TRANSACTION PAPER

A simple process control model for spiral concentrators

M.K.G. Vermaak; H.J. Visser; J.B. Bosman; G. Krebs

Department of Materials Science and Metallurgical Engineering, University of Pretoria, Pretoria, South Africa

SYNOPSIS

Spiral concentration forms a crucial part of gravity separation circuits. The application of process models in the operation of gravity separation circuits offers significant benefits in recoveries and grade control. Significant strides in the modelling of spiral concentrators have been made during the last couple of decades. Despite these advances in modelling techniques and models, application in industrial processes is not fully optimized. The adjustment of splitter positions to accommodate changes in the feed parameters is impractical and difficult, resulting in losses. In this work an optical method is employed to detect the concentrate band position as a function of operating variables. As expected, the results indicate a strong influence of the solids content and total heavy mineral (THM) feed grade on the predicted gangue-mineral interface. Viscosity modifiers indicated the band position to be sensitive to viscosity and therefore the slimes content. Validation on an industrial sample indicated the possibility of using this model in feed-forward control application.

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Paper received May 2007
Revised paper received Feb. 2008