Evaluation of Ion Exchange Materials in K Basin Floor Sludge and Potential211 Solvents for PCB Extraction from Ion Exchange Materials

摘要

Approximately 73 m(sup 3) of heterogeneous solid material, 'sludge' (upper bound211u001eestimate, Packer 1997) have accumulated at the bottom of the K Basins in the 100 211u001eK Area of the Hanford Site. This sludge is a mixture of spent fuel element 211u001ecorrosion products, ion exchange materials (organic and inorganic), graphite-211u001ebased gasket materials, iron and aluminum metal corrosion products, sand, and 211u001edebris (Makenas et al. 1996, 1997). In addition, small amounts of polychlorinated 211u001ebiphenyls (PCBs) have been found. These small amounts are significant from a 211u001eregulatory standpoint. Ultimately, it is planned to transfer the K Basins sludge 211u001eto the Hanford double shell tanks (DSTs). Chemical pretreatment is required to 211u001eaddress criticality issues and the destruction or removal of PCBs before the K 211u001eBasin sludge can be transferred to the DSTs. Eleven technologies have been 211u001eevaluated (Papp 1997) as potential pretreatment methods. Based on the evaluations 211u001eand engineering studies and limited testing, Fluor Daniel Hanford recommended 211u001esolvent washing of the K Basin sludge, followed by nitric acid dissolution and, 211u001epotentially, peroxide addition (FDH 1997). The solvent washing (extraction) and 211u001eperoxide addition would be used to facilitate PCB removal and destruction. 211u001eFollowing solvent extraction, the PCBs could be distilled and concentrated for 211u001edisposal as a low-level waste. The purpose of the work reported here was to 211u001econtinue investigating solvent extraction, first by better identifying the ion 211u001eexchange materials in the actual sludge samples and then evaluating various 211u001esolvents for removing the PCBs or possibly dissolving the resins. This report 211u001edocuments some of the process knowledge on ion exchange materials used and 211u001espilled in the K Basins and describes the materials identified from wet sieving 211u001eKE Basin floor and canister sludge and the results of other analyses. Several 211u001ephotographs are included to compare materials and illustrate material behavior. A 211u001esummary of previous tests on solvent extraction of PCB surrogates from simulant K 211u001eBasin sludge is also given.