A. Zakeri,, M. Sh. Bafghi, Sh. Shahriari,
Volume 4, Issue 3 (12-2007)
Abstract
Abstract: In this paper, kinetics of reductive leaching of manganese dioxide ore by ferrous ion in
sulfuric acid media has been examined. Experimental results show that increasing temperature
from 20 to 60 °C and decreasing ore particle size from −16+20 to −60+100 mesh considerably
enhance both the dissolution rate and efficiency. Molar ratios of Fe2+/MnO2 and H2SO4/MnO2 in
excess to the stoichiometric amounts were needed for successful manganese dissolution. Under the
optimum condition (ore particle size of −60+100 mesh, Fe2+/MnO2 molar ratio of 3.0,
H2SO4/MnO2 molar ratio of 2.0) manganese could be extracted with over 95% efficiency by 20
minutes leaching at room temperature. A kinetic analysis based on dimensionless time method
showed that shrinking core – ash diffusion control model fits the experimental results reasonably
well. Value of activation energy was found to be 28.1 kJ/mole for the proposed mechanism.
