Platinum group metals (PGMs) underpin many of the technologies we depend on. The PGMs (platinum, palladium, rhodium, ruthenium, and iridium) are used in vehicle emissions controls, chemical manufacturing, healthcare, and electronics. They produce a wide range of fine chemicals, and that use is particularly important given their durability and catalytic properties. Their ubiquity also raises a sustainability issue: how the industry should balance the benefits of PGM catalysts against the environmental cost of obtaining the metals. Work is underway to develop catalysts based on more common metals, and manufacturers are working to use PGMs more efficiently and recover them after use. To properly assess either option, you need a proper account of recycling.
PGMs can be refined and reused without compromising their inherent properties. Recycling is therefore very well established in many PGM supply chains. It operates along two distinct pathways, which appear in published market data in very different ways. In open-loop recycling, the metal recovered from a used product is sold into the general market. The largest source of this is scrapped automotive catalytic converters, with smaller contributions from electronics and jewelry. This metal is reported as secondary supply. In closed-loop recycling, the owner of a spent catalyst or component sends it in for refining and uses the recovered metal to make a replacement. Closed-loop recycling is very common in the chemical and pharma industries as well as in glass making. The catalyst owner doesn't need to buy the metal again, so the effect is to reduce reported market demand rather than show up as secondary supply. It can be a significant amount and remain largely invisible in headline recycling statistics.
Johnson Matthey's 2024 figures are 143 mt of open-loop PGM supply and 449 mt of primary supply. In terms of market supply only, recycled metal was about 24% of the total supply across the five metals. If you use Johnson Matthey's figure of 462 mt of closed-loop recycling, the picture changes. Open- and closed-loop recycling combined would have been 605 mt compared to 1,075 mt of gross demand (i.e., the amount used before closed-loop recycling is deducted). On that basis, recycling met approximately 56% of gross PGM demand in 2024.
The proportion varied by metal: 65% for platinum, 45% for palladium, 60% for rhodium, 53% for ruthenium, and 63% for iridium. This reflects different usage patterns. Pt and Rh are used in glass equipment, where the valuable metal is recovered through well-established closed loops. Pd is used in vehicles, electronics, and dentistry, where end-of-life collection is less complete. These are recycled metal figures relative to gross use in 2024, not end-of-life recycling rates. The products recycled that year may have been made many years earlier. The closed-loop estimates are also likely more uncertain than the open-loop supply figures, as industrial catalysts and equipment are replaced at irregular intervals. That said, the numbers clearly show why relying on market supply alone grossly underestimates recycling's contribution.
A PGM's environmental footprint depends heavily on whether it comes from mining or recycling. Life cycle data published by the IPGMAs for production in 2022 show that recycled platinum, palladium, and rhodium have a significantly lower global warming potential per kg than the equivalent newly mined metal. The difference between an open and a closed loop doesn't appear to affect the carbon footprint of recycling per kg. A closed loop ensures the spent material is collected and that the owner can reuse the recovered metal. The facility may then only need to buy a small amount of new metal to replace any losses.
For a catalyst assessment, the sourcing scenario is paramount. A catalyst made entirely of newly mined metal will have a very different metal footprint from one made from a representative mix of primary and recycled material. Johnson Matthey describes a theoretical high-efficiency closed loop in which 98% of the metal is recycled, and 2% is replaced. That should not be taken as the norm, as losses in use, collection, and refining vary by process. The same applies when you are comparing PGM catalysts with alternatives based on earth-abundant metals. For a fair comparison, look at catalyst performance and metal recovery potential rather than assuming every PGM catalyst has the footprint of a catalyst made from newly mined material.
Recycling can certainly grow, especially if we can collect more end-of-life products. The world's vehicle fleet will be a significant future source of recoverable PGMs. Recycling, however, will not eliminate the need for mining. Some metal is lost during use, and some is dispersed too widely in the end product to be of practical value. For example, platinum used in silicone can end up in the final product at very low concentrations. New applications (e.g., hydrogen) may also require more metal before the existing products reach the end of their life.
The sustainability of the PGMs is therefore not a function of a single recycling figure. It depends on the metal's source, the application, the effectiveness of collection and recovery, and changes in the energy used for mining and refining. For industrial catalysts (particularly in the fine chemicals area), establishing a viable closed loop is one of the most important ways to reduce the metal-related environmental footprint.
