Tues 24th April @ noon, Rm 312.222

Abstract:

Iron oxide minerals are found in almost every surficial environment on Earth where they participate in a variety of biogeochemical processes, record paleo-environmental conditions and host economic quantities of critical metals. Highly crystalline iron oxides (e.g., goethite, hematite) are thought to resist alteration under ambient conditions in aqueous fluids. However, we have recently discovered that dissolved Fe(II) in aqueous solution rapidly and, in some cases, completely exchanges isotopes with structural Fe(III) in these minerals. Dissolved Fe(II) effectively acts as a catalyst to recrystallise these ‘stable’ minerals, thereby cycling iron and associated elements between solid and solution. I will summarise these new reaction pathways and how they can be applied towards quantifying mineral reactivity and calibrating isotopic fractionation factors. These processes have implications for interpreting the trace element contents and isotopic compositions of iron-rich chemical sediments and may be applied to mineral processing technologies for extracting critical metals (e.g., Ni and Co) from laterite ore.

Short bio:

Andrew Frierdich is a Lecturer and DECRA Fellow at Monash University who studies the reactivity and isotope geochemistry of metals and minerals in aqueous environments.