The objectives of this study were to develop a reliable thermodynamic model for the Nd-F system based on critical review and experimental studies. The SIT model was used to convert concentration constants reported in the literature to constants at zero ionic strengths for cross comparison and selection of reliable values. The critically evaluated thermodynamic constants for the formation of NdF2+ and NdF2+ were then used to interpret the extensive NdF3(cr) solubility data in NaF and NH4F solutions, ranging in concentrations from extremely low values to as high as 1.0 mol.kg-1, equilibrated for different periods ranging up to as long as 72 days. These efforts have resulted in log ßn0 for the reaction [Nd3+ + nF- = NdFn3-n] of (3.81 ± 0.10), (5.89 ± 0.77), and
Revised: September 23, 2013 |
Published: August 1, 2013
Citation
Rai D., D. Rai, M. Yui, A. Kitamura, H. Yoshikawa, and A.R. Felmy. 2013.Thermodynamic Model for the Solubility of NdF3(cr) in the Na-NH4-Nd-F-H2O System at 25°C.Journal of Solution Chemistry 42, no. 7:1500-1517.PNNL-SA-91840.doi:10.1007/s10953-013-0049-z