DEVELOPMENT OF A KINETIC MODEL OF BOEHMITE DISSOLUTION IN CAUSTIC SOLUTIONS APPLIED TO OPTIMIZE HANFORD WASTE PROCESSING

DISSELKAMP RS

关键词: AR FACILITIES;    HANFORD RESERVATION;    HIGH-LEVEL RADIOACTIVE WASTES;    RADIOACTIVE WASTE PROCESSING;    ALUMINIUM OXIDES;    LEACHING;    KINETIC EQUATIONS;    HYDROXIDES;    CONCENTRATION RATIO;    TEMPERATURE DEPENDENCE;    SPECIFIC SURFACE AREA;    SOLUTES;    ACTIVATION ENERGY;    DISSOLUTION;    SAVANNAH RIVER PLANT;    SLUDGES;   

DOI  :  10.2172/1004085
RP-ID  :  RPP-RPT-45806 Rev 0
PID  :  OSTI ID: 1004085
Others  :  TRN: US1101210

学科分类：核能源与工程

美国|英语

来源: SciTech Connect

【 摘 要 】

Boehmite (e.g., aluminum oxyhydroxide) is a major non-radioactive component in Hanford and Savannah River nuclear tank waste sludge. Boehmite dissolution from sludge using caustic at elevated temperatures is being planned at Hanford to minimize the mass of material disposed of as high-level waste (HLW) during operation of the Waste Treatment Plant (WTP). To more thoroughly understand the chemistry of this dissolution process, we have developed an empirical kinetic model for aluminate production due to boehmite dissolution. Application of this model to Hanford tank wastes would allow predictability and optimization of the caustic leaching of aluminum solids, potentially yielding significant improvements to overall processing time, disposal cost, and schedule. This report presents an empirical kinetic model that can be used to estimate the aluminate production from the leaching of boehmite in Hanford waste as a function of the following parameters: (1) hydroxide concentration; (2) temperature; (3) specific surface area of boehmite; (4) initial soluble aluminate plus gibbsite present in waste; (5) concentration of boehmite in the waste; and (6) (pre-fit) Arrhenius kinetic parameters. The model was fit to laboratory, non-radioactive (e.g. 'simulant boehmite') leaching results, providing best-fit values of the Arrhenius A-factor, A, and apparent activation energy, E{sub A}, of A = 5.0 x 10{sup 12} hour{sup -1} and E{sub A} = 90 kJ/mole. These parameters were then used to predict boehmite leaching behavior observed in previously reported actual waste leaching studies. Acceptable aluminate versus leaching time profiles were predicted for waste leaching data from both Hanford and Savannah River site studies.