ABSTRACT
Bentonite clay has a wide range of industrial uses such as drilling fluid, purification, painting and others. The majority of investigated local raw materials are mainly of low grade due to the existence of other clay minerals mainly kaolinite. Upgrading the bentonite in their ores in aqueous media is considered a mineral beneficiation challenge due to the close physicochemical characteristics of bentonite and kaolinite. In this paper, beneficiation of some local bentonite ore (containing high percentage of kaolinite) is tried using selective separation technique in aqueous media as a function of pH. Initially, a mineralogical study was carried out using x-ray diffraction, infrared, and thermal analysis for pure kaolinite, bentonite samples and local clay deposits from different locations. Then, surface charge investigation was tried using a zeta-meter. Measurements were carried out as a function of pH. Laboratory selective separation, depending on the degree of dispersion for each mineral, reflected that not only zeta potential magnitude controls the effectiveness of separation but also other factors such as, size of particles, crystal nature of kaolins and the existence of dissolved ionic species from other gangue minerals associated with kaolin.
