| 摘要 |
The present invention concerns a process and an apparatus for preparing calcium carbonate. The process comprises reacting a calcium oxide raw material, which contains at least some hydrated calcium oxide, with carbonate ions in an aqueous medium for preparing precipitated calcium carbonate. The calcium carbonate is separated from the suspension and subjected to further treatment for preparation of the desired end product. The invention is characterized in that at least 80 % of the particles of the hydrated calcium oxide have a particle size of less than 3 mu m and the reaction is allowed to proceed without mixing the reaction mixture. When a pigment suitable for paper coating, having a particle size of 0.2 to 0.4 mu m, is to be prepared, the carbonation reaction is allowed to continue for 20 to 25 minutes before it is interrupted in an impact mixer (12). |
