Minerals Engineering, Vol.124, 74-76, 2018
Effect of different grinding media composition on the flotation of a PGM ore
In the present study, the effect of using different grinding media, viz, ceramic (CE), forged steel (FS), 15% Cr steel (CS), stainless steel (SS) and a mixture of stainless steel and 15% Cr steel balls (50:50) (SS + CS) were investigated using a Platinum Group Metal (PGM) ore, UG2. Test work was conducted using a laboratory scale horizontal tumbling mill and a batch flotation cell. Power draw to achieve a specific P-80 was determined for each media type. The different flotation behaviour obtained from different media is discussed in terms of particle size distribution, water recovery, solid recovery and valuable mineral recovery. pH, Redox potential (Eh) and dissolved oxygen (DO) level were also measured. Grinding products of five different media produced the same solids and water recovery, but the grades and recoveries of PGM and chromite were different. Grinding products of ceramic media had the best flotation performance, which produced the highest PGM recovery and the lowest Cr2O3 recovery. Meanwhile grinding products of stainless steel balls (SS) produced the lowest PGM recovery and highest Cr2O3 grade and recovery in the concentrates. The paper proposes possible reasons to explain these observations.