The first stage of the innovative filter system has been reducing diffuse emissions in primary copper production since 2021. The expansion doubles the entire system’s reduction capability to roughly 80 percent, compared to about 40 percent for the first stage. With this total investment of approximately €115 million – around €85 million went into stage 1 – Aurubis is significantly cutting diffuse emissions again, setting new standards in the industry. The project received funding from the KfW Development Bank.
“With the expanded system, we are setting new benchmarks in low-impact fabrication of strategically critical metals,” Tim Kurth, chief operating officer custom smelting & products, said. “We are investing in our capabilities to enhance the processing of complex input materials at the Hamburg site even further going forward, while bolstering our position in sustainable multimetal production.”
The heart of the system is a high-power extraction and filter system: Production air is captured via a total of seven openings, referred to as ridge turrets, and conducted to a central pipeline system. The system transports more than 1.6 million standard cubic meters of air per hour through a 4.5-meter-diameter pipe. This makes RDE one of the most powerful systems of its kind in the world, able to effectively filter out particles smaller than 10 µm.
About 19,000 filter elements treat the exhaust air, removing even the finest particles from the air stream. The cleaned air is then discharged in a controlled flow via three roughly 110 meter high exhaust towers called stacks.
The closed cycle is central to the concept: The filtered diffuse emissions still contain valuable metals, so they are redirected back to production. Aurubis links environmental protection with resource efficiency, combining them with a targeted closed-loop approach and the aim of processing all raw materials into marketable products without generating waste. The system operates especially energy efficiently thanks to its fully automated, dynamic control system.
The expansion is part of extensive investments in the Hamburg site: In addition to RDE, Aurubis is investing approximately €490 million in other projects such as the Complex Recycling Hamburg recycling plant, as well as a new precious metal processing facility. The company is strengthening its position as a leading multimetal producer and recycler in Europe, directing investments into ensuring the site is fit for the future.
Published June 2026