On the origin of bi-modal bubble size distributions in the absence of frother

Continuous formation of microbubbles during partial coalescence of bubbles from a submerged capillary nozzle

“…Different from the nozzle of millimeter scale, a special coalescence bubbling regime was observed for the micron‐sized nozzle, where some subsequent small bubbles (trailing bubbles) grew rapidly and merged into the detached larger bubble (leading bubble). This phenomenon was firstly reported by Xie et al 19 and also found by Ata et al, 20 Quinn and Finch 21 in experiments. Qu et al 22 and Zhang et al 23 investigated the effect of nozzle diameter and gas flow rate on this coalescence behavior with upward‐pointing capillary nozzles.…”

Amphiphilic cellulose and surfactant mixtures as green frothers in mineral flotation. 2. Flotation of chalcopyrite and Cu-containing tailings

“…The most peculiar observation from Figure 13 is the spontaneous formation of a bi-modal distribution in the presence of both samples of pure HPMC molecules. It is known that pure water exhibits a bimodal bubble size distribution, which has been connected to different bubblebubble interactions (Quinn and Finch, 2012). According to the current frother knowledge, the distribution always progresses towards a uni-modal distribution when the frother concentration approaches its CCC, as is observed in the case of pure NF240 (Finch et al, 2008;Jàvor, 2014).…”

Amphiphilic cellulose and surfactant mixtures as green frothers in mineral flotation. 1. Characterization of interfacial and foam stabilization properties

“…example. The distribution in pure water is of a bi-modal nature, which was previously attributed to bubble-bubble interactions by Quinn and Finch [54]. It has been generally observed that such bi-modal distribution progresses towards a uni-modal distribution as the frother concentration approaches its critical coalescence concentration (CCC) value [14,55].…”