By methods of pH monitoring of filtration solutions as well as due to determinationof residual concentrations of ions Мg2+ and РО43- the bishofite–phosphate acid interaction was studied with the given ratio [РО43-]:[Мg2+]=0,187-5,24. The precipitation arising from the reaction was studied by chemical, thermal gravimetric and X-ray phase analysis and its compliance with the formula xNH4MgPO4∙yMgHPO4 was established, where х = 0,25; у = 0,75.
