Solvent extraction of lanthanides and yttrium from nitrate medium with CYANEX 925 in heptane

The extraction behavior of lanthanides and yttrium usinsg CYANEX 925 (mixture of branched chain alkylated phosphine oxides) in n-heptane from nitrate medium has been studied. The effects of aqueous phase ionic strength, CYANEX 925 concentration in the organic phase, and temperature on Sm3+, Nd3+ and Y3+ extraction have been investigated. The extractability of the lanthanides and yttrium increases with increasing nitrate concentration, as well as with increasing CYANEX 925 concentration. An extraction mechanism is proposed based on slope analysis. Furthermore, the infra-red spectra of CYANEX 925 saturated with lanthanides are employed to provide evidence of the composition of the complex. The relationship between the logarithm of the distribution ratio and lanthanide atomic number is also discussed which indicates that yttrium can be separated from fight lanthanides. In addition separation of the light and heavy lanthanide groups is also possible using CYANEX 925. From the temperature dependence data, the thermodynamic parameters values (Delta H, Delta S and Delta G) are calculated.

The extraction and separation of Ho, Y, and Er(III) with the mixtures of Cyanex 302 and another organic extractant

The extraction and separation of Ho, Y, and Er(III) with the mixtures of bis(2,4,4-trimetylpentyl)monothiophosphinic acid (Cyanex 302) and another organic extractant, such as acidic organic extractant (di-2-ethylhexyl phosphoric acid P204, 2-ethythexyl phosphoric acid mono-2-ethylhexyl ester P507, di-2-ethylhexyl phosphinic acid P229, and sec-nonylphenoxy acetic acid CA-100), neutral organic extractant (tri-n-butyl phosphate TBP, di-(1-metylheptyl)metyl phosphate P350, and branched trialkylphosphinic oxide Cyanex 925) or primary amine N1923, has been investigated in this paper. The extractability and separation ability for the Ho, Y, and Er with the mixtures of Cyanex 302 and organic extractants has been compared. The synergistic effect of the Ho, Y, and Er extraction with the mixtures of Cyanex 302 and P229, Cyanex 925, CA-100, or N1923 has been explored and the synergistic enhancement coefficients have been calculated. At last, the Y3+ synergistic extraction with the mixtures of Cyanex 302 and CA-100 has been determined and the extracted complex has been deduced.

Extraction kinetics of Sc(III), Y(III), La(III) and Gd(III) from chloride medium by Cyanex 302 in heptane using the constant interfacial cell with laminar flow

The extraction kinetics of Sc, Y, La and Gd(III) from the hydrochloric acid medium using Cyanex 302 (hereafter HL) in heptane solution have been measured by the constant interfacial cell with laminar flow. Reaction regions are explored at liquid-liquid interface. Extraction regimes are deduced to be diffusion-controlled for Sc(Ill) and mixed controlled for Y, La and Gd(Ill). Extraction mechanisms are discussed according to the dimeric model of Cyanex 302 in non-polar solution. From the temperature dependence of rate measurement, the values of E-a, Delta H-+/-, Delta S-+/- and Delta G(300)(+/-) are calculated and it is found that the absolute values of these parameters keep crescent trend for Sc, Y, La and Gd(III). At the same time, it is found that it can easily achieve the mutual separation among the Sc, Y and La(III) with kinetics extraction methods.