.webp?crop=0x25x100x100&resize=1920x1080)
Rhenium (Re) remains one of the most critical and rarest elements in the global supply chain, largely due to its unique properties and limited primary production sources. Despite having significant geological endowments, the supply of rhenium remains constrained by several factors, including its status as a by-product of molybdenum (Mo) and copper (Cu) mining, geopolitical instability in key producing countries, and the growing demand for high-temperature alloys in aerospace and catalysts in petroleum refining. Given these limitations, increasing the efficiency of rhenium recycling may be the most viable path to ensuring long-term supply security.
Unlike most base metals, rhenium is not mined as a primary commodity. The only known rhenium-containing mineral, rheniite (ReS₂), does not occur in economically viable concentrations for direct extraction. Instead, rhenium is recovered as a by-product of molybdenite (MoS₂) processing, primarily through pyrometallurgical roasting and solvent extraction. The element is typically captured in flue gases as perrhenic acid (HReO₄) and further processed into ammonium perrhenate (NH₄ReO₄) before being reduced to metallic rhenium powder or pellets.
Chile, a dominant global supplier, produces over half of the world’s rhenium, with additional contributions from the USA, Poland, China, and Kazakhstan. However, the production of rhenium remains inherently tied to the production of molybdenum and copper, making it susceptible to fluctuations in these industries. Political and social instability in Chile, especially following civil unrest and debates over mining taxation, further complicates supply chain stability. The fact that a single company, Molymet S.A., controls 60% of global rhenium production adds another layer of risk, as any disruptions in its operations could have a severe impact on global supply.
The global demand for rhenium is driven by its critical applications in high-temperature superalloys, particularly in jet engine turbine blades, which account for ~40 metric tons (t) annually. Additional demand comes from petroleum refining catalysts (~5 t) and other minor industrial uses (~5 t). This demand, coupled with the limited primary production capacity, has led to concerns over long-term supply sustainability.
Although rhenium production increased steadily during the 1970s and 1980s, it has remained relatively stable in recent decades, closely tracking copper and molybdenum production trends. The lack of significant new rhenium-bearing deposits further exacerbates concerns about future supply constraints. Given these dynamics, boosting rhenium recycling has become an essential strategy for mitigating supply risks.
Currently, rhenium recycling rates range from 25–50%, primarily through the recovery of superalloy scrap and foundry revert materials from jet engines. The relatively few companies dominating the jet engine market, such as GE and Rolls-Royce, have adopted product stewardship programs that facilitate recycling. Rolls-Royce’s leasing model, for instance, ensures that used turbine blades are returned for refurbishment or material recovery.
However, rhenium used in petroleum refining catalysts is more challenging to recover due to dissipation in refining processes. Even so, secondary recovery from spent catalysts yields approximately 4–15 t of rhenium per year, demonstrating the feasibility of further expansion in this area.
Material flow analyses indicate that as much as 80% of rhenium could be recovered from post-user waste, highlighting a significant untapped recycling potential. The high unit price of rhenium provides strong economic incentives for increasing recycling efficiency. Analysts suggest that improving collection systems, refining technologies, and establishing more robust recycling policies could significantly enhance rhenium recovery rates, reducing reliance on uncertain primary production sources.
The persistent deficit in rhenium supply, coupled with rising demand in aerospace and industrial applications, underscores the need for enhanced recycling efforts. While current recovery rates are relatively high compared to other critical metals, there remains significant potential for further improvement. With geopolitical risks, economic uncertainties, and environmental concerns shaping the future of rhenium production, increasing recycling efforts may not only alleviate supply chain constraints but also contribute to a more sustainable and secure global rhenium market. Investing in recycling infrastructure and policy frameworks will be crucial in ensuring a stable supply of this indispensable element in the years to come.