Abstract: The invention provides a process for improving the rheological properties of an aqueous suspension of a clay mineral in which the aqueous suspension is mixed with a water-soluble organic compound having a plurality of basic groups and a number average molecular weight not greater than 1,000. The treated clay minerals may be used, for example, as the pigment in a paper coating composition.

Abstract: The invention relates to a process for preparing paper or cardboard in which starch and a mineral filler are incorporated into cellulosic fibres. The process uses a blend, which is prepared under specified conditions, of raw starch and starch phosphate. The procedure for incorporating the starch blend and the mineral filler into the cellulosic fibres is also specified.

Abstract: A method of preparing a mineral which is suitable for use in the coating of paper includes the steps of (i) forming a substantially uniform suspension of fine particles of the mineral in water; (ii) admixing the suspension thus obtained with a water-soluble or water-dispersible polymer which is such that, on dewatering and drying the suspension, the particles of the mineral adhere to the polymer and to one another and the polymer is rendered irreversibly insoluble and non-dispersible in water; and (iii) dewatering and drying the suspension to form the desired mineral.