The densification of the stable particulate dispersions resulting from the oil sands extraction is commonly achieved via polymer flocculation. Even though kinetics of the initial water release is fast, polymer flocculants as standalone treatment agents have been limited by the inherent variability of the tailings streams. Moreover, the polymer chain binding and bridging between mineral particles, which vary in size, charge density and surface reactivity, often results in the formation of nonuniform flocs and unsatisfactory long term densification. In recent years, the use of nanoparticles has gained momentum as an alternative tailings reclamation technique. In this work we present a novel treatment method using bare silica nanoparticles, which resulted in the destabilization of the tailings systems and allowed the formation of three distinct layers in the resulting sediment. Each layer varied in solids content and the consequent yield stress. The sediment properties were studied by relating the microstructural characteristics, examined by the scanning electron and confocal laser microscopy, to its rheological properties. In order to overcome the drawbacks of the slow dynamics of sediment formation with silica treatment, we studied the synergistic effect of silica and polymer flocculation. Here, the silica nanoparticles were found to enhance the polymer flocculation by imparting the favorable surface chemistry and the resulting sediment compactness, while the polymer bringing enabled the necessary treatment dynamics to take place. The hybrid approach presents a promising new route towards the efficient tailings treatment.<br/>

Enhancement of the solid-liquid separation in oil sands tailings treatment using silica nanoparticles

256th National Meeting (2018)

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