| 摘要 |
<p>Novel precipitated calcium carbonate particles of varying size and shape, are prepared by adding gaseous carbon dioxide to an aqueous slurry containing basic calcium carbonate under a selectively controlled reaction environment. In its preferred embodiment precipitated calcium carbonate particles having a prismatic shape and an average equivalent spheroidal diameter of between about 1.5 and about 6.5 microns; large irregularly shaped particles having an average equivalent spherical diameter of between about 15 and about 25 microns; and multi-faceted spheroidal particles having an average equivalent spherical diameter of between 5 and about 15 microns, are provided. The reaction environment includes temperatures of between 0 °C and 60 °C and a surface active polyphosphate additive present in amounts of from about 0.1 and about 1.0 percent by weight.</p> |
