Leaching of mercury-containing cement monoliths aged for one year.
A directive from the Swedish Government states that waste containing more than 1% of mercury shall be permanently deposited. The stabilization of mercury by conversion to a sparingly soluble compound like the sulphide is crucial to ensure long-term immobilization in a permanent storage. Immobilization by the solidification/stabilization (S/S) method and possible formation of HgS from mercury oxide or elemental mercury by reaction with a sulphur source (S or FeS) is investigated by a modified version of the NEN 7345 Dutch tank-leaching test. The diffusion of mercury during 11 months from 1-year-old mercury containing monoliths of Portland and slag cement is demonstrated. In a geologic repository under conditions representative of deep granitic bedrock (bicarbonate buffered to pH 8.6), a favourable monolith combination is slag cement with addition of the iron sulphide troilite. The apparent diffusion coefficient of mercury is estimated.
Svensson
Margareta
M
Man-Technology-Environment Research Centre, Orebro University, SE-701 82 Orebro, Sweden. Margareta.Svensson@sakab.se
Allard
Bert
B
D003252:Construction Materials / Q000032:analysis*; D004058:Diffusion; D006256:Hazardous Waste / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D008628:Mercury / Q000032:analysis* / Q000737:chemistry*; D012037:Refuse Disposal / Q000379:methods*; D013548:Sweden; D013997:Time Factors; D014867:Water / Q000737:chemistry*
D006256:Hazardous Waste; D014867:Water; D008628:Mercury