| 摘要 |
PURPOSE:To produce columnar CaCO3 having calcite type crystal shape advantageously on an industrial scale by stirring and aging CaCO3 slurry having higher viscosity above a specified value after producing the slurry by the gas/liquid reaction between gaseous CO2 and Ca(OH)2. CONSTITUTION:In the production of CaCO3 by the gas/liquid reaction between gaseous CO2 and Ca(OH)2 the slurry having >=1,000cP viscosity measured by a B type viscometer at 60rpm is aged further while stirring so as to make the whole body of the slurry uniform. Thus, calcite type columnar CaCO3 is produced advantageously on an industrial scale. When the obtd. CaCO3 is used as coating pigment for printing white paper, the gloss of the coated paper before and after printing, ink receptivity, and the viscosity of the coating material at high shear plane are all satisfied at the same time. Moreover, when the CaCO3 is used as filler for tissue paper, expensive TiO2 is saved because the CaCO3 has superior opacity and whiteness as compared to conventional spindle-shaped coating material.
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