PRODUCTION OF CALCITE-TYPE SPHERICAL CALCIUM CARBONATE

摘要

PURPOSE:To obtain a calcite-type calcium carbonate having spherical form with a diameter of 1-5mum by adding hydrogen peroxide to an aqueous suspension of calcium hydroxide and contacting and reacting the mixture with a carbon dioxide-containing gas at a specific temperature. CONSTITUTION:The objective calcium carbonate can be produced by adding =0.8mol (based on 1mol of calcium hydroxide) of hydrogen peroxide to an aqueous suspension of calcium hydroxide and starting the contact reaction with a carbon dioxide-containing gas at a liquid temperature of =40 deg.C. When the amount of hydrogen peroxide added to the suspension is 80mol% based on calcium hydroxide, the formed calcite-type calcium carbonate has cubic form with a diameter of =0.1mum. The addition of hydrogen peroxide is preferably performed before the introduction of carbon dioxide gas. When it is added after the introduction of carbon dioxide gas, the formed calcite-type calcium carbonate also has cubic form with a diameter of =0.1mum. The reaction initiation temperature exceeding 40 deg.C is undesirable because of the formation of cubic calcite-type calcium carbonate having a diameter of =0.1mum.