Environmental impacts of steel slag reused in road construction: a crystallographic and molecular (XANES) approach.
Basic oxygen furnace (BOF) steel slag is a residue from the basic oxygen converter in steel-making operations, and is partially reused as an aggregate for road constructions. Although BOF slag is an attractive building material, its long-term behaviour and the associated environmental impacts must be taken into account. Indeed BOF slag is mainly composed of calcium, silicon and iron but also contains trace amounts of potential toxic elements, specifically chromium and vanadium, which can be released. The present research focuses (i) on the release of Cr and V during leaching and (ii) on their speciation within the bearing phase. Indeed the mobility and toxicity of heavy metals strongly depend on their speciation. Leaching tests show that only low amounts of Cr, present at relatively high concentration in steel slag, are released while the release of V is significantly high. X-ray absorption near-edge structure (XANES) spectroscopy indicates that Cr is present in the less mobile and less toxic trivalent form and that its speciation does not evolve during leaching. On the contrary, V which is predominantly present in the 4+ oxidation state seems to become oxidized to the pentavalent form (the most toxic form) during leaching.
Chaurand
Perrine
P
CEREGE, UMR 6635 CNRS, University Paul Cézanne, IFR 112 PMSE, Europôle Méditerranéen de l'Arbois, BP 80, 13545 Aix en Provence Cedex 04, France. chaurand@cerege.fr
Rose
Jerome
J
Briois
Valérie
V
Olivi
Luca
L
Hazemann
Jean-Louis
JL
Proux
Olivier
O
Domas
Jérémie
J
Bottero
Jean-Yves
JY
D002857:Chromium / Q000032:analysis*; D003252:Construction Materials / Q000592:standards*; D018360:Crystallography, X-Ray; D004777:Environment; D007220:Industrial Waste; D013057:Spectrum Analysis; D013232:Steel; D014639:Vanadium / Q000032:analysis*; D014965:X-Rays
D007220:Industrial Waste; D014639:Vanadium; D002857:Chromium; D013232:Steel