PURIFICATION OF KAOLINS BY SELECTIVE DISPERSION AND FLOCCULATION

To fulfill the increasingly higher requirements on thequality of kaolins from industries, the purification of kaolins has becomemore and more important. Kaolins from different mines were studied withthe aim to remove the various impurities. The mineralogical studies on thekaolins indicated that kaolinite and the major gangue minerals in the orewere all very fine. Therefore, it was difficult to separate kaolinite fromthe gangue minerals by conventional mineral processing techniques,such asgravity concentration, magnetic separation and flotation. Techniques forfine particles processing, i. e. selective dispersion and flocculation weretried to purify the kaolins. The experiments were first carried out withpure minerals of kaolinite and the gangue,minerals to study the dispersionand flocculation characteristics of the different mineral suspensions undervarious conditions. The key factors affecting the dispersion and floccula-tion of the minerals in water were the pH of the suspension, the type anddosage of t

PURIFICATION OF KAOLINS BY SELECTIVE DISPERSION AND FLOCCULATION

To fulfill the increasingly higher requirements on the quality of kaolins from industries, the purification of kaolins has become more and more important. Kaolins from different mines mere studied with the aitn to remove the various impurities. The mineralogical studies on the kaolins indicated that kaolinite and the major gangue minerals in the ore were all very fine. Therefore, it was difficult to separate kaolinite from the gangue minerals by conventional mineral processing techniques, such as gravity concentration, magnetic separation and flotation. Techniques for fine particles processing, i. e. selective dispersion and flocculation ivere tried to purify the kaolins. The experiments were first carried out with pure minerals of kaolinite and the gangue minerals to study the dispersion and flocculation characteristics of the different mineral suspensions under various conditions. The key factors affecting the dispersion and floccula-tion of the minerals in water were the pH of the suspension, the type and dosage of the reagents, and the strength and time of agitation. These fac-tors were adjusted to separate kaolinite from the gangue minerals. Satis-factory results were obtained with kaolin ores with different impurities from different mines. The quality of the kaolins was significantly im-proved ivith the impurities reduced to the level according ivith the specifi-cation set by the industries. The principles of the separation of kaolinite from the gangue minerals by selective dispersion and flocculation ivere dis-cussed.