Transformations of sulfides during aqueous carbonation of oil shale ash

Oil shale ash (OSA) is a sorbent for CO2 mineralization and Ca-source for PCC. In the current study, transformations of sulfides, including formation of H2S(g), in the model systems of CaS - H2O and OSA - H2O in anaerobic (in N-2) and aerobic conditions (in air) as well as in the process of aqueous carbonation, was investigated. The results revealed that concentration of sulfides in OSA aqueous suspension depends on resource of sulfides, pH, diffusion limitation, and the presence of oxidants. At pH values <10, desorption of H2S(g) is preferred to oxidation of sulfides, which was expressed by the intense emission of H2S(g). (C) 2013 The Authors. Published by Elsevier Ltd.