title: Recycling of ladle slag in cement composites: Environmental impacts.
abstract: In the present work compact and ground cement composites in which 30% of cement by mass was replaced by ladle slag were investigated for their chemical and physico-mechanical properties. To evaluate long-term environmental impacts, leachability test based on diffusion, which combined both, diffusion and dissolution of contaminants, was performed in water and saline water. Total element concentrations and Cr(VI) were determined in leachates over a time period of 180days. At the end of the experiment, the mineralogical composition and the physico-mechanical stability of cement composites was also assessed. The results revealed that Cr(III) and Cr(VI) were immobilized by the hydration products formed in the cement composites with the addition of ladle slag. Cr(VI) content originating from the cement was also appreciably reduced by Fe(II) from minerals present in the added ladle slag, which thus had significant positive environmental effects. Among metals, only Mo and Ba were leached in elevated concentrations, but solely in ground cement composites with the addition of ladle slag. Lower V concentrations were observed in leachates of ground than compact composite. It was demonstrated that the presence of ladle slag in cement composites can even contribute to improved mortar resistance. The investigated ladle slag can be successfully implemented in cement composites as supplementary cementitious material.
authors.affiliation: Slovenian National Building and Civil Engineering Institute, Dimičeva 12, 1000 Ljubljana, Slovenia.
authors.forename: Vesna Zalar
authors.initials: VZ
authors.lastname: Serjun
authors.affiliation: Slovenian National Building and Civil Engineering Institute, Dimičeva 12, 1000 Ljubljana, Slovenia.
authors.forename: Ana
authors.initials: A
authors.lastname: Mladenovič
authors.affiliation: University of Ljubljana, Faculty of Natural Sciences and Engineering, Department of Geology, Aškerčeva 12, 1000 Ljubljana, Slovenia.
authors.forename: Breda
authors.initials: B
authors.lastname: Mirtič
authors.affiliation: University of Ljubljana, Faculty of Chemistry and Chemical Technology, Večna pot 113, 1000 Ljubljana, Slovenia.
authors.forename: Anton
authors.initials: A
authors.lastname: Meden
authors.affiliation: Department of Environmental Sciences, Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia.
authors.forename: Janez
authors.initials: J
authors.lastname: Ščančar
authors.affiliation: Department of Environmental Sciences, Jožef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia. Electronic address: radmila.milacic@ijs.si.
authors.forename: Radmila
authors.initials: R
authors.lastname: Milačič
mesh_terms: D001464:Barium / Q000032:analysis / Q000737:chemistry; D002857:Chromium / Q000032:analysis / Q000737:chemistry; D003252:Construction Materials; D004777:Environment; D008669:Metallurgy; D008982:Molybdenum / Q000032:analysis / Q000737:chemistry; D059027:Recycling; D014866:Waste Products
chemical_list: D014866:Waste Products; D002857:Chromium; D001464:Barium; D008982:Molybdenum
keywords: Cement composites; Environmental impacts; Hexavalent chromium; Ladle slag; Physico-mechanical characteristics