Precious Metal Recycling from Complex Solid Waste Using Highly Selective Porous Polymers

Platinum group metals (PGMs) are critical minerals central to numerous climate-related technologies, such as fuel cells and catalytic converters. However, significant challenges remain in existing processes for recycling PGM-containing solid wastes (e.g., catalytic converter wastes), thwarting efforts to improve PGM recycling rates. For example, numerous complex and/or energy-intensive steps (e.g., pyrometallurgy) are used to first remove the many undesired components (e.g., base metals) from the solid wastes before purified PGMs can be collected. As a result, domestic and global PGM supply chains still rely predominantly on virgin mining operations. This reliance has led to major U.S. domestic supply chain risks, as PGM imports are heavily sourced from geopolitically sensitive regions, while also leading to serious environmental damage. For example, the EPA has estimated that 44% of all toxic chemical releases into the environment in 2021 came from the metal mining industry. Improved PGM recycling processes are urgently needed to increase recycling rates and meet the growing global PGM demand. ChemFinity Technologies offers a fresh perspective to the traditional methods of recycling PGM-containing solid waste, using catalytic converter waste in this project as a proof-of-concept example. At the heart of our technological approach is a method to selectively extract individual precious metals directly from catalytic converter leachate, without the need to remove other undesired components first. Our process then refines the extracted PGM metals into a concentrated form, ready for either new catalytic converter production or trade. Altogether, our process has the potential to drastically reduce recycling costs and emissions, by eliminating the need for numerous costly and energy-intensive refining steps. Furthermore, the high modularity of our process allows for potential widespread implementation across dispersed regions, such as to local scrapyard or refinery customers. Our process innovations are enabled by a novel class of porous polymer sorbent materials. These materials display unprecedented performances for PGM separations in terms of selectivity, capacity, extraction kinetics, and durability – all of which significantly enhance both the economic viability and PGM recycling performance. For example, preliminary experiments suggest that our materials exhibit more than five times higher PGM capacities than commercial incumbent sorbent materials. In this project, we will test the proof-of-concept viability of our materials and process for recovering PGMs from real catalytic converter waste samples provided by scrapyard partners. Beyond this project, developments here will ultimately also be applied to the recycling of precious metals from other solid wastes, such as e-waste.