Unconventional occurrence forms of critical metals in complex ores and development of identification methods

Mineral processing mineralogy methodologies play a crucial role in the predictive assessment of rare and critical elements in ores of ferrous, non-ferrous, noble metals, and non-metallic minerals. These assessments fundamentally guide the feasibility studies and strategic planning of raw material development projects, including the evaluation of potential substitutes for strategic materials. This study focuses on the detection, identification, and characterization of unconventional occurrence forms of critical metals in ores and rocks of diverse compositions and genesis, which contain these elements in trace amounts. An optimized suite of analytical techniques was employed to obtain reliable data, facilitating the development and refinement of physical and chemical extraction, leaching, and recovery methods for valuable metals. The capabilities of mineralogical analysis techniques for identifying and diagnosing rare earth minerals—such as members of the crandallite group and svanbergite—were demonstrated on pyrochlore-monazite-crandallite ores from the Tomtorskoye deposit and bauxite ores from the Sredny Timan deposits. It was established that rare earth metals occur both as discrete mineral phases and as isomorphic substitutions within the crystal lattices of ore-forming minerals. Examples of optimally selected analytical methods are presented and discussed. Selected analytical methods, including Raman spectroscopy and X-ray diffraction (XRD), showed excellent concordance, highlighting Raman spectroscopy’s potential as a rapid and reliable diagnostic tool for complex polymineralic materials. The study emphasizes the importance of examining poorly studied minerals with potential industrial significance. For instance, svanbergite, commonly found in these ores, shows promising applications in environmental and energy-related technologies.This research was conducted under the State Assignment of the Institute of Geology of the Komi Scientific Center of the Ural Branch of RAS.