Production of magnesium hydroxide from magnesium silicate for the purpose of CO2 mineralization – Part 2: Mg extraction modeling and application to different Mg silicate rocks

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.

Mg extraction values from different serpentinite rocks at increasing temperatures (reaction times: below 30 min and S/AS: 0.5–0.77 g/g).Figure optionsDownload as PowerPoint slideHighlights
► Mg(OH)2 production from magnesium silicates was applied to a range of rocks.
► Depending on rock type, different temperatures and other conditions must be chosen.
► For serpentine-type rock better results are obtained than with olivine.