Dephosphorization treatment of high phosphorus oolitic iron ore by hydrometallurgical process and leaching kinetics

Abstract

Dephosphorization process of high phosphorus oolitic iron ore by acid leaching and leaching kinetics were investigated in the paper. The high phosphorus ore samples (51%T.Fe, 0.52%P) used in this work were analysed by SEM-EDS and XRD, which showed their oolitic structure and mineral phases. Among the three kinds of acids (H2SO4, HCl and HNO3), sulfuric acid was the most appropriate one for dephosphorization, and structure changes after leaching were also investigated through the SEM and EDS analysis. The effects of acidity, particle size, stirring speed and temperature were researched in detail. Through acid leaching, phosphorus could be removed effectively, and iron loss was negligible, which was also studied by thermodynamic calculation. The experimental data could be well described by the unreacted shrinking core model and rate controlling step was found to be chemical reaction between apatite and acid. The apparent activation energy was calculated as 45.02 kJ/mol. © 2013 ISIJ.