Specification First grade Upper grade Appearance White crystal White crystal Total content % í¦99 í¦99 P2O5 content % í¦61 í¦61 N content % í¦12 í¦12 Moisture % í_0.2 í_0.2 Water insoluble matters % í_0.1 í_0.1 Heavy metal ( base on Pb ) % -- í_0.001 As ( base on As ) % -- í_0.0003 Fluoride ( base on F ) % -- í_0.005 Use : Used as fire retardant, fire-proofing agent, fire-proof agent additive for wood, paper, fabric, used in manufacturing late making, medicine and radio tube, also used in phosphorus, nitrogen high efficient compound fertilizer. Upper grade is mainly used as nutrient. Packing : 25kg woven bag with plastic liner.