Abstract: A high opacity, defined kaolin clay product having a relatively narrow particle size distribution, low colloidal particle content and an average particle surface area of less than about 30 square meters per gram is prepared by defining an aqueous kaolin clay slurry via controlled centrifugation to remove a substantial portion of the colloidal particles therein. Prior to being subjected to centrifugation, the aqueous kaolin clay slurry is prepared so as to improve the defining process achieved via centrifugation by first subjecting the aqueous kaolin clay suspension to scrub grinding so as to break up agglomerates into individual kaolin clay particles without substantial delamination of the kaolin clay particles.

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: An aqueous beneficiated clay slurry is concentrated from a lower solids content to a higher solids content by evaporating water therefrom by passing the aqueous clay slurry through one or more non-contact evaporative heat exchangers in indirect heat exchange relationship with a hot drying fluid. The driving fluid, that is the heating medium which is passed in indirect heat exchange relationship with the aqueous clay slurry to initiate the evaporation process, comprises a hot liquid, preferably a moderate temperature hot liquid such as hot water having a temperature ranging from about 120.degree. F. to about 200.degree. F.

Abstract: The present invention provides an energy conserving process for calcining a clay and apparatus for carrying out the process. A dry pulverized clay powder (1) is fed to a calciner (20) to be calcined therein. The calcined clay product (3) is removed from the calciner (20) and preferably passed in heat exchange relationship with a cooling medium (71) whereby the calcined clay product (3) is cooled and the cooling medium is heated. The hot off-gas (7) discharged from the calciner (20) is passed through an electrostatic precipitator (30) to remove at least a substantial portion of calcined clay product dust (11) entrained in the exhaust gas from the calciner. The clean gas (13) leaving the electrostatic precipitator (30) is passed in heat exchange relationship with a cooling fluid (51) to further cool the gas, and preferably to evaporate at least a portion of the cooling portion to produce a heating vapor (53).

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: A high solids kaolin clay slurry having unexpectedly improved high shear viscosity is prepared by blending a chemically dispersed fine particle size Tertiary kaolin with a coarser particle size Cretaceous kaolin to provide a resultant blend having a controlled particle size range and particle size distribution.

Abstract: A beneficiated kaolin clay slurry is concentrated from a solids content of about 50% to 60% by weight to a solids content of at least 65% by weight by evaporating water therefrom by passing the aqueous clay slurry through one or more non-contact evaporated heat exchangers. The kaolin clay slurry is passed in indirect heat exchange relationship with a heating vapor, with the heating vapor comprising water vapor previously evaporated from the aqueous clay slurry.

Abstract: A process for beneficiating a crude kaolinitic clay mineral to produce a clay filler for use in papermaking to improve the brightness, the color characteristics and the light scattering efficiency of the paper product. The crude kaolin clay is blunged with water containing a dispersing agent consisting of a blend of from about 20% to about 50% by weight of a water-soluble carbonate, about 20% to about 50% by weight of a water-soluble polyacrylate, and from 0% to about 60% by weight of a water-soluble anionic phosphate, to form a high solids fluid aqueous clay suspension having an acidic pH. This clay suspension is then fractionated to reduce the percentage of particles therein larger than 45 microns to not more than 0.2% by weight. The fractionated clay suspension is treated with an alkaline leaching solution containing a reducing agent effective in converting ferric ions to ferrous ions.

Abstract: A process for beneficiating a poor grade crude kaloinitic clay mineral to produce a clay filler for use in papermaking to improve the brightness of the paper product. The crude kaolin clay is blunged with water containing a dispersing agent to form a high solids fluid aqueous clay suspension. This clay suspension is then screened and fractionated to reduce the particle size thereof to 92-95% finer than 2 microns. The fractionated clay suspension is treated with an alkaline leaching solution containing a reducing agent effective in converting ferric ions to ferrous ions and, preferably, a water-soluble anionic phosphate. The leached clay suspension, which has a solids content of at least 55%, is then treated with an oxidizing agent to oxidize unreacted leaching agent and byproducts formed during the leaching process.

Abstract: An organoclay-antiozonant complex suitable for incorporating in rubber formulations as an additive to inhibit and retard ozone attack is formed by complexing a substituted paraphenylenediamine antiozonant with an organoclay having been produced by treating a smectite-containing clay with a quaternary amine. The organoclay-antiozonant complex is preferably incorporated into the rubber formulation by first mixing the prepared organoclay-antiozonant complex with a naphthenic oil and a polar solvent to form a paste which is then added to the rubber formulation.

Abstract: An organoclay functional as a rheological modifier for control of the viscosity and thixotropy of polyester-styrene compositions is prepared by a dry process wherein a quaternary ammonium salt is reacted with unfractionated smectite in an aqueous dispersion thereby eliminating the fractionating step required in the typical prior art wet process as exemplified by U.S. Pat. No. 4,240,951 and permitting the preparation of the organoclay rheological modifier to be carried out at a high solids content thereby reducing drying costs in the recovery of the product organoclay.

Abstract: An organically modified smectite is produced by reacting unfractionated pulverized bentonite with an aqueous dispersion or solution of a methyl benzyl dialkyl ammonium halide salt via cation exchange. The product organoclay is equivalent in quality to a "wet" processed organoclay, and has particular utility as an ingredient in forming invert emulsion drilling mud for enhancing the rheological properties of the mud. An invert emulsion drilling mud derived from an organoclay produced by the method of the present invention will have a viscosity of at least seventy (70) centipoise at 26 C and a 10-second gel strength at 26 C of at least thirty (30) pounds per 100 square feet.

Abstract: A method of processing naturally occurring kaolin clay wherein ion exchange resins are utilized to remove charged soluble impurities from the clay thereby eliminating the filtration step required in conventional clay beneficiation process. Further, by saturating the ion exchange resin utilized with a bleaching agent, ferric ions in the clay will be reduced to soluble ferrous ions and removed from the clay without the conventional acid leaching.