Abstract
Power Metals Corp. is evaluating the potential of cesium production from pollucite concentrates from its Case Lake Project in northeastern Ontario, Canada. The West Joe dykes host the world’s fourth largest known hard-rock cesium resource, with an inferred resource of 13,000 tonnes averaging 2.40% Cs₂O. X-ray tomography-based ore sorting (by TOMRA in Germany) on a bulk sample produced a high-grade concentrate assaying 18.6% Cs₂O, representing a Cs2O recovery of 96.3%. The grades ranged from 25.3% Cs2O to 4.7% Cs2O for the coarse size fraction and 25.6% Cs2O to 8.2% Cs2O for the fine size fraction. A concentrate blend (19.5% Cs2O) from ore sorting testwork was subjected to hydrometallurgical process development testing. The program included hot sulphuric acid leaching, two-stage crystallization and recrystallization, and sequential impurity removal stages, followed by the production of cesium formate and cesium chloride. The flowsheet achieved production of high-purity cesium formate (99.8%) and cesium chloride (99.6%) demonstrating the technical feasibility of processing Case Lake pollucite concentrates into high purity cesium chemicals. This paper presents and discusses the results of the various hydrometallurgical investigations.