Device for bleaching nitric acid solution through urea method and preparation method therefor

Abstract

The invention provides a device for bleaching a nitric acid solution through a urea method and a preparation method therefor. The device comprises an acid preparation tank and a urea storage tank, wherein the acid preparation tank is connected with the urea storage tank through a communicating pipe; the top end of the acid preparation tank is connected with one inlet end of an ejector through a nitrogen dioxide pipe, the other inlet end of the ejector is connected with the urea storage tank, and the outlet end of the ejector is connected with a liquid distributor horizontally arranged inside the acid preparation tank through a urea pipe; and the outlet of the urea storage tank is connected with the urea pipe and the ejector respectively through a circulating conveying pump. Under micro negative pressure, NO2 in nitric acid and a urea solution both enter the ejector for reaction, and enter the acid preparation tank together with the urea solution to react with carbon dioxide generated later. Long-acting colorlessness of the nitric acid solution can be realized for a long time, so that the content of carbon dioxide in the acid preparation tank is quickly controlled, and the content overstandard problem of nitrogen dioxide is solved.

Description

technical field [0001] The invention relates to the technical field of production and preparation of nitric acid, in particular to a device for bleaching nitric acid solution by urea method and a preparation method thereof. Background technique [0002] Nitric acid is a strong oxidizing and corrosive inorganic acid, and its anhydride is dinitrogen pentoxide. Nitric acid is easily soluble in water and completely ionized in water. At room temperature, the dilute solution of nitric acid is colorless or light yellow and transparent, and the concentrated solution is brown. Nitric acid is unstable and easily decomposed by light. It should be stored in a brown bottle in a dark place away from light, and contact with reducing agents is strictly prohibited. Nitric acid is mainly produced by ammonia oxidation in industry, and is used to manufacture fertilizers, explosives, nitrates, etc. In organic chemistry, the mixture of concentrated nitric acid and concentrated sulfuric aci...

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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, even if the colorless dilute nitric acid decomposes NO in a small amount during transportation 2 ,polluted environment

[0005] Conventional dilute nitric acid bleaching often utilizes air or steam, namely "cold bleaching" or "hot bleaching". NO produced during storage and transportation 2

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