The influence of iron oxide on the chromium leachability of EAF slag: a full-scale study at Ovako Hofors
2012 (English)In: Scanmet IV: 4th International Conference on Process Development in Iron and Steelmaking, Luleå: MEFOS , 2012, Vol. 2, 329-338 p.Conference paper (Refereed)
Ovako Hofors has adopted a zero-waste vision. The purpose of this vision is to identify application areas for all residues as alternatives to deposition. In terms of tonnage, the largest residue from the steel production at Ovako in Hofors is the slag from the electric arc furnace, EAF. The properties of EAF slag make it an excellent construction material, for instance, as an aggregate in asphalt. The leaching of chromium must be controlled if the slag is to be used as construction material in an environmentally friendly way. Ovako Hofors is actively working to keep the leaching of chromium at a low level. Progress has been made earlier by introducing dolomite in the slag forming agents. Phases capable of stabilising chromium are spinels and solid solution of MgO. The aim of this work is to investigate if it is possible to completely prevent leaching of chromium by stabilising the solid solution of MgO by increasing the FeO content.All the experiments were performed in the EAF at Ovako Hofors. Three different methods to raise the FeO content in the slag were tried and evaluated. Slag produced earlier was used as reference samples. From each test, three different slag samples were collected and analysed. To evaluate the results SEM, XRD, leaching and chemical analyses were conducted.A new oxygen burner increased the iron oxide content, while the other two methods did not show any additional increase. Leaching of chromium could only be detected in a few of the slag samples. Although this makes correlations harder to see, it indicates that a higher FeO content may affect the leaching in a positive way. It was discovered that the leaching of chromium does not depend on the chromium content in the slag, thereby proving the hypothesis that chromium can be bound in stable phases to prevent it from leaching.
Place, publisher, year, edition, pages
Luleå: MEFOS , 2012. Vol. 2, 329-338 p.
Research subject Process Metallurgy
IdentifiersURN: urn:nbn:se:ltu:diva-30528Local ID: 4605cd2b-212a-4cce-be3d-40920c878525ISBN: 978-91-637-0859-6OAI: oai:DiVA.org:ltu-30528DiVA: diva2:1003755
International Conference on Process Development in Iron and Steelmaking : 10/06/2012 - 13/06/2012
Godkänd; 2012; 20120614 (ysko)2016-09-302016-09-30Bibliographically approved