Abstract: A low brightness pigment and method is provided from a heretofore rejected waste kaolin stream. Kaolin processing rejects are high in iron-stained TiO.sub.2. After separating the stained TiO.sub.2 from the high brightness kaolin and concentrating the resulting fraction, the material can be processed to produce a low brightness pigment suitable of many applications where lower brightness is desirable, such as coating paper board without mottling.

Abstract: A low brightness pigment and method is provided from a heretofore rejected waste kaolin stream. Kaolin processing rejects are high in iron-stained TiO.sub.2. After separating the stained TiO.sub.2 from the high brightness kaolin and concentrating the resulting fraction, the material can be processed to produce a low brightness pigment suitable of many applications where lower brightness is desirable, such as coating paper board without mottling.

Abstract: A low brightness pigment and method is provided from a heretofore rejected waste kaolin stream. Kaolin processing rejects are high in iron-stained TiO.sub.2. After separating the stained TiO.sub.2 from the high brightness kaolin and concentrating the resulting fraction, the material can be processed to produce a low brightness pigment suitable of many applications where lower brightness is desirable, such as coating paper board without mottling.

Abstract: A low brightness pigment and method is provided from a heretofore rejected waste kaolin stream. Kaolin processing rejects are high in iron-stained TiO.sub.2. After separating the stained TiO.sub.2 from the high brightness kaolin and concentrating the resulting fraction, the material can be processed to produce a low brightness pigment suitable of many applications where lower brightness is desirable, such as coating paper board without mottling.

Abstract: A low brightness pigment and method is provided from a heretofore rejected waste kaolin stream. Kaolin processing rejects are high in iron-stained TiO.sub.2. After separating the stained TiO.sub.2 from the high brightness kaolin and concentrating the resulting fraction, the material can be processed to produce a low brightness pigment suitable of many applications where lower brightness is desirable, such as coating paper board without mottling.

Abstract: A mineral dye coloring pigment has been developed which includes a water-soluble organic dye which has been insolubilized or "fixed" onto a mineral pigment substrate by means of a cationic or anionic chemical compound. Also, a method for producing the mineral dye pigment and products containing the mineral dye pigment have been developed.

Abstract: Kaolin clay treated with 0.5 to 1.5 wt. % of aluminum chlorohydrate or a double hydroxide of aluminum and magnesium are an effective pitch adsorption agent for use in paper making processes.

Abstract: Kaolin clay treated with 0.5 to 1.5 wt. % of aluminum chlorohydrate or a double hydroxide of aluminum and magnesium are an effective pitch adsorption agent for use in paper making processes.

Abstract: A process for producing ultrafine ground calcium carbonate is disclosed in which a dry feed stone is slurried to a 15 to 60% by weight solids slurry and dispersed with an organic dispersant. The dispersed slurry is fed to an attrition mill where it is bead ground to 50-70% less than 2 microns. The ground calcium carbonate is classified in a centrifuge into a product stream having from 70-99% of its particles less than 2 microns and an underflow stream of larger particles. The product stream is treated with ozone which serves not only to increase the brightness of the product but to return the slurry to a non-dispersed state. The calcium carbonate slurry is then dewatered to produce a 58-69% solids product suitable for preparing a higher solids slurry or for spray drying.

Abstract: An electrokinetic dewatering apparatus is disclosed which includes a pair of oppositely electrically charged continuously traveling webs or belts positioned to contact a quantity of clay material passed into a nip formed at the inlet to the dewatering apparatus. The clay cake is continuously contacted by the two webs while the cake passes therebetween. The clay material is not subjected to any pressure force substantially in excess of the contact pressure during the electrokinetic separation and removal of a portion of the water contained therein.

Abstract: An electroflocculation cell for the separation of clay particles from an aqueous suspension thereof, the cell being equipped with an anode and cathode separated by a first semipermeable membrane impermeable to clay particles which divides the cell into anode and cathode compartments. A second semipermeable membrane is provided in the anode compartment spaced from the anode and the first membrane. Upon application of a direct current to the anode and cathode, clay particles in a suspension fed to the area of the cell between the first and second membranes deposit electrophoretically on the second membrane. By avoiding contact of the clay deposit with the anode, contamination of the deposit by anode corrosion products is thereby avoided.

Abstract: A process for the electrokinetic separation of finely divided clay particles from an aqueous suspension thereof, the suspension being contained in an electrokinetic cell equipped with an anode and cathode separated by a semi-permeable membrane impermeable to clay particles. Upon activation of the cell with direct current, clay particles are caused to deposit electrophoretically on the anode. Simultaneously with the deposition of the clay deposit, portions of the water contained in the suspension and entrained in the deposit are caused to migrate electroosmotically through the membrane and collected at a cathode compartment, thereby increasing clay solids content.

Abstract: A method for reducing the viscosity and for refining crude kaolin clays is disclosed. The inherent viscosities of crude kaolin clay ores, particularly those having acceptable optical and purity properties for use in preparing paper coating pigments, but normally rejected because of their high inherent viscosities, are significantly reduced by contacting an aqueous slurry of the crude clay with an inorganic polymeric complex having the general formula[Al (OH).sub.y A.sub.3-y ].sub.xwherein x = 6 to 24, y = 1.0 to 2.75 and A is selected from the group consisting of Cl.sup.-, (SO.sub.4.sup.--).sub.0.5 and NO.sub.3.sup.-. In a preferred embodiment the above treated clay is also subjected to a high shear mixing action or kneading prior to further conventional processing procedures, such as fractionation, leaching, etc.

Abstract: An electroflocculation cell for the separation of clay particles from an aqueous suspension thereof, the cell being equipped with an anode and cathode separated by a first semipermeable membrane impermeable to clay particles which divides the cell into anode and cathode compartments. A second semipermeable membrane is provided in the anode compartment spaced from the anode and the first membrane. Upon application of a direct current to the anode and cathode, clay particles in a suspension fed to the area of the cell between the first and second membranes deposit electrophoretically on the second membrane. By avoiding contact of the clay deposit with the anode, contamination of the deposit by anode corrosion products is thereby avoided.

Abstract: A method for reducing the viscosity and for refining crude kaolin clays is disclosed. The inherent viscosities or crude kaolin clay ores, particularly those having acceptable optical and purity properties for use in preparing paper coating pigments, but normally rejected because of their high inherent viscosities, are significantly reduced by contacting an aqueous slurry of the crude clay with an inorganic polymeric complex having the general formula[AI(OH).sub.y A.sub.3.sub.-y ].sub.xwherein x = 6 to 24, y = 1.0 to 2.75 and A is selected from the group consisting of Cl.sup.-, (SO.sub.4 .sup.=).sub.0.5 and NO.sub.3 .sup.-. In a preferred embodiment the above treated clay is also subjected to a high shear mixing action or kneading prior to further conventional processing procedures, such as fractionation, leaching, etc.

Abstract: A method of filtering solid particles contained in a suspension thereof wherein a rotatable filter assembly is rotated through the suspension to cause a filter cake to accumulate thereon and a DC voltage is applied across the filter cake to cause liquid entrained therein to migrate electroosmotically from the cake and through the filter cloth of the filter assembly.

Abstract: A process for the electrokinetic separation of finely divided clay particles from an aqueous suspension thereof, the suspension being contained in an electrokinetic cell equipped with an anode and cathode separated by a semi-permeable membrane impermeable to clay particles. Upon activation of the cell with direct current, clay particles are caused to deposit electrophoretically on the anode. Simultaneously with the deposition of the clay deposit, portions of the water contained in the suspension and entrained in the deposit are caused to migrate electroosmotically through the membrane and collected at a cathode compartment.

Abstract: An electrokinetic cell for the separation of solid particles from an aqueous suspension thereof, the cell being equipped with an anode and cathode separated by a semi-permeable membrane impermeable to clay particles which divides the cell into anode and cathode compartments. Upon application of direct current to the anode and cathode, clay particles in a suspension fed to the anode compartment deposit electrophoretically on the anode. Water contained in the suspension and entrained in the deposit simultaneously migrates electrosomotically therefrom and through the membrane where it is collected in the cathode compartment and thereafter removed from the cell.