Institute for Mineral and Energy Resources publications

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Browsing Institute for Mineral and Energy Resources publications by Author "Akroyd, T."

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    A model study of copper rougher recovery optimisation at PT Freeport Indonesia
    (Australasian Institute of Mining and Metallurgy, 2007) Grano, S.; Akroyd, T.; Mular, M.; Nelson, M.; Mill Operators' Conference (9th : 2007 : Fremantle, Western Australia); Institute for Mineral and Energy Resources
    A fundamental model, which considers the subprocesses of particle collection by bubbles in flotation, is applied to two comprehensive flotation surveys in the rougher stages of C3 concentrator, PT Freeport Indonesia. The flotation surveys focused on the collection of: • cell-by-cell and size-by-size metallurgical, • cell hydrodynamic, and • pulp and surface chemistry information. The two surveys were conducted at significantly different feed tonnages, giving rise to significantly different feed particle size distributions, pulp densities and mean pulp residence times. A series of model simulations are performed with the aim of quantifying changes in copper recovery, on both a size-by-size and unsized basis, with changes in values of the hydrodynamic parameters and hydrophobicity of the copper sulfide mineral. This was carried out in an effort to identify the most promising route to increase overall copper recovery in roughing. It was found that by increasing the hydrophobicity of the copper sulfide mineral surfaces it became possible to optimise cell hydrodynamics, which targeted increased fine (-12 μm) copper sulfide mineral recovery but without adversely affecting coarse (+150 μm) copper sulfide mineral recovery.
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    Flotation Rate Constant Prediction for Metal Sulfide Particles
    (AusIMM, 2005) Ralston, J.; Fornasiero, D.; Grano, S.; Duan, F.; Akroyd, T.; Centenary of Flotation Symposium (2005 : Brisbane, Queensland); Johnson, G.; Institute for Mineral and Energy Resources
    We have determined the experimental rate constants for chalcopyrite particles floated from a complex sulfide ore and compared them with those calculated using a recently developed flotation model. The model incorporates contributions from the efficiencies of collision, attachment and stability between particles and bubbles, as well as their frequency of collision. For these calculations, the contact angle of the chalcopyrite particles in the ore was obtained independently using a surface spectroscopic approach. The calculated flotation rate constants were in good agreement with the experimental data and able to reproduce the characteristic maximum in flotation rate constant for particles of intermediate size. The values of bubble velocity and turbulent dissipation energy derived from these calculations are relatively low and may well correspond to mean values of these parameters inside the flotation cell. We have extended this approach through the application of a property based model to an operating plant, with a satisfactory outcome.