A breakthrough Australian process is increasing the purity of aluminium materials while boosting the global decarbonisation project.
High-purity alumina (HPA) is a material of the future that is in huge demand today. This value-added mineral is a critical ingredient in breakthrough technologies – from improving lithium-ion battery safety, to making AI chips cooler and faster, to enabling more efficient lithium extraction.
In the industrial hub of Gladstone, Queensland, Alpha HPA is at the forefront of the material’s refinement into ever-higher grades of commercial purity. The specialty aluminium materials and technology ASX-listed company has developed a world-first process for purification and refining.
“The idea of producing high-purity alumina isn’t new – but the way we do it is,” said Rob Williamson, Managing Director of Alpha HPA. “We’ve re-engineered the process from the ground up to deliver unmatched purity at commercial scale, with near-zero waste and drastically lower emissions.
“It’s not just an evolution – it’s a step-change that positions Australia at the forefront of a critical global supply chain.”
Outstanding hardness
An odourless crystalline material, aluminium oxide is notable for its high thermal conductivity, low electrical conductivity, and outstanding hardness and strength that make it a material of choice for various industrial applications.
A refined form of the non-metallurgical material, HPA must consist of more than 99.99 per cent aluminium oxide. Classifications of HPA are indicated by the number of nines in its purity level. A 4N (“four nines”) HPA signifies at least 99.99 per cent purity, 5N is at least 99.999 per cent purity and 6N is at least 99.9999 per cent purity.
These levels are achieved through processes that minimise trace impurities, such as electrolysis or zone refining.
The rapid development of high-tech fields has seen aluminium’s purity requirements increase. As the evolution of AI unfolds, demand for power-hungry data centres is seeing the exponential growth of HPA’s use in thermal management.
HPA provides multiple performance benefits when it is used as a cooling agent in the advanced semiconductor chips needed to power AI data centres, which as a by-product produces enormous amounts of heat.
Traditionally, high-purity silica has dominated the market as a semiconductor heat sink. But with thermal conductivity 25 times higher than silica, HPA is becoming the most in-demand semiconductor material.
“Silica will still have a place in lower-performing chips, but when it comes to high-performance applications – like GPUs and power semiconductors – high-purity alumina is becoming the material of choice,” Williamson said. “HPA delivers the cooling performance needed to keep next-gen chips running efficiently and reliably.”
Enter Alpha HPA
Alpha HPA’s innovative manufacturing process is capable of selectively extracting alumina from a proprietary solution using a solvent extraction process with “scalpel-like precision”, Williamson said.
The hydrometallurgical technology was first commercially used in the 1970s and is commonly used for copper, zinc and rare earths. Williamson is understandably coy on Alpha HPA’s proprietary process for aluminium extraction, which is based on established solvent extraction (SX) technology.
“Solvent extraction is essentially a way to selectively purify metals, almost like a molecular-level filter that isolates the element you’re targeting,” Williamson said. “What we’ve done is take this proven hydrometallurgical technology and refine it specifically for aluminium. To the best of my knowledge, we’re the first to successfully achieve this level of precision and purity for high-purity alumina.”
The traditional production methods for HPA rely on outdated, emissions-intensive technology, typically synthesising it from aluminium metal feedstock. This is energy-intensive and produces high carbon and chemical emissions, along with a significant amount of waste.
Alpha HPA uses a chemical aluminium hydrate feedstock sourced from Rio Tinto. It looks like bricklayers’ sand, Williamson said, and it would notionally go on to become smelter-grade alumina. It is dissolved in acid and polished before Alpha HPA’s proprietary Smart SX Technology process performs the highly selective extraction of Al3+ cations from aluminium-loaded liquor.
The aluminium-loaded organic solvent is then transformed through two crystallisation steps into an intermediary product that can be calcined to HPA. The loaded organic stream can be directed to any acid stream to generate 5N+ purity aluminium precursors (salts), or 4N+ boehmite or alumina. Byproducts are sent to mining explosives company Orica, a 5 per cent shareholder in Alpha HPA, and returned as reagents in an almost waste-free process.
The company’s proprietary technology creates a growing range of high-purity aluminium materials – aluminium oxides, aluminium hydroxides and aluminium nitrates – of an ultra-high purity that is considered a best-in-class low-alpha feedstock.
“It’s so pure that we eliminate uranium and thorium,” Williamson said. “That’s critical because these elements emit alpha radiation which can ionise the materials within the nanolayers of a semiconductor. When that happens, electrons are displaced, which leads to data errors or, worse, premature failure of the chip itself.
“We’re achieving uranium and thorium levels below one part per billion – essentially at non-detectable levels. We can’t technically claim zero, but it’s significantly lower than the five parts per billion typically seen in competitor products.”
Energy transition
Another standout application for Alpha HPA’s proprietary alumina relates to batteries. HPA is widely used to coat the separator between the anode and cathode to provide multiple battery-performance benefits, including an improvement in thermal capacity and reducing the rare risk of fires in mobile phones and EVs.
“We are particularly focused on battery safety, using our aluminium nitrate as a precursor to coat the graphite anode within the lithium-ion cells,” Williamson said. “That aluminium oxide coating plays a critical role in halting the chain reaction that can occur when the battery experiences trauma. In essence, it prevents thermal runaway, while also allowing the battery to operate at slightly higher temperatures, which can improve charging and discharging performance.”
Alpha HPA’s materials are also proving essential in the global energy transition through their role in chemical mechanical planarisation slurries, used to polish high-performance semiconductors, especially silicon carbide (SiC) substrates.
“Our material is used in the polishing step for three types of semiconductors – silicon carbide, gallium nitride and sapphire,” Williamson said. “These are fundamental to power-switching devices in EV battery systems, solar PV systems, wind turbines – essentially any application requiring high-power switching.”
Recent testing has shown that Alpha HPA’s materials deliver more than 50 per cent higher removal rates on SiC wafers compared to conventional abrasives, underscoring their performance advantage in next-gen semiconductor manufacturing.
Brand-new facility
Australia is the world’s largest exporter of alumina, but does not currently produce commercial quantities of high-purity alumina.
Alpha HPA’s new purpose-built, renewably powered facility will change that. Currently under construction, the full-scale facility is expected to begin producing HPA in 2027. An estimated annual output of 10,000 t per year will make it the world’s largest single-site manufacturing facility for high-purity aluminium materials.
The commercial plant will also deliver 4N purity HPA at a cost significantly lower than any other commercial process currently on the market.
“The underlying concept of producing HPA hasn’t changed,” Williamson said. “What we’ve done is perfected it to make sure it’s commercially viable at scale. A hydrometallurgical plant like this has to have a tight mass balance, ensuring all elements are accounted for in every stream, and that impurity levels don’t accumulate to a point where they compromise the economics. Many technologies work well in a lab beaker, but their waste streams are too costly to manage at industrial scale.”
Rather than relying on experimental equipment, Alpha HPA has designed the facility around proven, standardised hydrometallurgical systems.
“There’s nothing exotic about the hardware,” Williamson said. “We didn’t need to invent any mechanical apparatus. It’s tanks, mixers, filter presses, dryers, rotary calciners … off-the-shelf equipment. The innovation lies entirely in chemistry, not machinery.”
By solving the accessibility of large-volume, high-purity aluminium nitrate, Alpha HPA says it has unlocked the potential of fast and affordable application of aluminium-oxide coatings onto both cathode and anode active materials.
“It’s a disruptive technology with the lowest carbon emissions, giving us a significant commercial advantage. It’s very exciting times and great to be moving way further down that value chain in Australia.”
The Australian Government’s support of $400 million for Alpha HPA’s Gladstone facility is part of the Critical Minerals Strategy ambition to “increase Australia’s footprint in downstream processing” of critical minerals.
This article was originally published in the August 2025 edition of create with the headline ‘Alpha performance’.
