TY - GEN
T1 - PHREEQC modelling of leaching of major elements and heavy metals from cementitious waste forms
AU - Martens, Evelien
AU - Jacques, Diederik
AU - Van Gerven, Tom
AU - Wang, Lian
AU - Mallants, Dirk
N1 - Score = 1
PY - 2008/12
Y1 - 2008/12
N2 - In this study, Ca, Mg, Al, and Pb concentrations leached from uncarbonated and carbonated ordinary Portland cement - dried waste incinerator bottom ash samples during single extraction tests (EN12457 test) at a pH from 1 to 12, were modelled using the geochemical code PHREEQC. A good agreement was found between modelling results and experiments in terms of leached concentrations for Ca, Mg, and Al by defining a single set of pure mineralogical phases for both the uncarbonated and carbonated (three levels) samples. The model also predicted well the observed decrease in Ca leaching with increasing carbonation. Modelling results further revealed that leaching of Pb is not controlled by dissolution/precipitation of pure Pb containing minerals only (carbonates and (hydr)oxides). The addition of solid solutions (calcite-cerrusite and gibbsite-ferrihydrite-litharge solid solutions) and adsorption reactions on amorphous Fe- and Al-oxides improved the model representation of the experimentally observed amphoteric leaching profile of Pb from the cementitious material.
AB - In this study, Ca, Mg, Al, and Pb concentrations leached from uncarbonated and carbonated ordinary Portland cement - dried waste incinerator bottom ash samples during single extraction tests (EN12457 test) at a pH from 1 to 12, were modelled using the geochemical code PHREEQC. A good agreement was found between modelling results and experiments in terms of leached concentrations for Ca, Mg, and Al by defining a single set of pure mineralogical phases for both the uncarbonated and carbonated (three levels) samples. The model also predicted well the observed decrease in Ca leaching with increasing carbonation. Modelling results further revealed that leaching of Pb is not controlled by dissolution/precipitation of pure Pb containing minerals only (carbonates and (hydr)oxides). The addition of solid solutions (calcite-cerrusite and gibbsite-ferrihydrite-litharge solid solutions) and adsorption reactions on amorphous Fe- and Al-oxides improved the model representation of the experimentally observed amphoteric leaching profile of Pb from the cementitious material.
KW - Cementitious waste forms
KW - PHREEQC modelling
KW - Lead leaching
KW - Chemical toxicity
KW - Source term models
KW - Solid-solutions
KW - Surface complexation
KW - Portland cement
UR - http://ecm.sckcen.be/OTCS/llisapi.dll/open/ezp_91304
U2 - 10.1557/proc-1107-475
DO - 10.1557/proc-1107-475
M3 - In-proceedings paper
SN - 9781605110790
T3 - Materials Research Society Symposium Proceedings
SP - 475
EP - 482
BT - Materials Research Society Symposium Proceedings
PB - MRS - Materials Research Society
CY - Warrendale, United States
T2 - MRS 2007 - Materials Research Society - UK
Y2 - 16 September 2007 through 21 September 2007
ER -