| 摘要 |
<p>A method for reducing the abrasion of a silica-containing calcined kaolin pigment by the controlled leaching of silica from the pigment, preferably by the use of a caustic solution to dissolve the silica out of the calcined kaolin. In another aspect of the invention, the brightness, opacity, or both of a calcined kaolin is increased by increasing the fineness of the kaolin feed supplied to the calciner. The combination of these methods results in the production of a calcined kaolin with low abrasion and high brightness and opacity. Another aspect of the invention concerns an improved method of filtration of dilatent materials such as the leached calcined clay.</p> |
