SILICA-CALCIUM CARBONATE COMPOSITE PARTICLE

摘要

Silica-calcium carbonate composite particles, characterized in that they are produced by a method wherein, in a carbonation step of forming calcium carbonate, typically a step of introducing a mixed gas of carbon dioxide and air into a calcium hydroxide slurry with stirring to carry out a carbonization reaction, a synthetic silica such as colloidal silica is added in a period after the start of the carbonization and before carbonization percentage reaches 95 %, the mixed gas is continuously introduced thereafter to continue the carbonization, and the carbonization is stopped when the pH of the slurry reaches 7; a paper having said particles filled therein; and the above method. Said composite particles have both of the characteristics inherent in a synthetic silica and in calcium carbonate, without detriment to the characteristics.