Imperial said the process, which involves a high-pressure caustic leach (HPC) followed by hydrochloric acid leach of the HPC residue, showed very high recovery of scandium and the rare earth elements from Imperial's Crater Lake Sc-REE mineralisation.

Using the method, the company achieved 87% scandium recovery from the primary leach solution (PLS), and 84% recovery of total rare earth element, including yttrium (TREE+Y).

"We are extremely pleased with the results obtained to date from our metallurgical test work on Crater Lake mineralization," said Peter Cashin, Imperial's president & CEO. "Along with our partners MPlan-Dorfner ANZAPLAN, we have now obtained high scandium and rare earth recoveries from both the mineral concentration and hydrometallurgical study phases of the program. More importantly, the process that we have developed is effective across the various mineralization types defined on the project thus far. We are now ready to move to the final stages of our test work to recover a high-purity scandium oxide product."

Imperial  is partnering with German mineral and metal projects consultancy DORFNER ANZAPLAN on hydrometallurgical development. The partners next plan to continue to develop a hydrometallurgical flowsheet by treating a 100 kg mineral concentrate produced from two bulk samples collected from Crater Lake drillcore.

The Crater Lake Project is located 200km northeast of Schefferville, Québec and is accessible via fixed-wing aircraft or helicopter.