Action is needed to ensure that a supply-demand imbalance does not emerge in the iridium market as the hydrogen economy develops, according to panellists on a webinar organised by German technology group Heraeus.

Iridium is a precious metal used in catalysts in proton-exchange-membrane (PEM) electrolysers. It is one of the rarest elements on earth and is mined from the same ore as platinum and other platinum group metals (PGMs).

Thin volumes in the iridium market make it vulnerable to price shocks. In early 2021, prices quadrupled to an all-time high of $6,000/oz due to a mine closure in South Africa, where around 80% of iridum is mined. This triggered concerns among PEM manufacturers about the reliability of the supply chain.

A recent jump in demand from shipowners wanting iridium-based catalysts to treat bilge water, following a change in regulations by the International Maritime Organization, has added to these concerns.

“The market can turn very quickly in iridium” Holmes, Heraeus

Although the market remains balanced currently, forecasts are for an iridium deficit in 2–3 years, according to David Holmes, senior vice-president at Heraeus Precious Metals.

“That is the principal cause of concern at the moment,” he said. “The market can turn very quickly in iridium.”

Iridium is always mined in conjunction with other PGMs: platinum, palladium, gold, rhodium and ruthenium. The metals occur together in ore bodies, with iridium being the rarest. Typically, mining 1t of this ore will yield 5g of platinum but only 0.3g of iridium.

All these factors mean it is more challenging for the supply side of the iridium market to respond to the demand side than in conventional commodity markets.

According to the panel, to help balance the market action needs to be taken on the demand side on three fronts: thrifting, substitution and recycling.

Thrifting

Most manufacturers are already working hard to reduce the amount of iridium being used in PEM electrolysers. Technology firm Schaeffler believes it can eventually reduce the amount needed from 400kg/GW to 50kg/GW.

“We know we can achieve this level from our laboratory results,” said Peter Bouwman, industrial lead in the hydrogen division at Schaeffler. “Our R&D team is striving to achieve it [in a commercial product] as quickly as we can.”

Substitution

PGM producer Sibanye-Stillwater—which produces around a quarter of the world’s precious metals—is working on a project that would partially replace iridium in catalysts with ruthenium.

“There is three-and-a-half times more ruthenium than iridium in the world,” said Kleantha Pillay, executive vice-president of sales & marketing at Sibanye-Stillwater. “This is about replacing iridium with a metal with similar properties in a mixed oxide catalyst,” she said.

Recycling

Recycling already happens in the iridium market, particularly in the electronics crucible market, where recoveries are as high as 98%. 

These levels of recovery now need to be applied to other parts of the sector, including the growing electrolyser segment, according to Pillay.

“Recycling is going to be absolutely critical, not just because of ESG considerations, but because we are going to need that supply to come back into the market so we can make sure we are… creating a sustainable industry for the hydrogen,” she said.

PGMs are likely to be almost completely recyclable from old electrolysers, and many manufacturers may offer this as a service to be able to better predict recycling rates.

There is also a growing likelihood of increased recovery rates from other parts of the market. Recent technology development means robots can be used to recover iridium from discarded sparkplugs—something previously impossible.

“The spark plugs have not been thrown away. They have been stockpiled,” said Holmes, “This may make it cost-effective to recover the iridium.”

Reduced demand for spark plugs as internal combustion engine vehicles are slowly phased out around the world could also go a long way to rebalancing the market over the next decade.

---

Author: Tom Young