Flotation cell technology and circuit design - an Anglo Platinum perspective

Froth flotation is the primary mineral processing separation step employed in the beneficiation of PGM ore bodies. Anglo Platinum operates a significant portion of the total installed flotation capacity in the PGM industry, which is installed at 20 operating plants across the Bushveld. PGM flotation has undergone a considerable evolution in both the capacity of flotation cells employed as well as in the circuit design configuration over the past 30 years. Certain of Anglo Platinum's flotation circuits have been in operation for a relatively long time (in some operations installed equipment dates from the 1960s), and this allows comparative operating performance between various equipment types and circuits to be evaluated. This paper summarizes some aspects of this experience. Research trends in flotation are continuously monitored so that appropriate findings can be incorporate into existing and future circuit designs. Continuous evaluation and monitoring of flotation performance is undertaken to identify opportunities for increasing flotation efficiencies. Mineralogical and fractional analyses of plant composites and survey samples are analysed to interrogate speciation and association data. This analysis has enabled a better understanding of priorities and opportunities for improved metallurgical performance. These opportunities are divided into three improvement areas: stability, liberation, and fines flotation. The paper discusses these, as well as the circuit design improvements required to take full advantage of the opportunities identified.