Chemistry of the Extraction of La(NO3)3 and Ce(NO3)3 from Nitrate Solutions with Mixtures of Tri-n-Octylmethylammonium Nitrate and Tri-n-Butyl Phosphate in Toluene

Separation of Rare-Earth Elements from Nitrate Solutions by Solvent Extraction Using Mixtures of Methyltri-n-octylammonium Nitrate and Tri-n-butyl Phosphate

“…Isomolar series [14] S.I. Stepanov et al applied an approach that allows definition of the variety of extractable compounds in a wide range of a mixture's molar ratios of lanthanide and solvents [15][16][17]. In studies [16,17], the SE chemistry of La(III), Ce(III), Pr(III), and Nd(III) using TOMANO 3 -TBP mixtures was investigated applying a wide range of changes in their molar ratios in toluene solutions using the isomolar series method.…”

“…Stepanov et al applied an approach that allows definition of the variety of extractable compounds in a wide range of a mixture's molar ratios of lanthanide and solvents [15][16][17]. In studies [16,17], the SE chemistry of La(III), Ce(III), Pr(III), and Nd(III) using TOMANO 3 -TBP mixtures was investigated applying a wide range of changes in their molar ratios in toluene solutions using the isomolar series method. By studying the SE of these four REEs using TOMANO 3 -TBP mixtures, the manifestation of a synergistic effect (S Ln ) was established, and the areas of synergistic SE and the compositions of extractable mixed complexes in maxima on the curves S Ln = f (composition of the mixture) were determined.…”

“…The SE of La(III) from a solution containing 0.88 mol/L La(NO 3 ) 3 , 4.0 mol/L NH 4 NO 3 , and 0.01 mol/L HNO 3 using 1.0 mol/L isomolar mixtures of TOMANO 3 -TBP in toluene was accompanied by the manifestation on the synergetic curve of two maxima corresponding to the formation of the complexes (R 4 N)[La(NO 3 ) 4 •(2-3)TBP] and (R 4 N) 2 [La(NO 3 ) 5 •2TBP] for synergetic compositions 0.15 mol/L TOMANO 3 -0.85 mol/L TBP and 0.9 mol/L TOMANO 3 -0.1 mol/L TBP [16].…”

“…. The synergic SE domain ranged from the composition 0.2 mol/L TOMANO 3 -0.8 mol/L TBP to 0.7 mol/L TOMANO 3 -0.3 mol/L TBP [16].…”

“…According to most of the research cited above on the extraction of REE nitrates by mixtures of quaternary ammonium nitrates and neutral organophosphorus compounds (NOPC) [16][17][18][19][20][21][22][23], the general formula of the resulting compounds can be written as follows: (R 4 N) n [Ln(NO 3 ) 3+n •mS], where S is the NOPC molecule, n = 1-3, m = 1-4. Various studies have shown that the nitrate groups of TOMANO 3 and phosphoryl groups of NOPC are included in the internal coordination sphere of the mixed complex.…”