Cleaning method of biurea mother liquid

Abstract

The invention discloses a cleaning method of a biurea mother liquid. The cleaning method comprises the following specific steps: (A) recovering biurea particles with a biurea mother liquid, and absorbing a hydrogen chloride gas into a hydrochloric acid of which the hydrogen chloride content is 11%-15%; (B) separating the 11%-15% hydrochloric acid from separated sodium chloride to obtain a mother liquid A and sodium chloride; (C) absorbing the hydrogen chloride gas with the mother liquid A until the hydrogen chloride content is 31%, and obtaining a mixture of the hydrochloric acid and ammonia chloride crystal; (D) separating the mixture of the hydrochloric acid and the ammonia chloride crystal to obtain the hydrochloric acid and ammonia chloride; and (E) respectively washing the ammonia chloride and the sodium chloride crystal to be neutral, and drying. The cleaning method disclosed by the invention has the beneficial effects that the ammonia chloride and the sodium chloride in the biurea mother liquid are respectively recovered and changed into treasures, so that the emission of sewage is reduced; the comprehensive utilization rate of the biurea mother liquid is improved; the blank that a lot of inorganic salt in the biurea mother liquid cannot be treated or recovered at present is filled; low-cost management with the biurea mother liquid is realized; resources are recovered; and the economic benefits are significant.

Description

technical field [0001] The invention relates to the technical field of environment and resource utilization, in particular to a method for cleaning and treating biurea mother liquor. Background technique [0002] Biurea (Biurea) molecular formula: C 2 h 6 N 4 o 2 , is an intermediate in the production of azodicarbonamide. Azodicarbonamide is one of the most widely used blowing agents due to its non-toxicity, no residue and low price, and its consumption accounts for more than 90% of the total amount of blowing agents. [0003] Biurea is a downstream fine chemical intermediate product derived from the chlor-alkali industry. The main raw materials are urea, chlorine gas and caustic soda. The production process of the hydrochloric acid condensation method is as follows: figure 1 As shown, the principle is as follows: [0004] Sodium hypochlorite synthesis: NaOH+Cl 2 →NaClO+NaCl+H 2 o [0005] Synthesis of hydrazine hydrate: NaOH+NaClO+NH 2 CONH 2 →NH 2 NH 2 ·H 2 O...

AI Technical Summary

Problems solved by technology

[0013] The purpose of the present invention is just in order to overcome the deficiency of above-mentioned technology, and provide a kind of cleaning treatment method of biurea mother liquor, solve the problem that a large amount of inorganic salts in biurea mother liquor can not be processed (or be difficult to low-cost processing), change Waste into treasure, the method of recycling reaction by-products

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