Acta Phys. -Chim. Sin. ›› 1990, Vol. 6 ›› Issue (04): 430-436.doi: 10.3866/PKU.WHXB19900409

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The Thermodynamics of Extraction of Uranyl Nitrate by Bidentate Organophosphorus Extractant Dhdecmp

Yang Xue-Xian   

  1. Institute for Application of Atomic Energy, CAAS, Beijing
  • Received:1989-04-19 Revised:1989-09-24 Published:1990-08-15
  • Contact: Yang Xue-Xian

Abstract: The distribution data for U(Ⅵ) from 0.25-5 mol·L~(-1) nitric acid media with 1--40 V% DHDECMP (dihexyl N,N-diethyl carbamoylmethyl phosphonate) in DEB (diethyl benzene) were determined in the temperature range 288--343 K. From the variation of the distribution ratios with temperature the enthalpy changes associated with the extraction were evaluated. Using extrapolation technique the thermodynamic value of the enthalpy (ΔH°_t) for zero ionic strength was obtained to be -27.5 kJ·mol~(-1). The thermodynamic equilibrium constant (K_t), free energy (ΔG°) and entropy changes (ΔS°) were calculated at 25 ℃ to be 1.15×10~3, -17.5 kJ·mol~(-1) and -33.5 J·mol~(-1)·K~(-1), respectively.