DRI Smelting Furnace is based on Metso’s Outotec technology starting from when the first flash smelter was built in the 1940’s. Since then, we have delivered more than 110 smelters for different kinds of metals and ferroalloy productions, but not for direct reduced iron (DRI) directly. Iron has often played more of the role of a side product, like in ilmenite smelting, or as a part of the final product, like in ferrochrome processes.
Due to the amount of successfully delivered smelters, we have accumulated numerous invaluable experiences, and have developed our own products that are now utilized in the DRI Smelting Furnace. For instance, the flash smelter steel structure and binding system is used almost directly in an electric DRI Smelting Furnace. It is the same situation with our world-famous electrode equipment and copper cooling elements, as those are ready components for our application.
DRI Smelting Furnace itself can be a very large piece of equipment. When discussing our biggest offered DRI Smelting Furnace so far, the furnace dimensions are 35 meters x 12 meters – pretty much the size of a swimming pool. This kind of a “monster” can have inventory of more than 3000 tons of hot metal and over 1000 tons of slag inside and is capable to produce 1 500 000 tons of hot metal for downstream processes to be converted into green steel products.
However, if a customer is looking for a smaller scale furnace with a capacity to produce around 200 000 tons of hot metal, we have the right equipment for that too. For this application – and even higher capacities – our suits better.
In a primary steel production chain, our DRI Smelting Furnace is located after the direct reduction plant where DRI is produced from iron ore. Direct reduction process can be either a hydrogen-based Metso Circored™ process for fine iron ores, rotary kiln-based process like our SLRN XTRA, or it can be a commonly used shaft furnace process from other suppliers, such as Midrex or Energiron. A direct reduction plant could also be coupled with our DRI Smelting Furnace, directly enabling the DRI to be fed into the hot smelting furnace, saving remarkable share of energy within the smelting furnace.
Our smelting furnace is used to convert solid DRI into liquid form, remove the gangue part form metallic part into slag phase and to finalize the reduction of iron oxides still present in the DRI. As a downstream process, the typical solution is to utilize existing basic oxygen furnaces (BOF) in primary steel plant. Other possibilities are to utilize electric arc furnace (EAF), especially in cases where customers are also recycling large volumes of external steel scrap in their products. In the future the development of ladle furnace will allow a shorter production route without BOF or EAF with a capability to decarbonize hot metal directly. Metal granulation process can be used to solidify and cool down liquid hot metal into “green iron granules” which can be then sold and safely transported in steel plants globally.
Much has transpired within the past year, as it’s been quite eventful. To name a few, the company has changed its name to Metso. Together with Metso’s Circored team, we have made our own green crude steel in laboratory scale tests. In the Metso Frankfurt Research Center in Germany, hydrogen reduced DRI was developed, shipped to Finland and further smelted in the Pori Research Center with induction furnaces. See below for produced green pig iron and green crude steel samples. These kinds of tests have been performed for internal use but also for several customers in iron mining and steel manufacturing fields for their own raw materials.
Similar to these laboratory scale tests, pilot scale tests were also performed at the Pori Research Center utilizing 2MW AC-furnace equipment. As a raw material, tests were performed with natural gas reduced, high-grade DRI pellets. The aim for these tests was to collect information of material smelting behaviour and understand how produced hot metal can be carburized within the smelting process. As a result, the process works how it is designed. To ensure customer specific requirements, more testing and research will be done.
One of the most important tasks for us while developing the DRI Smelting Furnace was participating in iron and steel conferences, aiming to show our capabilities and know-how to support the industry towards decarbonization. A good example is our presence at the METEC exhibition, held in Duesseldorf, Germany in June 2023. Together with Estad scientific conference, we were able to meet and discuss with our customers and partners from different areas. At the Estad conference, our Senior Sales Manager, Timo Haimi, presented our technology and simulation results to the experienced audience and received excellent feedback. Similarly, we were enjoying presentations from our competitors, researchers, and customers, and are always eager to learn and grow from industry experts.
Many iron ore miners and steel producers from around the world have shown great interest in our processes, and several studies of different levels have been completed within this past year, some together with Metso’s Circored team.
Metso’s work with the DRI Smelting Furnace and helping with the decarbonisation of the iron and steel industry continues. As of today, the entire DRI team is fully booked with customer cases. There are also numerous studies and requests ongoing and continuing at the Basic Engineering phase. Future conference papers are under preparation, with more to come in showcasing this technological innovation.
