Institute for Mineral and Energy Resources (IMER)

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https://hdl.handle.net/2440/65217
The Institute for Mineral and Energy Resources (IMER) is specifically designed to address the challenge of continuing to grow the critical mineral and energy resources industries in a technically, economically, socially and environmentally sustainable manner through interdisciplinary research. IMER will address these complex research challenges faced by providing integrated research, education, professional development and consulting services across all aspects of the mineral and energy resources industries.

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Browsing Institute for Mineral and Energy Resources (IMER) by Author "CHEMECA (36th : 2008 : Newcastle, Australia)"

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    Flotation behaviour of sulphide mineral size fractions with controlled contact angle
    (Engineers Australia, 2008) Muganda, S.; Zanin, M.; Grano, S.; CHEMECA (36th : 2008 : Newcastle, Australia); Institute for Minerals and Energy Resources (IMER)
    The flotation response of chalcopyrite has been characterized as a function of particle size and advancing contact angle. The advancing contact angle of individual size fractions was manipulated to different values, measured using the Washburn technique. A flotation feed sample was constituted from the individual size fractions. Parameters such as frother concentration, impeller rotational speed, and superficial gas velocity were the same in each flotation test. The chalcopyrite sample, in the absence of any steps to intentionally manipulate the contact angle, displayed advancing contact angles which varied with particle size fraction. In the presence of a standard thiol collector, the advancing contact angle was also particle size dependent, with the -20 micron fraction displaying the lowest contact angle. Flotation tests showed that the chalcopyrite size fractions above 20 microns floated independently of each other, and that the flotation response was the same for the same particle contact angle and size fraction across different flotation tests. The flotation response was characterized by the maximum recovery at infinite flotation time and the distributed rate constant, assuming a single floatable fraction existed within each size fraction. When the distributed and undistributed rate constants were compared, the latter gave a greater dependency on contact angle as it took into account the non-floating fraction. The two rate constants converged at high advancing contact angles as the non-floating fraction approached zero. Further work on mineral floatability characterization will lead to the development of calibration curves of rate constant against particle size and contact angle, a tool that could be used to benchmark flotation response.
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    Optimising regrinding chemistry for pyrrhotite flotation
    (Engineers Australia, 2008) Ye, X.; Gredelj, S.; Grano, S.; CHEMECA (36th : 2008 : Newcastle, Australia); Institute for Mineral and Energy Resources
    Changes in the surface properties of minerals with grinding and regrinding play a key role in mineral flotation performance, being recognised in industry through the development of the IsaMill and Stirred Mill Detritor. This paper describes some initial results in a larger study which attempts to quantify changes in the flotation properties of sulphide minerals with regrinding using different mills. Pyrrhotite has been chosen in the current study due its importance in the recovery of Platinum Group Minerals and in its separation from pentlandite in Sudbury basin nickel ores. This current paper focuses on the results obtained using a Magotteaux Mill only. Factors which affected pyrrhotite flotation were particle size, grinding media contamination, and exposure of new mineral surface. Pyrrhotite recovery decreased with size reduction from 90%, achieved before regrinding, to 77%, 64%, 30% and 7% after regrinding with stainless steel medium to d{80} values of 60, 40, 20 and 10 m, respectively. Contact angle measurements were applied to quantify surface hydrophobicity as a function of particle size and the B.E.T. method was used to obtain the surface area. Increased collector addition only partially restored pyrrhotite recovery. The surface of the pyrrhotite mineral was changed by regrinding in a way that hindered collector adsorption onto the new mineral surface. A further dramatic depression of pyrrhotite recovery when using mild steel regrinding medium demonstrated that there was an additional contribution to pyrrhotite depression from media contamination in this case.