The effect of flotation deinking chemicals on bubble formation

The size, population and distribution of bubbles formed in solutions of a range of nonionic polethyleneoxide alkyl-type surfactants was investigated using image analysis. The bubbles were formed by passing gas into surfactant solutions through a porous plate. In accordance with theoretical predictions based on the Young-Laplace equation, the maximum bubble size increases and the number of bubbles formed decreases with increasing surface tension. Both dynamic and equilibrium surface tensions as well as froth stability and foam film thickness depend on the molecular size and hydrophobic/hydrophilic balance of the surfactant. Accordingly, these parameters will be important in flotation deinking, which is highly dependent on bubble and froth characteristics.