Investigation of Selective Reduction of Iron Oxide in Zinc Ferrite by Carbon and Hydrogen

The feasibility of selective reduction of iron oxide in zinc ferrite, which is one of the main components of electric arc furnace dust (EAFD), was examined. Experiments were carried out by using graphite powder or pure hydrogen gas as reducing agents. The carbothermal reduction experiments performed at temperatures between 973 and 1073 K in inert atmosphere indicated that the method was difficult to apply in practice due to slow rates of reaction and vaporization of zinc. Selective reduction of iron oxide in zinc ferrite was achieved by using pure hydrogen gas as the reductant. The iron oxide was reduced to metallic iron, while ZnO remained unreacted in the solid phase. As reaction times were increased at 873 K, ZnO was also reduced and zinc evaporated. The main advantages of H2 reduction are high reaction rates, low energy requirements, and no CO2 emissions. The addition of this process prior to the hydrometallurgical techniques for treatment of EAFD could overcome the difficulties for dissolution of zinc ferrite. © 2015, The Minerals, Metals & Materials Society (TMS).