Direct Conversion of Electric Arc Furnace Dust to Zinc Ferrite by Roasting: Effect of Roasting Temperature

The direct conversion of electric arc furnace (EAF) dust into zinc ferrite by roasting with a small amount of Fe 2 O 3 was explored with a focus on the influence of roasting temperature on zinc conversion, phase transformation, microstructural evolution, and product magnetic property. The results showed that the zinc compounds in the dust preferentially reacted with iron components to form zinc ferrite in the temperature range up to 1000 °C due to the low Gibbs free energy changes of the relevant reactions and high contents of Fe 2 O 3 and Fe 3 O 4 in the dust, increasing the percentage of zinc conversion of EAF dust to 91.36% after roasting at 1000 °C. When the temperature exceeded 1000 °C, however, the percentage of zinc conversion dropped to 90.26% due to the consumption of zinc for generating zinc-containing impurity phases, mainly Ca 2 ZnSi 2 O 7 and slag, and to the loss of zinc caused by volatilization of the metal. After roasting of EAF dust at the optimal temperature of 1000 °C for 2 h, 94.13% of total zinc existed in the form of insoluble zinc in the roasting product with the saturation magnetization ( M S ) of 47.9 emu/g and coercivity ( H C ) of 65.8 Oe. The product can serve as a good precursor for producing high-quality ferrite powders. Graphical Abstract