Subtask 1.7 -- Hot-water extraction of organics, metals, and chlorides from coal and mixed wastes. Semi-annual report, January 1--June 30, 1995

摘要

Supercritical and subcritical water have been demonstrated at the Energy and Environmental Research Center (EERC) to give high removal efficiencies of sulfatic, pyritic, and organic sulfur from coal (IBC-101). Under similar conditions, 78% of the mercury was removed from the coal, indicating that water can be used as an extraction fluid to both reduce the sulfur and hazardous metal content. Water extractions of metal-contaminated soils also demonstrate very high removals of mercury and arsenic, although metals such as vanadium are not efficiently removed. An extraction cell that is reliable for multiple water extractions at conditions up to 450 C and 400 atm has been developed jointly with Keystone Scientific and is now being commercialized. Subcritical water was shown to be an extremely efficient extraction fluid for polychlorinated biphenyls (PCBs) from contaminated soils, and > 99% removal of PCBs can be achieved in as little as 5 minutes. A method for determining the solubility behavior of organics in water up to 400 C and 400 atm has been developed and is currently being evaluated.