Key Info

Basic Information

Prof. Dr. Karl Bernhard Friedrich
Faculty / Institution:
Georesources and Materials Engineering
Project duration:
01.01.2021 to 31.12.2023
EU contribution:
3.339.905 euros


SisAl Slag Valorisation


Silicon and High Purity Alumina (HPA) are vital raw materials for the transition to the low carbon society; silicon as a dominant photovoltaic (PV) material for solar energy applications and as an important ingredient in light-weight applications (automotive and others), while HPA is a key material in Light Emitting Diodes (LEDs) and increasingly in Lithium Ion Batteries (LIBs). Unfortunately, both Si and HPA are today produced non-sustainably; for each tonne of Si you make a lot more CO2, plus harmful pollutants. Similarly, HPA is today made from ultrapure primary aluminium, having a large CO2 footprint.

The promise of the SisAl process is to resolve this problem of non-sustainable raw materials, by replacing carbon with secondary aluminium sources (scrap, dross) as reductant for Si production from quartz (SiO2), and in parallell making an intermediate slag which is a perfect precursor for HPA processing. By introducing integrated CO2 looping, the already superior low CO2 footprint of the SisAl process is strengthened. Elkem (Si), SiQAl & Mytilineos (HPA), and Calef (CO2 looping) will commercialise the technologies and products (Si & HPA) for the benefit of end users requiring sustainable raw materials with a minimal environmental and CO2 footprint.

With the SisAl process the transformation to a low carbon circular economy and other key challenges are turned upside down into new European opportunities. Carbon leakage means moving industry to countries with less strict emission regulations, giving no positive or even negative effects on global emissions. A reversed carbon leakage would be to move industry back to Europe, and by replacing just one traditional silicon smelter in China with a new SisAl smelter in Europe, we have estimated that 50 million Euros will be saved annually in avoided societal emission costs.


  • Norwegian University of Science and Technology NTNU, Norway (Coordinator)
  • BNW Energy, Norway
  • Consorzio per la Ricerca e lo Sviluppo delle Applicazioni Industriali del Laser e del Fascio Elettronico e dell’Ingegneria di Processo, Materiali, Metodi e Tecnologie di Produzione, Italy
  • Elkem AS Technology Kristiansand, Norway
  • ENALOS Research and Development, Greece
  • Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V., Germany
  • MYTILINEOS S.A., Greece
  • National Technical University of Athens NTUA, Greece
  • SiQAl UG, Germany
  • Walter Tosto, Italy
Logo Supported by RawMaterials and European Union