Jun 05, 2021 · Ammonium sulfate, manganese sulfate, and calcium hydrogen phosphate dihydrate form gypsum (CaSO 4) and MnNH 4 PO 4 ·H 2 O . Ammonium sulfate, magnesium ions and calcium bishydrate react to form struvite and gypsum . In the steps shown in,, Mn 2+, ammoniumnitrogen, and sulfate ions are immobilized. In addition, the gelation effect of calcium ...