Ultrasound-assisted shear flocculation of quartz tailings with dodecylamine hydrochloride (DAH)

Ultrasound creates extreme conditions such as acoustic streaming and acoustic cavitation in the liquid it propagates, depending on its frequency. Due to these extreme conditions, it is beneficial in various operations in the mineral processing industry. This study aims to improve the efficiency of shear flocculation of quartz mineral in the presence of dodecylamine hydrochloride (DAH), a common collector for quartz, by ultrasound application. The outcomes of this study indicated that the interface height decreased by 18% with shear flocculation compared to free-settling conditions at the 3% (w/w) solids ratio in 120 min sedimentation time. Moreover, the interface height between the turbid and supernatant phases of the quartz pulp could be reduced considerably by 70.33% with conventional shear flocculation at the conditions of 3% solids ratio, 3 min conditioning time, 1×10<sup>-4</sup> mol/dm<sup>3</sup> DAH concentration, and 1500 rpm mixing speed. Under these conditions, the turbidity of the supernatant was 377 NTU. This study also revealed that the interface height could be decreased by 80% by using ultrasound-assisted shear flocculation. However, in this case, the turbidity increased by 100-400% depending on the ultrasound power due to the dispersion effect of ultrasonic cavitation on ultrafine particles.