Joint production with multiple determining products: the case of platinum-group metals

Joint production with multiple determining products: the case of platinum-group metals | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Joint production with multiple determining products: the case of platinum-group metals Bo Weidema, Ivan Muñoz, Anastasia Papadopoulou, Edith Buhl This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-7848762/v2 This work is licensed under a CC BY 4.0 License Status: Posted Version 2 posted You are reading this latest preprint version Show more versions Abstract Purpose Platinum-group metals (PGM) constitute an extreme example of a joint production activity since mines, mainly in Africa and Russia, co-produce up to eight valuable metals simultaneously. While this multifunctionality has been traditionally dealt with by allocation (partitioning), in this article we aim at developing a life cycle inventory (LCI) model following consequential modelling principles, covering supply of five of the six metals in the group (platinum, palladium, rhodium, ruthenium, iridium). Methods An analysis of data from 33 mines around the world shows that PGM production can be considered a case of joint production with more than one determining product. Following this finding, we develop a consequential LCI model with a cradle-to-gate scope, considering supply from mines in South Africa, Russia and Zimbabwe, based on existing data for PGM mining in the ecoinvent database, together with public statistics on global PGM production trends and prices in the period 2019–2023. Results and discussion The model is evaluated at the impact assessment level, focusing only on greenhouse-gas (GHG) emissions per kg metal. The ranking of metals, from higher to lower emissions is rhodium, platinum, palladium, iridium and ruthenium. Sensitivity analyses show that results are strongly influenced by fluctuating market prices, the marginal supplying countries, and the identification of joint products being either fully utilised or not fully utilised. When the model is evaluated for the period 2014–2018, GHG emissions per kg metal are substantially different for rhodium, platinum and palladium. Conclusions A key finding of this research is that, from a consequential modelling standpoint, PGM mining constitutes a situation of joint production, where platinum, palladium and rhodium are co-determining products, either of the mines (platinum, palladium and rhodium) or of the further refining of the refinery residual (ruthenium and iridium). The main limitation of the developed model arises from the need to address the intrinsic variability in prices associated to the global PGM market, as a result of imbalances in supply and demand. While our model has been based on historical 5-year time series on production and prices, an alternative for future improvement would be to use longer time series, or more advanced forecasting such as Autoregressive integrated moving average (ARIMA) techniques for the future mine supply and metal prices. Environmental Engineering Environmental Economics Palladium iridium ruthenium rhodium consequential life cycle assessment Full Text Additional Declarations The authors declare no competing interests. Supplementary Files Supplementarymaterialv3clean.pdf Cite Share Download PDF Status: Posted Version 2 posted You are reading this latest preprint version Show more versions Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-7848762","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":529939358,"identity":"78ac3e95-861d-4625-83af-c39b7f39e165","order_by":0,"name":"Bo 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assessment","lastPublishedDoi":"10.21203/rs.3.rs-7848762/v2","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-7848762/v2","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003ch2\u003ePurpose\u003c/h2\u003e \u003cp\u003ePlatinum-group metals (PGM) constitute an extreme example of a joint production activity since mines, mainly in Africa and Russia, co-produce up to eight valuable metals simultaneously. While this multifunctionality has been traditionally dealt with by allocation (partitioning), in this article we aim at developing a life cycle inventory (LCI) model following consequential modelling principles, covering supply of five of the six metals in the group (platinum, palladium, rhodium, ruthenium, iridium).\u003c/p\u003e\u003ch2\u003eMethods\u003c/h2\u003e \u003cp\u003eAn analysis of data from 33 mines around the world shows that PGM production can be considered a case of joint production with more than one determining product. Following this finding, we develop a consequential LCI model with a cradle-to-gate scope, considering supply from mines in South Africa, Russia and Zimbabwe, based on existing data for PGM mining in the ecoinvent database, together with public statistics on global PGM production trends and prices in the period 2019\u0026ndash;2023.\u003c/p\u003e\u003ch2\u003eResults and discussion\u003c/h2\u003e \u003cp\u003eThe model is evaluated at the impact assessment level, focusing only on greenhouse-gas (GHG) emissions per kg metal. The ranking of metals, from higher to lower emissions is rhodium, platinum, palladium, iridium and ruthenium. Sensitivity analyses show that results are strongly influenced by fluctuating market prices, the marginal supplying countries, and the identification of joint products being either fully utilised or not fully utilised. When the model is evaluated for the period 2014\u0026ndash;2018, GHG emissions per kg metal are substantially different for rhodium, platinum and palladium.\u003c/p\u003e\u003ch2\u003eConclusions\u003c/h2\u003e \u003cp\u003eA key finding of this research is that, from a consequential modelling standpoint, PGM mining constitutes a situation of joint production, where platinum, palladium and rhodium are co-determining products, either of the mines (platinum, palladium and rhodium) or of the further refining of the refinery residual (ruthenium and iridium). The main limitation of the developed model arises from the need to address the intrinsic variability in prices associated to the global PGM market, as a result of imbalances in supply and demand. 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