Abstract:Extraction kinetics of zirconium and hafnium extracted by N263-HSCN system was studied by constant Lewis cell technique. Effects of stirring speed, interfacial area and temperature of extraction tank on extraction of zirconium and hafnium were explored to determine the type of extraction kinetics. The results show that when stirring speed is less than 130 r/min, the extraction rate constant of zirconium and hafnium rises with the increase of stirring speed, and the extraction process is controlled by diffusion reaction; When stirring speed is within 130—170 r/min, the extraction rate constants of zirconium and hafnium remains basically stable with the increase of stirring speed, and the extraction process is controlled by chemical reaction. With the increase of interfacial area and temperature, the extraction rate constants of zirconium and hafnium rise, the apparent activation energies of zirconium and hafnium extraction are 42.06 kJ/mol and 31.77 kJ/mol respectively, indicating that the extraction process is controlled by chemical reaction process at the phase interface. The enthalpy changes of zirconium and hafnium extraction are 39.59 kJ/mol and 29.30 kJ/mol respectively. The entropy changes are -147.53 J/(mol?K) and -174.38 J/(mol?K) respectively, and the Gibbs free energy changes are 83.57 kJ/mol and 81.29 kJ/mol respectively at 298.15 K.