Dr Craig Priest - Guest Lecture - August 31, 2016

Dr. Craig Priest                                

August 31, 2016      10:00 am

7-395 Donadeo Innovation Centre for Engineering

Title: Microfluidic solvent extraction: Real leach solutions, physical chemistry and numbering-up


Hydrometallurgy is of pivotal importance in many mineral processing circuits around the world, with liquid-liquid solvent extraction (SX) a key step in the separation of many base metals (e.g. Cu and Ni), radioisotopes, precious metals, and the ‘technology’ metals, such as rare earth elements (REEs). The standard equipment for SX in mineral processing is the mixer-settler, in which liquid dispersions are created, by agitation, to increase the surface-to-bulk ratio and, thus increase the mass transfer rate between the liquid phases. In stream-based microfluidic SX, these high surface-to-volume ratios are achieved by contacting microscopic streams, rather than forming small droplets, so that phase disengagement can be accelerated (essentially instantaneous via branching of the two streams of liquid at a channel junction). For mineral leach solutions, which may contain fine particles or other surface-acting agents, this step is profoundly different from bulk mixer-settler processing. We have shown that fine particles do not interfere with both extraction and phase disengagement in microfluidic SX of copper from industrial leach solutions. Platinum extraction from industrial leach solutions has also been demonstrated. In addition to practical advantages, extraction rates can be faster in microfluidic SX compared with bulk SX (e.g. for REEs), due to the higher surface to volume ratios involved. However, the small throughput of microfluidic systems to date remains the greatest challenge facing implementation. By investigating “parallelization” of microchips and fluidic networks, we have successfully shown that multichip ‘modules’ perform without any additional complexity or practical requirements. Collectively, these results demonstrate an opportunity for microfluidic SX to impact modest throughput extraction of high value metals.

Dr. Priest is a Foundation Fellow at the Future Industries Institute and the SA Node Director of the Australian National Fabrication Facility. He completed his PhD in Materials and Minerals at UniSA in 2004 and joined the Max Planck Institute for Dynamics and Self-Organization, Germany, to study droplet-based microfluidic systems. He returned to UniSA in 2006 and now leads a research team working on interfacial, physical, and analytical science in micro/nanofluidic devices (and other small scale environments). He works closely with industry partners in minerals, water quality, and advanced manufacturing. As Node Director of ANFF-SA, Dr Priest leads a $15M investment dedicated to micro/nanofabrication. The facility is used annually by more than 150 academic and industry users and continues to grow, including through strategic international partnerships.

Dr Priest’s research is funded through the ARC schemes (Discovery, Linkage, and Industrial Transformation Research Hub), the SA Government, and industry partnerships. He has published 3 book chapters, 50 journal articles, 16 conference papers, and 7 provisional patents. Dr Priest was awarded the SA Government’s Tall Poppy of the Year – Early Career Researcher Award in 2011. He was a member of the SA Government Premier’s Science and Industry Council from 2012-2014.