... , tanning, metal smelting, surface treatment and filler industries. Grade: Class I first quality Packing: 50kg, 25kg plastic bagQuality Standard: GB/T6009-2003 ... Guideline ItemGuidelineIIIThe best classThe first classThe first classSodium Sulphate Anhydrous (Na2SO4) Purity%≥99.399.098.0Water ...