m. eskandari nasab

Adsorption of Sc from single and bi-component Sc-Y solutions by Purolite C100Na was studied experimentally and kinetic and thermodynamic characteristics are described. The extended Freundlich isotherm was found to be successful in validating the experimental results. Moreover, the curve fitting the time-dependent data into different kinetics mechanisms showed a satisfactory correlation with the pseudo-second-order model. Binary system resultsshow a decrease in Sc adsorption capacity of the absorbent in presence of secondary ions due to competition for adsorption sites. Furthermore, thermodynamic parameters indicate similarity of reaction mechanisms for both single and binary systems, with Sc absorption adversely affected by temperature. Results from synthetic solutions with an actual Y/Sc ratio of 5 were used for extracting scandium from actual mining copper leach solution by circulating it through a resin column. The results demonstrate a satisfactory collection of Sc ions despite the fivefold concentration of Y over Sc. The elusion studies showed that the yttrium desorption peak occurs before that of Sc which corroborates the adsorption isotherm findings. This results in a 180 mg/L Sc rich solution or 60:1 concentration ratio over the original copper leach solution.

The stoichiometric relation for the extraction of thorium(IV) from acidic nitrate solutions with Cyanex272 was investigated. The effects of the extractant and nitric acid concentrations were studied. The extracted species at three different acidities (low, middle, and high levels) were found to be [Th(NO3)(OH)3.HA], [Th(NO3)(OH)2A.HA], and [Th(NO3)4.HA], respectively, based on the slope analysis method. The results showed that the extraction of thorium follow solvation mechanism in low, 0.001 M and high, 8 M concentration Nitric acid medium. While, in the middle acid conditions, 1 M, is in the form of cation exchange. The extracted Th(IV) species contain one CYANEX 272 molecule in the all acidic ranges.