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Thesis (PhD(Minerals and Resources))--University of South Australia, 2018. Includes bibliographical references The mineral waste tailings originating from hydrometallurgical processing of fine clay mineral containing ores are notoriously difficult to dewater, store and remediate. The economic, environmental and social impacts of tailings are considerable, posing a large concern for the sustainability of the minerals industry. Conventional dewatering behaviour by gravity thickening of ubiquitous clay-rich tailings is typified by slow dewatering rates, necessitating high flocculant dosage, which invariably results in mediocre sediment consolidation. Despite the recent advancements in conventional dewatering technology, thickener underflow sediments of only 20 to 30 wt.% solid clay are generally realised, leaving a majority of the process water and reagents effectively trapped in impoundment dams. Further natural consolidation can take several decades, over which most of the valuable process water is lost to evaporation and/or seepage. As an alternative cost-effective process, non-conventional electroosmotic (EO) dewatering, exploiting the charged surfaces of mineral particles in tailings, has shown promise for improved dewatering and consolidation of mineral waste tailings in numerous laboratory investigations. However, commercial application of the technique has been hindered by a number of technical roadblocks and knowledge gaps. This work investigated some of the gap in the extant knowledge regarding the effect of clay pulp physicochemical characteristics on EO dewatering water recovery efficacy and cost-effectiveness. The main research question answered by this work was how the fundamental knowledge of colloid science and engineering could be judiciously applied to regulate and enhance EO dewatering of clay mineral slurries. In addition, this research project investigated the practicality and cost of powering EO dewatering sustainably with solar cell energy. |
