Sodium metabisulfite: used for the production of insurance powder, sulfadimethylpyrimidine, analgin, caprolactam, etc., as well as the purification of chloroform, phenylprosulfone and benzaldehyde. It is used in the photographic industry as an ingredient for fixers. The fragrance industry is used in the production of vanillin. It is used as a preservative in the brewing industry, a rubber coagulant and a dechlorinator after bleaching cotton cloth. Organic intermediates, dyes, tanning are used as reducing agents in the electroplating industry, wastewater treatment in oil fields and as beneficiation agents in mines, etc. It is used in printing and dyeing, organic synthesis, printing, tanning, pharmaceutical and other departments in industry, and is used as a preservative, bleaching agent and loosening agent in food processing.