Super-scavenging of zinc tailings by FASTFLOT 2500 at Pasminco Mining, Broken Hill

A relocatable single stage prototype of the full scale FASTFLOT 2500 cell was tested on super-scavenging of zinc tailings at Pasminco Mining, Broken Hill. After commissioning of the plant and rectification of minor problems the plant operated very stably with liquid level control better than ± 2 mm most of the time, giving the operators excellent control over the concentrate grade/recovery curve. Modest reconditioning of the tailings stream by copper sulphate and Cytec 7016 led to substantial improvement of zinc recovery at about the same grade. With conditioning, the single stage plant recovered 13.1 to 57.4% of available zinc at grade ranging from 4.0 to 25.5% Zn, from a feed grade of 0.27 – 1.01% Zn. The recovered marmatite was predominantly in the −9 μm range where mechanical flotation cells exhibit very slow kinetics, and sometimes in the + 120 μm range, where the main plant historically shows poor recovery. Considering that the stream has 25 minutes residence time in the main plant circuit, super-scavenging results by the FASTFLOT process with 1 minute residence time confirm its expected superior performance in the fine particle range when compared to conventional mechanical cells.