Hydrodynamic and kinetic characterization of industrial columns in rougher circuit

Abstract

In the present investigation the relationship between collection zone rate constant ( k c) and gas dispersion parameters, viz. bubble size ( d b), superficial gas velocity ( J g), gas hold-up ( ε g) and bubble surface area flux ( S b) was evaluated. Experiments were conducted in an industrial (4 m in diameter and 12 m high) and a pilot (0.1 m in diameter and 4 m high) flotation column in rougher circuit at Miduk copper concentrator in Iran. Gas hold-up was measured using pressure difference technique and mean bubble sizes were estimated from a drift flux analysis. It was found that the collection zone rate constant was not correlated with d b and J g solely but was linearly dependent on ε g and S b for the range of interest. Collection efficiency ( E k) and floatability factor ( P) in the industrial columns were quantified ( E k = 3.1%; P = 7.7 × 10 −3). The influence of operating parameters comprising superficial gas velocity, slurry solids% and frother dosage/type on S b and flotation kinetics was discussed. Analysis of available industrial data suggested that S b and ε g were related by S b = 4.46 ε g over the range 30 < S b < 60 s −1 and 7% < ε g < 14%.