Abstract: A method for producing a low abrasion calcined kaolin pigment which comprises forming an aqueous pulp of crude kaolin dispersing the pulp by adding thereto sufficient water-soluble organic cationic dispersant to impart a positive zeta potential to said particles and, preferably, an acidic pH to said pulp, removing coarse particles from said dispersed pulp and fractionating the dispersed pulp to separate a fine particle size fraction of mineral particles from coarser particles. The fine particle size fraction is dried, pulverized, calcined and repulverized.

Abstract: A method for recovering a fine particle size fraction of a negatively charged mineral from an ore, such as a kaolin clay crude, which comprises forming an aqueous pulp of the ore, dispersing the pulp by adding thereto sufficient water-soluble organic cationic dispersant to impart a positive zeta potential to said particles and, preferably, an acidic pH to said pulp, removing coarse particles from said dispersed pulp and fractionating the dispersed pulp to separate a fine particle size fraction of mineral particles from coarser particles.

Abstract: A stable fluid acidic concentrated aqueous slurry of positively charged particles of a calcined kaolin clay pigment wherein the dispersant is a water-soluble organic cationic material, such as a quarternary ammonium polyelectrolyte.

Abstract: A bulked kaolin pigment is prepared by mixing a small but effective amount of a water-soluble cationic material such as a cationic polyelectrolyte flocculant with a kaolin clay pigment in the presence of water. The resultant bulked clay product can be dispersed to form high solids clay-water slurries useful in making aqueous coating colors suitable for manufacturing lightweight coated publication papers or the pigment can be used as a filler for paper webs. Slurries having stable viscosity during storage and at elevated temperature are prepared by using as the dispersant an anionic sulfonated disperant such as a lignosulfonate or a naphthalene formaldehyde sulfonate complex.

Abstract: A heat stabilized slurry of bulked kaolin pigment is prepared by mixing a small but effective amount of a water-soluble cationic material such as a cationic polyelectrolyte flocculant with a kaolin clay pigment in the presence of water. The resultant bulked clay product is dispersed to form a high solids clay-water slurry useful in making aqueous coating colors suitable for manufacturing lightweight coated publication papers or the pigment can be used as a filler for paper webs. Slurries having stable viscosity during storage at elevated temperature and improved resistance to the formation of sediment are prepared by using as the dispersant a combination of an anionic lignosulfonate and an anionic naphthalene sulfonate formaldehyde complex in combination with a polyacrylate salt.