The effect of grind and increased residence time on the floatability of Mufulira copper ore.

Abstract

The purpose of this project was to evaluating the effect of grind time and increased Residence time on the floatability of the Mufulira copper ore on a laboratory scale. The project was proposed mainly because of periodic fluctuations in the mineralogy of this complex copper sulphide ore. The aim was therefore to address this problem and generally improve the flotation performance of the Mufulira concentrator. Systematic sampling was employed where copper ore samples were cut from six different selected conveyor belts each feeding the ball mills. Grinding time was done from 15 to 40 minutes at an interval of 5 minutes. Thereafter, flotation testworks were carried out to determine the effect of increased residence time on the flotation performance. However, 25 minutes grind time was the optimum mesh of grind with corresponding copper recovery of 94.8% and a grade of 24.9%. At 4 minutes rougher and 8 minutes scavenger was the optimum residence time with copper recovery and grade of 88.9% and 21.2% respectively. All other parameters were kept constant such as reagent dose rate at 30 gram per litre and pulp density except for time which was under evaluation. It is recommended that the optimum mesh of grind should be 25 minutes at flotation time of 4 minutes rougher and 8 minutes scavenger and testworks should be done at a decreased grind time and decreased residence time to determine the floatability of the Mufulira copper ore.