Rhenium mineral resources: A global assessment

Abstract

Rhenium (Re) is essential to modern transportation because of its key role in the aerospace and petrochemical sectors and has been assessed as critical due to its complex supply chains and limited options for effective substitutes. Efforts to estimate global Re resources are complicated by its production as a ‘by-product of a by-product’ – i.e., its extraction as a by-product from molybdenum (Mo) concentrates, which in turn are commonly by-products from copper (Cu) mining, leading to very limited reporting of Re grades in mineral deposits. This has rendered past estimates of global Re resources subject to high uncertainty and variability.This study addresses this key issue using a new detailed database of mineral deposits reported to host Re that also includes deposits which are inferred to contain Re based on their Cu and Mo contents (using Re proxies). We also present an analysis of historical Re production and uses, and a review of Re mineralogy and key mineral deposit types. We estimate that 618 deposits hosting resources of Cu, Mo and other metals, which are dominated by porphyry Cu ± Mo deposits, host somewhere between ∼55,000–140,000 t Re. Our best estimate of ∼83,000 t Re is 3–4 times that of previous global Re resource estimates, and yet does not include other nickel, platinum group element or tungsten-related deposits that may also host Re. With current global demand at only ∼50 t Re/yr, our minimum global estimate would be sufficient to meet global demand for centuries, unless a major shift in the use of Re takes place to boost future demand. As has been demonstrated to be the case for other critical metals, the pertinent questions around future supply of Re appear not to be related to total quantity of mineral resources, but rather which mines and refineries will offer lower costs and more environmentally/socially sustainable and responsible supply chains.