A kind of bleaching process and its device in the preparation process of nitric acid

Abstract

The invention provides a bleaching process and its device in the nitric acid preparation process, comprising the following steps: (1) pumping the acid preparation tank for preparation of nitric acid into a slight negative pressure; (2) pumping the nitric acid solution into the acid preparation tank Add hydrogen peroxide and stir evenly, so that the molar ratio of hydrogen peroxide to NO2 in the acid distribution tank is greater than 1:2; (3) Recover excess NO2 at the outlet of the acid distribution tank. The invention uses compressed air to make hydrogen peroxide evenly add into the nitric acid solution in the acid mixing tank through a distributor to react with nitrogen dioxide to generate nitric acid and oxygen, thereby achieving the purpose of bleaching nitric acid; at the same time, excess nitrogen dioxide is released and is absorbed The negative pressure pump is used to quickly control the nitrogen dioxide content in the acid distribution tank, which solves the problem of excessive nitrogen dioxide content.

Description

technical field [0001] The invention relates to the technical field of nitric acid preparation, in particular to a bleaching process and a device in the nitric acid preparation process. Background technique [0002] Nitric acid is one of the most important chemical products. Nitric acid is mainly produced by ammonia oxidation in industry, and is used to make fertilizers, explosives, nitrates, etc. Pure nitric acid is a colorless transparent liquid, and industrial nitric acid solution is brown due to dissolved nitrogen dioxide. At present, nitric acid is used in all walks of life, but different industries have different requirements on the concentration of nitric acid. For example, the production of ammonium nitrate by neutralization requires nitric acid with a concentration of 37-43% as a raw material, while the production of ammonium nitrate by pressurization requires a concentration of 60%. Nitric acid is used as a raw material; the IT industry needs nitric acid with a co...

AI Technical Summary

Problems solved by technology

The concentration of nitric acid produced by the above device may not be able to meet the needs of customers. Customers still need to prepare nitric acid aqueous solutions of different concentrations by themselves. However, in the process of preparing nitric acid aqueous solution, the mixture of concentrated nitric acid and dilute nitric acid will generate heat, which will cause a small amount of nitric acid to decompose. Its reaction formula is 4HNO 3 ==2H 2 O +4NO 2 +O 2 , so that the dilute nitric acid solution turns red

Conventional nitric acid bleaching often uses air or steam, that is, "cold bleaching" or "hot bleaching", but both technologies have defects, often consume a lot of electricity or heat energy, and take a lot of time at the same time

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