KINETICS OF ZINC FERRITE FORMATION IN THE RATE DECELERATION PERIOD

The initial surface chemical reaction involved in zinc ferrite formati on is very rapid at any given temperature, and the reactants quickly b ecome covered with zinc ferrite. Then, the reaction rate becomes decel erated. In this work, the kinetics of zinc ferrite formation during th is rate deceleration period was studied in the temperature range of 87 3 to 1073 K. The experimental data were found to be best described by Jander's model and the activation energy was found to be about 168 kJ mol(-1). This activation energy indicates that diffusion is rate contr olling. The effect of briquetting pressure was more significant at low compaction pressures, and sample size had no effect in the range stud ied. These results contribute to an improved understanding of the form ation mechanism of some soft ferrites, such as MnZn-ferrite and NiZn-f errite, which are employed in the electronics industry, and also the f ormation of zinc ferrite during roasting and dust formation in pyromet allurgical processes.