Spectrophotometric Determination of Praseodymium by 1,4- Dihydroxyanthraquinone after its Selective Separation from Rosetta Monazite Rare Earth Concentrate by Solvent Extraction

Abstract

A rare earths concentrate of Rosetta monazite assays about 44, 23, 16.94 and 5.91 % for Ce, La, Nd and Pr respectively. Separation of cerium by air oxidation at 200^oC. Selective separation of Pr by D₂EHPA at pH1 followed by a sensitive spectrophotometric method which described for the determination of praseodymium (Pr) with l, 4-dihydroxyanthraquinone. The calibration curve was linear from   0.1 to 12 µgml ^-1 praseodymium. The influences of various parameters and reaction conditions for maximum colour development were investigated. The relative standard deviation for determination of 1 µgml^-1 praseodymium has found to be 1.3 after 5 repeated determinations; percent error 5.02%, molar absorptivity (ε) was 1.23x10⁶M^-1 cm^-1and detection limit was 0.1µgml^-1. The method for determination of praseodymium showed good accuracy and selectivity.