The sequestration of CO2 by carbonating natural minerals has a great potential for secure reduction of net CO2 emissions. Feedstock Mg-silicate minerals are usually converted into Mg rich solutions or Mg(OH)(2) before the carbonation process, due to the slow reaction kinetic of direct carbonation. The present work studied the alkaline digestion of Mg-silicate minerals into Mg(OH)(2) for CO2 sequestration. Powdered dunite containing similar to 73 +/- 2 wt% of forsterite (Mg2SiO4) was dissolved using highly concentrated NaOH aqueous systems at 90 and 180 degrees C with varied NaOH concentration and duration of reaction. Thermal analysis and Rietveld Refinement Quantitative Phase Analysis (QPA) confirmed that an effective digestion of dunite was possible at 180 degrees C achieving 80 wt% of Mg(OH)(2). It was found that NaOH concentration in solution, temperature and duration of reaction significantly influence the progress of digestion. (C) 2013 Elsevier Ltd. All rights reserved.