| 摘要 |
A method for continuously processing a kaolin clay which has relatively poor high-shear viscosity when prepared as a high-solids suspension, so as to obtain therefrom a fraction having a value of high-shear viscosity in high-solids suspension which is low relative to the starting clay, thereby being desirable for use in coating of paper. The method comprises the steps of forming the kaolin clay into a dilute aqueous suspension having from 10% to 20% solids by weight and forming said suspension into a continuous flow stream; mixing the stream of flowing suspension at a given point with from about 0.001% to 0.1% by weight of dry clay, of a high molecular weight anionic polyacrylamide polymer or derivative thereof, to selectively flocculate aggregates of minute kaolin platelets; and continuously separating the treated suspension downstream of the mixing point, into a sedimented phase containing a clay fraction of relatively high high-shear viscosity characteristics and a supernatant phase which is substantially free of aggregates and which contains in suspension as product, a fraction of the clay possessing relatively low high-shear viscosity properties.
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