The Dissolution of Olivine in Aqueous Solutions of Inorganic Acids

Abstract

Abstract The dissolution of olivine was studied in aqueous solutions of inorganic acids at temperatures of 35, 50, and 65°C in order to obtain basic information about the alteration and leaching processes in acid hot spring regions. The rates of dissolution have been determined by measuring the change in the concentrations of silica, magnesium, and the total iron leached in the solutions as a function of the time. Olivine dissolved in stirred aqueous solutions of 0.05–2n perchloric, hydrochloric, and sulphuric acids without any selective dissolution of components in the mineral. The rate at which olivine dissolved was found to be two-thirds of the reaction order with respect to the sample-powder (10–20 μ in diameter) weight (i.e., first order with respect to the surface area) and to decrease in the order of H2SO4>>HCl>HClO4. HSO4− enchanced the rate remarkably. The complexing affinity of the anions did not play an important part in the reaction with olivine powder.