Method of treating zeolite ores to remove discoloring impurities and improve its brightness and resulting finely ground zeolite

摘要

A method of treating zeolites to remove therefrom discoloring impurities and improve the brightness thereof, comprising the steps of mixing a pulverized sedimentary zeolite ore with a dispersant and water to form a dispersed aqueous zeolite slurry, degritting the resulting slurry, removing fines containing discoloring impurities from the degritted slurry, thereafter subjecting the zeolite slurry to a fine media milling, removing fines containing discoloring impurities from the resulting fine milled slurry, subjecting the fine milled slurry to magnetic separation to remove magnetic discoloring impurities, bleaching the resulting zeolite slurry and then recovering the zeolite in dry form from the resulting slurry. The dry finely ground zeolite made by this method has a particle size of at least 85% below 2 &mgr;m and a Tappi brightness of at least 90. It also exhibits the ion exchange characteristics of zeolites and possesses a bulk density (loose or packed) of about half or less of high quality kaolin clay pigments.