Research on Leaching Kinetics of Scandium From Red Mud

Acid leaching of scandium from candium-rich red mud which produces in aluminum production by Bayer process has been carried out,and kinetic model about leaching of scandium is founded.The results show that under the conditions of reaction temperature of 90 ℃,particle diameter of 65~80 μm,ratio of liquid-to-solid of 3∶1 and reaction time of 3 h,leaching rate of scandium is over 85%.The acid leaching process of scandium from the red mud corresponds with shrinking core model,the kinetics equation is of 1-(1-xB) 2/3-2/3xB=2.156e-17.8/RTt,the activation energy is of 17.8 kJ/mol,the leaching reaction is mostly controlled by solid-membrane diffusion process.