The interactions of (NH4)2SO4 and FeSO4 with the oxides of Zn, Cu, Cd, Mg, Ca, Pb, Fe, Al, individually and mixed ferrites of Zn, Cu, Cd have been investigated using DTA, TGA, X-ray phase analysis and Mossbauer spectroscopy. The temperature ranges over which the obtained sulphates are stable have been determined. The sulphatization effects of (NH4)2SO4 and FeSO4 have been compared. Their peculiarities under thermal treatment are presented and the optimum sulphatization temperature intervals have been determined.