DISSOLVED GAS FLOTATION IN MINERAL PROCESSING

Abstract

Potential use of dissolved gas bubbles in mineral flotation processes was investigated by conducting tests on the copper–nickel ore of Inco Ltd. in Sudbury, Ontario, Canada. Such bubbles were generated by pressurizing the ore pulp in an air or argon atmosphere at a 276 kPa gauge (40 psig) for a period of about 1 min and then releasing the pressure by discharging the pressurized pulp into a column where flotation took place. Based on the conclusions of an earlier work, dissolved gas bubbles were employed together with conventional bubbles, the latter produced by a gas sparger located inside the flotation column. The presence of dissolved gas bubbles in the flotation pulp was found to have a significant impact, particularly when argon was used as the flotation gas, resulting in substantially higher grades and recoveries in the concentrate. At the same time, mass recoveries by size showed a 20% increase across all sizes when air was used as the flotation gas and a 40–100% increase in the case of argon.