Method for recovery utilization of mother solution hydrochloric acid for ADC foaming agent production

A technology of ADC foaming agent and mother liquor, which is applied in the field of recycling hydrochloric acid of mother liquor of ADC foaming agent, can solve the problem of dilute hydrochloric acid distilled out, high energy consumption and other problems, so as to reduce pollutant discharge and low corrosion , significant economic benefits

Active Publication Date: 2008-07-16
HANGZHOU HI TECH FINE CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

CN1562732 then adopts adding sulfuric acid with a mole fraction of 25% to 32% in the distillation kettle as the extractant, heating and boiling, adding dilute waste hydrochloric acid semi-continuously, the distillation temperature is 95 to 110°C, and distills dilute hydrochloric acid at 155 to 165°C. After hydrochloric acid, the extractant is reused; but this method needs to distill a large amount of dilute hydrochloric acid at high temperature, which has high energy consumption and cannot solve the problem of distilling dilute hydrochloric acid

Method used

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  • Method for recovery utilization of mother solution hydrochloric acid for ADC foaming agent production
  • Method for recovery utilization of mother solution hydrochloric acid for ADC foaming agent production

Examples

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Effect test

Embodiment 1

[0032] Weigh 1.2 tons of biurea, add 8 kg of sodium bromide catalyst, 100 kg of ADC foaming agent mother liquor with a concentration of 16.8%, put 3 tons of water in the reactor, heat up to 40°C, and then feed chlorine for biurea The oxidation reaction of urea is cooled with cooling water in the coil during the reaction, and the reaction temperature is controlled to be 38-42°C. After the reaction reaches the end point, the ADC foaming agent and the mother liquor of hydrochloric acid are separated to obtain 1135 kg of ADC foaming agent. The measured concentration of hydrochloric acid mother liquor is 17.2%.

[0033] Put 2.8 tons of anhydrous magnesium chloride in advance in the 10 cubic distillation tower kettle, first put 4 tons of the mother liquor hydrochloric acid produced in the synthesis process of the ADC blowing agent above, start stirring, heat up distillation, and start to generate hydrogen chloride gas at 50 ° C, control Heating rate, so that hydrogen chloride gas is...

Embodiment 2

[0035] Put 2.8 tons of magnesium chloride dihydrate in advance in the 10 cubic distillation tower kettle, first put 4 tons of mother liquor hydrochloric acid produced during the synthesis of the ADC blowing agent in Example 1, start stirring, heat up distillation, and start to generate hydrogen chloride at 50 °C Gas, control the heating rate, so that hydrogen chloride gas is generated smoothly. When the temperature rises to about 105°C, start to add the remaining mother liquor hydrochloric acid continuously, control the heating rate and the flow rate of the mother liquor hydrochloric acid to ensure the stable generation of hydrogen chloride gas, and carry out distillation in accordance with the speed of the biurea condensation process. After adding 8 tons of mother liquor, stop feeding and continue to heat up to 115° C., so that the hydrogen chloride in the hydrochloric acid in the tower kettle is basically evaporated. After the distillation was finished, the concentration of ...

Embodiment 3

[0037] Put 3.0 tons of anhydrous magnesium chloride in advance in the 10 cubic distillation tower kettle, first put 4 tons of mother liquor hydrochloric acid produced during the synthesis of the ADC foaming agent in Example 1, start stirring, heat up distillation, and start to generate hydrogen chloride at 50 °C Gas, control the heating rate, so that hydrogen chloride gas is generated smoothly. When the temperature rises to about 105°C, start to add the remaining mother liquor hydrochloric acid continuously, control the heating rate and the flow rate of the mother liquor hydrochloric acid to ensure the stable generation of hydrogen chloride gas, and carry out distillation in accordance with the speed of the biurea condensation process. After adding 8 tons of mother liquor, stop feeding and keep the distillation temperature. When the amount of hydrogen chloride gas is significantly reduced, turn on the vacuum fan to keep the vacuum of -0.07--0.08MPa in the tower kettle, and cont...

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Abstract

The invention relates to a recycling and reusing method for producing an ADC foaming agent mother liquor hydrochloride, which includes the following steps: A) a hydrazine hydrate and a urea liquor carry out a concentration reaction by pumping a hydrogen chloride gas in or adding a sulfate; the hydrogen chloride gas is pumped in to control and maintain the pH value as 4 to 6 to generate a biurea and an ammonium salt; and a biurea solid and a corresponding ammonium salt mother liquor can be acquired after separation; B) the biurea is made into a suspension liquid of 10 to 40 percent and a sodium bromide which accounts for 0.2 to 1.0 percent of the amount of the biurea is added as a catalyzer to oxidize and generate the ADC foaming agent by pumping in an chlorine-oxygen, and then the ADC foaming agent and hydrochloride mother liquor can be gotten after separation; C) the separated hydrochloride mother liquor is added with an anhydrous magnesium chloride or a dihydrate magnesium chloride accounting for 20 to 40 percent of the amount of hydrochloride mother liquor feed rate, and then heated to distill a hydrogen chloride gas under the state of stirring; D) the distilled hydrogen chloride gas is returned to the biurea concentration technique to be used as the raw materials for neutralization . The beneficial effects of the invention are that the invention can save 60 percent of the amount of the acid used in the concentration process, make full use of the resources, reduce the production cost, decrease the discharging of the pollutions and has significant economic benefits.

Description

technical field [0001] The invention relates to a recycling method, in particular to a recycling method for producing ADC foaming agent mother liquor hydrochloric acid. Background technique [0002] The chemical name of ADC foaming agent is azodicarbonamide. When heated to a certain temperature, it can release nitrogen, carbon dioxide, carbon monoxide and other gases. It is the most commonly used chemical foaming agent. It is used in the foaming of various rubber and plastic products. Molecular foaming material is also a food additive. [0003] As we all know, the production of ADC foaming agent is to produce biurea through the condensation reaction of hydrazine hydrate and urea first, and the biurea is then oxidized by chlorine gas, sodium chlorate, hydrogen peroxide, etc. in the presence of a catalyst to generate ADC foaming agent. The preparation method of biurea is prepared by the condensation reaction of hydrazine hydrate and urea under acidic conditions. During the re...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C281/20C07C281/06C01B7/07C02F1/58C02F103/36
Inventor 陈海贤于家波
Owner HANGZHOU HI TECH FINE CHEM
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