Use of ultrasonic treatment as a pre-phase in the shear flocculation process

Abstract

The use of ultrasonic energy has mostly been investigated for the flotation process in mineral processing, but its application to flocculation with collectors is extremely limited. Therefore, in this study, the effect of ultrasound in the shear flocculation technique, was intended to be revealed by using a celestite sample. The initial studies carried out for this purpose showed that in the absence of any reagent, the ultrasonication decreased the surface charge of the mineral, which caused the coagulation of the celestite suspension. In this scope, the short application of ultrasound at high power (i.e., 2 min batch regime and 150 W) provided a more positive effect. In the flocculation process carried out with collectors, the use of ultrasonic energy as a pre-phase for the suspension enhanced the aggregation of celestite particles. This result also fits well with the rise in the contact angle and the decrease in the zeta potential of the mineral due to the ultrasound. However, when the ultrasound was applied directly to the flocculation phase (ultrasound-induced flocculation only), the aggregation of celestite particles was affected adversely. Consequently, it can be said that in the shear flocculation process, the ultrasonic treatment should be used as a pre-phase for mineral suspensions. In this case, the flocculation of fine mineral particles in suspensions with surfactants can be improved by ultrasonic processing.