In the electrolytic strip galvanizing process, a thin zinc layer is applied to steel strips using MMO anodes to enhance corrosion resistance. These anodes, which are specially designed for galvanized steel sheets used in sectors such as automotive body manufacturing and household appliances, are produced by Umicore MDS with a coating that contains iridium. Although these coatings need to be renewed at regular intervals, recycling the coating residues had not been economically feasible until now.
With an annual global production of only around 10,000 kg, iridium is among the rarest non-radioactive metals and holds strategic importance, particularly as an electrode material for hydrogen electrolyzers. Due to its scarcity, the price of this metal has risen sharply in recent years, making its recovery a critical need for the industry.
This is precisely where the new method developed by Salzgitter and Umicore comes into play. Dr. Marc Debeaux, an electroplating process specialist at Salzgitter Mannesmann Forschung GmbH, explained: “In short, our goal is to recover the iridium used in the anodes. We are talking about recovering up to one kilogram annually.”
Within the scope of the joint project carried out by anode manufacturer Umicore Galvanotechnik GmbH, Salzgitter Flachstahl GmbH and Salzgitter Mannesmann Forschung GmbH, new processes and interfaces have been developed that enable the economic recovery of iridium from coating residues.
Frank Friebel, Head of Electrocatalytic Electrodes at Umicore MDS, emphasized that iridium recycling is an extremely complex process and noted: “There are very few suppliers specialized in this field. Thanks to our long-standing experience in precious metal recycling, we supported the establishment of the process. As a result of joint trials and internal development, we succeeded in integrating the recycling steps into the daily operations of Salzgitter Flachstahl GmbH.”
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