The kinetics of the olivine dissolution under the extreme conditions of nano-silica production

Abstract This article addresses the kinetics of the dissolution of olivine for nano-silica production at extreme conditions. The extreme conditions are pH values between −0.7 and 1, temperature between 50 and 90 °C, solid content around 250 g/L and percentage dissolved between 80% and 99%. This work is structured in 3 parts: (1) chemical and mineralogical characterization of the dunites employed; (2) mechanism of the olivine dissolution focusing on the possible resistances to the transport; and (3) determination of the kinetic parameters kT and n. The results shown here demonstrate that: (1) the limiting step of this process is not the diffusion through a silica layer but the surface reacti…