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The treatment method of 4-methyl-2-hydrazinobenzothiazole production wastewater

A technology for producing benzothiazole and waste water, which is applied in water/sewage multistage treatment, water/sludge/sewage treatment, chemical instruments and methods, etc., can solve problems such as difficult and economical treatment of waste water, and achieve pollution reduction and The effect of waste and simple process

Active Publication Date: 2019-02-26
NANJING INNOVATION CENT FOR ENVIRONMENTAL PROTECTION IND
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The production process of 4-methyl-2-hydrazinobenzothiazole is roughly divided into four stages: condensation, ring closure, neutralization and substitution. The washing wastewater in the condensation process mainly includes ammonium sulfate, ammonium thiocyanate, sulfuric acid and condensation process The intermediate N,N'-di-o-tolylthiourea, the pH of the wastewater in this process is 1-2, the COD content is usually higher than 13000mg / L, and the salt content is above 100000mg / L, which is a typical high-COD and high-salt wastewater. And it contains a large number of unique intermediate residues. It is difficult for the existing treatment process to treat the wastewater generated by this process economically and rationally.

Method used

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  • The treatment method of 4-methyl-2-hydrazinobenzothiazole production wastewater
  • The treatment method of 4-methyl-2-hydrazinobenzothiazole production wastewater

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Embodiment 1

[0024] Such as figure 1 Shown, the treatment method of 4-methyl-2-hydrazinobenzothiazole production waste water of the present invention comprises the following specific steps:

[0025] (1) Neutralization and filtration: Adjust the pH value of the wastewater to 7. Under neutral conditions, the solubility of N,N'-di-o-tolylthiourea is lower than that in acidic environments, and then forms flocculent precipitates, which are collected by precision filters and sent to Return to the production system for cyclic production;

[0026] (2) Cyanide breaking by oxidation: add calcium hypochlorite 15% (percentage by volume) in step (1) gained waste water, with ammonium thiocyanate generation oxidation reaction as shown in following equation:

[0027] 2SCN - +11ClO - +4OH - =2HCO 3 - +N 2 ↑+2SO 4 2- +11Cl - +H 2 O;

[0028] (3) Resin adsorption: add 50ppm (volume percentage) of polyacrylamide to the effluent obtained in step (2), let it stand for precipitation, filter the fine ...

Embodiment 2

[0036] Such as figure 1 Shown, the treatment method of 4-methyl-2-hydrazinobenzothiazole production waste water of the present invention comprises the following specific steps:

[0037] (1) Neutralization and filtration: adjust the pH value of wastewater to 8. Under neutral conditions, the solubility of N,N'-di-o-tolylthiourea is lower than that in acidic environments, and then flocculents are formed, which are collected by filtration through fiber ball filters. Send back to the production system for cycle production;

[0038] (2) oxidative cyanide breaking: add sodium hypochlorite 20% (percentage by volume) in step (1) gained waste water, with ammonium thiocyanate generation as the oxidation reaction shown in following equation:

[0039] 2SCN - +11ClO - +4OH - =2HCO 3 - +N 2 ↑+2SO 4 2- +11Cl - +H 2 O;

[0040](3) Resin adsorption: add polyacrylamide 10ppm (volume percentage) to the effluent obtained in step (2), let it stand for precipitation, filter the fiber bal...

Embodiment 3

[0048] Such as figure 1 Shown, the treatment method of 4-methyl-2-hydrazinobenzothiazole production waste water of the present invention comprises the following specific steps:

[0049] (1) Neutralization and filtration: adjust the pH value of the wastewater to 7.5. Under neutral conditions, the solubility of N,N'-di-o-tolylthiourea is lower than that in acidic environments, and then form flocculent precipitates, which are collected by filtration through sand rate filters. Send back to the production system for cycle production;

[0050] (2) oxidative cyanide breaking: add calcium hypochlorite 8% (percentage by volume) in step (1) gained waste water, with ammonium thiocyanate generation as the oxidation reaction shown in following equation:

[0051] 2SCN - +11ClO - +4OH - =2HCO 3 - +N 2 ↑+2SO 4 2- +11Cl - +H 2 O;

[0052] (3) Resin adsorption: add polyacrylamide 30ppm (volume percentage) to the effluent obtained in step (2), let it stand for precipitation, filter t...

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Abstract

The invention relates to the field of chemical wastewater treatment and provides a treatment method for 4-methyl-2-benzothiazolehydrazine production wastewater. The treatment method comprises the following steps that Step1, neutralization and filtration are performed, wherein the pH value of wastewater is adjusted to 7-8, the solubility of 1,3-Di(o-tolyl)-2-thiourea is reduced, so floccule precipitates are formed, and then the flocculte precipitates are filtered out, collected and fed into a production system; Step2, cyanide breaking is performed through oxidization, wherein an oxidizing agent is added into the wastewater obtained from the Step1, so that ammonium thiocyanate is removed; Step3, resin adsorption is performed, wherein a coagulant aid is added into the wastewater obtained from the Step2, static precipitation is performed, the wastewater enters a resin adsorption column after suspended matters are removed through filtration, wherein the flow rate of the wastewater is 1.5-3 BV / h, and organic matters in the wastewater are adsorbed; Step4, evaporation and salting-out are performed, wherein the wastewater obtained from the Step3 is subject to salting-out and evaporation, so that ammonium sulfate products are obtained. According to the treatment method, resources are recycled, economy and environmental protection are achieved, operation is convenient, and COD, salts and intermediate products can be effectively removed from the wastewater.

Description

technical field [0001] The invention relates to the field of chemical wastewater treatment, in particular to a method for treating wastewater in the production process of 4-methyl-2-hydrazinobenzothiazole. Background technique [0002] 4-Methyl-2-hydrazinobenzothiazole (HMBT) is an organic intermediate, mainly used in the fields of pesticide production and organic synthesis, and is one of the important intermediates for the synthesis of pesticide tricyclazole. The production process of 4-methyl-2-hydrazinobenzothiazole is roughly divided into four stages: condensation, ring closure, neutralization and substitution. The washing wastewater in the condensation process mainly includes ammonium sulfate, ammonium thiocyanate, sulfuric acid and condensation process The intermediate N,N'-di-o-tolylthiourea, the pH of the wastewater in this process is 1-2, the COD content is usually higher than 13000mg / L, and the salt content is above 100000mg / L, which is a typical high-COD and high-...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C02F9/10C07C335/16
Inventor 赵卫伟陈冠寰梁英陈晧祥孙宝江刘福强
Owner NANJING INNOVATION CENT FOR ENVIRONMENTAL PROTECTION IND