THE INVESTIGATION OF THE SYSTEM КLa(SO4)2 - CaSO4
The system KLa(SO4)2 - CaSO4 was investigated by X-ray diffraction and differential thermogravimetric analysis. It is established that this system is not formed intermediate compounds or the existence of any homogeneity regions on the basis of structures КLa(SO4)2 or CaSO4. Double sulfate of potassium and lanthanum КLa(SO4)2 decomposes at a temperature of 905 0С with the formation of double sulfate of potassium and lanthanum composition 7:3 K7La3(SO4)8. Double sulfate K7La3(SO4)8 has a polymorphic transformation at a temperature of 9700 C and decomposes with the formation of potassium sulfate and oxide La2O3 at a temperature of 10600 C. The resulting lanthanum oxide promotes the decomposition temperature of calcium sulfate.