Metso Full portfolio Open Slag Bath Smelting Plant
Get higher metal recovery, lower raw material consumption, and low CO₂ and dust emissions with Metso's Outotec Open Slag Bath Smelting Plant.

Get higher metal recovery, lower raw material consumption, and low CO₂ and dust emissions. Our open slag bath smelting furnace is a closed-type, environmentally friendly, and energy efficient solution.

  • Minimizes energy, coke, and electrode paste consumption    
  • Enables high productivity and metals recovery    
  • Offers low operational costs and low CO₂ and dust emissions    
  • Improves electrode life with a robust design    
  • Allows for a clean working environment    
  • Enables effective utilization of cleaned CO gas in different plant applications
open slag bath smelting plant

Metso's Outotec open slag bath smelting furnace is a closed furnace that offers high productivity and efficiency in a sustainable way. It is robust, safe, and easy to operate. The furnace is custom designed for each individual application and the optimized furnace and feed system layout makes it a highly cost-efficient solution.


  • Raw material is reduced at high temperature with carbon reductant such as anthracite or coke    
  • Alloy sinks to the bottom and slag floats to the top – these are tapped intermittently through dedicated tap holes    
  • Off-gas, mainly carbon monoxide, is cleaned and can be reused as combustible fuel

We offer a range of furnace roof designs to suit different applications. A closed-roof solution makes smelting and maintenance safer. There are two types of roofs depending on the application and furnace size: a roof with water-cooled copper elements or roof with suspended bricks. The gas-tight sealing guarantees low emissions and efficient collection and utilization of CO gas.

Shells cooled by water film or copper cooling element, as well as forced air in the bottom of the furnace ensure effective cooling. The combination of the conductive lining and effective cooling forms an autogenous freeze layer on the hot face of the lining, which minimizes lining erosion and improves thermal efficiency.

High availability and low specific energy consumption is guaranteed by high quality materials and the easy-to-maintain design. Metso's Outotec open slag bath smelting plant is suitable for a wide range of commodities and applications, including:

  • Ilmenites (Ti) and titaniferous magnetites (Ti, V)    
  • Laterites (Ni)
  • Slag cleaning (Co, Cu, Ni, V)
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