Linking flotation chemistry and froth physics – The effect of frother type and concentration on air recovery and flotation performance

This work provides the first systematic quantification of how frother chemistry influences air recovery, an important indicator of froth stability and overall flotation performance. Air recovery research has so far for only focused on froth physics for a given flotation reagent suite, thus leaving a gap in our understanding of the links between flotation physics and chemistry. This research offers interesting opportunities for bridging those gaps and enabling advanced optimisation strategies. Two distinct frother types, an alcohol and a polyglycol, and a blend of these, were tested for a sulphide mineral system in a bench-scale continuous flotation tank, allowing air recovery to be measured at a range of superficial gas velocities. Concentrate and tailing samples were taken to quantify the impact of these changes on the metallurgical performance. Results demonstrated that for all chemistries tested, air recovery increased with frother concentration before reaching a plateau. Crucially, this plateau occurred at concentrations consistently higher than the CCC 99 . Pyrite recovery exhibited a similar trend with superficial gas velocity, reaching a maximum under conditions corresponding to peak air recovery. A strong positive relationship was observed between air recovery and pyrite recovery for all frother chemistries. However, the magnitude of this relationship depended on frother chemistry. For instance, while DF 250 generated the highest air recovery, the MIBC-DF 250 blend consistently produced the highest pyrite recovery, demonstrating that air recovery alone does not fully determine flotation performance. These findings not only demonstrate a relationship between frother type and air recovery but also challenge the conventional practice of dosing frother solely to control pulp bubble size, with important implications for metallurgical recovery.