An investigation in using UVP for assisting in rheological characterisation of mineral suspensions

Abstract

The rheological characterisation of mineral suspensions for the prediction of flow in pipes and open channels is of considerable practical importance. Most predictive models depend on accurate rheological parameters. Mineral suspensions including mining tailings are mostly non-Newtonian suspensions with many exhibiting an apparent yield stress. These models are empirical in nature and require extensive laboratory testing to determine their characteristics. The Flow Process Research Centre at the Cape Peninsula University of Technology has for a number of years been investigating the behaviour of such suspensions. Rheological parameters have been mainly obtained from tube viscometry. This means measuring pressure drop and flow rate in two or more tubes of different diameter to produce flow curves. For comparison, rotary viscometry has also been used. Mineral suspensions are opaque and laser technology cannot be used. To progress to a more fundamental understanding of the flow behaviour of these fluids in pipes, fittings and flumes it is essential to measure velocity profiles. The principal problem here is that the acoustic behaviour and measurement techniques for these fluids using UVP techniques is as yet unproven.. This objective of this paper is to show that these techniques are viable, and show some promising initial results in both the tube and flume geometries with two different mineral suspensions.