DEVELOPMENT OF A SOLVENTLESS EXTRACTION PROCESS FOR REMOVAL OF TARGET ORGANIC COMPOUNDS FROM SURROGATE TRANSURANIC SLUDGE

摘要

Supercritical fluid extraction (SFE) is proposed as anrnalternative to incineration for treatment of transuranicrnwaste containing problematic organics, such as IDC-003rnOrganic Setup Sludge. This sludge is composed of oils,rnvolatile chlorinated and non-chlorinated solvents, andrnpolychlorinated biphenyls (PCBs) solidified in a calciumrnsilicate matrix. This particular transuranic (TRU) wasterncurrently poses several problems. The IDC-003 sludgerncontains PCBs and as such, the sludge cannot currently bernaccepted by the Waste Isolation Pilot Plant (WIPP).rnSecondly, the Idaho National Engineering andrnEnvironmental Laboratory ( INEEL) is unable to transportrnthe sludge due to the unpredictable presence of hydrogenrngas and the potential on-going generation of hydrogen gasrnby radiolysis of hydrogenous organic compounds.rnSupercritical CO2 is a benign solvent that has been shownrnto effectively remove oils and organic contaminants fromrna variety of matrices such as soils, clays and metallicrndebris and cuttings. The application of this technology tornremove the organic compounds (oils, solvents, and PCBs)rnmay potentially solve both problems leaving 1) therninorganic constituents (including Pu) as an inorganic TRUrnwaste that is reduced in volume and has a low potentialrnfor hydrogen generation during transport, and 2) the oilrnfraction of the waste that will contain the organic solvents and the PCBs, absent the transuranics. These nonradioactivernoils and solvents may easily be destroyed atrnany of several commercial treatment facilities. Arnsolventless extraction process has been developed atrnArgonne National Laboratory (ANL) as a treatmentrnalternative for these previously incinerator-bound wastes.rnLaboratory-scale demonstration tests showed that thernsolventless extraction process was effective in removingrnin excess of 90-100 % of organic species from simulatedrnTRU sludge. Efforts focused on development ofrnextraction conditions and analytical characterizationrnmethods.