Study of the leaching behaviour of ladle slags by means of leaching tests combined with geochemical modelling and mineralogical investigations.
In this study, the leachability of freshly produced ladle slag derived from both austenitic and ferritic stainless steel production, and from electrical and structural steel production, was investigated, in order to determine whether variations in the chemical and mineralogical composition of these slags affect their leaching behaviour. The effect of the method used for slag cooling was also studied. The results obtained by using the single batch test were combined with those obtained by means of more sophisticated characterisation leaching tests, which, in combination with geochemical speciation modelling, helped to better identify the release mechanisms and phases that control the release of individual elements. It was found that, although variations in the chemical composition of the slag can affect the slag's minerology, neither such variations, nor the choice of the slag cooling treatment, have a significant effect on the leachability of individual elements, since the leaching is governed by surface phenomena. In fact, the mineral transformations on the slag surface, rather than the bulk mineral composition, dictate the release of these elements from the ladle slag. The solubility-controlling phases were predicted by multi-element modelling, and verified to the extent made possible by the performed mineralogical investigations.
Acroni, d. o. o., Cesta Borisa Kidriča 44, SI-4270 Jesenice, Slovenia. Electronic address: mojca.loncnar@acroni.si.
Mojca
M
Loncnar
Hans van der Sloot Consultancy, Dorpsstraat 216, 1721 BV Langedijk, The Netherlands, The Netherlands.
Hans A
HA
van der Sloot
Slovenian National Building and Civil Engineering Institute, Dimičeva cesta 12, SI-1000 Ljubljana, Slovenia.
Ana
A
Mladenovič
Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, SI-1000 Ljubljana, Slovenia.
Marija
M
Zupančič
Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, SI-1000 Ljubljana, Slovenia.
Lara
L
Kobal
Faculty of Chemistry and Chemical Technology, University of Ljubljana, Večna pot 113, SI-1000 Ljubljana, Slovenia.
Peter
P
Bukovec
Geochemical speciation; Ladle slag; Leaching; Mineralogy; Slag cooling treatment