Chemically aggregated mineral pigments

摘要

A method is described for forming bulked aggregates of mineral particles such as kaolins. An aqueous slurry of the mineral is treated with a source of a multi-valent cation to floc the mineral, polyacrylic is added and the slurry is then neutralized with a base to an alkaline pH. This treatment causes the polyacrylic acid to undergo cross-linking with the cations to form the polyacrylate which precipitates in situ on the mineral floc and preserves and retains the bulked, porous floc structure, whereby pore radius and volume of the treated mineral are increased. The products are useful as fillers or as coating pigments in paper manufacture.