2016 Volume 53 Issue 12 Pages 768-773
A solid-state mechanochemical reaction between ZnO and Fe2O3 to form ZnFe2O4 was kinetically analyzed based on the mechanical energy applied to the reactants. A powder mixture of ZnO and Fe2O3 was mechanochemically treated by a planetary ball mill at different revolution speeds of the vessel for changing the impact energy and collision frequency of grinding balls. An increase in the conversion of ZnO to ZnFe2O4 with increasing milling time was well described in terms of a solid-state reaction model taking into account three-dimensional diffusion of reactants. A plot of the reaction rate constant on semi-logarithmic scale as a function of reciprocal of the translational kinetic energy of reactant particles gave a straight line with a negative slope. This relationship suggests that the rate constant depends on the kinetic energy and collision frequency of reactant particles, indicating that kinetics of the mechanochemical reaction may be explained by statistical mechanics and thermodynamics.
