Abstract— A study on physical beneficiation of platinum group metals (PGMs) flotation tailings was carried out by means of spiral classifiers and a gravity separator (Knelson Concentrator – KC-CVD 6 unit). The economic mineral reserves for PGMs are found in the Busheveld Complex geological formation of South Africa particularly in the narrow strata of Merensky Reef, (Platreef) and the UG2 chromitite layer. In addition, there are about 450 million tonnes of mine waste material (tailings and smelter slags) across the platinum industry which contains sufficient PGMs for economic exploitation. The major minerals in UG2 flotation tailings are chromite {FeCr 2 O 4 , S.G = 4.5 – 4.8}, orthopyroxene {(Mg, Fe) 2 Si 2 O 6 , S.G = 3.2 – 3.9} and plagioclase {Na 0.5 Ca 0.5 Si 3 AlO 8 , S.G = 2.6 – 2.8} with small amounts of talc {Mg 3 Si 4 O 10 (OH) 2 , S.G = 2.7 – 2.8} and clay minerals (chlorites/phlogopite, S.G = 2.2 – 2.75). PGMs in flotation tailings are either associated with silicates (60%) or are free PGMs particles (10%) while 30% of them are associated with sulphide minerals (pentlandite, chalcopyrite, pyrrhotite pyrite and millerite). On the basis of mineralogical data, about 70% of total PGMs associated with silicates and native alloys can be separated from oxide and sulphide minerals using gravity separators. This was confirmed by results from the spiral classifier and Knelson Concentrator where 71% of total PGMs were recovered to the tailings (lighter fraction) and the overall grade of PGMs increased from 0.75 g/t to 1.07 g/t. The highest amount of palladium to be transferred from the feed solids (10 kg) to tailings (5 kg) was about 84%. The optimum conditions for operating a Knelson Concentrator (KC-CVD 6) and spiral with regards to PGMs beneficiation are discussed further in this study. Even though the feed solids to the KC-CVD 6 gravity separator were deslimed, its capacity to upgrade PGMs from 0.7 g/t to 1.11 g/t at an average recovery of 71% compared well with the results from a spiral classifier where the fines remained part of the feed. The recovery of PGMs by gravity separation was about 75% at an upgrade ratio of 1.8. Keywords— Beneficiation, Classifier, Gravity Separation, Knelson Concentrator, Platinum, Spiral Classifier, UG2 Tailings. I. INTRODUCTION AILINGS consist of ground rock and process effluents that are generated in a mine processing plant. Mechanical J. Siame is with the Copperbelt University, School of Mines and Mineral Sciences, Department of Chemical Engineering, P.O. Box 21692, Kitwe, Zambia. (Phone: +260 969 206022; Fax: +260 212 228212; E-mail: jsiamem@yahoo.co.uk). H. Kasaini is with Rare Element Resources Corporation, Denver, USA. (E-mail: henry_kasaini@yahoo.com). and chemical processes are used to extract the desired product from the run of the mine ore and produce a waste stream known as tailings. This process of product extraction is never 100% efficient, nor is it possible to reclaim all reusable and expended processing reagents and chemicals. The unrecoverable and uneconomic metals, minerals, chemicals, organics and process water are discharged, normally as slurry, to a final storage area commonly known as a Tailings Management Facility (TMF). Tailings are generally stored on the surface either within retaining structures or in the form of piles (dry stacks) but can also be stored underground in mined out voids by a process commonly referred to as backfill [1]. The challenges associated with tailings storage are ever increasing. Advances in technology allow lower grade ores to be exploited, generating higher volumes of waste that require safe storage. Environmental regulations are also advancing, placing more stringent requirements on the mining industry, particularly with regard to tailings storage practices. This ultimately places added pressure on the operators of a tailings facility who carry out the day to day roles of tailings discharge and water management [2]. The economic benefits of physical beneficiation of ores include the reduction of the impact on the environment, capital and operational expenditures which are often associated with extractive metallurgical operations (concentrators, roasting, smelting, leaching and purification of solutions). Furthermore, physical beneficiation can be applied to reduce the carbon print of a mining firm by scaling down its dependence on chemicals, energy and water for extracting minerals. In general, physical pre-treatment of low grade ores is necessary for reducing the total mass of reagent-consuming minerals and other gangue minerals in order to improve metallurgical plant efficiency and productivity. There are over 450 million tonnes of flotation tailings and smelter slags containing appreciable amounts of PGMs in South Africa. This is a huge resource for secondary PGMs. Several researchers have carried out feasibility studies of recovering PGMs (often associated with gold) by recycling the tailings back to the flotation banks or by lixiviation with HCl/H 2 SO 4 acid [3]. The average grade of total PGMs in tailings vary from one mining firm to another. The average PGM recoveries on concentrator feed solids vary between 80 and 88% across the industry and depending on the feed grade Feasibility Study on Physical Beneficiation of Low-Grade PGM Flotation Tailings using Spiral Classifiers and Enhanced Gravity Separators J. Siame, and H. Kasaini T 2nd International Conference on Trends in Industrial and Mechanical Engineering (ICTIME'2013) Sept 17-18, 2013 Hong Kong 46