Quality Index (PRC chemical industry HG/T2520-93 standard) Product Grade/Test Item Superior (%) Grade I (%) Assay (In H3PO3) 99.0 98.0 Iron (In Fe) 0.0012 0.005 Chloride (In Cl) 0.01 0.01 Sulfate (In SO4) 0.006 0.006 Phosphate (In PO4) 0.1 0.1 Appearance Pure white crystal White crystal Aqueous solution test (70%) Colorless and transparent Colorless and transparent, no impurity II. Packing: (1) Net weight 25kg/bag, plastic woven bag; (2) Net weight 50kg/bag, fiber drum or iron drum; (3) Net weight 1000kg/bag; (4) Other, packed according to customers' requirements.