Mass transfer and extraction kinetics of yttrium with the purified Cyanex 923 in n-heptane from nitrate medium have been investigated by using a constant interfacial cell with laminar flow at 298K. The interfacial ads...Mass transfer and extraction kinetics of yttrium with the purified Cyanex 923 in n-heptane from nitrate medium have been investigated by using a constant interfacial cell with laminar flow at 298K. The interfacial adsorption properties of purified Cyanex 923-heptane-0.20mol/L (H, Na)NO3 were studied at 298K. The experimental results show that the mass transfer is controlled by diffusion and the chemical reactions are carried out in the interfacial zone. The extraction rates of yttrium were measured at different chemical compositions by varying ionic strength, pH values and the purified Cyanex 923 concentrations. The initial extraction rate equations were obtained.展开更多
Ce 4+ extraction rate from aqueous sulphate solutions by Cyanex923 in heptane was studied using a constant interfacial cell with laminar flow at 30 ℃. The experimental hydrodynamic conditions were chosen and the...Ce 4+ extraction rate from aqueous sulphate solutions by Cyanex923 in heptane was studied using a constant interfacial cell with laminar flow at 30 ℃. The experimental hydrodynamic conditions were chosen and the contribution of diffusion to the measured rate of reaction was minimized. Cerium extraction rate was measured at different chemical composition by varying the concentrations of hydrogen ion, sulphate and Cyanex923. A cerium Cyanex923(B) extractive is formed at the interface. The data were analyszed in terms of pseudo first order constants and a reaction mechanism was developed.展开更多
The extraction and stripping of ytterbium（ Ⅲ） from sulfuric acid medium using Cyanex 923 in heptane solution was investigated. The effects of extraetant concentration, pH and sulfate ion as well as stripping agents...The extraction and stripping of ytterbium（ Ⅲ） from sulfuric acid medium using Cyanex 923 in heptane solution was investigated. The effects of extraetant concentration, pH and sulfate ion as well as stripping agents, acidity and temperature on the extraction and stripping were studied. The equilibrium constants and thermodynamic parameters, such as △n （10.76 kJ·mol^-1）, △G （-79.26 kJ·mol^-1） and △S （292.41 J·K^-1·mol^-1）, were calculated. The extraction mechanism and the complex species extracted were determined by slope analysis and FTIR spectra. Furthermore, it was found that the extraction of Yb （Ⅲ） from sulfuric acid medium by Cyanex 923 increased with pH, concentration of SO4^2-, HSO4^-, and extractant concentration, and approximately a quantitative extraction of Yb（ Ⅲ） was achieved at an equilibrium pH near 3.0, and the extracted complex was YbSO4（HSO4）·2Cyanex923（o）.展开更多
The effect of boric acid on the extraction of bastnasite leaching liquor by Cyanex 923 was studied. Boric acid wasn’t extracted alone by Cyanex 923 and didn’t influence the cerium(IV) extraction. But it can enhance ...The effect of boric acid on the extraction of bastnasite leaching liquor by Cyanex 923 was studied. Boric acid wasn’t extracted alone by Cyanex 923 and didn’t influence the cerium(IV) extraction. But it can enhance the extraction of hydrofluoric acid evidently and came into organic phase in form of (HF)(H3BO3).(Cyanex 923).展开更多
A mathematical model was developed to monitor the facilitated transport of germanium(IV) from oxalic acid solutions through a flat sheet supported liquid membrane(FSSLM) containing four trialkylphosphine oxides(Cyanex...A mathematical model was developed to monitor the facilitated transport of germanium(IV) from oxalic acid solutions through a flat sheet supported liquid membrane(FSSLM) containing four trialkylphosphine oxides(Cyanex 923). The FSSLM modeling was based on the extraction constant(Kext) calculated from the liquid-liquid extraction(LLX) modeling. The LLX model presented a reliable calculation of the extraction constant(Kex= 2.057×103 L/mol4). The FSSLM model was solved using Matlab■ software according to extraction constant, Fick’s law, and diffusional principles. The model predicts the overall mass transfer coefficient(Korg) to be 3.84 cm/s. Using this value, diffusion coefficients(Dm) for various Cyanex 923 concentrations of 0.126, 0.252, 0.378, 0.505, 0.631 and 0.757 mol/L are found to be 8.50×10^-4, 4.30×10^-4, 1.87×10^-4, 5.87×10^-5, 2.57×10^-5, 2.09×10^-5 cm2/s, respectively. The results show that the diffusion rate of the current study is approximately more than that of similar FSSLM systems containing Cyanex 923 used to transport various metals. The modeling values are in good agreement with the experimental data, showing the good reliability of the mathematical model.展开更多
The extraction of Yttrium (Ⅲ) into [Cnmim][PF6] (n= 4, 6, 8) containing Cyanex 923 was studied in this paper. The mechanism of this extraction was indicated to be cation exchange. In addition, the extraction process ...The extraction of Yttrium (Ⅲ) into [Cnmim][PF6] (n= 4, 6, 8) containing Cyanex 923 was studied in this paper. The mechanism of this extraction was indicated to be cation exchange. In addition, the extraction process is an endothermic reaction. The RTILs with shorter alkyl chain behave higher extraction efficiency during the extraction, however, which has also more loss to aqueous phase since the cation exchange mechanism.展开更多
Solvent extraction kinetics of lanthanum with purified Cyanex 923 in heptane from nitrate medium was investigated by using a constant interfacial cell with laminar flow at 303 K. The effects of stirring speed, tempera...Solvent extraction kinetics of lanthanum with purified Cyanex 923 in heptane from nitrate medium was investigated by using a constant interfacial cell with laminar flow at 303 K. The effects of stirring speed, temperature and specific interface on the extraction rate were studied. The experimental results showed that the extraction apparent activation energy was 32.0 kJ\5mol -1 and the extraction process was controlled by both chemical reaction and diffusion. The extraction rates were measured at different chemical compositions by varying ionic strength, pH value and the concentration of purified Cyanex 923. The initial extraction rate equation was obtained.展开更多
The solvent extinction behavior Of Th(Ⅳ) and Ce(Ⅳ) with Cyanex 925 in nhexane hem nitric acid medium was studied. The extinction mechanisms of Th(Ⅳ)and Ce(Ⅵ) by Cyanex 923 were determined by the method of slope an...The solvent extinction behavior Of Th(Ⅳ) and Ce(Ⅳ) with Cyanex 925 in nhexane hem nitric acid medium was studied. The extinction mechanisms of Th(Ⅳ)and Ce(Ⅵ) by Cyanex 923 were determined by the method of slope analysis, and the extracted species might be Th(NO3)4.S(Cyanex 923)(o) and Ce(NO3)4.2(Cyanex 923)(o). The extraction characteristics with purified Cyanex 925 and commercial Cyanex 925 were compared. Results showed Ce(Ⅳ) and Th(Ⅳ) could be separted with Cyanex 923 hem RE(Ⅲ) in nitric acid solution. The influence of temperature on the Th(Ⅳ) extinction was investigated and the thermodynamic functions were calculated.展开更多
The extraction of zirconium (IV) from aqueous HCl solution by binary mixture TOA and Cyanex 923 using kerosene as diluent was studied. The effect of parameters like aqueous phase acid concentration, extractant concent...The extraction of zirconium (IV) from aqueous HCl solution by binary mixture TOA and Cyanex 923 using kerosene as diluent was studied. The effect of parameters like aqueous phase acid concentration, extractant concentration, chloride ion concentration, diverse ion effect, metal loading, nature of diluents and temperature on the extraction of Zr (IV) was investigated. The percentage of extraction of Zr(IV) became 100% with 0.1 M TOA and 0.01 M Cyanex 923 from 7 M HCl and also from 4 M HCl with 0.1 M TOA and 0.02 M Cyanex 923. Benzene was found to be effective diluent for the extraction of Zr(IV) with binary mixture of TOA and Cyanex 923. The positive enthalpy change and positive entropy change in the binary extraction system show endothermic process with increase in randomness. Stripping of Zr (IV) from the loaded organic phase containing mixture of TOA (0.1 M) and Cyanex 923 (0.01 M) indicated that HNO3 and Na2CO3 are the best stripping agents.展开更多
In order to lower the usage of expensive Cyanex 923 and increase the extraction capacity of the system of Cextrant 230,the synergistic extraction of thorium from chloride media by a mixture of Cextrant 230 and Cyanex ...In order to lower the usage of expensive Cyanex 923 and increase the extraction capacity of the system of Cextrant 230,the synergistic extraction of thorium from chloride media by a mixture of Cextrant 230 and Cyanex 923 was investigated.The maximum synergistic enhancement coefficient(R)of 1.53 is obtained at 1:1 molar ratio of Cextrant 230/Cyanex 923.The syne rgistic extracted species of Th^(4+)is determined as ThCl_(4)·2Cextrant 230·Cyanex 923.The synergistic extraction of Th^(4+)is an entropy-driven exothermic process.The loading capacity of 0.60 mol/L mixed extractant for thorium is about 17.10 g/L(calculated as ThO_(2)),and the loaded thorium in the organic phase can be effectively stripped by distilled water.For comparison,rare earth cations are barely extracted under the similar conditions,suggesting that the mixtures can be applied to separate thorium from rare earths.A cascade extraction process was developed based on the synergistic extraction system to separate thorium from the hydrochloric acid leaching of bastnaesite.The content of thorium in the leaching solution decreases obviously from 19.90 mg/L to1.4μg/L by 3 stages of extraction,which is superior to sole Cextrant 230 or Cyanex 923.The introduction of Cextrant 230 into the extraction system not only lowers the usage of Cyanex 923 but also enhances the selective extraction of thorium at low acidity,implying that the synergistic extraction system can selectively extract thorium more efficiently and economically than the sole systems.展开更多
The extraction behaviors of zinc from ammoniacal solutions were investigated using β-diketone （HA） and their mixtures with CYANEX923 or LIX84I. The effects of pH, total ammonia concentration, extractant concentrati...The extraction behaviors of zinc from ammoniacal solutions were investigated using β-diketone （HA） and their mixtures with CYANEX923 or LIX84I. The effects of pH, total ammonia concentration, extractant concentration, anion species and temperature on zinc extraction were examined. The synergistic mechanism was discussed with regard to the structure of extractant and the extracted zinc complexes. It is found that the increase of total ammonia concentration and pH inhibits zinc extraction for all extraction systems due to the formation of zinc ammine complexes in aqueous phase. This effect of HA with CYANEX923 is evidently smaller than that of HA with LIX84I or HA alone system. Effect of anion species on the zinc extraction by HA with CYANEX923 can be neglected, but this effect of HA alone and the mixture of HA with LIX84I decreases in the order of （NH4）2SO4 〉 NH4NO3 〉 NH4Cl.展开更多
文摘Mass transfer and extraction kinetics of yttrium with the purified Cyanex 923 in n-heptane from nitrate medium have been investigated by using a constant interfacial cell with laminar flow at 298K. The interfacial adsorption properties of purified Cyanex 923-heptane-0.20mol/L (H, Na)NO3 were studied at 298K. The experimental results show that the mass transfer is controlled by diffusion and the chemical reactions are carried out in the interfacial zone. The extraction rates of yttrium were measured at different chemical compositions by varying ionic strength, pH values and the purified Cyanex 923 concentrations. The initial extraction rate equations were obtained.
文摘Ce 4+ extraction rate from aqueous sulphate solutions by Cyanex923 in heptane was studied using a constant interfacial cell with laminar flow at 30 ℃. The experimental hydrodynamic conditions were chosen and the contribution of diffusion to the measured rate of reaction was minimized. Cerium extraction rate was measured at different chemical composition by varying the concentrations of hydrogen ion, sulphate and Cyanex923. A cerium Cyanex923(B) extractive is formed at the interface. The data were analyszed in terms of pseudo first order constants and a reaction mechanism was developed.
基金Project supported by the State Key Project of the Foundation Research (2004CB719506) and the National Natural ScienceFoundation of China (20371046 ,50574080) ,and the National‘863’Project (2002AA647070)
文摘The extraction and stripping of ytterbium（ Ⅲ） from sulfuric acid medium using Cyanex 923 in heptane solution was investigated. The effects of extraetant concentration, pH and sulfate ion as well as stripping agents, acidity and temperature on the extraction and stripping were studied. The equilibrium constants and thermodynamic parameters, such as △n （10.76 kJ·mol^-1）, △G （-79.26 kJ·mol^-1） and △S （292.41 J·K^-1·mol^-1）, were calculated. The extraction mechanism and the complex species extracted were determined by slope analysis and FTIR spectra. Furthermore, it was found that the extraction of Yb （Ⅲ） from sulfuric acid medium by Cyanex 923 increased with pH, concentration of SO4^2-, HSO4^-, and extractant concentration, and approximately a quantitative extraction of Yb（ Ⅲ） was achieved at an equilibrium pH near 3.0, and the extracted complex was YbSO4（HSO4）·2Cyanex923（o）.
基金Supported by the NNSFC (No. 29771028, & No. 29801004) and the National Rogram entitled "Basic Research of Rare Earths" (G199
文摘The effect of boric acid on the extraction of bastnasite leaching liquor by Cyanex 923 was studied. Boric acid wasn’t extracted alone by Cyanex 923 and didn’t influence the cerium(IV) extraction. But it can enhance the extraction of hydrofluoric acid evidently and came into organic phase in form of (HF)(H3BO3).(Cyanex 923).
文摘A mathematical model was developed to monitor the facilitated transport of germanium(IV) from oxalic acid solutions through a flat sheet supported liquid membrane(FSSLM) containing four trialkylphosphine oxides(Cyanex 923). The FSSLM modeling was based on the extraction constant(Kext) calculated from the liquid-liquid extraction(LLX) modeling. The LLX model presented a reliable calculation of the extraction constant(Kex= 2.057×103 L/mol4). The FSSLM model was solved using Matlab■ software according to extraction constant, Fick’s law, and diffusional principles. The model predicts the overall mass transfer coefficient(Korg) to be 3.84 cm/s. Using this value, diffusion coefficients(Dm) for various Cyanex 923 concentrations of 0.126, 0.252, 0.378, 0.505, 0.631 and 0.757 mol/L are found to be 8.50×10^-4, 4.30×10^-4, 1.87×10^-4, 5.87×10^-5, 2.57×10^-5, 2.09×10^-5 cm2/s, respectively. The results show that the diffusion rate of the current study is approximately more than that of similar FSSLM systems containing Cyanex 923 used to transport various metals. The modeling values are in good agreement with the experimental data, showing the good reliability of the mathematical model.
基金Project supported bythe Hundreds Talents Program'from Chinese Academy of Sciences,National Natural Science Foundationof China (50574080)Distinguished Young Scholar Foundation of Jilin Province (20060114)
文摘The extraction of Yttrium (Ⅲ) into [Cnmim][PF6] (n= 4, 6, 8) containing Cyanex 923 was studied in this paper. The mechanism of this extraction was indicated to be cation exchange. In addition, the extraction process is an endothermic reaction. The RTILs with shorter alkyl chain behave higher extraction efficiency during the extraction, however, which has also more loss to aqueous phase since the cation exchange mechanism.
文摘Solvent extraction kinetics of lanthanum with purified Cyanex 923 in heptane from nitrate medium was investigated by using a constant interfacial cell with laminar flow at 303 K. The effects of stirring speed, temperature and specific interface on the extraction rate were studied. The experimental results showed that the extraction apparent activation energy was 32.0 kJ\5mol -1 and the extraction process was controlled by both chemical reaction and diffusion. The extraction rates were measured at different chemical compositions by varying ionic strength, pH value and the concentration of purified Cyanex 923. The initial extraction rate equation was obtained.
文摘The solvent extinction behavior Of Th(Ⅳ) and Ce(Ⅳ) with Cyanex 925 in nhexane hem nitric acid medium was studied. The extinction mechanisms of Th(Ⅳ)and Ce(Ⅵ) by Cyanex 923 were determined by the method of slope analysis, and the extracted species might be Th(NO3)4.S(Cyanex 923)(o) and Ce(NO3)4.2(Cyanex 923)(o). The extraction characteristics with purified Cyanex 925 and commercial Cyanex 925 were compared. Results showed Ce(Ⅳ) and Th(Ⅳ) could be separted with Cyanex 923 hem RE(Ⅲ) in nitric acid solution. The influence of temperature on the Th(Ⅳ) extinction was investigated and the thermodynamic functions were calculated.
文摘The extraction of zirconium (IV) from aqueous HCl solution by binary mixture TOA and Cyanex 923 using kerosene as diluent was studied. The effect of parameters like aqueous phase acid concentration, extractant concentration, chloride ion concentration, diverse ion effect, metal loading, nature of diluents and temperature on the extraction of Zr (IV) was investigated. The percentage of extraction of Zr(IV) became 100% with 0.1 M TOA and 0.01 M Cyanex 923 from 7 M HCl and also from 4 M HCl with 0.1 M TOA and 0.02 M Cyanex 923. Benzene was found to be effective diluent for the extraction of Zr(IV) with binary mixture of TOA and Cyanex 923. The positive enthalpy change and positive entropy change in the binary extraction system show endothermic process with increase in randomness. Stripping of Zr (IV) from the loaded organic phase containing mixture of TOA (0.1 M) and Cyanex 923 (0.01 M) indicated that HNO3 and Na2CO3 are the best stripping agents.
基金Project supported by the National Key Research and Development Project of China(2022YFC2905201)the Science and Technology Service Network Initiative Program of the Chinese Academy of Sciences(KFJ-STSQYZD-2021-18-001)+3 种基金the Research Projects of Ganjiang Innovation Academy,Chinese Academy of Sciences(E055C002)Jiangxi"Double Thous and Plan"(jxsq.2020101005)Jiangxi Province Natural Science Foundation(20212BAB213033)Ganzhou Science and Technology Program(2022CXRC9671)。
文摘In order to lower the usage of expensive Cyanex 923 and increase the extraction capacity of the system of Cextrant 230,the synergistic extraction of thorium from chloride media by a mixture of Cextrant 230 and Cyanex 923 was investigated.The maximum synergistic enhancement coefficient(R)of 1.53 is obtained at 1:1 molar ratio of Cextrant 230/Cyanex 923.The syne rgistic extracted species of Th^(4+)is determined as ThCl_(4)·2Cextrant 230·Cyanex 923.The synergistic extraction of Th^(4+)is an entropy-driven exothermic process.The loading capacity of 0.60 mol/L mixed extractant for thorium is about 17.10 g/L(calculated as ThO_(2)),and the loaded thorium in the organic phase can be effectively stripped by distilled water.For comparison,rare earth cations are barely extracted under the similar conditions,suggesting that the mixtures can be applied to separate thorium from rare earths.A cascade extraction process was developed based on the synergistic extraction system to separate thorium from the hydrochloric acid leaching of bastnaesite.The content of thorium in the leaching solution decreases obviously from 19.90 mg/L to1.4μg/L by 3 stages of extraction,which is superior to sole Cextrant 230 or Cyanex 923.The introduction of Cextrant 230 into the extraction system not only lowers the usage of Cyanex 923 but also enhances the selective extraction of thorium at low acidity,implying that the synergistic extraction system can selectively extract thorium more efficiently and economically than the sole systems.
基金Project (2007CB613601) supported by the National Basic Research Program of ChinaProject (CX2010B112) supported by Hunan Provincial Innovation Foundation for Postgraduate, China
文摘The extraction behaviors of zinc from ammoniacal solutions were investigated using β-diketone （HA） and their mixtures with CYANEX923 or LIX84I. The effects of pH, total ammonia concentration, extractant concentration, anion species and temperature on zinc extraction were examined. The synergistic mechanism was discussed with regard to the structure of extractant and the extracted zinc complexes. It is found that the increase of total ammonia concentration and pH inhibits zinc extraction for all extraction systems due to the formation of zinc ammine complexes in aqueous phase. This effect of HA with CYANEX923 is evidently smaller than that of HA with LIX84I or HA alone system. Effect of anion species on the zinc extraction by HA with CYANEX923 can be neglected, but this effect of HA alone and the mixture of HA with LIX84I decreases in the order of （NH4）2SO4 〉 NH4NO3 〉 NH4Cl.
