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Journal of the Southern African Institute of Mining and Metallurgy

On-line version ISSN 2411-9717
Print version ISSN 0038-223X

J. S. Afr. Inst. Min. Metall. vol.111 n.2 Johannesburg  2011




Application of fundamentals in optimizing platinum concentrator performance



M.M. Valenta; H. Mapheto

Metallicon Process Consulting (Pty) Ltd




A number of challenges face platinum concentrator plant operators. These challenges include the increase in operating costs, the increase in smelter cost for the processing of concentrate, the shortage and cost of power, and the tightening of specifications on concentrate quality by the toll-smelting operations.
Over the years the focus has moved from extracting the platinum group metals (PGM) from the Merensky Reef to the UG2 reef. This has a number of advantages, including the higher 'basket price' for UG2 concentrate, reduced mining cost per unit volume as a result of the higher density of UG2, and the reduction in overall concentrate tonnage to be smelted. In many cases the Merensky ore has been fully exploited and it makes sense for the focus to shift to the UG2 ore that can be accessed through the Merensky shaft infrastructure. The presence of relatively high levels of chromite in UG2 concentrate is, however, a major disadvantage due to the problems associated with smelting such a concentrate in conventional submerged arc furnaces.
In addition to increasing the specification on the minimum PGM grade of concentrates, smelters have had to impose strict specifications on the levels of chromite in the concentrate. The threat of high penalties has forced concentrators to change their modus operandi, often resulting in a significant loss in recovery.
The final concentrate grades and PGM recoveries are shown to vary significantly throughout the industry. The reasons for this include varying ore mineralogy and different operating philosophies. This would therefore imply that the opportunity exists to optimize the operations by considering fundamental aspects such as the PGM mineralogy and the application of appropriate technologies.
By returning to the fundamentals of flotation and applying the findings of detailed process reviews, it has been possible to increase the concentrate PGM grade, reduce the concentrate chromite grade, and in some cases increase the recovery of PGM to concentrate. This paper presents case studies where this approach has been used to successfully optimize concentrator performance, resulting in lower operating cost and higher PGM production.

Keywords: Process optimization, platinum concentrator, milling, flotation, grade, recovery



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BRADSHAW, D.J., HARRIS, P.J., and O'CONNOR, C.T. The effect of collectors and their interaction with depressants on the behaviour of the froth phase in flotation. Centenary of Flotation Symposium, Brisbane, Australia, 2005.         [ Links ]

LASKOWSKI, J.S. Frothers and Flotation Froth, Mineral Processing and Extractive Metallurgy Review, vol. 12, 1993.         [ Links ]

LASKOWSKI, J.S. Testing flotation frothers, Physicochemical Problems in Mineral Processing, vol. 38, 2004.         [ Links ]

MCCLAREN, C.H. AND DE VILLIERS, J.P.R. The Platinum-Group Chemistry and Mineralogy of the UG-2 Chromitite Layer of the Bushveld Complex. Economic Geology, vol. 77, 1982. pp. 1348-1366.         [ Links ]

NEL, E., COETZEE, V.E., KUMALINGA, N., and VALENTA, M. The effect of high cleaner feed density due to upstream thickening on cleaner circuit performance. Minerals Engineering International Flotation '07 Conference, Cape Town, 2007.         [ Links ]

OVERBEEK, P.J., LOO, J.P., and DUNNE, R.C. The development of a concentration procedure for Platinum Group Metals and Chromite from the UG-2 Reef of the Bushveld Complex. 1st Symposium on Precious Metals Recovery, Nevada, USA, 1984.         [ Links ]

PHILIPS, R.E., JONE, R.T., and CHENNELLS, P. Commercialisation of the ConRoast process, Third International Platinum Conference 'Platinum in Transformation', SAIMM, 2008. pp. 141-148.         [ Links ]

VALENTA, M.M. Balancing the reagent suite to optimise grade and recovery, Minerals Engineering Journal, vol. 20, no. 10, August 2007.         [ Links ]

VALENTA, M.M. and HARRIS, M.C. Evaluation of Entrainment in Flotation within a Mechanistic Framework. SAIMM Minerals Processing 2005 Conference, Cape Town, 2005.         [ Links ]

VALENTA, M.M. and HARRIS, M.C. Quantifying the effect of entrainment in mineral flotation using a mechanistic model. Minerals Engineering International Flotation '07 Conference, Cape Town, 2007.         [ Links ]

WOOLLACOTT, L.C. and ERIC, R.H. Mineral Extraction: An Overview, SAIMM Monograph Series M8, Chapter 5D: Flotation, 1994.         [ Links ]

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