Rheology of ore suspensions with fibrous minerals and its impact on flotation performance
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Flotation separation and recovery of value minerals from ores containing fibrous silicate minerals are known to be quite challenging. Earlier studies have established that the metallurgical challenges (poor selectivity and recovery, high energy consumption, etc.) arise from the impact of the fibrous minerals (with high aspect ratio) on pulp rheology, which was found be rather complex. The complex rheological behavior of ore suspensions containing particles with high aspect ratio and its influence on flotation outcome are investigated in this study. Flotation tests and rheological measurements were carried out with both ores (containing fibrous minerals) and a model system comprising nylon fibers (chemically inert) added to a copper ore that had no fibrous mineral. These studies allowed the determination of contributions of physical properties of the fiber to pulp rheological behavior. Optical microscopy images of the fiber pulp indicated that the fibers entangled to form two levels of microstructures: two-dimensional (2D) aggregates under semi-dilute (< 20% solids) conditions and three-dimensional (3D) microstructures at concentrations > 30% solids. The yield stress (σ) values determined for the fiber pulp were logarithmically related to the volume fraction of the 2D/3D structures. The relationships developed here for different ARs showed that the yield stress of a flotation pulp changes with respect to shape, size, and the concentrations of the microstructures. Implications to the effects of such entangle networks on selectivity of flotation separation are discussed.
KeywordsMicrostructure Planar aggregates Aspect ratio Flotation Froth phase
The authors acknowledge the support of Manqiu Xu, Zongfu Dai, Andrew Lee, and Ken Scholey at the Vale Technical Services in Mississauga, Canada. The authors acknowledge the support received for this research work from the National Science Foundation Industry/University Collaborative Research Center of Particulate and Surfactant Systems (IIP 1362078).
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Conflict of Interest
The authors declare that they have no conflict of interest.
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