摘要 |
An improved method for improving the brightness of clay of the type that is capable of being bleached by an oxidative reagent such as Georgia gray kaolin. Such clay, in the form of a dispersed slurry, is treated with a combination of sodium silicate, sodium hypochlorite and ozone, most preferably followed by magnetic purification and a reduction bleach. Sodium hypochlorite is added shortly before ozonation. |