Brazilian Rare Earths Ltd. has validated a low-temperature sulphuric acid curing process that delivers a 97 per cent extraction rate for total rare earth oxides and uranium, a development that could cut operating costs compared with high-temperature routes.
Results from the metallurgical optimisation program show that peak extraction was achieved at 150°C using a low-temperature, acid-cure process, thereby removing the need for high-temperature rotary kilns.
The testing, conducted at Brazilian federal research institute CDTN, achieved a 97 per cent extraction rate for total rare earth oxides, 97 per cent for neodymium and praseodymium, 83 per cent for dysprosium, 87 per cent for terbium and 97 per cent for uranium.
Brazilian Rare Earths CEO Bernardo da Veiga said: “The results support the potential for leading total system yields – from mineral to product – a key driver for efficiency and cost performance.
“These results are key to unlocking value from the high-grade mineralisation across our Rocha da Rocha province.
“This acid-cure process eliminates the need for energy-intensive thermal cracking and supports the engineering simplicity required for scalable deployment at our centralised Camaçari rare earth processing hub.
“We are now focused on applying this proven flowsheet to our broader resource base that will allow us to integrate multiple high-grade feedstocks into a flexible ‘hub-and-spoke’ production platform.”
The sulphuric acid curing process supports a simplified low-intensity process for processing rare earths.
Conventional hard-rock rare process routes often rely on energy-intensive rotary kilns operating at temperatures of more than 250°C to activate mineral phases. These systems can require high energy input, specialised corrosion-resistant and complex off-gas scrubbing systems.
Operating at lower temperatures could lower operating and capital costs as well as minimise chemical and thermal stress on the processing plant.
Brazilian Rare Earths has not deployed the process at commercial scale, but a 15-kilogram composite scale-up test replicated the very high extractions achieved at the laboratory, providing increased confidence in the scalability of the process.
The company is advancing a multi-stage work program designed to confirm feed flexibility, validate at larger scale and complete end-to-end product production.