SXLSQI and SXFIT are two modeling programs permitting a thorough interpretation of thermodynamic data. SXFIT is the latest in a series of programs designed to model solvent extraction systems of increasing complexity, with complete freedom to define the constituents from which the composition of each phase is to be specified in the data and from which all species of a model for a system are assumed to be formed.  Activity coefficients in the nonaqueous and aqueous phases, water activity, apparent molar volumes of aqueous species, and solution density needed for the conversion of concentration from the molarity to the molality scale are all taken into account by the program. Over the years, the stoichiometry and speciations involved in many systems have been elucidated. For example, the cesium extraction efficiency of the CSSX process chosen by the USDOE for cesium removal from high-level waste stored at the Savannah River Site can be predicted correctly for varying feed composition. Cesium and strontium extracted using cobalt dicarbollide and polyethylene glycol can also be modeled accurately. And lately, these thermodynamic modeling programs are being used to model europium extraction using TALSPEAK-like conditions, therefore increasing the understanding of the behavior in this complex system. Other examples will also be presented.

Modeling solvent extraction systems using the programs SXLSQI and SXFIT

244th National Meeting (2012)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.