In mineral processing operations, phenomena that strongly influence the overall outcome of the operation usually function over a very wide range of length scales.
To a large extent, this is a result of the multiphase nature of the flows involved in processing ores and extracting metals.
For example, a process vessel may involve interaction of phenomena at a multitude of scales — from the vessel scale, where large-scale mixing occurs, through the bubble scales, where small-scale mixing and interfacial mass transfer occur, down to fine particle and polymer scales, where important surface interactions occur. This scale hierarchy can be further extended: available now, using a technique known as multi-scale modelling.
Already we are well advanced in the development of a multi-scale model of the mineral flotation cell, which links existing macro-scale models to models of bubble-particle attachment.
Likewise we are developing a multi-scale model of an aluminium reduction cell which links a model of the entire cell to a model of bubble formation, growth and movement on the anode surface.
These more accurate and predictive models will allow a step-change in our ability to transform existing processes and develop radically new processes. upwards to the whole plant, and downwards to the molecular level where reactions actually occur.
Modelling of such systems has taken huge strides in the past two decades with the development and refinement of multi-phase computational fluid dynamics models.
However, it is still not possible to simulate a wide range of length scales in one CFD model.
CSIRO Minerals is taking on the major challenge of developing the next generation of models that will allow interactions between widely separated scales to be taken into account with the computational resources using a technique known as multi-scale modelling.
Already we are well advanced in the development of a multi-scale model of the mineral flotation cell, which links existing macro-scale models to models of bubble-particle attachment.
Likewise we are developing a multi-scale model of an aluminium reduction cell which links a model of the entire cell to a model of bubble formation, growth and movement on the anode surface.
These more accurate and predictive models will allow a step-change in our ability to transform existing processes and develop radically new processes.
This article first appeared in Process (October 2007) – a publication of CSIRO’s Minerals Resources sector.
Phil.Schwarz@csiro.au
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