High purity alumina’s place in the future of global critical minerals

As Australia sharpens its focus on becoming a global leader in critical minerals, high purity alumina (HPA) is emerging as a material of strategic significance, vital for the green energy transition with applications in LEDs, sapphire glass, industrial catalysts, and Li-ion battery production.

Australia is positioned supremely, with a wide range of aluminium-containing resources and the potential to produce HPA locally, presenting an important economic opportunity to capture value from raw materials and support local industries while assisting the nation’s decarbonisation goals.

Still, as demand for HPA grows, so too does the demand for advanced, standardised, accessible methods of purity testing to ensure global competitiveness and quality.

At the centre of this challenge is a new generation of researchers helping to redefine how ‘purity’ can be measured. Among them is CSIRO’s Dr Tommaso Tacchetto, Postdoctoral Research Fellow working on the High Purity Alumina project at the Australian Critical Minerals R&D Hub.

Driving innovation in purity: a researcher’s perspective

Tommaso and the CSIRO team are focused on the characterisation of high-purity materials. Specifically, he is leading cutting-edge research to produce a comprehensive roadmap of analytical methods to drive innovation in high-purity materials testing. 

“My work aims to enhance CSIRO’s analytical capabilities in support of the broader Australian critical minerals industry,” Tommaso said. 

“Within the Hub-funded research project, I’m working on identifying existing technologies and pioneering new analytical approaches to improve the characterisation of HPA. This involves novel techniques that can elevate the precision, efficiency and reliability of HPA analysis.” 

The delicate art of purity analysis

One of the main analytical challenges in analysing high-purity materials is to accurately quantify the extremely low levels of trace impurities while avoiding the contamination of the sample during testing. A reliable elemental analysis is crucial, not only for developing effective purification processes, but also for ensuring the material meets the market requirements. 

“In the case of HPA, the challenge of detecting impurities at parts-per-billion levels is amplified by the very refractory and chemically stable character of the material,” Tommaso said. 

“This challenges conventional (and more affordable) wet chemistry bulk analytical approaches such as Inductively Coupled Plasma – Mass Spectrometry (ICP-MS). To be analysed by this method, the sample of HPA must be fully digested, typically using strong acids (e.g., H2SO4 or aqua regia), which increases the risk of contamination.” 

What are we doing about this?

For this project, Tommaso has conducted a comprehensive review of the existing methodologies for the analysis of high-purity alumina. Where the equipment was present, the team experimented with techniques within CSIRO to identify areas of improvement, as well as provide internal support to the processing team. 

For purity testing, together with the analytical team at CSIRO, they worked on refining digestion methods for ICP-based approaches, such as borate fusion or acid-based microwave, comparing the results against those from commercial laboratories. 

These results were also cross validated using specialised techniques like Glow Discharge Mass Spectrometry, which is widely regarded in purity analyses. Other complementary techniques studied include WD-XRF and Laser Ablation ICP-MS. 

On the material property side, Tommaso has expanded conventional characterisation approaches to an advanced investigation of HPA and its precursors. This involved the systematic application of high-resolution nanoscale techniques such as Transmission Electron Microscopy (TEM), Time of Flight Secondary Ion Mass Spectrometry (ToF-SIMS) and Atom Probe Tomography (APT).

The impacts and outcomes 

Tommaso and the team have successfully produced HPA from a variety of investigated feedstocks. 

“Some of the innovations include methods of recrystallisation and calcination treatments,” Tommaso said. 

“Other breakthroughs include results from high-end characterisation, which provided unprecedented insights into mechanisms of trace element mobility or impurity localisation within the crystals, which we intend to report on through journal publications.” 

The work being done is critical for ensuring Australia is well positioned as a key player in the global supply chain by advancing cutting-edge analytical methods, which are currently outsourced overseas in a time intensive and costly manner. 

Tommaso says the opportunity for Australian industry, including start-ups and SMEs should not be understated. 

“Many of the emerging companies in this field strongly rely on established, lower-risk traditional methods for HPA purification, which come with their own sets of challenges,” 

“The research we are conducting is providing new insights into purification strategies, characterisation methods and feedstock diversification that could offer safer, more scalable and environmentally friendly options. 

“These findings could be used by Australian industry to improve their production methods, differentiate the market and enter the high-producers market in batteries and semiconductors.” 

The chance to learn more 

A key mission of the Australian Critical Minerals R&D Hub, beyond commissioning ground-breaking R&D in the critical minerals sector, is to connect and coordinate the R&D ecosystem and assist with the exchange of knowledge and expertise. One mechanism of doing so is through our science webinars. 

Tommaso will be joining a panel to discuss How pure is pure? The future of purity testing in Australia where he will present more on the HPA project and perspective alongside differing views and experiences from experts at QUT, Eurofins USA and Labwest.

“This will be a great occasion to discuss the latest in high-purity testing, sharing common challenges and alternative solutions,” Tommaso said.

“This event not only aims to inform industry about the state-of-the-art analytical approaches in the characterisation of HPA but also serve as a platform to share valuable feedback from industry, which can help to guide future R&D efforts.” 

If you haven’t already, register your attendance here.