Abstract:The leaching kinetics of bastnaesite concentrate in HCl solution was investigated with respect to the effects of HCl concentration by changing HCl concentration, leaching temperature, liquid to solid ratio, and particle size. A particle size of 25 μm was required to leach 89.6% RE₂(CO₃)₃ and 1.5%REF₃ at 90 °C for 90 min, when HCl concentration was 6 mol/L and liquid to solid ratio was 15:1. The leaching kinetics of bastnaesite concentrate is represented by shrinking core model with diffusion through a porous product layer. The activation energies for the dissolution reaction of RE₂(CO₃)₃ and REF₃ were calculated to be 59.39 kJ/mol and 66.13 kJ/mol respectively.

Key words: bastnaesite; RE₂(CO₃)₃; REF₃; leaching kinetics