Method for preparing high-purity chlorine dioxide and sodium chlorite by ferrous sulfide method

Abstract

The invention discloses a method for preparing high-purity chlorine dioxide and sodium chlorite by a ferrous sulfate method. The method comprises the following steps of: crushing ferrous sulfide; dissolving sodium chlorate into water to obtain sodium chlorate solution; diluting concentrated sulfuric acid by adding water, adding the diluted sulfuric acid into the sodium chlorate solution and uniformly mixing the solution; adding the mixed solution into ferrous sulfide powder; performing reduction reaction when stirring to produce high-purity chlorine dioxide gas; and inputting the gas into mixed absorption liquid consisting of hydrogen peroxide and sodium hydroxide, and thus obtaining the high-purity sodium chlorite solution, wherein the purity of the high-purity sodium chlorite solution is larger than 98 percent. According to the method, due to the adoption of the ferrous sulfide, the chlorine dioxide is obtained by the one-step reaction, and the sodium chlorite can be obtained by the two-step reaction; the conversion rate is up to more than 97 percent, the purity of the obtained chlorine dioxide and sodium chlorite is high, and the method has a simple production process and low cost, and is easy to industrialize.

Description

technical field [0001] The invention belongs to the field of bleaching agents and bactericidal disinfectants, and relates to a preparation method of chlorine dioxide and sodium chlorite, in particular to a method for preparing chlorine dioxide and sodium chlorite by a ferrous sulfate method. Background technique [0002] Ferrous sulfide exists mainly in the form of pyrrhotite in nature. The reduction in ferrous sulfide is negative divalent sulfur element and positive divalent iron element, and each mole of ferrous sulfide can provide 9 moles of electrons. [0003] Sodium chlorite is a white crystal, often yellow-green due to chlorine dioxide, and has two forms: anhydrous and trihydrate, with a transition temperature of 38°C, slightly hygroscopic, and relatively stable at room temperature. Because industrial sodium chlorite contains water and other impurities, it will decompose and release oxygen when heated to 130-140°C or even lower temperature. The alkaline aqueous solut...

AI Technical Summary

Problems solved by technology

Among these methods, some will pollute the generated chlorine dioxide because the reactant is a gas, and some will cause side reactions due to the presence of chlorine ions to generate by-product chlorine, reducing the concentration of chlorine dioxide

And the chlorine dioxide produced will generally entrain sulfur dioxide, chlorine gas, etc. into the chlorine dioxide absorber, which will not only consume lye, but also reduce the concentration of chlorite at the same time

Chinese patent ZL 02115238.1 discloses a preparation method of sodium chlorite, which is to mix and dissolve hydrogen peroxide and solid sodium chlorate in water, add the solution and sulfuric acid to a chlorine dioxide generator, and generate chlorine dioxide And oxygen is sent in the mixed solution that sodium hydroxide and hydrogen peroxide are housed, obtains sodium chlorite product, conversion rate and purity all exceed 95%, but use hydrogen peroxide as reducing agent to prepare chlorine dioxide in this method, lead to higher production costs