Investigation of residence time and fluid volume in spiral concentrators

Abstract

The iron ore industry is flowing in northern Quebec with spirals as the leading concentrator equipment for which the understanding still needs to be improved. In general, the feed slurry throughput is thought to influence the spiral performance, although experimental evidence of that assumption is still lacking. A possible explanation for the difficulty of making an obvious assessment of the effect of the spiral feed rate may lie in a possible invariability of the residence time of the slurry in the spiral trough. The results of three tracer tests conducted on a WW6Plus Mineral Technologies spiral show that the fluid remains for approximately 7.5 s in the spiral trough and that this period is independent of the spiral feed rate. Direct measurements of the volume of liquid in the spiral trough confirmed the previous tracer results and showed that the volume of fluid retained in the spiral increases proportionally to the spiral volumetric feed rate. These tests point towards confirming the invariability of the fluid residence time in spirals.