Abstract: Processes for making high quality PCC compositions, and the resulting PCC products thereof. A precipitated calcium carbonate (PCC) composition is prepared by a process comprising the step of wet media mill grinding an aqueous slurry of PCC made by carbonation of lime milk, with the grinding being done at a low solids content in a plurality of separate grinding stages, which can done while essentially free of the presence of organic dispersant. After the multi-stage wet grinding step, the ground PCC slurry is partially dewatered in the presence of an organic dispersant in a solid bowl centrifuge. Then, the partially dewatered PCC slurry is subjected, in the presence of an organic dispersant, to fluid shearing forces created in a rotor/stator type mixer. While these three steps are advantageously used together within a single PCC process flow for optimal effect, the individual steps also can be incorporated singly or in lesser combinations thereof into different PCC manufacturing schemes to beneficial effect.

Abstract: Sodium alumino-silicates are produced by silicate/clay reactions under hydrothermal conditions with increased solids during processing while still producing structural materials characterized by low oil absorption values, high total pore volume and increased differential pore volumes. The products are useful as coating pigments for paper and paperboard, paper fillers, paint pigments and as reinforcing pigments for rubber.

Abstract: Pigments for use in paper are comprised of structured aggregate clays which are reaction products of kaolin clays and colloidal silicas. Silica modified clays of low treatment level can under certain high-shear mixing conditions be attritioned back to their starting clay particle size consequently yielding silica coated clay particles that provide unique properties. Also provided are structured aggregate clay products produced by the reaction of kaolin clay, colloidal silicas and spacer particles such as titanium dioxide, which products have improved porosity and light scattering characteristics. Also provided are clay slurry products which comprise mixtures of the reaction product of kaolin clay and colloidal silica, and optionally titanium dioxide, blended with other clay products.

Abstract: A continuous process is disclosed for the production of monoalkali metal cyanurates. In the process, cyanuric acid and an aqueous solution of the alkali metal hydroxide are continuously reacted in a first reactor to produce a first slurry comprised of cyanuric acid and a monoalkali metal cyanurate. This first slurry is conveyed to a second reactor to further react the cyanuric acid with the alkali metal hydroxide to produce a second slurry comprised of the monalkali metal cyanurate.The novel process produces slurries of monoalkali metal cyanurate which are consistent both with respect to chemical composition and solids content while reducing equipment and operating costs.

Abstract: A device for dispensing solid into a liquid medium. The device utilizes a funnel with a vortical stream therein for feeding solids into a reaction zone. A portion of the contents of the reaction zone are recycled to supply the fluid for the vortical stream. The device finds particular use in dispersing dry particulate blends of isocyanuric acid and trichloroisocyanuric acid into a reaction slurry.