The article presents information about the possibility of using sodium arsenite hydrolyzed as a new type of arsenic-containing raw material for obtaining marketable products of various qualities. The methods of purification of arsenic (III) oxide as the main product of sodium arsenite hydrolyzed processing to various degrees of purity (3-6N) are given, which allows using it as a raw material for the synthesis of a wide range of arsenic compounds: arsenic acid, elemental arsenic, arsenic trichloride.