Fractal Energy: Combining fractal dimension of fracture surfaces and Size Specific Energy to describe comminution
Abstract The ubiquitous ‘P80’ is a useful descriptor of a particle size distribution, except when it isn’t. First described by Fred Bond as the point where the linear segment of the size distribution starts, it is valid only when the feed and product size distributions are parallel in log/log space. Many alternative approaches have been developed to enable the continued use of P80 outside of these limitations, but as the number of exceptions grows, a re-think is required. Although only coined recently, Size Specific Energy (SSE) has been used to describe comminution systems for over a century, since well before Bond. It is a tried-and-true methodology that assesses the energy consumed to generate fines. When assessed at a range of fine marker sizes, SSE can also describe the fractal dimension of the fracture surfaces generated. Fractal Energy combines SSE and the fractal dimension in an approach that has applicability to ore characterisation, circuit design and optimisation. This paper will present the value proposition for adopting this approach and present case studies for different ores, comminution equipment and testing apparatus.