|Aubrey (centre) with Magnus Evertsson and Hakan Benzer at Comminution '16|
Monday, 6 February 2017
The synergistic relationship between comminution and classification in comminution circuits is well known and has been extensively proven both in research and plant operation practice – but why do we often get it wrong? This will be the subject of a keynote lecture at next year's Comminution '18, by Prof. Aubrey Mainza of the University of Cape Town.
Aubrey is Head of Comminution and Classification Research in the Centre for Minerals Research, his research areas including comminution and classification, where he uses Discrete Element Method, Computational Fluid Dynamics, and Positron Emission Particle Tracking as tools in his modelling methods. Aubrey is a familiar figure at international conferences, particularly MEI's comminution series, where he has acted as a consultant for a number of years.
The comminution circuit is usually made up of comminution devices operated in closed circuit with different types of classifier. The closed circuit arrangement can have separate comminution and classification devices linked through pump-sump arrangements or integrated comminution-classifier systems. It is well documented that the choice and operation of the classifier have a major influence on the performance of the comminution circuit as a whole. An inefficient classifier can increase the energy consumption of the comminution circuit and in most cases also compromise the quality of the product reporting to downstream processes, leading to losses in recovery of the valuable mineral. Despite the known pitfalls of inadequately designed classification components of the comminution circuit the status quo has continued in most design teams. Substantially more effort and resources are expended on testwork for selecting and sizing comminution equipment compared to the accompanying classifying equipment, which is subjected to minimal or sometimes no confirmatory testwork.
In his keynote Prof. Mainza will ask why clear evidence of inefficient circuit performance that is directly attributable to a mismatch of the comminution and classification devices often appear to be totally ignored, and how can this perennial problem be eliminated in our standard comminution circuit design approach? He will ask what solutions have mining research and innovation programs provided in resolving the subtle incompatibility problems between comminution and classification devices and he will address the problems encountered when common approaches are used in selecting key comminution circuit equipment, proposing amendments that should be considered to avoid the known deficiencies.