Sodium metabisulfite is white or yellow crystalline powder or small crystals, with a strong smell of SO2, the aqueous solution is acidic, and the contact with strong acid releases SO2 and generates the corresponding salts, long in the air, it is oxidized to Na2S2O6, so the product can not last long

It is used as a preservative, bleach and loose agent in food processing. Industrial sodium sulfite used in printing and dyeing, organic synthesis, printing, leather, pharmaceutical and other departments; Sodium pyrosulfite is used in the chemical and pharmaceutical industries for the production of insurance powder, sulfadimethylpyrimidine, caprolactam, etc., as well as the purification of chloroform, phenylpropansulfone and benzene Chemicalbook formaldehyde. Used in the photographic industry as a fixing agent ingredient. The spice industry is used to produce vanillin. Used as preservative in brewing industry, rubber coagulant and dechlorination agent after cotton bleaching. Organic intermediates, dyes, tannery used as reducing agents used in electroplating industry, wastewater treatment in oil fields and as beneficiation agents in mines.