COMPOSITION AND REACTIONS OF LIQUID MANURE (GULLE), WITH PARTICULAR REFERENCE TO PHOSPHATE .2. SOLID-PHASE COMPONENTS

Several components were detected in the solid phase of guelle samples. Struvite (NH//4MgPO//4 multiplied by (times) 6H//2O) was isolated from one sample and identified by X-ray diffraction. Its presence was confirmed in this and other samples by solubility studies, which also showed the existence of trimagnesium phosphate (Mg//3(PO//4)//2 multiplied by (times) 8H//2O), octacalcium phosphate (Ca//4H(PO//4)//3 multiplied by (times) 3H//2O), dicalcium phosphate (CaHPO//4 multiplied by (times) 2H//2O), and possibly NH//4CaPO//4 multiplied by (times) H//2O. More evidence for struvite, trimagnesium phosphate, and octacalcium phosphate, as well as estimates of their content in samples was obtained from measurements of solution composition during acid titration of guelle suspensions. Organic phosphate contents of the solid phase could be calculated from these measurements, which also showed the existence of appreciable quantities of solid ammonium and calcium organic salts.