The Leaching Behavior of Cement Stabilized Air Pollution Control Residues: A Comparison of Field and Laboratory Investigations
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- 作者：Isabel Baur ; Christian Ludwig ; and C. Annette Johnson
- 刊名：Environmental Science & Technology
- 出版年：2001
- 出版时间：July 1, 2001
- 年：2001
- 卷：35
- 期：13
- 页码：2817 - 2822
- 全文大小：96K
- 年卷期：v.35,no.13(July 1, 2001)
- ISSN：1520-5851
文摘
The factors controlling leachate composition of cementstabilized air pollution control (APC) residues (41% APCresidues, 22% cement, 3% Na2CO3, and 32% water, w/w)have been investigated both in the laboratory and in a pilotlandfill. Batch leaching and tank leaching tests werecarried out in the laboratory in order to determine solubilitycontrolling phases and diffusion controlled species. Themajor species Ca, SO4, Al, and Si could be partially modeledby assuming calcium silicate hydrate (C-S-H), portlandite,and ettringite to be the solubility controlling phasesboth in field and laboratory. There were obviously additionalminerals that could not be taken into account incalculations because of the lack of data. The determinedeffective diffusion coefficients (De) for Na and K (2.18e-12and 5.43e-12 m2s-1) were used to model field concentrations.Agreement with field data was good. Heavy metalconcentrations were in the range of 10-8 mol dm-1 (Cd,Co, Cu, Mn, Ni) to 10-6 mol dm-1 (Mo, Pb, W, Zn) in allexperiments and often lower in the field leachate thanexpected from batch experiments. In laboratory experiments,the solubility of Mo and W was most probably controlledby their calcium metalates, Cu by CuO, Ni by Ni(OH)2, and Znprobably by a Zn containing C-S-H phase. In the field,diffusion seems to control Mo and W leachability, withcalculated De values of 3.49e-14 and 1.35e-15 m2 s-1.