Synthesis of Aragonite by the Carbonation Process

Abstract

The conditions necessary for synthesizing aragonite by the carbonation process were investigated. Aragonite formation was found to have no relation to the pH value, the mole ratio of MgCl 2 /Ca(OH) 2 , or the magnesium/calcium ion concentration in a solution. The synthesis of aragonite requires a concentration of magnesium ions in the appropriate range (∼0.1–0.26 mol/L) and a concentration of calcium ions below a certain range (less than ∼0.16–0.25 mol/L). An excess of calcium ions or magnesium ions favors calcite formation. Needlelike aragonite with a large aspect ratio was successfully synthesized in the present study.