Sodium formate method is used to produce hydrosulfite, oxygen is obtained by air separation, and sulfur dioxide is obtained by pure oxygen-sulfur combustion method. Sodium metabisulfite is reacted with water to produce sodium bisulfite, and then sodium formate, sodium bisulfite and sulfur dioxide are reacted in methanol aqueous solution to form sodium hydrosulfite, which is washed with alcohol, filtered, dried and packaged to obtain the final product. In the production process of hydrosulfite, the reaction medium methanol is recycled and reused by rectification, and acid gas and basic gas are generated in the reaction process, which are discharged after multi-stage absorption. The methanol distillation residue is extracted with sodium formate and sodium thiosulfate and discharged into the sewage system.
