Patent ID: 9074067
Filing Date: 2015-07-07
Classification: C01P,C08K,C09C

Abstract:
1. A process for making a calcium carbonate slurry comprising the steps of (a) forming a mixture comprising water, an acidic dispersant system, and a collection of calcium carbonate particles having D50 more than 2 micrometers, wherein said acidic dispersion system is selected from the group consisting of one or more anionic polymer partially neutralized with sodium, one or more anionic polymer fully neutralized with sodium, and mixtures thereof, (b) grinding said mixture to form a preliminary slurry of particles of said calcium carbonate, wherein 50% or more by weight of said calcium carbonate in said preliminary slurry, based on the total weight of said calcium carbonate in said preliminary slurry, is in the form of particles having diameter of 2 micrometers or less, and wherein the pH of said preliminary slurry is 9.0 or below, and (c) after step (b), adding one or more organic neutralizing agent to bring the pH of said preliminary slurry to 9.4 or above.