Effect of water-soluble polymers on the performance of dust-suppression foams: Wettability, surface viscosity and stability

Foam dust suppression is an important way to control dust hazards. Polymers are believed to be able to change foam properties. To investigate the effect of polymers addition to foaming agent solution on the key dust-suppression performance of the foam, tests were conducted by measuring and comparing the contact angle, viscous modulus and foam-drainage rate of several different surfactant/polymer solutions, which can characterize the wettability, surface viscosity and stability of foam. The results show that the polymer (HEC, HPAM, PVA) addition increased the contact angle between the liquid and coal dust by increasing the surface tension of the surfactant solution. The variation is more obvious with an increase in polymer concentration (especially over 0.3 wt.%); simultaneously, the polymer increases the surface viscosity of the foaming agent solution significantly, and slows down the foam-drainage rate, which is advantageous for increasing the foam stability. Because of the variation, the low concentration of polymer (0.1-0.3 wt.%) has a weak influence on the wetting ability of the foaming agent while improves the surface viscosity and stability of foam significantly, which is an improvement in terms of the dust-suppressing ability of foams.