Foam stability of flotation frothers under dynamic and static conditions

The objective of this paper is to provide a detailed understanding of the relationship between frother type and foam stability under dynamic and static conditions. The dynamic foam stability for eighteen non-ionic frothers from different frother families was assessed using foaminess, which quantified the ratio of foam height to the gas superficial velocity. For all tested frothers, the foaminess increased as the concentration was increased. The static foam stability was assessed by measuring the half-life and the decay rate of the foams at different superficial gas velocities and concentrations. The foam stability results showed that for aliphatic alcohols, the greater the number of hydrocarbon groups, the more stable the foam was under dynamic and static conditions. For polypropylene glycols, increasing the number of propylene oxide groups increased foaminess and half-life, however, a further increase in the number of propylene oxide groups (m > 7) led to a decrease in foaminess. There was not a clear relationship between the number of propylene oxide groups and the maximum foam half-life. Interestingly, the foam decay rate coefficient increased by increasing the number of propylene oxide groups. For propylene glycol methyl ethers, foaminess, foam half-life and decay rate coefficient increased with an increase in the number of propylene oxide groups.