The conditions for the synthesis of aragonite by a carbonation process were investigated, and these results were applied to the recycling of dusts generated from a steel works. The formation of aragonite has no relation with the pH value, the molar ratio of MgCl2/Ca(OH)2 and Mg/Ca ion concentration in the solution. The condition for the synthesis of aragonite requires that the concentration of Mg ions should be in the appropriate range (about 0.1~0.26 mol/L), and the concentration of Ca ions below a certain range (about 0.25 mol/L). Too much Ca ions or Mg ions favor the formation of calcite. Needlelike aragonite was successively synthesized using dusts, and thus effective recycling of dusts can be expected.

Keywords: CaCO3, aragonite, carbonation process, recycling, dusts