三Superphosphate

Triple superphosphate is a fertilizer produced by the action of concentrated phosphoric acid on ground phosphate rock.[2] Ca3(PO4)2(s) + 4 H3PO4(aq) → 3 Ca 2+(aq) + 6 H2PO41-(aq) → 3 Ca(H2PO4)2(aq) The active ingredient of the product, monocalcium phosphate, is identical to that of superphosphate, but without the presence of calcium sulfate that is formed if sulfuric acid is used instead of phosphoric acid. The phosphorus content of triple superphosphate (17 - 23% P; 44 to 52% P2O5) is therefore greater than that of superphosphate (7 - 9.5% P; 16 to 22% P2O5). Triple superphosphate was the most common phosphate (P) fertilizer in the USA until the 1960s, when ammonium phosphates became more popular. It is produced in granular and nongranular form and is used both in fertilizer blends (with potassium and nitrogen fertilizers) and by itself.