Abstract: Disclosed herein is a rubber composition comprising a rubber and particulate kaolin clay as a filler wherein: the kaolin particles have a particle size distribution such that at least about 95% of the particles, relative to the volume of the particles, have a particle diameter less than 3?m. The particulate kaolin particles may comprise calcined kaolin chosen from at least one of particulate soak calcined kaolin and particulate flash calcined kaolin. The rubber composition can comprise additional particulate fillers including those chosen from silica, carbon black, and other particulate fillers. Also disclosed herein is a process for producing such a composition, and the method of using a cured form of the composition in a rubber composition, such as a vehicle tire composition.

Abstract: A method for preparing an aqueous suspension comprising microfibrillated cellulose and inorganic particulate material, the method comprising a step of microfibrillating a fibrous substrate comprising cellulose in an aqueous environment in the presence of an inorganic particulate material.

Abstract: A coating composition may include a coating vehicle, kaolin having a d50 of not more than 2 microns, alkaline earth metal carbonate having a d50 of not more than 2 microns, and not more than 10% by weight titanium dioxide relative to the weight of the coating composition. A method for improving opacity of a coating composition may include adding kaolin and alkaline earth metal carbonate to the coating composition. A method for reducing titanium dioxide content of a coating composition and at least substantially maintaining opacity of the coating may include adding fine kaolin and fine alkaline earth metal carbonate to the coating composition, wherein a volume concentration ratio of the fine kaolin to the fine alkaline earth metal carbonate ranges between 0.5:1 and 10:1.

Abstract: A method of making magnesium hydroxide may include calcining a mineral source of magnesium carbonate to form magnesium oxide, and slaking the magnesium oxide in water. When the mineral source of magnesium carbonate further includes a mineral source of calcium carbonate, the calcination may be carried out such that less than about 20 wt % calcium oxide is formed following calcining and prior to slaking in water.

Abstract: A method of preparing a steep particle size inorganic particulate material includes grinding an aqueous suspension of an inorganic particulate material having a solids content of less than 35% and including a sub-effective amount of a dispersant for the inorganic particulate material. The method may further include dewatering the aqueous suspension to a solids content of at least 50% and dispersing the dewatered aqueous suspension by adding an additional amount of dispersant, and wherein, after grinding, the inorganic particulate material has a steepness factor above 35.

Abstract: There is disclosed a composition comprising a fine particulate glass cullet. The particulate material may be obtained by a suitable grinding process. The particulate cullet is useful as an inexpensive filler for polymer compositions and in abrasive compositions.

Abstract: The invention provides a method for preparing particulate brucite comprising grinding and beneficiating particulate brucite wherein the ground beneficiated particulate brucite has a d90 of less than or equal to about 6.4 ?m as measured by laser light scattering.

Abstract: There is disclosed a particulate glass cullet having a d90 less than about 20 ?m, and a particulate glass cullet having a d90 wherein the particles have been surface treated to modify on or more properties of the cullet. The particulate materials may be obtained by a suitable grinding process. The particulate glass cullet and surface treated particulate glass cullet are useful as anti-blocking pigments in polymer compositions.

Abstract: There is disclosed a polymer composition comprising a polymer resin and, as opacifier, a flash calcined kaolin clay filler and a TiO2. The polymer composition may be formed into shaped articles, particularly polyolefin film.

Abstract: The invention provides the use of a dehydrated particulate mineral having a d50 of less than or equal to about 0.5 ?m as a filler in combination with a thermoplastic polymer in an infrared absorbing polymer film. The polymer film may be used in greenhouses and the like.

Abstract: A dispersion of a particulate inorganic material comprises a non-aqueous liquid medium containing a particulate inorganic material dispersed therein and an effective amount of one or more dispersing agent which serves to maintain the particulate inorganic material in dispersion in the non-aqueous medium, wherein the particulate inorganic material has an average particle size (d50) less than about 9 ?m, the particulate inorganic material is present in the non-aqueous medium in an amount greater than about 70% by weight of the dispersion and the viscosity of the dispersion is less than about 150 Pa·s measured at room temperature on a Bohlin rheometer using a 20 mm cone/plate at a shear rate of 1/sec. A substantially dry particulate inorganic material surface treated with the dispersing agent and optionally one or more hydrophobising surface treatment agent, and capable of forming the said dispersion, is a further feature of the invention.

Abstract: A method for increasing the brightness of metakaolins comprises calcining a metakaolin under reducing conditions. The calcined metakaolins are suitable for use in a variety of applications including in polymer products and paints.

Abstract: There is provided a method of producing a kaolin particulate material suitable for use as an improved super-calendered filler. This method includes: (a) preparing an aqueous feed suspension of kaolin; (b) treating the kaolin of the feed suspension by attrition grinding in a vessel using grinding media granules; (c) delivering an aqueous suspension of the kaolin ground in (b) to a particle size classifier and separating the kaolin of the suspension into a coarse fraction and a fine fraction; (d) returning an aqueous suspension of the coarse fraction produced in (c) to the grinding vessel to be further attrition ground; and (e) extracting an aqueous suspension of the fine fraction produced in (c) as a product suspension. Advantageously, the kaolin of the feed suspension in (a) is such that not more than 30% by weight has a particle size less than 2 ?m and not more than 30% by weight has a particle size greater than 10 ?m.

Abstract: A method of treating solid containing material derived from effluent or sludge from a plant for deinking paper, the material containing calcium in the form of one or more insoluble calcium compounds, the method including the steps of treating the material with an acid to cause dissolution of the calcium thereby forming a calcium ion-containing solution in which insoluble solids are suspended, separating the solution from the insoluble solids and incinerating the separated solids. The solution containing calcium ions may be treated by adding one or more reagents to form a calcium compound precipitate, eg calcium carbonate. The particulate solids produced following the incineration step and following the precipitate formation may be employed as pigments or fillers in paper making or paper coating.

Abstract: Abstract of the Disclosure A method of treating solid containing material derived from effluent or sludge from a plant for de-inking paper, the material containing calcium in the form of one or more insoluble calcium compounds, the method including the steps of treating the material with an acid to cause dissolution of the calcium thereby forming a calcium ion-containing solution in which insoluble solids are suspended, separating the solution from the insoluble solids and incinerating the separated solids. The solution containing calcium ions may be treated by adding one or more reagents to form a calcium compound precipitate, eg calcium carbonate. The particulate solids produced following the incineration step and following the precipitate formation may be employed as pigments or fillers in paper making or paper coating.

Abstract: Abstract of the Disclosure A method of treating solid containing material derived from effluent or sludge from a plant for de-inking paper, the material containing calcium in the form of one or more insoluble calcium compounds, the method including the steps of treating the material with an acid to cause dissolution of the calcium thereby forming a calcium ion-containing solution in which insoluble solids are suspended, separating the solution from the insoluble solids and incinerating the separated solids. The solution containing calcium ions may be treated by adding one or more reagents to form a calcium compound precipitate, eg calcium carbonate. The particulate solids produced following the incineration step and following the precipitate formation may be employed as pigments or fillers in paper making or paper coating.

Abstract: A particulate hydrous mineral suitable for use as an opacifying pigment, filler or extender has a shape factor which is greater than S, where S is defined by Equation 1 as follows: S=(d50/0.036)+20  Equation 1; where d50 is the mean particle size of the particles of the mineral measured in microns. The particulate mineral is preferably a kaolin, which is particularly suitable for use in aqueous matt paint compositions.

Abstract: A method of treating solid containing material derived from effluent or sludge from a plant for de-inking paper, the material containing calcium in the form of one or more insoluble calcium compounds, the method including the steps of treating the material with an acid to cause dissolution of the calcium thereby forming a calcium ion-containing solution in which insoluble solids are suspended, separating the solution from the insoluble solids and incinerating the separated solids. The solution containing calcium ions may be treated by adding one or more reagents to form a calcium compound precipitate, eg calcium carbonate. The particulate solids produced following the incineration step and following the precipitate formation may be employed as pigments or fillers in paper making or paper coating.

Abstract: A method of producing a rheologically stable concentrated aqueous suspension of a particulate alkaline earth metal carbonate which method comprises the following steps: (a) preparing a dilute aqueous suspension of the carbonate having a solids content of not more than 40% by weight; (b) dewatering the dilute aqueous suspension to form a carbonate suspension having a solids content in the range of from 45% to 65% by weight; (c) optionally mixing with the dewatered suspension formed in step (b) a dispersing agent for the carbonate to form a fluid suspension; (d) further dewatering the fluid suspension formed in step (b) by thermal evaporation under reduced pressure to raise the solids content of the suspension by a further differential amount of at least 5% by weight; and (e) after at least some of the dewatering in step (c) treating the suspension by a mechanical working process in which at least 1 kW.hr per tonne of carbonate on a dry weight basis is dissipated to refluidise the suspension.

Abstract: There is disclosed a method for the preparation of a precipitated calcium carbonate (PCC) for use as a pigment in paper coating compositions, the method comprising the steps of (a) carbonating an aqueous lime-containing medium to produce an aqueous suspension of a PCC predominantly in a selected crystal form, (b) at least partially dewatering the PCC-containing suspension; and (c) subjecting the PCC-containing suspension to comminution by high shear attrition grinding with an attrition grinding medium. Steps (b) and (c) may be applied in either order, ie. (b) followed by (c) or alternatively (c) followed by (b). The dewatering step (b) is preferably carried out using a pressure filter device operating at a pressure of at least 5 MPa, preferably at least 10 MPa. A pH reduction step may be applied after steps (b) and (c). Also disclosed are pigments produced by the method and pigment and paper coating compositions including such pigments.