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Chemical Engineering Seminar

Dr. Pengbo Chu

Assistant Professor in Mineral Processing
Department of Mining and Metallurgical Engineering
University of Nevada, Reno

Abstract

Approximately about 250 minerals are known to contain rare earth elements (REE). Nevertheless, only about 60 of them contain REEs in significant amounts to warrant extracting. Over 95% of the world’s rare earth oxides come form bastnäsite, monazite and xenotime. Carbonatite deposits host at least 50% of global REE resources. As the demand for REEs increases due to their ever-increasing applications in advanced technologies, many deposits containing other forms of minerals will have to be developed. This presentation provides an overview of alternative process development studies in progress for two peralkaline ores of complex mineralogy with total rare earth oxide (TREO) grade of 0.4% and 1.0%. Both contain several unique rare earth minerals but no significant amounts of monazite, bastnäsite or xenotime. All REE-bearing minerals responded favorably to flotation with hydroxamate-based collectors at alkaline pH conditions. Sodium silicate and CMC were the depressants used.

Our study shows that 92% recovery in 13% of the mass was achievable by flotation only for one of the two ores investigated, whereas 90% recovery of REEs in 40% of the mass was achieved for the other ore. Using magnetic and gravity separations instead of flotation increased the recovery to 93.8% and reduced the mass pull to 35%. Alternatively, gravity alone can be applied, but the mass pull will increase to about 50% at a recovery of 92%. The best results were obtained using a hybrid flowsheet consisting of magnetic separation and flotation. The recovery increased to 97% while the mass pull was reduced to 26%. This is an upgrade ratio of 3.2 at a loss of only 3%.

Bio

Dr. Pengbo Chu is an assistant professor in mineral processing at the Department of Mining and Metallurgical Engineering at University of Nevada, Reno. Prior to his appointment, he worked as a postdoctoral research scientist with the Department of Natural Resources Canada. He has worked on mineral processing of low grade rare earth ores and machine learning in mineral processing applications. He completed his academic trainings from McGill University in Canada, which include his PhD with Prof. Jim Finch in Materials Engineering with focus on mineral processing, MEng with Prof. Peter Radziszewski in Mechanical Engineering on mineral processing equipment optimization, and BEng in Mechanical Engineering. His current research interests are in mineral processing of Mountain Pass rare earth minerals and Nevada sedimentary lithium claystones. His research addresses both fundamental and applied aspects of these problems.