Green steel smelting production successfully piloted in Metso Research Center

Metso has built an experimental plant to test and validate direct reduced iron (DRI) smelting for green steel production. The pilot furnace has a 3-in-line configuration and can process feed material of up to 1000 kg/h. It is composed of Metso’s Outotec^® propriety equipment engineered into a new state-of-the-art Electric Smelting Furnace (ESF).

The pilot equipment was recently hot commissioned and two successful test campaigns have been completed in 2025. Preparations for the first customer pilot are on-going.

Piloting in the research centre is a great manifestation of teamwork. The operating team consists of 5 shifts with 7 operators and 3 engineers. The success of the campaign was largely due to the shared experience from decades of piloting with other pyrometallurgical set-ups such as pilot-scale flash smelting furnace, Kaldo and other electric smelting furnaces for ferroalloys.

Piloting is a great product development platform for our digital offering. The furnace camera (see article in this newsletter) has demonstrated its value in process control, and then during the campaigns, we identified development ideas for the camera hardware and software that will be tested in upcoming campaigns.

The data collected from the pilot campaigns data is being used to validate Metso process models, to ultimately serve as valuable input for our Geminex metallurgical digital twin and DRI Advisor development. This campaign allowed us to gain even more knowledge on refractory performance, as well as how to ensure the best performance of the equipment itself.

The target of the campaigns was first to hot commission the equipment and to demonstrate the carburization behaviour of high and low carbon feed materials. In both campaigns, the target carbon level of the hot metal was achieved. At the same time, the effect of process conditions on the element distributions and slag properties could be thoroughly investigated.

The comparison to laboratory-scale results strengthened the knowledge and the technology is now ready for scale-up.

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