On-line simulation & dynamic analysis of dense medium cyclone circuits

The effects of changes in dense medium circuits have been widely explored using static models derived from empirical data. However, there has been little comparable dynamic modelling. Some dynamic models of dense medium circuits have been constructed by Askew (1983), and more recently, Addison (2010) and Meyer (2010), and were used for assisting with plant control and investigating variability in medium density in response to other plant fluctuations.This paper describes research conducted at two Queensland coal preparation plants as part of a joint project between the Commonwealth Scientific and Industrial Research Organisation (CSIRO) and the University of Queensland's Julius Kruttschnitt Mineral Research Centre (JKMRC). Instrumentation has been developed to measure dense medium cyclone (DMC) overflow and underflow densities, DMC feed flow rate, medium to coal ratio and product and reject tonnages. The instrumentation has proven to be robust, and the resulting information has identified fluctuations in the circuit that would otherwise not have been noticed. The instruments have been linked to existing empirical models to predict DMC performance such as cut-point and Ep in real time. The addition of the instrumentation has also enhanced the ability to explain circuit behaviour, and is enabling construction of a more detailed dynamic model.