... of Sodium Tripolyphosphate (STPP) 2,Free sample 3,High quality and competitive price 4,Quickly deliveryProduct DescriptionProduct: Sodium Tripolyphosphate ... Ca 2+, Mg 2+, can soften hard water, change suspension into solution, slightly alkaline, without causticity. 2, Usage: ... pre-tanning agent, dye auxiliary agent, and dispersant of suspension such as paint, kaolin, magnesium oxide, calcium carbonate ...