Liquid-Liquid Extraction and Separation of Pr (III), Nd (III), Sm (III) from Nitric Acid Medium by CYANEX 923 in Kerosene

Extraction of some lanthanides namely, Pr (III), Sm (III) and Nd (III), from 1 M nitric acid using CYANEX 923 in kerosene has been studied at 25 degree C. The effects of the different parameters on the extraction process were separately investigated. On the basis of the slope analysis method of the obtained data, the composition of the different extracted species was found to be [Nd(NO₃)₂(OH).2 CY], [Pr(NO₃)₂(OH).2 CY], and [Sm(NO₃)₂(OH).2 CY]for Nd (III), Pr (III), and Sm (III), respectively, where CY denotes CYANEX 923. The apparent extraction constant values K_ex were found to be 98.38, 128.88, and 181.15 for Pr (III), Nd(III), and Sm(III),respectively. The thermodynamic parameters ΔG, ΔH, and ΔS were calculated. The stripping investigations indicate that mineral acids are the most suitable stripping agents. The separation factors were also calculated and found to decrease in the order S_Sm/Pr > S_Sm/Nd > S_Nd/Pr