A process is provided for making a calcium carbonate slurry comprising the steps of (a) forming a mixture comprising water, an acidic dispersant system, and calcium carbonate, (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.