St George Mining is taking aim at the “basket value” problem that plagues many rare earths projects, signing a Memorandum of Understanding (MoU) to explore a downstream process that could upgrade the product mix from its Brazilian Araxá project.
Under a non-binding deal with Brazilian fine chemicals group Nanum Nanotecnologia, St George will assess pathways to strip cerium and lanthanum from its key rare earths concentrate, whilst chasing commercial opportunities for the cerium component.
Cerium is the most abundant rare earth element and is used in automotive catalytic converters, metal alloys and some magnets and electrodes.
By separating and monetising the high-volume, typically lower-priced cerium and lanthanum, the company aims to produce a beneficiated concentrate weighted more heavily to higher-value light and heavy magnet rare earths.
Araxá is already a chunky rare earths asset, with a mineral resource of 70.91 million tonnes at 4.06 per cent total rare earth oxides (TREO).
However, the company says its rare earths mix is dominated by cerium at about 49 per cent TREO and lanthanum at about 25 per cent, accounting for almost three-quarters of its total inventory.
That matters because end-product pricing is driven by the proportion of rare earths used in high-performance permanent magnets relative to the rest of the rare earth mix.
Key elements of Araxa’s deposit include neodymium and praseodymium (Nd-Pr) for high-power permanent magnets and heavy rare earths such as terbium and dysprosium (Tb-Dy), which help magnets perform in demanding conditions. Holmium also attracts interest for applications requiring especially high power.
Those demanding conditions can include high temperatures due to environmental factors or extreme power loads.
St George Mining executive chairman John Prineas said: “The magnet and heavy rare earths hosted in our world-class Araxá rare earths resource are very significant and the main driver for development of a rare earths mining operation. The opportunity to also monetise the cerium component of the Araxá rare earths deposit can add material value to a potential mining operation at Araxá.”
In essence, St George’s downstream strategy amounts to a savvy form of beneficiation. If cerium and lanthanum are split off and sold separately, the remaining concentrate should carry a much higher proportion of valuable Nd-Pr and other desirable heavy rare earths.
The company says the concept could increase the concentration of the most desirable rare earths in its current product mix by as much as three times.
The collaborative work with Nanum will include metallurgical tests to maximise recoveries of cerium and high-value light and heavy magnet rare earths, using rare earth oxalate samples from the Araxá mineralisation.
The pair will also assess technologies for producing cerium products at Araxá, drawing on Nanum’s proprietary nano-material capabilities. If all goes according to plan, Nanum has flagged its interest in signing a long-term offtake agreement for the cerium.
For St George, the benefits are clear. A higher-purity mix could improve market appeal, support stronger pricing and create a clearer pathway to end users in electric vehicles, wind turbines and other advanced technologies.
In the rare earths game, it’s not just how much you’ve got - it’s what’s in the mix.
If St George can turn a cerium-heavy concentrate into a magnet rare earths-rich product - while also getting paid for the cerium - Araxá could take on a whole new shine.
Is your ASX-listed company doing something interesting? Contact: matt.birney@businessnews.com.au
By Doug Bright
