Rare earths in focus: powering energy transition

The rare earth elements (REEs) are part of a broader category of critical minerals. REE's are vital to a wide range of modern technologies and energy transition. In particular, REE-based Nd-Fe-B magnets are the most powerful permanent magnets available today, widely employed in electric vehicles and wind turbines. Over the past decade, Western Australia has become one of the major global suppliers of rare earths, while REE exploration and project development is also under way in other states. This article by Geological Survey of Queensland lead economist Artem Golem provides an overview of the REE market, and then outlines the status of rare earths in Queensland. Brief market overview Rare earths are a group of 15 elements, which includes 14 lanthanides (except for short-lived radioactivate promethium) and yttrium (Y). Sometimes scandium (Sc) is also added to the list. These elements are unique in terms of their physical, chemical and light-emitting characteristics, and are critically important for modern technologies, including renewable energy generation and storage, electric cars, digital electronics, energy efficient lights, as well as for the aerospace and military applications. Despite their name, REEs are not rare in the geological sense as they are as abundant as copper, zinc, nickel, and lead. Geological Survey of Queensland lead economist Artem Golev However, it is often difficult to feasibly extract and refine them. Similar chemical and physical properties of REEs result in the same geological occurrence. Thus, a combined extraction from ore into concentrate, and then processing into a mixed chemicals or oxides product is required. Only in the final (refining) stage rare earths are separated into individual rare earth oxides (REO) – the main intermediate product(s). The latter is crucial for understanding the economics of rare earths and the difficulties in balancing their supply and demand. Specifically, some REEs can be in high demand, but meeting that demand means overproduction of all other REEs, due to a constant composition in the ore. This is reflected in a multiple times difference in prices for individual REOs – currently ranging from US$1 to $1,800 per kg (SMM) – while their production costs are not far apart (except for some very rare elements). The separated REOs can either be used for the composition of REE-based chemicals (e.g. for catalysts, optical applications, electronics, fuel cells, etc.) or reduced to a pure metal (magnets and alloys). Mixed REOs can be also accepted in some applications, e.g. polishing powders and NiMH batteries. The current REE market is largely driven by demand for four elements that are mainly employed in magnets, including neodymium (Nd), praseodymium (Pr), dysprosium (Dy) and terbium (Tb). Despite accounting for about a quarter in the global REO mine output (by weight), these elements make up more than 80% of the REO market value. Global mine production of REOs was estimated at 280 kt in 2021 (USGS), worth about US$8 billion. China holds the major known REE reserves (40%), and heavily dominates their mine production (60%), refining (85%), and final use (70%). Australia has a 3.3% share in the world’s reserves, and about an 8% share in the REE mine production (DISER). There is currently only one REE mine in operation in Australia (Mount Weld, WA) (Lynas). In addition, there is a new project on the way – for reprocessing and refining of REE concentrates accumulated over the years as a by-product of mineral sands mining, expected to be operational in 2025 (Iluka). Several other projects are at the stage of feasibility studies in WA, NT, NSW, and Victoria (Geoscience Australia). Rare earths in Queensland There is no production of REEs in Queensland, nor are there any projects under consideration. However, the mineral occurrences of these elements in the State have been known for some time. The potential sources of REEs in Queensland fall into several groups, as summarised in the table below. Notes: multiple sources of information, Queensland Department of Resources. The primary sources of REEs in Queensland are mainly represented by hard rock deposits such as iron ore-copper-gold (IOCG) and phosphate deposits. These are relatively small, being characterised by a (very) low grade if compared with existing REE mines and projects under consideration elsewhere. The secondary sources of REEs in Queensland are more significant, likely representing better opportunities for development. Among those is Mary Kathleen – the only significant REE deposit in Queensland – represented by mine tailings left from uranium production in 1963-1982 (Department of Resources). These tailings, however, still have residual hazardous elements to deal with, while the REE composition (i.e. per cent of valuable REEs in the mix) is likely relatively poor to justify conventional processing and refining. Rare earths at Mary Kathleen are mainly represented by low-value cerium (Ce) and lanthanum (La), which account for about 85% of total REOs by weight. This is a higher concentration of low-value elements than found elsewhere. Typically, Ce and La would account for 50-80% of REOs in hard rock deposits, while below 50% in ion adsorption clays. Ce and La oxides are currently priced at about 1,000 US$/t – significantly lower than most base metals. This is in contrast to around 100,000 U$/t (or 100 times higher) for neodymium (Nd) oxide – another relatively abundant REE and the main sought-after element used in Nd-Fe-B magnets. What are “ionic rare earths”? From an exploration point of view, one source of REEs has attracted a lot of attention recently. This is ion adsorption deposits where REEs occur being adsorbed onto clay mineral surfaces. Essentially, this means that the REE-hosting minerals have been “cracked” (by nature) and the rare earths are readily available for recovery, e.g. through a low-cost (in-situ) leaching process instead of a set of complex mining, mineral beneficiation, and hydrometallurgical operations. In the past, deposits of this type were found in China only, explained by meeting specific geological and historic climate conditions. However, in the last decade new ion adsorption deposits have been discovered and came into production in Burma, Thailand, Vietnam, and Madagascar, and are under investigation in other countries including Australia. Despite low grades (0.05-0.2% of REO), ion adsorption deposits are one of the most economic. Better REE composition (in particular, depleted on cerium), low-cost recovery, as well as very low radioactivity make them an important source of REEs, accounting for an estimated 35-40% of global supply. These deposits are also the main source of rare and typically more valuable heavy REEs. “Ionic” or ion exchangeable rare earths are rather a common natural phenomenon, driven by weathering of REE-hosting rock and favourable conditions for REE adsorption (onto clay and other suitable hosts) versus dissipation and/or formation of secondary minerals. There is likely a variety of near surface clay-rich ore bodies that are worth investigating for ion exchangeable REEs. This might open new opportunities for a feasible co-production of REEs alongside some major mined minerals. Conclusion Rare earths are still waiting to be further discovered and developed in Queensland. Undoubtedly, they would be a valuable addition to the State’s new economy minerals portfolio, and a great fit for a circular economy approach in the case of co-production with other minerals. Mineral occurrences of rare earths in Queensland are also compared against major REE projects in Australia in the graph below. Additional information about Australian REE deposits and projects can be found at the Geoscience Australia website. Major rare earths projects in Australia and selected mineral occurrences in Queensland Data sources: S&P Global Market Intelligence, Queensland Department of Resources, Geological Survey of Western Australia, companies’ reports and announcements. Photo: The Rehabilitated Mary Kathleen Uranium Mine

Rare earths in focus: powering energy transition

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