Crystalline Silicotitanate ion exchange media long-term storage evaluation

Abstract

Some of the distribution coefficient (K d ) values in Table ES-1 indicate that the measured value exceeds the calculated value. This difference in measured versus predicted is attributed to error in the measurements and reference state of the material. Because of the way that the distribution coefficient is calculated, small variance in measurements of mass and analytical instrument results can cause large changes in the observed value. The predicted distribution coefficients were calculated using the ZAM computer model, which is based on the powdered form of CST, and there is typically an adjustment of the output to account for the dilution factor due to the binder present in IE-911. The absence of the need for a dilution factor adjustment for this batch of material is attributed to different initial conditions for the material such as preconditioning steps and drying. The loading measurements (Q) match the predicted values very well. This Q parameter is less sensitive than the distribution coefficient parameter to slight variance in measurements performed during testing.

Tank Closure Cesium Removal Project CST Simulant Cesium Batch Contact Kinetics Test Results and Column Performance Predictions

“…Cesium loading kinetic data was needed to conduct column performance comparisons (i.e., model predictions) for the two CST batches. a average and %RSD of replicate data b pre-wetted CST c analysis indicated that this data point may be low due to incomplete CST particle wetting during initial simulant contact d data reported previously (King, et. al., 2018a) SRNL-STI-2019-00088 Revision 0 The cesium loading data was analyzed using the ZAM Isotherm and VERSE Column models.…”

“…A sample of IE-911 CST Lot #2081000056 (Mat. #80562-556p, Drum #36232-1-5) stored for many years at SRS was collected from a drum (described in detail in an earlier report, King, et al, 2018a) and sub-sampled for batch contact testing as described above for R9120-B CST. The IE-911 media had been provided by UOP in the caustic-washed, sodium form and was not further preconditioned or treated by SRNL prior to testing.…”

“…To evaluate the cesium removal capabilities of the caustic-washed R9120-B version of crystalline silicotitanate (CST) ion exchange media from Savannah River Site (SRS) waste during Tank Closure Cesium Removal (TCCR) column processing, batch contact kinetics tests were performed at 23 °C in SRS Average simulant. Cesium loading kinetics data was also collected (in current and previous testing; King, et al, 2018a) using the same simulant for an older CST sample (IE-911) which was caustic-washed by the vendor many years ago and was recently retrieved from drums stored at SRS. (Note that R9120-B and IE-911 are believed to be identical materials, after the R9120-B was caustic washed by SRNL, and differ only by particle size and manufacturing date, and thus can be considered different batches).…”

“…CST subsamples were characterized under nitrogen purge gas by Thermal Gravimetric Analysis (TGA) as described in earlier reports (King, et al, 2018a and2018c). The particle size of the R9120-B media was measured using a Microtrac S3500 Laser Diffraction Analyzer.…”

Characterization and CST Batch Contact Equilibrium Testing of Aged TCCR Tank 10H Batch 1A and 2 Process Supernate Samples

“…The R9140-B batch is a recently prepared CST batch while the IE-911 CST media has been stored at SRS for nearly two decades. Recent batch contact testing with the IE-911 CST batch and SRS Average simulant confirmed that the cesium removal performance of this batch had not changed significantly during storage [10].…”