Mineral carbonation of Mg silicates via a gas/solid carbonation of magnesium hydroxide, Mg(OH)(2) in a fluidized bed (FB) reactor process route is the most actively investigated route of carbon capture and storage by CO2 mineralization (CCS) research in Finland. This paper reports Mg extraction behavior and production of magnesium hydroxide, Mg(OH)(2) from different Mg-silicate rocks from worldwide locations (Finland, Lithuania, Australia and Norway). Magnesium hydroxide, the reactive material for gas/solid mineralization of CO2 can be produced from different Mg-silicate minerals via a staged solid/solid reaction with ammonium sulfate (AS) salt followed by precipitation in aqueous ammonia solution. A comparison is made for five different minerals. The kinetics of Mg extraction from Mg-silicate minerals and the possible effects of iron by-products on reactivity and kinetics were studied and modeled as well. (c) 2011 Elsevier Ltd. All rights reserved.