Recycling method of byproduct saline during preparation of hydrazine hydrate by using urea method

Abstract

The invention discloses a recycling method of a byproduct saline during preparation of hydrazine hydrate by using a urea method. The method includes adding excess CO2 into a coarse hydrazine solution, and keeping the negative pressure of a steel cylinder containing the CO2 to be 100pa to 150pa and the flow to be 0.5-0.8mol / L; stirring the mixture continuously for 0.5 hour when the negative pressure in the steel cylinder is zero; freezing and crystallizing the solution through general freezing brine, and controlling the temperature in a range from 2 DEG C to 6 DEG C and the freezing time to be 2 hours; performing cold filtering to obtain filter residues, drying the filter residues in a vacuum drying oven for 4 hours, and keeping the temperature of the drying oven to be 35 DEG C to 45 DEG C; adding urea into the filtrate obtained through cold filtering, adding sulfuric acids to regulate the pH to be 3 to 4, controlling the temperature to be 106 DEG C to 120 DEG C, and reacting the mixture for 2 hours; and feeding chlorine into a biurea reaction still to perform oxidation to obtain the resultant ADC foaming agents, wherein the filtrate is sent to an electrolytic tank. The recycling method of byproduct saline during preparation of hydrazine hydrate by using the urea method has the advantages that the byproduct sodium salt of the hydrazine hydrate is fully recycled, the cost is reduced, and the method is a green chemical process.

Description

technical field

[0001] The invention relates to a treatment method for by-products in the production of hydrazine hydrate by the urea method, more specifically, sodium chloride, sodium carbonate and sodium hydroxide, etc. Salinity recovery treatment method. Background technique

[0002] Hydrazine hydrate, also known as hydrazine hydrate, is the monohydrate of hydrazine (N 2 h 4 ·H 2 O), the appearance is a colorless transparent liquid, which can be mixed with water and alcohol arbitrarily, and is insoluble in ether and chloroform. Hydrazine hydrate is an important fine chemical intermediate, which is widely used in the synthesis of pesticides, medicines, water treatment, foaming agents, initiators and curing agents, etc., and has broad prospects for development and utilization.

[0003] The production methods of hydrazine hydrate include Raschig method, urea method, ketazine method, hydrogen peroxide method and air oxidation method.

[0004] The urea method to produce h...

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