This work presented the results of tungstic precipitation from Na2WO4-Na2SO4-H20 system at 293.15 K, with which the Pitzer parameters of β（0）Na2wo4 and β（1）Na2wo4 were determined from Pitzer equation by regressi...This work presented the results of tungstic precipitation from Na2WO4-Na2SO4-H20 system at 293.15 K, with which the Pitzer parameters of β（0）Na2wo4 and β（1）Na2wo4 were determined from Pitzer equation by regression. Thus the mean ionic activity coeffi- cients of sodium tungstate were calculated. The obtained β（0）Na2wo4 and β（1）Na2wo4 were substituted as fixed values in extraction modeling from Na2WO4-H2SO4-H20 system by primary amine （N1923） in toluene as diluent. Meanwhile the activity coeffi- cient expressions in organic phase were varied based on Pitzer theory that the interaction term for the solvent should not be in- cluded. The Pitzer parameters for organic phase were re-regressed in order to make the model more accurate. The average ab- solute relative deviation （AARD） for calculated and experimental molality of WO42 in aqueous phase was 5.24%. The results showed that the model can not only correlate but also predict the liquid-liquid equilibrium （LLE） data.展开更多
By measuring the vapor-liquid equilibrium of ethanol-hexamethylene-NaI and testing the data using the ternary Gibbs-Duhem equation,the experimental results of the vapor-liquid equilibrium with thermodynamics consisten...By measuring the vapor-liquid equilibrium of ethanol-hexamethylene-NaI and testing the data using the ternary Gibbs-Duhem equation,the experimental results of the vapor-liquid equilibrium with thermodynamics consistency are obtained.Applying the Pitzer equation of the activity coefficients of 1-1 type electrolyte to non-aqueous mixed solvents,each parameter of the equation was obtained by the method of least squares.The calculation results show that the activity coefficients of NaI in ethanol-hexamethylene system with constant composition decrease as its concentration increases.This method is adapted to determination of electrolytical activity coefficients in non-aqueous solvents.展开更多
基金supported by the National Natural Science Foundation of China(21206168,51178446)
文摘This work presented the results of tungstic precipitation from Na2WO4-Na2SO4-H20 system at 293.15 K, with which the Pitzer parameters of β（0）Na2wo4 and β（1）Na2wo4 were determined from Pitzer equation by regression. Thus the mean ionic activity coeffi- cients of sodium tungstate were calculated. The obtained β（0）Na2wo4 and β（1）Na2wo4 were substituted as fixed values in extraction modeling from Na2WO4-H2SO4-H20 system by primary amine （N1923） in toluene as diluent. Meanwhile the activity coeffi- cient expressions in organic phase were varied based on Pitzer theory that the interaction term for the solvent should not be in- cluded. The Pitzer parameters for organic phase were re-regressed in order to make the model more accurate. The average ab- solute relative deviation （AARD） for calculated and experimental molality of WO42 in aqueous phase was 5.24%. The results showed that the model can not only correlate but also predict the liquid-liquid equilibrium （LLE） data.
文摘By measuring the vapor-liquid equilibrium of ethanol-hexamethylene-NaI and testing the data using the ternary Gibbs-Duhem equation,the experimental results of the vapor-liquid equilibrium with thermodynamics consistency are obtained.Applying the Pitzer equation of the activity coefficients of 1-1 type electrolyte to non-aqueous mixed solvents,each parameter of the equation was obtained by the method of least squares.The calculation results show that the activity coefficients of NaI in ethanol-hexamethylene system with constant composition decrease as its concentration increases.This method is adapted to determination of electrolytical activity coefficients in non-aqueous solvents.
