Mineral dust resuspension under vibration: Onset conditions and the role of humidity

BALLADORE, F.J.; BENITO, J.G.; UÑAC, R.O.; VIDALES, A.M.

PARTICUOLOGY

ELSEVIER SCIENCE INC

Año: 2020 vol. 50 p. 112 - 119

1674-2001

tThe vibration of dusty surfaces inevitably causes re-entrainment of particles into the atmosphere. Giventhat movement of mineral dust particles deposited on a surface begins at a critical frequency (fc) andamplitude, an experimental laboratory study was conducted to determine the onset conditions for resus-pension of a vibrated granular soil. We determined the resuspension state diagram as a function offrequency and amplitude of a sinusoidal vibration, the granulometry of the dust and the thickness ofthe soil bed. The mitigation effect of humidity was also evaluated. Critical frequencies ranged between2.5 and 23 Hz when amplitudes were less than 12 mm. These results were independent of bed thicknessand perturbation type. For all particle sizes observed, fcdecreased monotonically with A, contrasting withbehavior observed for individual particles. In dry samples, fcfor large size classes was markedly less whenA was greater than 6 mm; while the fcfor fine fractions only decreased once amplitudes reached 10 mm.Experiments with wet granular soils demonstrated that wetting above an optimum humidity did notnecessarily impede movement and caused agglomeration. This study provides guidelines for managingresuspension of granular soils subjected to vibrations.