| 摘要 |
A process for producing precipitated calcium carbonate having a particle size D50 of from 1 to 2 microns inclusive includes the steps of first contacting carbon dioxide gas with either ammonium hydroxide or with ammonia gas in the presence of water, to produce a solution of ammonium carbonate, and then contacting the solution of ammonium carbonate with a solution of calcium nitrate at a temperature below 58 ~C and at a pH from 6.5 to 9.0 inclusive, optionally under pressure, to precipitate the calcium carbonate as a fine powder.
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