Dissolution of Magnesium from Serpentine Mineral in Sulfuric Acid Solution

As the volume of CO2, one of greenhouse gases linked to global warming, in the atmosphere increases, there has been an increasing interest in CO2 sequestration. Aqueous carbonation, which involves the extraction of Mg from serpentine minerals and the subsequent carbonation reaction with CO2 to form the geologically stable mineral MgCO3, has been proposed as a promising CO2 sequestration technology. This study investigates the dissolution of Mg from serpentine mineral in H2SO4 solution. The study is part of a major research project aimed at developing an effective CO2 sequestration technology using the serpentine mineral which is readily available in Korea. Complete dissolution of Mg from natural serpentine was achieved in 30min at a temperature of 90 C under 0.5M H2SO4. The rate of dissolution of Mg was independent of the agitation speed at speeds above 300 rpm. The fraction of Mg dissolved from milled serpentine was found to be a little higher than that from natural serpentine up to 70 C in 0.5M H2SO4. The Jander equation was used to explain the dissolution rate data. The rate of Mg dissolution seemed to be limited by diffusion through the thin channels formed between the silica layers in the serpentine particles. [doi:10.2320/matertrans.M2009019]