Patent ID: 6251357
Filing Date: 2001-06-26
Classification: C01B

Abstract:
A method of producing sodium chlorite with a low carbonate level, which comprises:effecting the generation of chloride dioxide by reducing chlorate ions to chlorine dioxide in an aqueous acid reaction medium at its boiling point under a subatmospheric pressure in a first reaction zone,removing a gaseous admixture containing chlorine dioxide from said first reaction zone,feeding said chlorine dioxide to a second reaction zone,reacting the chlorine dioxide with an aqueous sodium hydroxide solution and hydrogen peroxide as a reducing agent in an aqueous reaction medium in said second reaction zone, said second reaction zone being maintained under a subatmospheric pressure of about 50 to about 200 mmHg, and removing an aqueous solution of alkali metal chlorite having a low carbonate ion concentration from said second reaction zone.