Evaluation of wettability of mineral particles via cavitation thresholds

Abstract

An acoustic method was proposed to evaluate the wettability of mineral particles. A high-intensity focused ultrasound (HIFU) device was set up to measure the cavitation thresholds of mineral particles of different wettability and under different conditions. The hydrophobicity and surface topography of different minerals were compared by contact angle tests and scanning electron microscope (SEM) images, respectively. The nuclei (unwetted part) on the particle surface were induced for cavitation by HIFU. Cavitation behaviors were detected by the echo waves reflected by cavitation bubbles. Results indicate that the cavitation threshold of unwetted particles is larger than that of the wetted particles. The difference in cavitation threshold is owning to the number and size of nuclei in mineral suspension. Furthermore, the heterogeneity of the wettability of minerals can be obtained from the cavitation probability curve, which is a unique advantage for this acoustic method compared with other methods.