Evaluation of the applicability of ultrasonic velocity profiling in conditions related to wet low intensity magnetic separation

The internal material transport and selection processes of the wet low-intensity magnetic separators (LIMS) are poorly understood; this calls for improved measurement techniques. In this work an ultrasonic velocity profiling (UVP) technique for measuring how material flow velocity varies with penetration depth is presented. A measurement depth of just a couple of centimetres would greatly improve the understanding of the separation process in a LIMS. pplied to flows of mineral suspensions with high volumetric solids concentration, similar to those in the separators, UVP is unique in combining:• trusive measurements. es using just one sensor element (transducer). vely good spatial resolution. ates opaque suspensions. ampling rate. flows are studied in a rectangular duct (50 × 75 mm). Using magnetite suspensions, measurement through the whole depth of 50 mm is made with good accuracy. Velocity profiles are presented for solids concentrations of 5% and 9% solids by volume (20% and 36% by weight). Even at 9 vol% solids it is possible to reach a penetration depth of more than 25 mm.