The link between particle size and froth stability – Implications for reprocessing of flotation tailings

Abstract

Historic tailings dams can often be considered as valuable mineral reserves due to the declining headgrades of primary deposits. The reprocessing of such material is of great interest to the minerals processing industry, not only from an economic point of view, but also from an environmental one. However,tailings material is generally comprised of fine particles, which poses a challenge for its reprocessingusing froth flotation due to reduced recoveries of these particle sizes. In addition, there is some debate asto the effect that these fine particles have on the froth stability, which in turn is linked to mineralrecovery.In this work, air recovery was used as a measure of froth stability to determine the flotation responseof a copper tailings ore to changes in particle size distribution and superficial gas velocity. The systemexhibited a maximum in air recovery, which correlates well with the local peak in dynamic froth stabilitypresented in previous work. This maximum in froth stability is also shown to correspond to animprovement in flotation performance, thus highlighting the importance of considering the link betweenparticle size, air rate and froth stability when determining the flotation strategy for tailings reprocessing.The results are discussed in terms of the implications for the reprocessing plant from where the oresamples were obtained and, more generally, for the efficient flotation reprocessing of tailings