| 摘要 |
Silica-calcium carbonate composition particles having the characteristics of both synthetic silica and calcium carbonate without a lowering thereof are described along with paper internally filling the particles and a method for making the particles. In the carbonation reaction which is the step of forming calcium carbonate, typically, in the course of carbonation reaction where while agitating a calcium hydroxide slurry, a mixed gas of carbon dioxide and air is introduced thereinto, synthetic silica such as colloidal silica or the like is added to before a carbonation rate arrives at 95% but after commencement of the carbonation reaction, followed by further introduction of the mixed gas to continue the carbonation reaction and completion of the carbonation reaction at the time when a pH of the slurry reaches 7, thereby providing composite particles.
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