Item Top Grade First Grade Purity,%,≥ 99.8 99.0 Moisture,%,≤ 0.1 0.2 PH value 7.5-9.5 Ash,%, ≤ 0.03 0.05 Water dissolve test of formaldehydeTurbidity(kaolin) ≤ 20 30 Chroma(Hazen)Unit—(Pt-Co)≤ 20 30