DETERMINATION OF LANTHANIDES IN KOLA NITROPHOSPHATE SOLUTION BY CATION-EXCHANGE ION CHROMATOGRAPHY

Lanthanides and yttrium are present in Kola phosphate rock. Digestion of this rock with concentrated nitric acid in the Odda process of fertilizer production leads to the dissolution of these metals in the resulting nitrophosphate solution. This nitrophosphate solution is considered as a complex analytical matrix. In this paper, we present an analytical method with a total analysis time of 18 min for the direct determination of lanthanides and yttrium in the above nitrophosphate solution, based on cation-exchange ion chromatography. The analytical columns involved in this method are silica-based cation exchanges. Elution was carried out with a concentration gradient of HIBA (alpha-hydroxyisobutyric acid) at a pH range between 3.8 and 4.2, coupled with post-column spectrophotometric detection with PAR or ARSENAZO III at 530 and 658 nm respectively. These silica columns can also offer the direct analysis of lanthanides in organic solutions taken from experimental research samples, investigating the extraction of these metals from the nitrophosphate solution by liquid-liquid extraction.