Concentrating vanadium in spinel phase in steel slags
Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
The slag from the steel converting stage at SSAB (Swedish Steel AB) in Luleå and Oxelösund contains a considerable amount of Vanadium. The vanadium content is however not high enough to be able to sell the slag as a vanadium source. Today half the amount of converter slag produced by SSAB is recycled within the plant while the other half is stored within the plant site. Today there are two process options to increase the vanadium content in the slag, the LUVA-‐ and ViLD-‐process which are explained in this thesis. The vanadium content is however not high enough in these two slags as well. The vanadium is mainly situated in a spinel phase, (Mn,Fe)(Cr,V)2O4, in the LUVA-‐slag which has magnetic properties. One problem with both slags is the relatively high amount of metallic iron in the slags which has to be separated. Other problems are the required limited amount of phosphorus, calcium and silica in the raw material when producing vanadium. The main objective with this thesis is to see if it is possible to use physical separation to increase the vanadium content even further of these two slags, preferably by separating both the metallic iron and the spinel phase from the calcium/silicate phase.Several trials were made on both the LUVA-‐slag and ViLD-‐slag. Both dry magnetic separation and wet magnetic separation were made on each slag. In addition to the magnetic separation there was also wet gravity separation preformed on the LUVA-‐slag.The metallic iron could be separated from the LUVA-‐slag but no considerable concentration of the spinel phase was however made during this thesis. It seems that it is hard to liberate the spinel phase from the calcium/silicate phase. Further investigations proved that controlled cooling of the LUVA-‐ slag increased the spinel size significantly.Like the LUVA-‐slag the metallic iron was quite easily separated from the ViLD-‐slag. And since this slag has overall increased vanadium content no further concentration of vanadium is needed. However, the phosphorous content in the slag was still a bit too high. V/Fe=2,20 and V/P=218 was achieved with wet magnetic separation, while V/P>500 is preferred. Further investigation of this slag in larger scale should be considered in the future.
Place, publisher, year, edition, pages
2012. , 54 p.
Physics Chemistry Maths
Fysik, Kemi, Matematik, Vanadium, Spinel, Controlled cooling, Physical separation
IdentifiersURN: urn:nbn:se:ltu:diva-56422Local ID: d3242606-fb9d-4bd7-9574-e108910a4a87OAI: oai:DiVA.org:ltu-56422DiVA: diva2:1029809
Subject / course
Student thesis, at least 30 credits
Chemical Engineering, master's level
Validerat; 20120213 (anonymous)2016-10-042016-10-04Bibliographically approved