Thermal solid-solid interactions and physicochemical properties of NiO/Fe2O3 system treated with K2O

ABSTRACT

The effects of calcination temperature and doping with K2O on solid-solid interactions and physicochemical properties of NiO/Fe2O3 system were investigated using TG, DTA and XRD techniques. The amounts of potassium, expressed as mol% K2O were 0.62, 1.23, 2.44 and 4.76. The pure and variously doped mixed solids were thermally treated at 300, 500, 750, 900 and 1000°C. The catalytic activity was determined for each solid in H2O2 decomposition reaction at 30-50°C. The results obtained showed that the doping process much affected the degree of crystallinity of NiO and Fe2O3 detected for all solids calcined at 300 and 500°C. Fe2O3 interacted readily with NiO at temperature starting from 700°C producing crystalline NiFe2O4 phase. The degree of reaction propagation increased with calcination temperature. K2O-treatment stimulates the ferrite formation to an extent proportional to its amount added in the formation of KFe11O17