Kinetic studies of aluminum formation in the caustic side solvent extraction (CSSX) process
Naik, Punith Pavoor
This project focused on aluminum precipitation within the Caustic Side Solvent Extraction (CSSX) process at the Savannah River Site (SRS). The CSSX process uses a solvent to separate cesium. In the scrubbing section, the solvent containing cesium is scrubbed with 0.05 M nitric acid to remove soluble sodium and potassium ions. During scrubbing, aluminum precipitation has been observed. Solids precipitation is of concern as solids might erode centrifugal contactor internals and/or plug transfer pipelines. Hence, it is important to identify conditions under which solids precipitation may occur and identify an operating region where solids precipitation is minimized. Room temperature experiments on the CSSX scrubbing process were conducted. Experimental results were compared with predictions from ESP (Environmental Simulation Program). The order and specific rate for the reversible aluminum precipitation reaction were obtained as a function of initial stream dilution and % carryover. The reaction was first order based on regression results.