CO2 is an unavoidable by-product from silicon and ferroalloy production in current industrial practice. Replacing carbon with electricity in metal production requires a higher energy consumption, but when using a carbon free electric energy source, the goal of zero CO2 emissions from manganese ferroalloy and silicon production can be reached. The electrolysis process results in production of oxygen gas and relatively pure metals, reducing the need for metal refinement. All-electric production of silicon and manganese would represent a step-change in the decarbonization of Norwegian ferroalloy production, eliminating all process-related CO2-emissions. The products would be globally unique, and attractive as alloying elements in green steel and aluminium.
In the KSP ZeSiM project, we suggest developing CO2-free electrolysis processes for manganese ferroalloys and silicon along two different paths.
- Production of liquid manganese or manganese ferroalloys from manganese oxide using an oxide-based electrolyte. Advantages include a potential for high production rate, utilization of fine-grained materials, and producing the marketable product low carbon ferromanganese (LCFeMn) directly.
- Producing solid silicon plates directly from quartz using a chloride/oxide electrolyte. Advantages are low-cost chemicals, easily harvested product, and relatively low temperatures.
ZeSiM will focus on challenges and knowledge needs related to the electrolysis processes like electrolyte chemistry, metal quality and energy consumption through laboratory experiments and modelling work. Expertise gained through the project is an important step before research and development can be done on materials selection.
SINTEF is the project manager with NTNU as a research partner. Si/FeSi producers Elkem, Wacker and Finnfjord and Mn-alloy producer Eramet are industrial partners through The Norwegian Ferroalloy Research Association (FFF).
The project is funded by the Research Council of Norway.