Interest in monazite as a feedstock for rare earth (RE) processing is rising as producers look for sources outside China, bringing mineral sands projects into the RE supply chain.
Deposits of RE elements are typically found in rock formations including carbonatites and granites, in calc-silicate sequences and ionic adsorption clay deposits — primarily in China and surrounding countries.
But as downstream consumers and governments increasingly look to diversify their supply chains, monazite is becoming attractive as an alternative source. Monazite is a phosphate mineral that contains about 55-60pc RE oxides. It contains 17 RE elements, including cerium, neodymium, lanthanum, thorium and yttrium.
Reflecting this, US-based uranium and rare earths producer Energy Fuels is acquiring Australia-based mineral sands developer Base Resources to gain access to the monazite stream from its Toliara project in Africa as an RE feedstock.
The Toliara heavy mineral sands project in Madagascar plans to produce monazite as a by-product of its primary titanium and zirconium output. The acquisition marks Energy Fuels' entry into the mineral sands business as it invests in operations in Australia, Brazil and Madagascar to supply RE concentrate.
Toliara's monazite stream will provide the feedstock Energy Fuels needs for RE oxide production at its White Mesa uranium and vanadium mill in Utah. The facility will also process the uranium content from the feed and if needed, it can recover thorium.
The mill has been processing monazite to produce a mixed RE carbonate, which it has been selling commercially since 2021.
"We're putting together two pieces of the puzzle that nobody has put together," Energy Fuels president and chief executive Mark Chalmers said at the recent Metal Events Rare Earths conference in Singapore. "We're putting together the physical metallurgy and the hydrometallurgy."
White Mesa has been processing monazite supplied by US titanium dioxide producer Chemours. But its output has been limited as there is not enough monazite in the feed, Chalmers said, whereas Toliara contains more than 1mn t of monazite and has about 1.5mn t of existing tailings capacity.
Energy Fuels is in the process of commissioning its Phase 1 neodymium-praseodymium (NdPr) separation facility, which is scheduled to start production by the end of the first half of 2024. It plans to produce 35t of NdPr oxalate in 2024. Phase 1 will have the capacity to process 8,000-10,000 t/yr of monazite to produce up to 800-1,000 t/yr of NdPr oxide.
The company plans to increase its NdPr capacity to 3,000 t/yr in 2026-27 and add heavy RE processing in 2027-28. It is starting to pilot heavy RE separation and is exploring moving downstream into metal and alloy production.
The first stage of Base's Toliara project, scheduled for September 2027, aims to produce an average of 17,400 t/yr of monazite. The second stage would ramp up to 26,100 t/yr.
Energy Fuels also owns the Bahia project in Brazil, which could supply 4,000-5,000 t/yr of monazite to White Mesa Mill to produce 400-500 t/yr of NdPr oxide and 20-25 t/yr of dysprosium and terbium oxides.
Energy Fuels has the potential to produce 4,000-6,000 t/yr of NdPr oxide, 150-225 t/yr of dysprosium oxide and 50-75 t/yr of terbium oxide, which would supply enough magnetic RE oxides to supply 3mn-6mn electric vehicles (EVs) per year.
RE oxides are in demand from US, European and Asian EV, wind energy and other clean energy manufacturers, as well as emerging commercial metal-making, alloying and magnet-making facilities that are under development in the US. The US defence industry could include offtake of other non-magnetic oxides contained in monazite.
Developments at other mineral sands producers outside China also indicate that demand for concentrate for its monazite content rather than zircon or titanium is on the rise.
Indonesia-focused zircon producer PYX Resources said last week that it has made its first shipment of monazite-rich zircon concentrate to a customer in Hainan, China, exporting 750t. PYX expects to report further exports in the future.
Mineral sands producer Iluka is also moving into the RE market using its monazite by-product. The company has stockpiled monazite since the 1990s at its Narngulu Mineral Separation Plant in Eneabba, Western Australia.
Iluka is now developing RE production at Eneabba, commissioning a concentrator plant to process the stockpiled material. It will separate the monazite and additional zircon to produce a 90pc concentrate to feed its RE refinery. The company aims to produce neodymium, praseodymium, dysprosium and terbium oxides from 2026. It holds other mineral sands deposits that could feed the RE refinery, and it will be able to handle third-party deposits if it requires additional feedstock.
Companies had stopped processing monazite owing to the high cost of disposing radioactive thorium. But thorium is now becoming attractive for advanced nuclear reactor design and medical isotopes, which could drive offtake.
