PROCESS FOR PREPARATION OF AN ACID RESISTANT COATING ON FILLER PARTICLES

摘要

The invention relates to a process for the preparation of an acid-resistant coating and calcium carbonate particles, in which process a slurry of calcium carbonate particles is mixed simultaneously with the solution of a zinc compound and a solution of a silica-containing substance at a temperature of 70-95 C, the pH being maintained at 8-11. The invention also relates to calcium carbonate particles having an acidresistant coating in accordance with the above-mentioned process In addition, the invention relates to the use of calcium carbonate particles having an acid-resistant coating in accordance with the above-mentioned process, as an acidresistant filler in the production of paper at pH 4.0-7.0.