FLOWSHEET FOR ALUMINUM REMOVAL FROM SLUDGE BATCH 6

Pike, J ; Jeffrey Gillam, J

关键词: AR FACILITIES;    ALUMINIUM;    DISSOLUTION;    FLOWSHEETS;    LIQUID WASTES;    SLUDGES;    RADIOACTIVE WASTE PROCESSING;   

DOI  :  10.2172/945007
RP-ID  :  SRNL-STI-2008-00389
PID  :  OSTI ID: 945007
Others  :  TRN: US0900792

学科分类：核能源与工程

美国|英语

来源: SciTech Connect

【 摘 要 】

Samples of Tank 12 sludge slurry show a substantially larger fraction of aluminum than originally identified in sludge batch planning. The Liquid Waste Organization (LWO) plans to formulate Sludge Batch 6 (SB6) with about one half of the sludge slurry in Tank 12 and one half of the sludge slurry in Tank 4. LWO identified aluminum dissolution as a method to mitigate the effect of having about 50% more solids in High Level Waste (HLW) sludge than previously planned. Previous aluminum dissolution performed in a HLW tank in 1982 was performed at approximately 85 C for 5 days and dissolved nearly 80% of the aluminum in the sludge slurry. In 2008, LWO successfully dissolved 64% of the aluminum at approximately 60 C in 46 days with minimal tank modifications and using only slurry pumps as a heat source. This report establishes the technical basis and flowsheet for performing an aluminum removal process in Tank 51 for SB6 that incorporates the lessons learned from previous aluminum dissolution evolutions. For SB6, aluminum dissolution process temperature will be held at a minimum of 65 C for at least 24 days, but as long as practical or until as much as 80% of the aluminum is dissolved. As planned, an aluminum removal process can reduce the aluminum in SB6 from about 84,500 kg to as little as 17,900 kg with a corresponding reduction of total insoluble solids in the batch from 246,000 kg to 131,000 kg. The extent of the reduction may be limited by the time available to maintain Tank 51 at dissolution temperature. The range of dissolution in four weeks based on the known variability in dissolution kinetics can range from 44 to more than 80%. At 44% of the aluminum dissolved, the mass reduction is approximately 1/2 of the mass noted above, i.e., 33,300 kg of aluminum instead of 66,600 kg. Planning to reach 80% of the aluminum dissolved should allow a maximum of 81 days for dissolution and reduce the allowance if test data shows faster kinetics. 47,800 kg of the dissolved aluminum will be stored in Tank 8 and 21,000 kg will be stored in saltcake via evaporation. Up to 77% of the total aluminum planned for SB6 may be removed via aluminum dissolution. Storage of the aluminum-laden supernate in Tank 8 will require routine evaluation of the free hydroxide concentration in order to maintain aluminum in solution. Periodic evaluation will be established on concurrent frequency with corrosion program samples as previously established for aluminum-laden supernate from SB5 that is stored in Tank 11.