Abstract: Sintered, substantially round and spherical particles and methods for producing such sintered, substantially round and spherical particles from an alumina-containing raw material and a metal oxide sintering aid. The alumina-containing raw material contains from about 40% to about 55% alumina. Methods for using such sintered, substantially round and spherical particles in hydraulic fracturing operations.

Abstract: Sintered, substantially round and spherical particles and methods for producing such sintered, substantially round and spherical particles from an alumina-containing raw material and a metal oxide sintering aid. The alumina-containing raw material contains from about 40% to about 55% alumina. Methods for using such sintered, substantially round and spherical particles in hydraulic fracturing operations.

Abstract: A kaolin clay pigment comprises a coarse kaolin clay or a blend of a coarse kaolin clay with a fine kaolin clay. The coarse kaolin clay is a delaminated and defined pigment product with an overall shape factor greater than about 12. If the coarse kaolin clay is fluid at about 65% to about 75% solids, then it is used by itself as the kaolin pigment. If it is not fluid, it is blended with a fine kaolin clay in amounts ranging from about 0.1% to about 30.0% by weight of the blend. The coarse kaolin clay fraction has a Hinckley Crystallinity Index greater than about 0.6 and the fine kaolin clay has a Hinckley Crystallinity Index less than about 0.5. The pigment has a G.E. brightness of about 90.5 and a particle size distribution such that at least about 90% by weight of the particles has an e.s.d. less than about 2 &mgr;m and about 30% by weight of the particles has an e.s.d. less than about 0.25 microns.

Abstract: An improved method for dry milling calcined kaolin clays involves use of an effective amount of an ammonium polyacrylate dry grinding aid which is applied to a calcined kaolin clay product prior to dry milling. This improves flowability of the product through the mill, resulting in an increase in the grinding efficiency and, therefore, an increase in the production rate of the mill. The final product displays an increase in Hercules high shear viscosity, and therefore, an increase in the rheology in very high solids aqueous slurries, which is particularly useful in the coating of paper and paperboard products.

Abstract: A process for preparing a high brightness, low abrasion calcined kaolin. A cretaceous crude is wet beneficiated by subjecting same as an aqueous slurry to degritting, classification, magnetic separation, and scrub grinding. The slurry from the foregoing is diluted to less than 15% solids and subjected while well dispersed to a separation in a centrifuge to yield an underflow and an overflow fine fraction having less than 5% solids and a P.S.D. such that at least 85% by weight are of <0.5 .mu.m E.S.D. and at least 30% by weight are of <0.25 .mu.m E.S.D. The overflow fine fraction slurry of dispersed kaolin is subjected to a partial filtration by passing same in cross flow relation to a microporous membrane through which substantially none of the suspended kaolin particles pass, to raise the solids content of the said slurry to at least 20%.

Abstract: A method for producing calcined kaolin pigments of high opacifying properties and low abrasion. A kaolin crude is selected having a G.E. brightness in the range of 70 to 80, a titania content of 2.0 to 3.0% by weight, less than 2% iron expressed as Fe.sub.2 O.sub.3, and a particle size distribution such that at least 88% by weight of the particles of said crude are of less than 2 .mu.m E.S.D.. The crude is blunged with water, and the resultant slurry degritted to form an aqueous slurry having at least 65% by weight solids. The slurry is centrifuged and a fraction recovered having over 65% solids, and in which at least 92% by weight of the particles are of less than 2 .mu.m. The recovered fraction is dried to less than 1% moisture, and pulverized to break up agglomerates. The pulverized fraction is then calcined by heating same to 1450.degree. to 1600.degree. F. after which the calcined kaolin is milled to yield a product having a G.E. brightness of 79 to 81 and an Einleiner abrasion of not mere than 2.

Abstract: An improved method of everting a knitted sleeve-like portion of wearing apparel or the like, such as a hose precursor before the toe end is stitched, which includes drawing such sleeve over the free end of a cylindrical mounting tube and over and past a turning ring on said tube, which turning ring prevents the following end of the sleeve from sliding back towards the tube's free end when the drawing motion is reversed, pulling the leading end of the sleeve back over the sleeve towards the tube's free end. The simple drawing motion and reversal thereof not only everts the sleeve but positions the leading end free about the tube's free end, in position for stitching when the leading end is the toe end of a sock or other hose. Also provided is an apparatus for use in this method.