Abstract
Froth flotation is the main technique used for REE-bearing mineral (REM) separation from most gangue minerals. A better understanding of the parameters influencing the performance of REM flotation is of interest for REE and other critical elements commonly found in non-sulfide minerals such as niobium and lithium. The present study explores the effect of grinding conditions and water quality on the flotation performance of REMs at laboratory scale using material from the Ashram carbonatite deposit (Canada).
The experimental work used Denver cell tests to evaluate the impact of different particle sizes (P80 between 20 and 30 µm) and rod size distributions in conventional grinding on the performance of REM flotation using a hydroxamic acid collector. A potential interaction of iron species generated by grinding media corrosion with the collector was identified, along with the effect of different water sources. The results showed that, along with entrainment, aggregation (which seemed to be promoted in the presence of rust) and/or slow gangue flotation play an important role in determining whether selective separation of REM from gangue minerals is achieved. While REE recoveries of 80% were achieved, dolomite recoveries varied from 20% to 60% when going from tap water to rust-contaminated water.