Abstract: A selected kaolin crude or crude fraction is purified by physical or physical/chemical means, such as froth flotation and/or selective flocculation, to remove discrete particles of TiO.sub.2 and in some cases, discrete iron minerals. The pure (or purified clay) must then be agitated in the presence of water with a particulate grinding media such as, for example, sand, alumina or zirconia beads, to increase the 2 micron content of the kaolin. An intermediate ground product that contains a substantial weight percentage of particles finer than 1 micron is generated as a result of grinding. The particles finer than 1 micron in the ground kaolin also include those particles in the previously pure or purified kaolin that were present in the naturally occurring clay. A pulp of the ground clay is then fractionated to remove particles larger than 2 microns, e.g., to remove at least 95%, preferably at 100% by weight, of the particles larger than 2 microns, while minimizing the removal of particles finer than 1 micron.

Abstract: A method for preparing high solids suspensions of calcined clay which are stable without the necessity of adding a colloidal thickening agent and have minimal dilatancy. A calcined kaolin clay pigment, substantially free of anionic dispersant, is dispersed in water by addition of alkali to provide a neutral to mildly alkaline aqueous slurry. To the dispersed slurry, a water-soluble cationic organic polymer is added in minor amounts, to partially flocculate and thicken the slurry, thereby stabilizing the slurry against sedimentation.

Abstract: This invention relates to microspheres produced by spray drying clay slurries and calcining the product to form attrition resistant microspheres. Phosphoric acid is injected in a neutral to mildly alkaline dispersed high solids kaolin slurry immediately before spray drying to improve properties of the microspheres.

Abstract: Disclosed is a vanadium trap for use in FCC which comprises a major amount of calcined kaolin clay, free magnesium oxide and an in situ formed magnesium silicate cement binder. Also disclosed are procedures for the preparation of the trap by forming a slurry in water of hydrous kaolin clay, magnesium oxide or magnesium hydroxide and sodium silicate, aging the slurry to form magnesium silicate in situ, optionally adding additional kaolin, colloidal silica or both, spray drying, and calcining the resulting spray dried microspheres without forming appreciable amounts of crystalline magnesium silicates or crystalline magnesium aluminates.

Abstract: Disclosed is a vanadium trap for use in FCC which comprises a major amount of calcined kaolin clay, free magnesium oxide and an in situ formed magnesium silicate cement binder. Also disclosed are procedures for the preparation of the trap by forming a slurry in water of hydrous kaolin clay, magnesium oxide or magnesium hydroxide and sodium silicate, aging the slurry to form magnesium silicate in situ, optionally adding additional kaolin, colloidal silica or both, spray drying, and calcining the resulting spray dried microspheres without forming appreciable amounts of crystalline magnesium silicates or crystalline magnesium aluminates.

Abstract: A method for preparing a calcined kaolin clay powder having good high shear rheology in high solids aqueous slurries. A kaolin clay powder of fine particle size is calcined at a sufficient temperature and for a sufficient period to destroy the crystallinity thereof; and the calcined product is dry milled in a media mill, using a work input of from 100 to 160 hp-hr/ton of dry clay.

Abstract: The bulk handling characteristics of a calcined kaolin clay powder, including the bulk density and flowability, are significantly improved by forming an aqueous slurry of the calcined kaolin clay powder and spray drying the slurry.

Abstract: The bulk handling characteristics of a calcined kaolin clay powder, including the bulk density and flowability, are significantly improved by forming an aqueous slurry of the calcined kaolin clay powder and spray drying the slurry.

Abstract: 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.

Abstract: The rheology of an aqueous slurry of a calcined kaolin clay powder is significantly improved by spray drying a slurry of the calcined kaolin clay powder, recovering the spray-dried material, and forming an aqueous slurry from said spray-dried material.

Abstract: A method is provided for reducing the abrasiveness of calcined clay, e.g., kaolin clay. The method comprises intermixing the clay prior to calcination with a finely-divided silica, preferably in the form of colloidal or fumed silica, in an amount sufficient to reduce the abrasiveness of the calcined product.