Process for preparing sodium dichromate

Abstract

The invention provides a process for preparing sodium dichromate, namely producing the sodium dichromate through a carbonization method comprising: converting sodium chromate into the sodium dichromate via carbon dioxide under pressurizing condition; delivering sodium chromate neutral liquor with impurities removed to a carbonization tower after a cascade reaction of more than three continuous towers; obtaining carbonizing liquor by controlling different gradient parameters (concentration and temperature of the carbonizing liquor, partial pressure of the carbon dioxide, carbonizing time and the like), continuously carbonizing and separating under pressure; obtaining sodium dichromate finished products through concentrating, filtering, evaporating, crystallizing and centrifugal dehydrating.

Description

technical field

[0001] The present invention relates to the preparation method of red vitriol sodium in chromium salt industry. Background technique

[0002] Sodium red alum (sodium dichromate) is an important basic chemical raw material, mainly used in the production of chemical products such as chromic anhydride, chrome yellow, chromium oxide green and potassium dichromate. It is used as an auxiliary agent in the printing and dyeing industry, electroplating industry and leather industry, and also as an oxidizing agent in the chemical industry and pharmaceutical industry. It has a wide range of applications.

[0003] At present, the methods of making red vitriol sodium from sodium chromate in various countries in the world mainly include sulfuric acid method, electrolysis method and carbonization method. The sulfuric acid method is the method adopted by our country and most countries, but the disadvantage of the sulfuric acid method is the consumption of sulfuric acid, the...

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