An improvement on selective separation by applying ultrasound to rougher and re-cleaner stages of copper flotation

The ultrasonic treatment has been commonly used as a pre-treatment and rarely applied as an on-treatment technique to improve grade and recovery in froth flotation processes. This work aims at investigating the impact of ultrasonic wave under different conditions on a porphyry copper ore during the flotation of rougher and re-cleaner stages. For this purposes, four different operating configurations were examined as I) un-treated, II) only homogenizer, III) only ultrasonic bath and IV) homogenizer and ultrasonic bath. The ultrasonic vibration was generated during the flotation using a homogenizer (21 kHz, 1 kW) in froth zone and ultrasonic bath (35 kHz, 300 W) for the bulk zone. The rougher and re-cleaner flotation experiments were conducted at 4.2 L and 1 L Denver type mechanically agitation cells. In addition to the grade and recovery, the separation efficiency (S.E) and selectivity index (SI) criteria were used for evaluating the separation performance of the flotation trials. It was found out that combination of the ultrasonic bath and the homogenizer provided an absolute improvement of 4.0%±0.6 and 7.0%±0.5 of the S.E. compared to the untreated ore for rougher and re-cleaner stages, respectively. The detailed argument was discussed in this work regarding the role of US on both froth and bulk zone according to four configurations.