Developing a process to recover rare earth elements and scandium from coal fly ash

2019

Rory Cameron, CanmetMining; Yves Thibault, CanmetMining; Rolando Lastra, CanmetMining; Alain Bilodeau, CanmetMining; Jean-Michel Bondy, CanmetMining

Rare earth elements (REEs) may be produced from secondary waste sources such as: uranium tailings, red mud, coal by-products, wastes from phosphate fertilizer production, and mineral by-products. This presentation reports on research designed to develop a process flowsheet for REE production from a Canadian fly ash, resulting in almost no residual waste. In the proposed flowsheet, atmospheric tank leaching with a short retention time with dilute sulphuric acid was used to solubilize a fraction of the Sc and REEs (20 to 50%); a two-step ion exchange (IX) process was used to selectively recover Sc in the first step, followed by the recovery of the other REEs in the second step; and finally the residual fly ash is used as a supplementary cementing material in concrete.

Mots Clés: Rare earth elements, scandium, fly ash, reprocessing, waste