Energy efficient process for making pyrophyllite-based ceramic tiles using phosphoric acid and mineralizers

The processing parameters for making ceramic tiles in the pyrophyllite–phosphoric acid binder (P–PA) system have been optimized. The optimized raw material composition requires sintering at a lower temperature of 950 °C. The X-ray powder diffraction studies on the powdered sample of optimized composition have confirmed the presence of dehydroxylate pyrophyllite, tridymite (T-AlPO4), cristyoballite (C-AlPO4) forms of aluminium phosphate and formation of silico-phosphate (SiP2O7) and alkali aluminium silicates (NaAlSiO4, KAlSi3O8). The IR studies of the sample show Al–O, Si–O·P–O and Na/K–O linkages. The thermal analysis shows the formation of dehydroxylate pyrophyllite and different forms of AlPO4. Scanning electron microphotograph reveals the chunky morphology of the dehydroxylate pyrophyllite, the rhombohedral morphology of T-AlPO4 and spherical C-AlPO4 and silico-phosphate particles