STUDIES ON IMPELLER TYPE, IMPELLER SPEED AND AIR-FLOW RATE IN AN INDUSTRIAL-SCALE FLOTATION CELL .2. EFFECT ON GAS HOLDUP

Gas holdup was measured at different locations in a 2.8 m(3) portable industrial scale subaeration flotation cell, treating zinc cleaner fee d at Hellyer Concentrator in Tasmania, Australia. The cell was fitted in turn with four different impeller-stater systems, and operated over a range of airflow rates and impeller speeds. The gas holdup was foun d to increase with increase in impeller speed as well as with increase in airflow rate, the manner in which it increased depended on the imp eller type. Values ranged from 2% to 33%, with the greatest values pro duced by the Outokumpu impeller.