Mining and mineral processing have rarely been considered ‘high tech’ endeavours. In early 2008, Professor Habashi asked us to consider organising a special volume of IJCFD for mining and mineral processing. After reflecting for a while on Professor Habashi's request, we decided that it might be the right time to tell the world that some portions of the mining industry have become quite ‘high tech’. The use of multi-physics modelling for problem solving in the mining industry has moved us into the rarified atmosphere of aeronautics, aerospace, etc. This volume is meant to show the world of science and technology that mining has interesting problems and is willing to seek high technology solutions involving CFD and DEM.
The authors who have contributed here show applications of numerical modelling to grinding devices, screens, hydro-cyclones, sedimentation devices, agitators, flotation cells, fluidised beds, rotary dryers, slurry pumps, distributors and samplers. The numerical modelling techniques they have applied range from those included in commercial software packages to fully customised solutions of the problems at hand.
The volume contains 10 articles organised into two groups; new methodologies and new applications in minerals engineering.
Sun, J., Xiao, H., and Gao, D., Numerical study of segregation using multiscale models, propose a hybrid method, an Eulerian–Lagrangian multiphase model for the particulate flow. This model is an integration of a control volume method for continuum fluid mechanics with DEM for solid particles. The Eulerian–Eularian multiphase model is also reviewed. Results from both approaches are compared and discussed.
Croft, T.N., McBride, D., Cross, M., and Gebhardt, J.E., Multi-component free surface flows and rotating devices in the context of minerals processing, couple a mixture model with a VOF model. The new model is able to address the relative homogeneous particulate flows with free surfaces.
Gao, D. and Herbst, J.A., Alternative ways of coupling particle behaviour with fluid dynamics in mineral processing, propose a novel Lagrangian–Lagrangian multiphase model that integrates DEM with SPH. The model is totally particle-based, eliminating the need for a mesh. An alternative one way coupling method is also mentioned and applied to pump analysis.
Guo, B.-Y., Dong, K.-J., and Yu, A.-B., Optimisation of sputnik distributor using numerical method, use a CFX VOF model to simulate water–air free surface flow, and use one-way coupling DEM (introduce the velocity field from CFX results into the DEM) to calculate particle motion. The authors also roughly describe the complete multiphase coupling between CFD and DEM, and point out the difficulty of implementation.
Cleary, P.W. and Morrison, R.D., Particle methods for modelling in mineral processing, review particle-based methods including: DEM and SPH. They show a variety of mineral processing applications including comminution and classification.
Cilliers, J., Physics-based froth modelling: new developments and applications, describes a physics-based froth model. The methodology of combining physical models for each phase into a complete description is reviewed. The successful applications of this model to optimising industrial flotation is illustrated with examples.
Wang, M.-H., Huang, C., Nandakumar, K., Minev, P., Luo, J., and Chiovelli, S., Computational fluid dynamics modelling and experimental study of erosion in slurry jet flows, make creative use of CFD approaches (CFX) for the study of erosion. CFD is used to predict flow patterns, particle impact profiles and predict erosion rates and patterns. The modelling results are validated by an experimental study and thoroughly discussed. Several erosion models are described and investigated.
Fletcher, D.F. and Brown, G.J., Numerical simulation of solid suspension via mechanical agitation: effect of the modelling approach, turbulence model and hindered settling drag law, present a comprehensive application of CFX to the simulation of solid suspensions by mechanical agitation. Two different modelling approaches: Eulerian–Eulerian and mixture model (Algebraic slip modelling) are explored. The influence of turbulent models and drag laws are also investigated and thoroughly discussed.
Delgadillo, J.A. and Rajamani, R.K., Computational fluid dynamics prediction of the air-core in hydrocyclones, use a VOF model along with a LES turbulence model in FLUENT to capture the air-core profiles. The effect of geometry changes (spigot, hydrocyclone diameter, vortex finder) on air-core is investigated.
Hobbs, A., Simulation of an aggregate dryer using coupled CFD and DEM methods, pioneers the application of commercial package coupling CFD with DEM to simulate heat transfer from the burner flame to the solid particles.
These editors would like to take this opportunity to thank Metso Minerals Industries for allowing us to participate in the creation of this special issue. We would also like to express our appreciation to the authors and Professor Habashi and his staff. It is our hope that this will be the first of many volumes.