CHARACTERIZATION AND CONCENTRATION OF CRITICAL MINERALS AND RARE EARTH ELEMENTS FROM PRIMARY AND SECONDARY SILICATE DEPOSITS

Critical materials (CMs) are crucial for sustainable energy. This investigation explored the extraction of rare earth elements (REEs) from the Halleck Creek deposit in Wyoming, and CMs from a construction sand deposit in Missouri. The Halleck Creek deposit is REE enriched (0.32%) as the mineral allanite within silicious host rock. Density fractionation tests revealed that 70% of the gangue can be rejected while recovering 90% of the REEs with an upgrading ratio of 4.5:1. By exploiting allanite’s paramagnetic properties, magnetic separations achieved a TREE upgrade ratio of 3:1 with 87% TREE recovery. Based on the density fractionation results, a rougher-scavenger-cleaner circuit was designed and simulated, which predicted the potential to produce a TREE grade of 2.13% from the -500+300 micron material at 68.2% TREE recovery. For the -300+50 micron fraction, the circuit simulation showed the ability to achieve 1.76% grade at 76.4% TREE recovery. Excellent overall efficiency is predicted with Ep values of 0.07 and 0.13, respectively. Characterization of the Missouri sand deposit showed that the highest total heavy mineral sand grade was 10.5% from the plant samples and 3.1% from the drilling cores. The results demonstrated the potential for titanium, vanadium and magnetite enrichment, with titanium grades reaching 9%.