The problems associated with using non-conventional rare-earth minerals

•Major characteristics of carbonaceous rocks and bauxites as a raw source are given.•Possible ways of processing of non-conventional rare-earth ores are shown.•Shows the practicability of using of non-conventional sources of rare-earth metals.

In this paper, non-conventional sources of rare-earth raw materials, primarily located in the territory of the Russian Federation, are discussed. The focus is on carbon-bearing rocks containing oils or bitumen, metal-bearing coals, combustible shales and bauxites. The rare-earth metal concentrations in most of the sources considered in this paper are low, but it is possible to produce large amounts of rare-earth metals by processing large volumes of material. A brief review of recent research topics related to rare-earth minerals is provided, factual data are presented on rare-earth metal contents in non-conventional rare-metal bearing sites and a likely mechanism of concentrating rare-earth metals is considered. The paper draws attention to the current state of the art, outlining problems related to the extraction of rare metals from non-conventional ores and possible solutions to those problems.