Abstract

MCGRATH, T.D.H.; EKSTEEN, J.J.  and  HEATH, J.. The behaviour of free gold particles in a simulated flash flotation environment. J. S. Afr. Inst. Min. Metall. [online]. 2015, vol.115, n.2, pp.103-112. ISSN 2411-9717.

A reliable laboratory method to characterize the response of free gold particles to flash flotation conditions has been developed. The test has been performed on free milling gold ores as well as synthetic ores, using either a gravity concentrate or gold powder as the gold source, to assess the floatability of gold particles. Trends in free gold flotation kinetics, as well as size and milling effects, were identified for gold recovery based on the different feed types, reagent dosages, and residence times. It was shown that the ultimate recoveries and kinetic trends of gold particles from the gravity concentrate could be enhanced with increased dosage of collector, potassium amyl xanthate. Interestingly, in comparison to gravity-recoverable gold, recovery from pure Au powders was better in collectorless flotation, and cumulative recovery decreased with higher levels of collector addition. Improved coarse particle recovery appeared linked to increased collector additions for both the gravity concentrate and the pure gold powders. In general, coarse gold particles demonstrated slower kinetic rates thaen the fine or intermediate components in comparable tests.

Keywords : gold; flotation; flash flotation; natural hydrophobicity; kinetics.

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