| Georgia is one of the leading states in the production of non-fuel minerals. Kaolinite and crushed stone are the main mining products. This dissertation addresses fundamental problems related to the particulate nature of these products in two major units. The first unit is dedicated to the crushed stone industry and it involves fundamental studies on pond screenings produced during crushing operations. The second unit focuses on the kaolinite industry, with emphasis on ion removal and potential applications in dewatering.; Approximately 3M tons of pond screenings are produced annually in Georgia with no market opportunities. Three alternatives are explored. First, the flexibility of the Georgia DoT rating system for the addition of fines into manufactured sand is analyzed using Montecarlo simulation; results show that this is not a feasible alternative for the reutilization of pond screenings. Second, emphasis is placed on reducing the production of fines while still meeting cubicity requirements. Laboratory results and field observations provide unique insight into fine generation mechanisms, the development of cubicity and the underlying fracturing processes within crushers. Third, stocked fines are studied, stressing the role of mica content on the mechanical behavior of pond screenings in view of their possible reutilization in low-strength base materials. Micro and macro scale tests show the unique packing conditions in mixtures made of round and platy particles, and the significant effect mica exerts on low, medium and large strain parameters.; The wet processing of kaolinite involves adding different chemicals in order to attain flocculation, dispersion and whiteness. Yet, high ionic concentration is not desirable for some applications, such as paper coating. A unique experimental study is implemented to explore the effect of electric fields on the removal of ions from electrolytes and slurries and to identify intervening phenomena. The study addresses each component in the electrochemical cell, and the controlling variables. Experimental and analytical results confirm the potential of this technology as part of a single-phase dewatering/ion-removal process. |
