Studies on magnesium-ammonium phosphate recovery from wastewater

During the conducted research, several factors were described as having influenced magnesium ammonium phosphate recovery from the model solution and the effluents of the wet process phosphoric acid production. The factors comprised the pH (8.5-11), the molar ratio Mg2+:NH4+:PO4(3-) and the presence of fluorides. It was established that the process of MgNH4PO4 6H2O precipitation should be carried out at the pH 10.5 - 11, and the molar ratio Mg2+ : NH4+ : PO4(3-) 1.8 : 1.1. The possibility of distributive phosphates precipitation as struvite and the fluorides as CaF2, was determined.