90-100°C, and stir for 1.5h;

[0040] 3) Put the solution obtained in step 2) into the oxidation reactor, and oxidize it with air at 70-80°C until the reaction solution changes from brownish-yellow or yellow to white, and the pH value is 7-8, which is regarded as the oxidation end point ;

[0041] 4) The reaction solution after oxidation is vacuum evaporated, decolorized by activated carbon, pressure filtered, cooled, crystallized, centrifuged and sieved to obtain industrial-grade sodium thiosulfate product (big soda); the mother liquor after crystallization and separation is returned to the oxidation reaction ...

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Abstract

The invention relates to a method for recycling residues of sodium dithionite. The method comprises the following steps of (1) putting the residues into an incinerator for incinerating, and removing organic salts in the residues; (2) feeding the material residues into a reactor in a stirring state, heating until the material residues boil, adding sulfur of which the weight is 5 to 15 percent of that of the residues, continuously heating, stirring and reacting for 1 to 2 h; (3) feeding solution obtained in step (3) into an oxidation reactor, oxidizing by air at the temperature of between 70 and 80 DEG C, and stopping oxidizing until the color of reaction solution is changed into white, and the pH value is between 7 and 8; and (4) performing vacuum evaporation, activated carbon decolorizing, filter pressing, cooling, crystallizing, centrifugal separation and screening on the oxidized reaction solution, and thus obtaining an industrial-class sodium thiosulfate product; and returning mother solution to the oxidation reactor. According to the treatment method provided by the invention, the residues generated in the production process of the sodium dithionite can be recycled, and can be discharged on standard after being subjected to a series of recycling comprehensive utilization, and higher economic benefit can be reached.

Description

technical field [0001] The invention relates to the field of hydrosulfite production, in particular to a method for recycling hydrosulfite residues. Background technique [0002] During the production of sodium hydrosulfite, after raw materials are added, the main product hydrosulfite and by-product sodium nitrate are produced. After recovering sodium formate and methanol in the mother liquor, the residue remains at last. See the process flow figure 1 . The residue contains 15-20% sodium thiosulfate, 7-10% sodium sulfite, and a small amount of sodium hydroxide, sodium formate, organic salts and other substances. In traditional production, the residues are only incinerated and discharged directly, which wastes resources and pollutes the environment. Contents of the invention [0003] The purpose of the present invention is to recycle the residue (semi-fluid) in the production of sodium hydrosulfite, thereby maximizing the benefits, reducing the cost of producing sodium hy...

Claims

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Application Information

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IPC IPC(8): C01B17/64
Inventor 秦宏硕刘承海
Owner HUBEI YIHUA CHEMICAL INDUSTRY CO LTD
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