Metso delivers new Ausmelt Furnace cooling elements to Dowa’s Kosaka Plant in Japan

The original cooling elements were installed in 2007, underscoring the design’s reliability. Late in October 2024, Kosaka commissioned Metso to manufacture and supply a replacement set. All elements were manufactured and shipped in time for Kosaka’s scheduled maintenance shutdown in September 2025 so that they could be installed in time without impact on planned production.

Precision manufacturing and quality assurance

The new elements underwent rigorous quality testing and trial fitting to ensure compatibility with Kosaka’s existing furnace. During this phase, technical representatives from Kosaka visited the manufacturing facility alongside Metso’s engineering and quality team to oversee inspections and observe the trial fitting firsthand. 

“High quality manufacturing of copper cooling elements is absolutely critical to ensure they are fit for use in the aggressive environment of a TSL furnace,” says Neil Jacobson - Product Manager for Ausmelt TSL Smelting at Metso. “All elements are subjected to extensive testing and inspections to confirm composition, material properties, water flow capacity, pressure rating and dimensions. This ensures that on-site installation of the copper elements will go smoothly and that the panels will provide many years of reliable service.“

On-site technical support

Once delivered to site, Metso dispatched two technical specialists who were joined with Metso’s Japan-based site account manager to guide Kosaka’s crew through the installation process.

“Metso’s on-site support ensured our team installed the cooling elements efficiently and safely,” stated Shirohisa Matsuhashi - Kosaka’s Equipment Maintenance Section Manager.

Commissioning and full production

Following installation, Kosaka completed a smooth furnace heat-up and transitioned back to full production, processing recycled feedstocks into valuable metals including antimony, gold, silver, copper and lead.

“Our TSL furnace has completed the heat-up and slag coating as planned and has been operating normally since yesterday,” Shirohisa Matsuhashi confirmed on 20 October 2025. “We’re extremely grateful for Metso’s cooperation and support throughout this project.”

Continued collaboration & reliability through expertise

Metso is looking forward to continued collaboration, and exploring measures to extend the service life of the copper elements.

“We appreciate Metso’s ongoing support and look forward to continued cooperation in the future,” says Shirohisa Matsuhashi.

This successful equipment supply and installation highlight Metso’s end-to-end capabilities - from design and manufacturing to field support - ensuring reliable, sustainable operations for complex smelting plants.

This article is part of our Smelting Newsletter 2025. Visit the issue front page for all articles and greetings from Jyrki Makkonen - VP, Smelting.