Department of Mining and Materials Engineering, McGill University , 3610 Rue University, Montréal, Québec H3A 0C5, Canada.
RAP Innovation and Development Proprietary Limited , Post Office Box 559, Indooroopilly, Queensland 4068, Australia.
Langmuir. 2017 Apr 4;33(13):3200-3207. doi: 10.1021/acs.langmuir.7b00114. Epub 2017 Mar 27.
Frothers, a class of surfactants, are widely employed in froth flotation to aid the generation of small bubbles. Their action is commonly explained by their ability to hinder coalescence. There are occasional references suggesting that the frother may also play a role in the initial breakup of the injected air mass. This work investigates the possible effect of the frother on breakup by monitoring air bubbles produced quasi-statically at an underwater capillary. Under this condition, breakup is isolated from coalescence and an impact of frothers on the detached bubble can be ascribed to an impact on breakup. The breakaway process was monitored by an acoustic technique along with high-speed cinematography. The results showed that the presence of frothers did influence the breakaway process and that the acoustic technique was able to detect the impact. It was demonstrated that the acoustic frequency and acoustic damping ratio depend upon the frother type and concentration and that they are associated with a liquid jet, which initially excites the bubble and then decays to form a surface wave. The addition of the frother did not influence the formation of the jet but did increase its decay rate, hence, dampening the surface wave. It is postulated that the action of the frother is related to an effect on the magnitude of surface tension gradients.
起泡剂是一类表面活性剂，广泛应用于泡沫浮选以帮助产生小气泡。它们的作用通常可以通过其阻碍聚结的能力来解释。偶尔有一些参考文献表明，起泡剂在注入的空气团的初始破裂中也可能起作用。这项工作通过在水下毛细管中准静态地监测产生的空气泡来研究起泡剂对破裂的可能影响。在这种情况下，破裂与聚结分离，并且起泡剂对分离出的气泡的影响可以归因于对破裂的影响。通过声学技术和高速摄影监测了脱离过程。结果表明，起泡剂确实会影响脱离过程，并且声学技术能够检测到这种影响。结果表明，声学频率和声衰减比取决于起泡剂的类型和浓度，并且它们与最初会激发气泡、然后衰减形成表面波的液体射流有关。添加起泡剂不会影响射流的形成，但会增加其衰减速率，从而使表面波衰减。有人假设，起泡剂的作用与表面张力梯度幅度的影响有关。
