Kinetics of sulfation-roasting of nickel laterite for recovery of nickel and cobalt

Mineralogical characterizations of the nickel laterite material were done by X-ray fluorescence(XRF),X-ray diffraction(XRD),scanning electron microscope(SEM) and other techniques.Nickel and cobalt were extracted from nickel laterite by sulfation-roasting-leaching process and the kinetics of nickel and cobalt sulfation was studied.The results show that the sulfation of nickel and cobalt accords with the liquid-solid regional reaction model raised by Bagdasarym and the kinetic equation is expressed as ln(?ln(1?α))=ln k+nln t(where α is reaction degree;k is reaction rate constant;t is reaction time;n is the function of property and geometric shape of particles in minerals).The activation energies are determined to be 21.45 kJ/mol for nickel and 34.81 kJ/mol for cobalt respectively,which are characteristic of an internal diffusion controlled process.