An enhanced scoping study for Rainbow Rare Earths’ Gakara rare earths project points to a doubling of rare earth elements cracking plant capacity, from 5 000 t/y to 10 000 t/y.
Rainbow sought to update the feasibility of the processing facility to produce a high-purity cerium-depleted mixed rare earth carbonate from its Gakara rare earths project, in Burundi.
Metallurgical Engineering Technology and Construction (METC) was engaged by Rainbow to revalidate and update a preliminary economic assessment (PEA) conducted in 2015 by SGS Lakefield Canada (SGS), providing an enhanced scoping study.
The 5 000 t/y plant was originally proposed in the SGS PEA, based on the strong acid agitated bake process developed from the test work completed by SGS.
In December 2020, METC updated and enhanced the scoping study, by reviewing and analysing the process design criteria from the SGS PEA. As a result, METC upgraded the processing capacity of the rare earth elements cracking plant from the originally proposed 5 000 t/y to 10 000 t/y.
However, METC enhanced the process, incorporating newer technologies, to deliver a flow sheet capable of producing a high-grade cerium-depleted mixed rare earth carbonate. This product contains about 39% neodymium and praseodymium – the critical input materials for permanent magnets required for electric vehicle and wind turbine technology.
In addition, the 2020 capital cost of $35.2-million, estimated by METC, for a 10 000 t/y plant compares favourably to the SGS 2015 estimate of $22.3-million for a 5 000 t/y plant.
The operating cost estimate produced by METC is $1 279/t, compared with the original SGS estimate of $1 654/t. This represents a 21% reduction in capital intensity and 23% in operating cost, providing an expected resilience to the project economics, even in the event of a volatile pricing environment, states Rainbow.
Further, the proposed plant location in South Africa, Rainbow says, will provide strong synergies with its other rare earths project at Phalaborwa, contribute to the local economy and facilitate a sustainable, transparent rare earths supply chain.
Rainbow CEO George Bennett says the validation of the feasibility of a 10 000 t/y downstream processing plant provides the company with the opportunity to deliver a significantly higher share of the total contained metal value of the Gakara project for shareholders.
He adds that the estimated capital and operating costs of this plant will likely be “some of the lowest in the industry” and therefore viable even in the event of volatile rare earths prices.
As such, Bennet says the updated feasibility of the plant confirms Rainbow’s belief that Gakara has the potential be a low capital intensity project.
Rainbow technical director Dave Dodd says the company operates Africa's only producing rare earths operation at Gakara, through the current trial mining operations, which employ a simple, reagent-free, low capital and operating cost gravity concentration process.
“By further processing the concentrate, we have the potential to participate in a greater proportion of the value chain, producing the rare earth elements required to accelerate the global green energy transition.”
In all, he says these factors combined, serve to further strengthen Rainbow’s determination to confidently progress through to commercial scale production at Gakara.