Mineralogical auditing of the Volta Grande Mine (SE Brazil) Sn-Ta-Nb-Li processing plant, aiming at REE recovery as by-products

Felipe E. A. Alves*a, Reiner Neumannbc, Ciro A. Ávilaac, Paulo E. M. Ferreirad, Caymon de S. Assumpçãod, Manuel C. Carneirob & Pedro H. V. Garciaea Programa de Pós-Graduação em Geologia, Institute of Geosciences, Federal University of Rio de Janeiro - UFRJ, Rio de Janeiro, RJ, Brazilb Centre for Mineral Technology - CETEM, Division for Technological Characterisation, Rio de Janeiro, RJ, Brazilc Department of Geology and Paleontology, National Museum, Federal University of Rio de Janeiro - UFRJ, Rio de Janeiro, RJ, Brazild AMG Mining, Nazareno, MG, Brazile National Institute of Industrial Property - INPI, Rio de Janeiro, RJ, BrazilCONTACT Felipe E. A. Alves felipeemersonaalves@gmail.com Programa de Pós-Graduação em Geologia, Instituto de Geociências, Universidade Federal do Rio de Janeiro, Cidade Universitária, 21949-900, Ilha do Fundão, Rio de Janeiro, RJ, BrazilSupplemental data for this article can be accessed at https://doi.org/10.1080/25726838.2021.1945875ABSTRACTRecovering rare earth elements (REE) as by-products of existing mineral operations is a low-investment option to increase supply in short terms. REE-minerals were reported for the São João del Rei Pegmatitic Province (southern Minas Gerais State, Brazil) since the late 1940s, but data is scarce and dubious. The largest pegmatites project in the Province – Volta Grande mine – has been mined since 1945, producing concentrates of cassiterite, columbite-subgroup minerals, and microlite, and since 2018 spodumene is also recovered. Here we prepare a stream-specific mineralogical characterisation of the beneficiation plants to identify REE-minerals for potential REE recovery. The results analyse the feasibility of reprocessing some streams to generate a high-apatite product adequate for phosphoric acid production with REE recovery as by-products. The further REE speciation also revealed the preferential distribution of heavy-REE into columbite-subgroup minerals and light-REE into microlite, which may represent promising targets for the production of concentrates with high-purity.