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Method for producing ethylenediamine tetraacetic acid directly from cyanogen containing industrial waste water

A technology of ethylenediaminetetraacetic acid and ethylenediaminetetraacetonitrile, which is applied in the field of ethylenediaminetetraacetic acid production, can solve the problems of high production cost of pure hydrocyanic acid, low EDTA yield, difficult separation and purification, etc., and achieve effective Conducive to environmental protection, stable product quality and simple process

Inactive Publication Date: 2007-09-05
鹤岗市英力农化有限公司 +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] There are many synthetic methods about EDTA in the literature, and CN98811975.7 describes that ethylenediamine, sodium cyanide and formaldehyde aqueous solution are reacted under alkaline conditions to prepare EDTA-Na, but the product produced by this method contains higher impurities, And separation and purification are difficult and costly
[0007] Document GB871380, JP55151537, CN02133458.7 have introduced adopting high-purity liquid hydrocyanic acid or thick hydrocyanic acid to produce EDTA with ethylenediamine, formaldehyde aqueous solution, although yield and purity are higher, but pure hydrocyanic acid production High cost and poor security
[0008] However, the traditional process of producing EDTA using chloroacetic acid and ethylenediamine has low yield, high cost, and pollutes the environment, and is gradually replaced by the hydrocyanic acid process.

Method used

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  • Method for producing ethylenediamine tetraacetic acid directly from cyanogen containing industrial waste water
  • Method for producing ethylenediamine tetraacetic acid directly from cyanogen containing industrial waste water

Examples

Experimental program
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Embodiment 1

[0033] Take 10Kg of ethylenediamine with a content of 99% and add it to a 100-liter reactor, control the temperature at 20-25°C, add 30Kg of formaldehyde solution with a concentration of 36% dropwise, mix well at this temperature, and set aside.

[0034]Put 670Kg of cyanide-containing pesticide industrial waste water (about 5.6% containing CN-) in 1000 liters of reaction kettles, cool to temperature 5-10 ℃, then add sulfuric acid dropwise, adjust pH value 2-4, control dropping rate, keep temperature at Below 10°C. After the sulfuric acid was added dropwise, it was stirred for another 20-30 minutes. At the above temperature, drop the prepared aldehyde-amine mixed solution within 20-30 minutes, control the pH value to 2-4, and then continue to stir for 10-30 minutes. At the above temperature, add 42Kg of 36% formaldehyde solution dropwise for about 20-30 minutes, then slowly raise the temperature to 60-80°C and continue the reaction for 2-4 hours. Cool below 10°C, and adjust t...

Embodiment 2

[0037] Take 10Kg of ethylenediamine with a content of 99% and add it to a 100-liter reactor, control the temperature at 20-25°C, add 30Kg of formaldehyde solution with a concentration of 36% dropwise, mix well at this temperature, and set aside.

[0038] Put 670Kg of cyanide-containing pesticide industrial waste water (about 5.6% containing CN-) in 1000 liters of reaction kettles, cool to temperature 5-10 ℃, then dropwise add hydrochloric acid, adjust pH value 3-5, control dropping rate, keep temperature at Below 10°C. After the hydrochloric acid was added dropwise, it was stirred for another 20-30 minutes. At the above temperature, drop the prepared aldehyde-amine mixed solution within 20-30 minutes, control the pH value to 4-6, and then continue to stir for 10-30 minutes. At the above temperature, add 48Kg of 36% formaldehyde solution dropwise for about 20-30 minutes, then slowly raise the temperature to 90-100°C and continue the reaction for 3-4 hours. Cool below 10°C and...

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Abstract

The technological process of producing ethylenediamine tetraacetic acid directly with cyanogen-containing industrial waste water includes the first acidifying cyanogen-containing industrial waste water, the subsequent reaction with water solution of ethylenediamine and formaldehyde to produce intermediate ethylenediamine tetraacetonitrile, and the final hydrolysis of ethylenediamine tetraacetonitrile under alkaline condition to obtain ethylenediamine tetraacetic acid. The said process can recover cyanide from waste water to produce product of purity over 99 %. The present invention is favorable to environment protection.

Description

technical field [0001] The invention relates to a method for directly recycling cyanide in cyanide-containing industrial wastewater. Specifically, it relates to a method for directly producing ethylenediaminetetraacetic acid from cyanide in cyanide-containing industrial wastewater. Background technique [0002] In the process of industrial production, the source of cyanide is very extensive. In the production process of metallurgy and chemical industry, non-ferrous metals, mineral processing, metal processing, electroplating, pesticides, fertilizers, chemical industry, etc., there are various quantities and concentrations of cyanide-containing wastewater discharged. As we all know, due to the highly toxic nature of cyanide in chlorine-containing wastewater, its toxicity can inhibit cell respiration, cause hypoxia in body tissues, and form suffocation. 270ppm of hydrogen cyanide in the air can cause death, and ingestion of 50-100mg of sodium cyanide can cause immediate death...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C227/02C07C229/16
Inventor 温立君尹应武高金胜孙志忠张家强宫艳波
Owner 鹤岗市英力农化有限公司