Equilibrium Model for Ion Exchange Between Multivalent Cations and Zeolite-A in a Molten Salt

Conference · Sat Oct 01 04:00:00 EDT 2005

DOI:https://doi.org/10.1002/aic.10784· OSTI ID:911756

Phongikaroon, Supathorn; Simpson, Michael

A two-site equilibrium model that previously only accommodated monovalent cations has been extended to include divalent and trivalent cations for ion exchange between zeolite-A and molten chloride salts, a process being considered for concentrating nuclear fission products into high level waste forms. Equilibrium constants were determined by fitting the model to equilibrium data sets for ion exchange between zeolite-A and Cs ternary salt (CsCl-LiCl-KCl), Rb ternary salt (RbCl-LiCl-KCl), Na ternary salt (NaCl-LiCl-KCl), Sr ternary salt (SrCl2-LiCl-KCl), and U ternary salt (UCl3-LiCl-KCl). The results reveal a good fit between the experimental data sets and the model. The two ion exchange sites, framework sites and occluded sites, demonstrate different relative selectivities for the cations. It was found that Sr2_ is the preferred cation in the ion exchange site, and Cs_ is the preferred cation in the occlusion site. Meanwhile, Li_ has the highest combined selectivity when both ion exchange and occlusion sites are considered. Interestingly, divalent and trivalent species are more preferred in the ion exchange site than the monovalent species with the exception of Li_.

• Research Organization: Idaho National Laboratory (INL)
• Sponsoring Organization: DOE - NE
• DOE Contract Number: AC07-99ID13727
• OSTI ID: 911756
• Report Number(s): INL/CON-05-00460
• Country of Publication: United States
• Language: English

Related Subjects

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE WASTES FROM NUCLEAR FACILITIES
CATIONS
CHLORIDES
FISSION PRODUCTS
ION EXCHANGE
MOLTEN SALTS
RUTHERFORD BACKSCATTERING SPECTROSCOPY
WASTE FORMS
ion exchange
molten salt
pyroprocessing
separation
zeolite