Abstract: Calcined kaolin clay having a high bulk density, improved wet out and slurry incorporation times is produced by using pressure to compact the clay. Other properties of the compacted clay are improved or equivalent to the non-compacted starting calcined clay material.

Abstract: The invention concerns a process and an installation for dehydroxylation treatment of aluminium silicate, in which particles containing aluminium silicate are exposed to a temperature of at least 500° C. The particles are in the form of a dry powder, and the dry powder (26) is optionally transported in a gas stream (30) at a temperature of from 600 to 850° C., for a time which is sufficient to achieve the desired degree of dehydroxylation. The powder may be obtained from a hydrated base paste by reducing the base paste into fragments (23), and by disaggregating the fragments (23) of base paste by mechanical action (at 3) in the presence of a hot gas (24) at a temperature of from 500° C. to 800° C., in order to form the dry powder (26).

Abstract: The present invention provides a lightweight clay which can be easily molded into a given shape, exhibits proper lightweight characteristics and storing characteristics, and can be manufactured at a low cost, and a manufacturing method thereof. In such a lightweight clay and the manufacturing method thereof, an average particle size of the organic hollow micro spheres is set to a value which falls within a range of 15 to 150 &mgr;m and, an addition quantity of the organic hollow micro spheres is set to a value which falls within a range of 0.1 to 6 weight % with respect to a total quantity of the lightweight clay, and whiteness degree (WL) measured in accordance with JIS L 0803 is set to not less than 50.

Abstract: Calcined kaolin clay having a high bulk density, improved wet out and slurry incorporation times is produced by using pressure to compact the clay. Other properties of the compacted clay are improved or equivalent to the non-compacted starting calcined clay material.

Abstract: A high performance kaolin pigment, a paper coating color containing high performance kaolin pigment, and a method for making high performance kaolin pigment, the kaolin pigment being provided with improved optical and rheological properties attained by strict control of size and shape of the particles, as well as size and shape distribution of the particles. The kaolin pigment has ISO brightness characteristics higher than 88.5, a particle size distribution of at least 94% by mass lower than 2 &mgr;m and at most 25% by mass lower than 0.2 &mgr;m and a Hercules viscosity at 1,100 RPM lower than 18 dynes in slurries with a solid content of 70%-75% solids.

Abstract: The present invention relates to calcined kaolin products, their production, and use. More specifically, the invention relates to calcined kaolin-containing products having a median diameter particle size of from about 0.5 &mgr;m to about 10 &mgr;m, and a multimodal particle size distribution defined herein. The calcined kaolin products of the invention possess a combination of physical properties and applied properties not previously seen together in calcined kaolin pigments. The products according to the invention find use as flattening (or matting) agents, and as fillers or extenders in paint and coating compositions. More generally, the inventive products may be used wherever calcined kaolins are used.

Abstract: A mechanically activated pozzolan prepared from granitic quarry fines. Quarry fines are milled by a high-energy milling process to convert the essentially inert raw granitic fines into a chemically reactive state. When added to a portland cement mortar mixture, mechanically activated fines combined with calcium hydroxide to improve the strength of the cured mortar compared to a similar mixture prepared with raw fines. Mortars prepared with mechanically activated granitic fines typically show strength values comparable to or exceeding similar mortars made using fly ash as a pozzolan. In some instances, the strength of a mortar prepared with mechanically activated granitic quarry fines exceeded a mortar prepared using 100% portland cement as the cementitious component.

Abstract: A pigment product suitable for use in a coating composition to provide a gloss coating on paper, the pigment product comprising a processed particulate kaolin whose particles have a particle size distribution such that at least 80% by weight of the particles have an equivalent spherical diameter less than 2 &mgr;m and not less than 8%, preferably not less than 12%, by weight of the particles have an equivalent spherical diameter less than 0.25 &mgr;m and whose particles have a shape factor of at least 45, preferably at least 50.

Abstract: Aggregated mineral pigments (such as kaolin clay pigments) having a high surface area and useful in coating and filling compositions for ink jet printing media are manufactured by dry grinding an unground mineral composition starting material and then optionally acid treating the ground material.

Abstract: A composition for improving grip between the hands and a tool or implement is provided, which comprises a chlorinated paraffin, a dispersing agent, and a solvent in an amount up to and including about 3.0% by weight relative to the total weight of the composition. A method of making the composition in the form of a dry powder, as well as a method of using the dry powder to improve friction or grip on the hands, are also provided.

Abstract: Provided is a polyamide resin composition comprising a melt blend of (A) a polyamide resin, (B) a phyllosilicate, and (C) an olefin compound having a carboxylic acid anhydride group in the molecule or a polymer of the olefin compound, in which the phyllosilicate (B) has a reactive functional group bonded thereto and is such that the exchangeable metal ions existing in the inter layers are ion-exchanged with organic onium ions. The composition has a reduced inorganic ash content and has both high stiffness and high ductility. Optionally, the composition contains an inorganic filler apart from the phyllosilicate, an impact modifier, and a flame retardant, still having high stiffness and high ductility.

Abstract: Systems and methods of making and using fine particle materials in pigment blends and for using the aforementioned pigment blends in paint, coating, or coloring compositions are provided. This invention further provides systems and methods of enhancing the visual appearance of a variety of substrates by introducing a paint, coating, or coloring composition to the substrate. The fine particle materials of the present invention have a substantially random geometric shape, a particle size less than about 100 microns, and help provide both functional and visual enhancing properties to compositions and substrates containing these fine particle materials.

Abstract: A method of treating a kaolinitic clay which is intended for use as an ingredient in a ceramic composition which method comprises the steps of: (a) mixing with the kaolinitic clay from 0.1% to 15.0% by weight, based on the dry weight of the kaolinitic clay, of a smectite clay; and (b) subjecting a mass in a moist plastic state of the clay mixture formed in step (a) to mechanical working under conditions such that there is dissipated in the moist plastic mass at least 5 kJ of energy per kilogram of clay mixture on a dry weight basis.

Abstract: A mechanically activated pozzolan prepared from granitic quarry fines. Quarry fines are milled by a high-energy milling process to convert the essentially inert raw granitic fines into a chemically reactive state. When added to a portland cement mortar mixture, mechanically activated fines combined with calcium hydroxide to improve the strength of the cured mortar compared to a similar mixture prepared with raw fines. Mortars prepared with mechanically activated granitic fines typically show strength values comparable to or exceeding similar mortars made using fly ash as a pozzolan. In some instances, the strength of a mortar prepared with mechanically activated granitic quarry fines exceeded a mortar prepared using 100% portland cement as the cementitious component.

Abstract: A pigment product suitable for use in a coating composition to provide a gloss coating on paper, the pigment product comprising a processed particulate kaolin produced from a naturally platy kaolin clay having a particle size distribution such that about 50% to 60% by weight of the particles have an esd less than 2 &mgr;m and less than 25% by weight of the particles have an esd less than 0.25 &mgr;m and a shape factor of at least 15. In processing, the crude kaolin is ground to a shape factor greater than 50 to produce even greater “platy” clay. The pigment product has a particle size distribution such that at least 80% by weight of the particles have an esd less than 2 &mgr;m and greater than 12% and less than 35% by weight of the particles have an esd less than 0.25 &mgr;m and whose surface area is greater than 12 m2/g when measured by the BET method.

Abstract: A paper coating pigment manufactured from kaolin crude containing minor amounts of minerals is used in lightweight coated and ultra-lightweight coated applications. The pigments comprise a phyllosilicate assemblage of minerals that yield a final pigment MgO content ranging between 0.04 to 0.3 weight percent and a K2O content ranging between 0.12 and 0.8 weight percent based on the dry weight of the kaolin crude. The mica in the pigment product is 1.0% to 6.7% by weight, and smectite is 1.2% to 9.1% by weight of the kaolin. The presence of these weight percentages can be identified by a shape factor of 15 or greater. The viscous clay content of the feed to produce the pigment product is between 70 and 100 weight percent based on the dry weight of the kaolin clay. The pigment has a shape factor ranging between 35 and 60 or greater, and greater than 80% by weight of the particle are less than 2 microns, and greater than 12% are less than 0.25 microns.

Abstract: Coarse platey, high brightness kaolin products and methods for making the same, including combining a coarse kaolin fraction and a fine kaolin fraction, where each coarse or fine kaolin fraction may be produced by processing one or more crude kaolin samples through different stages of the methods of the present invention, by blending of one or more crude kaolin samples so processed, or as a by-product of a coarse or fine kaolin product.

Abstract: A pigment product suitable for use in a coating composition to provide a gloss coating on paper, the pigment product comprising a processed particulate kaolin produced from a naturally platy kaolin clay having a particle size distribution such that about 50% to 60% by weight of the particles have an esd less than 2 &mgr;m and less than 25% by weight of the particles have an esd less than 0.25 &mgr;m and a shape factor of at least 15. This platy clay can be blended with b-fraction clay component. In processing, the crude kaolin is ground to a shape factor greater than 50 to produce even greater “platy” clay. The pigment product has a particle size distribution such that at least 80% by weight of the particles have an esd less than 2 &mgr;m and greater than 12% and less than 35% by weight of the particles have an esd less than 0.25 &mgr;m and whose surface area is greater than 12 m2/g when measured by the BET method.

Abstract: The present invention involves the use of fired clay, in particular flint clay, as a filler particulate and substitute for standard polymeric particulate commonly used in solid surface products. As well, it is also a substitute for ground stone as used in engineered stone products.

Abstract: A method of exploring for a primary kaolin and producing products therefrom.

Abstract: A novel clay pigment, the manufacture thereof and the use of the pigment in the coating of lightweight groundwood paper are disclosed. The kaolin clay particles initially have a shape factor between less than 10 and a particle size distribution where between 30 to 60% by weight is less than 2 microns and 20% by weight is less than 0.25 micron e.s.d. This clay is subjected to attrition grinding to produce clay particles having a shape factor between 13 and 18 and then classified to produce a particle size distribution where 80 to 90% by weight are less than 2 microns and 20% by weight are less than 0.25 micron. These pigments have a G.E. brightness ranging from 88 to 92; are deficient in ultra-fine particles; are fluid at a high solids concentration greater than 70%, and have a low shear Brookfield viscosity below 500 cps and a high shear Hercules viscosity of 18 dyne-cm above 200 rpm when using an “A” bob.

Abstract: Aggregated mineral pigments (such as kaolin clay pigments) having a high surface area and useful in coating and filling compositions for ink jet printing media are manufactured by dry grinding an unground mineral composition starting material and then optionally acid treating the ground material.

Abstract: Colored pigments having one or more desired parameters and/or properties are described. These parameters and/or properties include: a) a particles size of from about 10 nm to about 300 nm; b) an accusizer number of less than 1010 particles/ml of dispersion at 15% solids which are greater than 0.5 micron; c) a filterability such that when in a liquid medium, 100 ml having 10% solids of the colored pigment filters through a 3 micron nylon absolute filter; d) a colored pigment purity of greater than about 80%, based on extractable material; and/or e) a stability such that the above-described properties do not change by more than 50% at 25 degrees C. for at least one week. Colored pigments having at least one organic group and having one or more of the above-described characteristics is also described as well as a process for preparing surface-modified colored pigments.

Abstract: Aggregated mineral pigments (such as kaolin clay pigments) having a high surface area and useful in coating compositions for ink jet printing media are manufactured by dry grinding an unground mineral composition starting material and then optionally acid treating the ground material.

Abstract: Fine-grained Tertiary kaolin clay pigments providing improved opacity, sheet gloss and print gloss to paper coated with these pigments are produced by removing fine and coarse particles to produce pigments having a narrow particle size distribution.

Abstract: Paper coating composition comprising an engineered kaolin pigment containing stacks and platelets of unground coarse particles where greater than 96% by weight is less than 5 microns, of which some kaolinite books or stacks are concentrated in the greater than 1 micron size fraction; 88% to 95% by weight is less than 2 microns; 65% to 85% by weight is less than 1 micron; and 15% to 25% by weight is less than 0.25 micron. A first embodiment comprises particles with a shape factor Ad between 7 and 9 which represents a significant number of stacks and some platelets. A second embodiment comprises particles with a shape factor of 11 or 12 which represents the presence of some stacks with a majority of platelets. The kaolin clay pigments form clay-water slurries of 69% solids or greater. As a coating, the composition gives a G. E. brightness between 88 and 94. The engineered pigment is processed so that the desired shape factor is met, which shape factor is equated to the aspect ratio or morphology of the pigment.

Abstract: Intercalates formed by contacting a layered material, e.g., a phyllosilicate, with an intercalant monomer having a hydroxyl and/or an aromatic ring functionality to sorb or intercalate the intercalant monomer between adjacent platelets of the layered material. Sufficient intercalant monomer is sorbed between adjacent platelets to expand the adjacent platelets to a spacing of at least about 5 Å (as measured after water removal to a maximum of 5% by weight water), up to about 100 Å and preferably in the range of about 10-45 Å, so that the intercalate easily can be exfoliated into individual platelets. The intercalated complex can be combined with an organic liquid into a viscous carrier material, for delivery of the carrier material, or for delivery of an active compound; or the intercalated complex can be combined with a matrix polymer to form a strong, filled polymer matrix.

Abstract: Systems and methods of making and using fine particle materials in pigment blends and for using the aforementioned pigment blends in paint, coating, or coloring compositions are provided. This invention further provides systems and methods of enhancing the visual appearance of a variety of substrates by introducing a paint, coating, or coloring composition to the substrate. The fine particle materials of the present invention have a substantially random geometric shape, a particle size less than about 100 microns, and help provide both functional and visual enhancing properties to compositions and substrates containing these fine particle materials.

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: Calcined kaolin clay pigments having improved color are manufactured by adding a blue agent to the kaolin clay pigment prior to calcination, and then calcining the pigment and blue agent mixture.

Abstract: Systems and methods of making and using fine particle materials in pigment blends and for using the aforementioned pigment blends in paint, coating, or coloring compositions are provided. This invention further provides systems and methods of enhancing the visual appearance of a variety of substrates by introducing a paint, coating, or coloring composition to the substrate. The fine particle materials of the present invention have a substantially random geometric shape, a particle size less than about 100 microns, and help provide both functional and visual enhancing properties to compositions and substrates containing these fine particle materials.

Abstract: High brightness kaolin pigments and methods of making high brightness kaolin pigments are provided. Both delaminated and nondelaminated clays are provided having typical brightness of 87 or higher. The pigments have high brightness and good opacity, providing an optimum pigment for paper coating and paper filler. Also provided are blended high brightness kaolins having increased opacity properties.

Abstract: Intercalates formed by contacting a layered material, e.g., a phyllosilicate, with an intercalant monomer ether and/or ester to sorb or intercalate the intercalant monomer between adjacent platelets of the layered material. Sufficient intercalant monomer is sorbed between adjacent platelets to expand the adjacent platelets to a spacing of at least about 5 Å (as measured after water removal to a maximum of 5% by weight water), up to about 100 Å and preferably in the range of about 10-45 Å, so that the intercalate easily can be exfoliated into individual platelets. The intercalated complex can be combined with an organic liquid into a viscous carrier material, for delivery of the carrier material, or for delivery of an active compound; or the intercalated complex can be combined with a matrix polymer to form a strong, filled polymer matrix. Alternatively, the intercalated complex can be exfoliated prior to combination with the organic liquid or the matrix polymer.

Abstract: In one embodiment, the present invention relates to a method of making a highly reactive pozzolan, involving the steps of forming a slurry comprising metakaolin and a liquid; wet milling the slurry; and separating the metakaolin from the liquid to provide the highly reactive pozolan. In another embodiment, the present invention relates to a method of making a cement-based composition involving the steps of providing a highly reactive pozzolan by forming a slurry comprising metakaolin and a liquid, wet milling the slurry, and separating the metakaolin from the liquid; and combining the highly reactive pozzolan with at least one cementitious material.

Abstract: A method for producing a mineral filler and pozzolan product from fly ash is provided in which fly ash is dry processed in an air classifier to obtain a fine fraction having an average particle size of from about 0.1 to 5 microns and a coarse fraction having an average particle size of from about 6 to 20 microns. The fine fraction is then preferably passed through a magnetic separator to remove ferrous iron oxides and may optionally be treated with a surface modifier to form a mineral filler. The coarse fraction is preferably passed through a 100 mesh screen to form a pozzolan product.

Abstract: In one embodiment, the present invention relates to a method of making a highly reactive pozzolan, involving the steps of forming a slurry comprising metakaolin and a liquid; wet milling the slurry; and separating the metakaolin from the liquid to provide the highly reactive pozzolan. In another embodiment, the present invention relates to a method of making a cement-based composition involving the steps of providing a highly reactive pozzolan by forming a slurry comprising metakaolin and a liquid, wet milling the slurry, and separating the metakaolin from the liquid; and combining the highly reactive pozzolan with at least one cementitious material.

Abstract: An aqueous aluminium silicate suspension having a content of aluminium silicate of at least 30 wt. % is prepared by liquefaction of the aluminium silicate filter cake or by dispersion of aluminium silicate powder in water with the addition of aluminium silicate powder, surfactant and aluminium sulfate. It can be employed in papermaking.

Abstract: A method of producing a low structure pyrogenic metal oxide filler is disclosed. The method involves subjecting pyrogenically produced metal oxide agglomerates and aggregates selected from silicon oxide, aluminum oxide, zirconium oxide, or titanium oxide to a dry milling process whereby the pyrogenically produced metal oxide is contacted in an agitating zone with an energy specific force.

Abstract: An improved process for transforming clays that cannot be utilized in commercial pigment production to low-viscosity pigment for commercial application is described whereby a treated clay is produced having a reduced viscosity as compared to the initial clay when compared at equivalent solids content. The process comprises the steps of: drying the clay; mixing the dried clay with an aqueous solution of an alkali metal salt wherein the alkali metal salt is selected from the group consisting of lithium, potassium, rubidium and cesium salts; extruding the material obtained from alkali metal salt treatment; heat-treating the extruded material and high-shear blunging of the heat-treated material. Typically, a high viscosity clay that has been treated with this five-step procedure will exhibit a viscosity that is about 10% to about 20% of the viscosity of the starting clay.

Abstract: Paper coating composition comprising an engineered kaolin pigment containing stacks and platelets of unground coarse particles where greater than 96% by weight is less than 5 microns, of which some kaolinite books or stacks are concentrated in the greater than 1 micron size fraction; 88% to 95% by weight is less than 2 microns; 65% to 85% by weight is less than 1 micron; and 15% to 25% by weight is less than 0.25 micron. A first embodiment comprises particles with a shape factor between 7 and 9 which represents a significant number of stacks and some platelets. A second embodiment comprises particles with a shape factor of 11 or 12 which represents the presence of some stacks with a majority of platelets. The kaolin clay pigments form clay-water slurries of 69% solids or greater. As a coating, the composition gives a G.E. brightness between 88 and 94. The engineered pigment is processed so that the desired shape factor is met, which shape factor is equated to the aspect ratio or morphology of the pigment.

Abstract: A method for producing a mineral filler from fly ash is provided in which fly ash is dry processed in an air classifier to obtain a fine fraction having an average particle size of from about 0.1 to 5 microns. The fine fraction is then preferably passed through a magnetic separator to remove ferrous iron oxides and may optionally be treated with a surface modifier. The resulting processed fly ash may be used in a wide variety of filler applications.

Abstract: Intercalates formed by contacting a layered material, e.g., a phyllosilicate, with an intercalant monomer having a hydroxyl and/or an aromatic ring functionality to sorb or intercalate the intercalant monomer between adjacent platelets of the layered material. Sufficient intercalant monomer is sorbed between adjacent platelets to expand the adjacent platelets to a spacing of at least about 5 .ANG. (as measured after water removal to a maximum of 5% by weight water), up to about 100 .ANG. and preferably in the range of about 10-45 .ANG., so that the intercalate easily can be exfoliated into individual platelets. The intercalated complex can be combined with an organic liquid into a viscous carrier material, for delivery of the carrier material, or for delivery of an active compound; or the intercalated complex can be combined with a matrix polymer to form a strong, filled polymer matrix.

Abstract: Intercalates formed by contacting a layered material, e.g., a phyllosilicate, with an intercalant monomer having a hydroxyl and/or an aromatic ring functionality to sorb or intercalate the intercalant monomer between adjacent platelets of the layered material. Sufficient intercalant monomer is sorbed between adjacent platelets to expand the adjacent platelets to a spacing of at least about 5 .ANG. (as measured after water removal to a maximum of 5% by weight water), up to about 100 .ANG. and preferably in the range of about 10-45 .ANG., so that the intercalate easily can be exfoliated into individual platelets. The intercalated complex can be combined with an organic liquid into a viscous carrier material, for delivery of the carrier material, or for delivery of an active compound; or the intercalated complex can be combined with a matrix polymer to form a strong, filled polymer matrix.

Abstract: A process for manufacturing a composition useful as a soap or cosmetic comprising: pulverizing sillimanite of about 50 weight percent, zeolite of about 5 weight percent, topaz of about 20 weight percent, trona of about 5 weight percent and hematite of about 20 weight percent as the first step to about 325 mesh; putting the pulverized ingredients of the composition into an internal furnace of zeolite; placing kaolinite between the inner surface of the electric heating plate and the outer surface of the internal furnace; heating for about nine days at about 1500.degree. C. by means of the electric heating plate; pulverizing again the ingredients of the composition having had thermal deformation from the internal furnace to at least 900 mesh; filtering the ingredients of the composition with water through a sieve of 900 mesh; precipitating for about three days said filtered solution; and drying the precipitate.

Abstract: Disclosed are kaolin compositions of at least one hydrous kaolin characterized by a particle size distribution where 98% of the particles are less than about 2.mu., 90% are less than about 0.5.mu. and the median particle size is less than about 0.3.mu.. Also disclosed is a process which involves the steps (i) preparing an aqueous slurry of at least one hydrous kaolin; (ii) separating the particles from said slurry so that the particle size distribution is such that 98% of the particles are less than about 2.mu., 90% are less than about 0.5.mu. and a median particle size is less than about 0.3.mu.; and (iii) drying said separated particles. Pigment pastes and electrodeposition paints containing said compositions as well as cationic electrodeposition of said paint on a substrate and the article of manufacture prepared thereby are disclosed.

Abstract: Intercalates formed by contacting a layered material, e.g., a phyllosilicate, with an intercalant monomer having a hydroxyl and/or an aromatic ring functionality to sorb or intercalate the intercalant monomer between adjacent platelets of the layered material. Sufficient intercalant monomer is sorbed between adjacent platelets to expand the adjacent platelets to a spacing of at least about 5 .ANG. (as measured after water removal to a maximum of 5% by weight water), up to about 100 .ANG. and preferably in the range of about 10-45 .ANG., so that the intercalate easily can be exfoliated into individual platelets. The intercalated complex can be combined with an organic liquid into a viscous carrier material, for delivery of the carrier material, or for delivery of an active compound; or the intercalated complex can be combined with a matrix polymer to form a strong, filled polymer matrix.

Abstract: A method for preparing precipitated silicates and silicas having good high shear rheology in high solids aqueous slurries. Destructuring of aluminum silicate and silica via dry milling results in decreasing DBP oil absorption. The destructured materials are useful for ink jet coating formulations.

Abstract: Intercalates formed by contacting a layered material, e.g., a phyllosilicate, with an intercalant monomer carbonyl-functional compound and/or a carboxylic acid-functional compound to sorb or intercalate the intercalant monomer between adjacent platelets of the layered material. Sufficient intercalant monomer is sorbed between adjacent platelets to expand the adjacent platelets to a spacing of at least about 5 .ANG. (as measured after water removal to a maximum of 5% by weight water), up to about 100 .ANG. and preferably in the range of about 10-45 .ANG., so that the intercalate easily can be exfoliated into individual platelets. The intercalated complex can be combined with an organic liquid into a viscous carrier material, for delivery of the carrier material, or for delivery of an active compound; or the intercalated complex can be combined with a matrix polymer to form a strong, filled polymer matrix.

Abstract: A method of forming powdered metakaolin for use as an additive in cement based materials comprising the steps of calcining kaolin so as to reduce the hydroxyl content thereof to produce a meta-stable material have an identifiable amorphousness, and pulverizing the meta-stable material into a powder having a particle size of 50 microns or less.

Abstract: An improved process for preparing an aqueous clay slurry having superior gellation properties. The process involves the bead milling of the clay in an aqueous medium for a period of about 0.5 to 20 minutes at an energy input level of about 44 to 146 kilowatt-hours per metric ton of dry clay. The milling may carried out using any suitable horizontal or vertical sand mill or ball mill such as the "Morehouse Cowles Sandmill" or the "Polymill" containing a grinding medium such as zirconium silicate or zirconium oxide. The clay is preferably a smectite clay such as montmorillonite and is present in the slurry in the range of about 3 to 30 wt. %, based on the total weight of the slurry. The aqueous clay slurry is useful as a rheological additive in water-based coating formulations.