Carbothermic reduction of zinc ferrite by microwave heating

The kinetics of carbothermic reduction of ZnFe₂O₄ in the temperature range 823-1223 K, was investigated in a microwave reactor. The mechanism of formation of ZnO and Fe₃O₄/FeO by decomposition of ZnFe₂O₄ was explained using the equilibrium calculations and thermodynamics analysis using HSC chemistry software 6.0. In addition the effect of parameters such as the decomposition temperature, C/ZnFe₂O₄ ratio, particle size and microwave power were assessed on the decomposition kinetics. Zn recovery as high as 98.83% could be achieved at a decomposition temperature of 1023 K, C/ZnFe ₂O₄ ratio of 1:3, particle size of +74-61 μm and microwave power of 1200 W. The kinetics of decomposition was found to be carbon gasification reaction controlled, with the activation energy of 39.21 kJ/mol.