The potential of Positron Emission Particle Tracking data in developing comminution and classification models

The technique of Positron Emission Particle Tracking (PEPT), invented at the University of Birmingham, UK, enables a single radioactive tracer particle moving inside a piece of equipment to be tracked accurately at speeds up to 2ms-1.

The University of Cape Town has a well established team which has investigated the use of PEPT for systems such as tumbling mills, hydrocyclones, IsaMill™, vibrating screens and flotation cells. The capabilities of particle tracking and data processing to extract granular flow features required for modelling are well developed within the team. Typical particles that can be tracked using this method include steel balls, ceramic beads, and particles as small as 50 µm, which are typical rock fragments found in flotation and some comminution devices. For those attending Comminution '16 next month, UCT's Prof. Aubrey Mainza and Dr. Indresan Govender, now with the University of KwaZulu-Natal, will present a short introduction to the potential use of PEPT in developing comminution and classification models for design, optimisation and control.

Prof. Mainza writes on behalf of the UCT team:

The traditional nature of comminution modelling based largely on empiricism has made steady gains over the history of minerals processing. However, in the current climate of diminishing resources and the demand for more efficient processing techniques the tried-and-tested approach doesn’t provide models with sufficient understanding to allow extrapolation to conditions outside the data set used in their development, resulting in challenges during when employed to test innovative designs, precise optimisation outcomes and can’t be used for predictive control. To build these capabilities in models a theory of comminution based on a mechanistic model governing granular materials and their dynamic behaviour and constituent interactions is required. Advances in theoretical understanding go hand in hand with ever-improving real-world measurements to validate or exclude avenues of reasoning. With the help of PEPT work needed for mechanistic theory development of granular flow with the aim of providing a modelling framework with better predictive capabilities applicability to a wide variety of comminution and classification systems has been initiated at the University of Cape Town working in collaboration with University of Kwa Zulu Natal.

The unique Siemens EXACT3D scanner housed at the iThemba labs facility under the care of the UCT Department of Physics and the Centre for Minerals Research as well as the on-site world-class tracer production facilities grant us unprecedented millimetre accuracy with regards to location data acquisition of granular systems. Coupling this accuracy to strong advances of the mechanistic-based models in the field of granular flow describing power dissipation and transport phemomena as well as the implementation of these principles to the numerical analysis of the data distinguishes the quantitative as well as qualitative outputs of our research group. With the newly developed feature of multiple particle tracking within a PEPT context, systems comprised of varied constituents such as size and density, can be interrogated with enhanced precision.

The Comminution '16 presentation will showcase the none confidential aspect of the work done using PEPT including measurement aspects, numerical analysis and the modelling techniques employed by the team working on PEPT projects. A tour of the facility can be arranged for Friday for those interested in viewing the system.

Prepared by: Aubrey Mainza, Indresan Govender, Maximilian Richter, Gary Tupper, Dawid de Klerk, Lawrence Bbosa, Mussa Lisso & Michael van Heerden.

 

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