sodium metabisulfite Na2S2O5 (1)Molecular formula: Na2S2O5 (2) Physical appearance: white or yellow crystalline powder or small crystal (3)Purity(Na2S2O5): 96.5% min (4)Content of SO2: 65% (5)Main use: Dyeing mordant; antichlor fabric after bleaching; food preservatives；reducing agent and sulfonating agent in chemical, medicine industry; bleaching agent for bamboo, wood, paper fiber; non-ferrous metal ore-dressing agent; waste water treatment agent and rubber coagulator (6) Packing: Plastic woven bag internal with paper (7)Net weight: 25kg /bag (8)specification: Main content (Na2s2o5) >= 96.5%; SO2 >= 65.1% Content of iron (Fe) >=0.005% heavy metal( in pb) <= 0.001% Content of arsenic(As) <= 0.0002% PH: 4.3