EFRT M-12 Issue Resolution: Caustic-Leach Rate Constants from PEP and Laboratory-Scale Tests

Mahoney, Lenna A. ; Rassat, Scot D. ; Eslinger, Paul W. ; Aaberg, Rosanne L. ; Aker, Pamela M. ; Golovich, Elizabeth C. ; Hanson, Brady D. ; Hausmann, Tom S. ; Huckaby, James L. ; Kurath, Dean E. ; Minette, Michael J. ; Sundaram, S. K. ; Yokuda, Satoru T.

Pacific Northwest National Laboratory (U.S.)

关键词: Gibbsite;    Leaching;    Flowsheets;    Radioactive Waste Processing;    Chemical Reaction Kinetics;   

DOI  :  10.2172/973409
RP-ID  :  PNNL-18502 Rev 1
RP-ID  :  AC05-76RL01830
RP-ID  :  973409

美国|英语

来源: UNT Digital Library

【 摘 要 】

Pacific Northwest National Laboratory (PNNL) has been tasked by Bechtel National Inc. (BNI) on the River Protection Project-Hanford Tank Waste Treatment and Immobilization Plant (RPP-WTP) project to perform research and development activities to resolve technical issues identified for the Pretreatment Facility (PTF). The Pretreatment Engineering Platform (PEP) was designed, constructed and operated as part of a plan to respond to issue M12, “Undemonstrated Leaching Processes” of the External Flowsheet Review Team (EFRT) issue response plan.( ) The PEP is a 1/4.5-scale test platform designed to simulate the WTP pretreatment caustic leaching, oxidative leaching, ultrafiltration solids concentration, and slurry washing processes. The PEP replicates the WTP leaching processes using prototypic equipment and control strategies. The PEP also includes non-prototypic ancillary equipment to support the core processing. The work described in this report addresses caustic leaching under WTP conditions, based on tests performed with a Hanford waste simulant. Because gibbsite leaching kinetics are rapid (gibbsite is expected to be dissolved by the time the final leach temperature is reached), boehmite leach kinetics are the main focus of the caustic-leach tests. The tests were completed at the laboratory-scale and in the PEP, which is a 1/4.5-scale mock-up of key PTF process equipment. Two laboratory-scale caustic-leach tests were performed for each of the PEP runs. For each PEP run, unleached slurry was taken from the PEP caustic-leach vessel for one batch and used as feed for both of the corresponding laboratory-scale tests.