Daniel Francioli, Brazil

Daniel is an undergraduate student of Materials Engineering (BEng) at the Federal University of Rio, in Brazil. During the last two years he has been involved with mineral processing research working both in Brazil and Australia as a member of the Global Comminution Group (GCG), which includes the six most advanced comminution research centres in the world.

In 2013, he was awarded the best undergraduate research award for his work on characterising fragmentation of copper-gold ore. In addition, an international publication will be released in October 2014, during the International Mineral Processing Conference, in which he is competing for the best young author award.

His recent interests include mineral processing machine design, with special focus on grinding equipment. In his recent research at the Laboratório de Tecnologia Mineral (LTM/COPPE), he aims at integrating experimental results with simulation data and hopes it will provide further understanding to optimise operations by reducing energy consumption during comminution processes.

 

Characterising surface fragmentation for comminution modelling

Mathematical modelling of the comminution process requires the thorough understanding of breakage mechanisms. Modelling high energy impact breakage is well established, however, modelling low energy breakage is still under development. Comminution processes demand around 3% of global electric energy. Most of this energy is wasted due to our incomplete understanding of collisions, particle fragmentation and physical properties.

Free fall incremental impact tests were carried out to investigate the surface fragmentation of a copper-gold ore. This process was achieved by dropping particles individually onto a metallic plate. Changes to the plate angle and particle shape (angular and smooth) enabled the study of the influence of the tangential component of the impact energy.

By studying the fractional mass loss variation, two distinct stages of surface fragmentation were clearly determined: high fractional mass loss dominated in the first ten impacts and was attributed to chipping, whereas low fractional mass loss occurred in the remained of the impacts and was attributed to abrasion, The understanding of these two fragmentation processes indicates that state-of-the-art semi-empirical breakage models can still be optimized, potentially leading to gains in energy efficiency.