Procedure for treating pigments, fillers or minerals, which contain a natural carbonate and process for manufacturing an aqueous suspension from these treated pigments, fillers or minerals

摘要

Procedure for the treatment of pigments, fillers or minerals, in aqueous suspension, which contain a natural carbonate that allows the reduction of the paper weight at a constant surface, characterized in that - said pigment is treated with a combination of one or more donors of H3O + ions of moderately strong to strong and gaseous CO2, and why - it consists of the following 3 stages: a) Treatment with the donor or donors of H3O + ions of moderately strong to strong, - said donors of moderately strong H3O + ions are selected from among acids that have a pKa between 0 and 2.5 inclusive, at 22 ° C, and - said strong H3O + ion donors are selected from acids that have a pKa less than or equal to zero at 22 ° C, b) The treatment with gaseous CO2, whether this treatment is an integral part of stage a), is carried out in parallel with stage a) or is already carried out after stage a) - because the concentration of gaseous CO2 in the suspension It is, by volume, such that the ratio (volume of the suspension: volume of CO2 gas) is between 1: 0.05 and 1: 20 with said ratio between 1: 1 and 1: 20 in step a) and between 1: 0.05 and 1: 1 in stage b). c) The pH increase, measured at 20 ° C, above 7.5, over a period of time after the end of stages a) and b) between 1 hour and 10 hours, preferably between 1 hour and 5 hours without the addition of a base, or immediately after the end of steps a) and b) with the addition of a base, step c) being the last stage of the process.