Abstract: The embodiment of kaolin quality improvement includes a chemical, heating method for processing kaolin to high brightness levels and lower viscosities. This permits addition of natural titania for greater opacity in commercial paper coating. Mechanism of brightness improvement includes removal of iron oxides and iron sequestered by natural organic acids. Viscosity is improved by removal of organic and at least partial decomposition of expandable clay, such as montmorillonite. Kaolin crude is dispersed preferably with Calgon at minimum level. Classification to desired particle size is followed by adding 0.2 percent sodium sulfate decahydrate. After raising pH to 8.5 with dilute sodium hydroxide the slip is heated to 65 to 70 degrees centigrade for 5 to 60 minutes. Cooled to at least 40 degrees centigrade, the slip is bleached with sodium hydrosulfite. Time of bleach is 20 minutes at pH 3 to 3.5. Efficient filtration and rinsing is critical, a 2:1 ratio of water to dry clay rinse preferable.

Abstract: A defined and delaminated kaolin composition exhibiting high opacity is produced by defining and delaminating a base kaolin clay so as to reduce its colloidal content. The defined and delaminated kaolin composition may also be treated with hexamethylenediamine and aluminum sulfate to further enhance opacity. Whether treated or untreated, the defined and delaminated kaolin composition functions superiorly in paper coating formulations, alone or blended with known coating clays, improving the opacity, print gloss, sheet gloss and printability of paper sheet coated therewith.

Abstract: A high bulking kaolin pigment is provided which exhibits improved opacifying efficiency as a paper filler. The kaolin pigment comprises an uncalcined clay composition consisting essentially of kaolin particles which have not only been treated with an amine, but also upon which aluminum hydroxide has been precipitated, and, of which less than about 20% by weight have a particle size less than 0.3 microns in equivalent spherical dimeter. Further, a method is provided for producing the pigment from a hydrated kaolin clay having a brightness of at least about 89. The selected starting clay is dispersed in water and subjected as a slurry to delamination, defining, surface treatment with an amine and aluminum sulfate, and leaching. The treated kaolin slurry is subsequently rinsed and filtered to a produce a filter cake which is redispersed to yield a commercial paper filler.

Abstract: This invention provides a high bulking clay consisting essentially of selectively flocculated ultra fine particles of clay coated with a member from the group consisting of polyfunctional amines and long chain amines.

Abstract: A high bulk clay product and method of making the same are provided in which kaolinite is selectively flocculated to produce an ultra fine particle fraction in the presence of fine mica below 150 mesh in size and the resulting flocculant is collected and dried.

Abstract: A high bulk clay product and method of making the same are provided in which kaolinite is selectively flocculated to produce an ultra fine particle fraction in the presence of fine mica below 150 mesh in size and the resulting flocculant is collected and dried.