Essential ingredients – Aluminium and HPA33 The industries also operate on very different scales. World production of SGA is ~123,000,000 tonnes whereas the market
for HPA is ~50,000 tonnes annually.
34 Vernon, C.; Loh, J.; Lau, D.; Stanley, A. in Essential Readings in Light Metals, Volume 1: Alumina and Bauxite
DOI: 10.1007/978-3-319-48176-0_83
35 https://en.wikipedia.org/wiki/Orbite_Technologies#Orbite_process
36 https://www.coogee.com.au/Our-Businesses/Chemicals-Manufacturing/Chemicals/Alumina-Hydrated
37 https://www.alliedmarketresearch.com/high-purity-alumina-market
38 http://www.alphahpa.com.au/
39 https://www.fyiresources.com.au/
40 https://www.lavablue.com.au/hpa
Until the last decade, Australia was by far the world’s largest producer of alumina, before that production
was matched, now exceeded, by China. Australia produces approximately 20 million tonnes of smelting
grade alumina (SGA) annually via the Bayer process, to feed the world’s aluminium smelters (export value
approximately $8 billion). Standards for SGA are closely tied to surface area specifications and performance
in electrolytic cells. Purity rarely exceeds (or rarely needs to exceed) 99.7% as Al2O3, with the major
impurities being Na (always), and often Ca, Fe, Si and Ti. The High Purity Alumina (HPA) product required
for electronics and battery separator manufacture cannot be produced via the Bayer process. Australia’s
standing in metallurgical alumina production does not confer any advantage in entering the HPA market33,
chiefly because the major impurity, Na, is not tolerated in electronics applications. The Bayer process
is inherently limited to approximately 99.90% purity (and approximately 0.10% Na2O) due to a surface
equilibrium phenomenon that exists when precipitating gibbsite from pregnant liquor34.
High Purity Alumina is increasingly important in battery architecture and in fact there is often more HPA in
some battery designs than Ni or Co. HPA is typically >99.99% Al2O3 for the “4N” grade (there are 5N and
6N grades). The traditional process commences with high purity Al metal, dissolution and reprecipitation,
often via an alkoxide. Due to the energy intensity required for the production of metal, this is a costly route.
Companies such as Orbite35 (now bankrupt) have proposed more direct production through acid extraction
of bauxite, or even red mud, but their process was not robust at an industrial scale.
As previously stated, battery grade aluminas are not likely to be produced directly via the Bayer process.
Bayer-produced SGA is also not suitable for economic purification to HPA because it has been calcined
into insoluble phases. However, the crystalline gibbsite (Al(OH)3 , sometimes conveniently but incorrectly
described as Al2O3.3H2O, “trihydrate”) produced as an intermediate step in the process, has been used as
a starting point for the production of higher-purity alumina chemicals such as ultra-white fillers and water
treatment chemicals36, but the same could be said about any chemical-grade aluminium salt, or kaolin. On a
cost basis it is probably more logical to commence the process with a feedstock other than one as complex
as bauxite, such as clays which can occur in quite pure deposits. Any aluminium-based feedstock will suffice,
if elimination of impurities is economically feasible. As a guide, SGA as commonly produced in Australia is
valued around US$400 per tonne. 4N HPA is currently valued at between US$20,000 to $30,000 per tonne.
Al2O3 can exist in seven different non-hydrated phases and in amorphous form even after high temperature
calcination. The preferred phase for HPA appears to be α-Al2O3 (corundum) but the authors have not
tested this in the market. As previously mentioned, LED and other ceramic uses of alumina are high volume
consumers, but the whole market is expected37 to grow by nearly 22% year on year until 2028.
Altech Chemicals is headquartered in Perth WA, and will manufacture 4N electronic and battery grade
products at its facility in Malaysia. Its feedstock is reported to be kaolin, mined at Meckering WA.
There are no known producers of HPA in Australia at the present time. There are, however companies
pursuing HPA production in Australia (Table 5).
Table 5. Prospective HPA activities in Australia.
COMPANY LOCATION STAGE
ALPHA HPA38 Gladstone, Qld Pilot plant
FYI RESOURCES39 Kwinana, WA Pilot plant
ANDROMEDA METALS SA Testwork
ALCHEMY RESOURCES West Lynn, NSW Testwork
LAVA BLUE40 Lava Plains, Qld Mine operating. Pilot plant
