Scientists at Curtin University have uncovered gold nanoparticles in arsenopyrite using atom probing.
Curtin West Australian School of Mines (WASM) research associate in applied geology Dr. Denis Fougerouse and other researchers found metallic gold nanoparticles only nanometres in diameter within the mineral, a study which Fougerouse believes is the first of its kind.
According to Curtin University the study “challenges the understanding of nanoparticle formation and allowed the team to establish the main controls on gold incorporation in sulphides”.
Fougerouse explained,” The application of atom probe microscopy in geosciences is relatively new.”
“The technique is based on field-evaporation of atoms from tiny, needle-shaped specimens to provide three dimensional sub-nanometre scale information of the position and type of individual atoms in the specimen in the mineral,” he said.
“Typically the amount of material analysed is really, really small – a single grain of salt is more than a billion times larger than a typical analysis.”
Large amounts of these gold nanoparticles are ‘locked’ in gold-bearing arsenopyrite, a common iron arsenic sulphide.
“Arsrenopyrite is a very common mineral found in Australia and other mines, although not every arsenopyrite contains, it is common to find gold locked inside this mineral,” Fougerouse said.
“Our results show that gold can be hosted either as nanoparticles or as individual atoms in different parts of the crystal structure, and the different types of gold yield important information about the controls on gold deposition as the ore body forms.”
He went on to say this research supports the capacity of atom probe microscopy in geoscience.
“Our research shows the Geoscience Atom Probe has the potential to characterise gold deposition processes as the atomic level. In turn this could help unlock hidden gold resources in known deposits, and will enhance gold recovery.
“Nanogeoscience is a new, but rapidly growing research field; through this research and use of the Geoscience Atom Probe, we can show that tiny observations can yield big results that have potential economic importance.”