Following a detailed evaluation of the Longonjo flow sheet, London-listed rare earths miner Pensana says there is scope to increase the content of heavy rare earths within its high-value mixed rare earth carbonate (MREC) product by more than five times.

The company initiated a detailed review in response to growing demand from offtake partners that seek to secure supply of both light and heavy rare earth elements from 2027.

Heavy rare earths are essential for high-performance automotive and other advanced technology applications. The company owns the Longonjo rare earths mine, in Angola, which will initially produce 20 000 t/y of MREC before scaling up to a planned 40 000 t/y later on.

Pensana’s review finds that, by installing a selective heavy rare earth oxide (HREO) recovery circuit prior to the product precipitation process stream, the recovery of dysprosium (DyO) and terbium (TbO) can be significantly increased.

DyO and TbO are two of the most valuable heavy rare earth elements in the MREC product basket.

The findings suggest that the current 30 t/y of HREO contained within the MREC can be increased to up to 160 t/y, comprising 130 t of DyO and 30 t of TbO in the MREC product.

Early discussions with potential offtake partners have indicated that this increased content of HREO in the MREC product would strengthen the demand and valuation for this clean, high-value product.

Pensana is now finalising the capital and operating cost estimates for the HREO recovery circuit, but has already determined that the higher-value product can generate significantly higher revenue.

Dysprosium oxide currently trades at $208 000/t, while terbium oxide trades at $918 950/t.

“This evaluation has set Longonjo out as one of the few suppliers coming online in the near term capable of supporting the full mine-to-magnet supply chain with both light and heavy rare earths.

“Our offtake partners have been clear about their requirements and in response this circuit upgrade will further enhance Longonjo’s importance within the rare earths landscape,” says Pensana CEO Tim George.