Effects of Mineral Oxides on the Precipitation Micro-Morphology of Metallic Iron in the Reduction of Iron Oxides Under CO Atmosphere

Abstract

Grain sticking often occurs in the fluidized bed reduction of fine iron ore, which is closely related to the precipitation morphology of metallic iron on the surface of ore particles. In this work, simulating the gas-solid reduction process of iron ore, in situ observations were carried out to investigate effects of doping mineral oxides on the precipitation morphology evolution of metallic iron during reduction of iron oxides with CO. Results indicate that the precipitation morphology of metallic iron is related to the quantity of doped mineral oxides. The minimum mole fraction of doped oxide \(({N_{{A_y}{O_x}}})\) that can inhibit the growth of iron whiskers is related to its cation radius \(({r_{{A^{x + }}}})\), extranuclear electronic layers \(({n_{{A^{x + }}}})\) and valence electrons \(({q_{{A^{x + }}}})\). Their relation can be expressed as: \({N_{{A_y}{O_x}}} = 1.3 \times {10^{ - 5}} \cdot \frac{{r_{{A^{x + }}}^2 \cdot \sqrt {{n_{{A^{x + }}}}} }}{{({q_{{A^{x + }}}} - 1)!}}\)