Thickening sedimentation and sand discharge of tailings slurry under ultrasonic

To improve the thickening efficiency of tailings in sand bins and achieve a high-concentration sand discharge, the sound field as a research method was introduced, and the characteristics of sound-field radiation to transmit the non-contact sound field was innovatively used to tailings slurry. Tailings slurry with 40% in mass fraction was prepared for the experiment. After 15, 20, 25, 30, 35, and 40 min of sedimentation, an ultrasonic wave of 20 kHz and 50 W of power were applied to investigate the effect of ultrasonic waves on the final settling time and concentration with different settling times. Ultrasonic wave was also applied to the sand discharge stage, and the rheological parameters of the tailings slurry at different concentrations were measured. The results show that when an ultrasonic wave is applied after 20 min of sedimentation, the shortest slurry sedimentation time of 80 min can be obtained and the final sediment mass fraction of the tailings slurry can reach 77.5%. Therefore, under ultrasonic action, it is possible to achieve stable sand discharge with a high-concentration tailings slurry at the same time, and the discharge mass fraction up to 74.04%. Comparisons of the viscosity and yield stress of the tailings slurry before and after ultrasonic treatment indicate that the viscosity of the slurry can be effectively reduced by 22.3% by ultrasonic action, which is a good viscosity reduction effect. Ultrasonic vibration, cavitation, and the acoustic streaming effect are the reasons for the rapidly thickening sedimentation and discharge of the tailings slurry.