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 head grades 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 reprocessing using froth flotation due to reduced recoveries of these particle sizes. In addition, there is some debate as to the effect that these fine particles have on the froth stability, which in turn is linked to mineral recovery.In this work, air recovery was used as a measure of froth stability to determine the flotation response of a copper tailings ore to changes in particle size distribution and superficial gas velocity. The system exhibited a maximum in air recovery, which correlates well with the local peak in dynamic froth stability presented in previous work. This maximum in froth stability is also shown to correspond to an improvement in flotation performance, thus highlighting the importance of considering the link between particle 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 ore samples were obtained and, more generally, for the efficient flotation reprocessing of tailings.

The effect of impeller-stator design on bubble size: Implications for froth stability and flotation performance

“…The agreement obtained with different experimental procedures and equipment supports the hypothesis that pulp bubble size affects froth stability. It also supports the observation that there is a good agreement between the dynamic froth stability and the air recovery, as shown by Mackay et al (2020).…”

“…Froth stability can be affected by many factors, such as particle size and hydrophobicity (Ata, 2012;Norori-McCormac et al, 2017;Mackay et al, 2018Mackay et al, , 2020, frother type and concentration (Harvey et al, 2005;Wiese et al, 2011;McFadzean et al, 2016;Mesa et al, 2016), froth depth (Hadler et al, 2012) and impeller speed , among others. In particular, impeller speed generates turbulence within the pulp that can affect the pulp-froth interface (Schubert, 1999;Brito-Parada et al, 2017).…”

Iron Ore Slimes Flotation Tests Using Column and Amidoamine Collector without Depressant

“…The optimum superficial air velocity for each pilot test was not evaluated in this work. Mackay et al [4] highlighted the importance of considering the connection between particle size, air rate and froth stability when determining flotation strategies. Thus, the implementation of automatic air flow control in the cavitation system can also contribute to improve the results obtained in a slime flotation industrial circuit since, in addition to the variability of the run of mine, some adjustments in the industrial plant may change the size distribution of the slimes flotation feed, requiring a new optimized air flow, since these changes in the particle size distribution require a change in the air rate to maximize mineral recovery [5].…”

“…Achaye [3] showed that froth stability decreases with increasing particle size and fine particles had the greatest influence on froth stability. Some authors [4,5] investigated the relationship between froth stability, size distribution, and air recovery, demonstrating there is an ideal air rate for each particle size distribution.…”

Processing Tests, Adjusted Cost Models and the Economies of Reprocessing Copper Mine Tailings in Chile

“…As tailings have already been floated once, re-flotation in some cases is possible [10], but can result in low recoveries because of non-floatable minerals or very fine grain sizes. The small grain size can at least in part be overcome by using a tailored size distribution of the tailings material [11]. Besides froth flotation, leaching is the second most common method to process copper ore. Leaching can be carried out via conventional sulfuric acid leach or with support of bacteria.…”