An excellent extraction selectivity towards Sc over other REEs in 4 mol/L HCl solution was achieved with the separation factor βSc/REEs over 8000 by 2-ethylhexyl phosphoric acid mono 2-ethylhexyl ester(HEHEHP)and the...An excellent extraction selectivity towards Sc over other REEs in 4 mol/L HCl solution was achieved with the separation factor βSc/REEs over 8000 by 2-ethylhexyl phosphoric acid mono 2-ethylhexyl ester(HEHEHP)and the extraction equilibrium can be obtained within 20 min.The extracted Sc can be stripped using 5 mol/L NaOH solution as eluent at 363 K with the stripping rate of 92.1%obtained.The extraction mechanism was clearly elucidated by slope analysis,saturation extraction,IR,and NMR analysis.It was revealed that the extraction of Sc in 4 mol/L HCl solution is still dominated by cation exchange process between P-O-H and Sc,and coordination process between P=O and Sc,with 6 molecules of extractant as dimer participating in the process.Finally,a flowsheet for the recovery of Sc from ion-adsorption rare earth elements(REEs)concentrate was proposed and proved in lab-scale experiment.展开更多
D2EHPA(P204),tri-butyl-phosphate(TBP)and sodium chloride(NaCl)were attractive for selective extraction of scandium from acid leaching solution of red mud.The extraction parameters of P204 concentration(X_(P204)),NaCl ...D2EHPA(P204),tri-butyl-phosphate(TBP)and sodium chloride(NaCl)were attractive for selective extraction of scandium from acid leaching solution of red mud.The extraction parameters of P204 concentration(X_(P204)),NaCl concentration(C_(NaCl)),pH value,reaction time,stirring speed and O/A were investigated to extract scandium and separate iron from the acid leaching solution.The extraction mechanism was analyzed by Fourier transform infrared spectroscopy(FT-IR)and thermodynamic theory.The single-stage extraction efficiency of scandium,iron andβ(Sc/Fe)were 99.1%,9.4%and 1061.2,respectively,with C_(NaCl) of 75 g/L and XP204 of 0.75 at solution pH value of 1.2 and stirring speed of 200 r/min for 6 min,in which a good separation effect of scandium and iron was obtained.The vibration absorption peak Sc─O was contributed to the extraction of scandium with P204.The complex[FeCln]^(3−n) existed in the solution with adding NaCl into the acid leaching solution.The value of n was higher and the valence state of the complex[FeCln]^(3−n) was lower with an increase of chloride concentration,which restricts the extraction efficiency of iron with P204.The extraction of three stages in the counter-current simulation experiments was carried out according to the McCabe-Thiele diagram.Gibbs free energy change(ΔG)of−5.93 kJ/mol,enthalpy change(ΔH)of 23.45 kJ/mol and entropy change(ΔH)of 98.54 J/(mol·K)were obtained in the solvent extraction proces,which indicate that the extraction reaction is easily spontaneous and endothermic and a proper increase of temperature is conducive to the extraction of scandium.展开更多
A process of removing impurities,such as Fe,Zr,Ti,Al,Si,from scandium solution by ion exchange was proposed.Various resins’selectivity was studied in scandium chloride solution.The results indicated that D851resin ha...A process of removing impurities,such as Fe,Zr,Ti,Al,Si,from scandium solution by ion exchange was proposed.Various resins’selectivity was studied in scandium chloride solution.The results indicated that D851resin had high selectivity of Sc at low acidity,and high selectivity of Zr at high acidity;D370resin had high selectivity of Fe and Si in high acidity.A new technical process of removing impurities from scandium chloride solution was proposed,which includes D370resin adsorbing Fe in high acidity,D851resin adsorbing Zr in medium acidity and D851resin adsorbing Sc at low acidity.Flow experimental results show that removal rates of Al,Ca,Fe,Zr,Ti and Si,were100%,99.6%,100%,100%,99.5%and100%respectively.展开更多
基金Projects(11705032,11975082,U1967218)supported by the National Natural Science Foundation of ChinaProject(2017GXNSFBA198175)supported by the Natural Science Foundation of Guangxi Province,ChinaProject(AA17204100)supported by the Science and Technology Major Project of Guangxi Province,China。
文摘An excellent extraction selectivity towards Sc over other REEs in 4 mol/L HCl solution was achieved with the separation factor βSc/REEs over 8000 by 2-ethylhexyl phosphoric acid mono 2-ethylhexyl ester(HEHEHP)and the extraction equilibrium can be obtained within 20 min.The extracted Sc can be stripped using 5 mol/L NaOH solution as eluent at 363 K with the stripping rate of 92.1%obtained.The extraction mechanism was clearly elucidated by slope analysis,saturation extraction,IR,and NMR analysis.It was revealed that the extraction of Sc in 4 mol/L HCl solution is still dominated by cation exchange process between P-O-H and Sc,and coordination process between P=O and Sc,with 6 molecules of extractant as dimer participating in the process.Finally,a flowsheet for the recovery of Sc from ion-adsorption rare earth elements(REEs)concentrate was proposed and proved in lab-scale experiment.
基金Projects(51904097,51804103)supported by the National Natural Science Foundation of ChinaProject(2019GGJS056)supported by the Training Program for Young Backbone Teachers in Colleges and Universities of Henan Province,China+2 种基金Project(HB201905)supported by Open Foundation of State Environmental Protection Key Laboratory of Mineral Metallurgical Resources Utilization and Pollution Control,ChinaProject(202102310548)supported by Scientific and Technological Project of Henan Province,ChinaProject(21IRTSTHN006)supported by Program for Innovative Research Team in the University of Henan Province,China。
文摘D2EHPA(P204),tri-butyl-phosphate(TBP)and sodium chloride(NaCl)were attractive for selective extraction of scandium from acid leaching solution of red mud.The extraction parameters of P204 concentration(X_(P204)),NaCl concentration(C_(NaCl)),pH value,reaction time,stirring speed and O/A were investigated to extract scandium and separate iron from the acid leaching solution.The extraction mechanism was analyzed by Fourier transform infrared spectroscopy(FT-IR)and thermodynamic theory.The single-stage extraction efficiency of scandium,iron andβ(Sc/Fe)were 99.1%,9.4%and 1061.2,respectively,with C_(NaCl) of 75 g/L and XP204 of 0.75 at solution pH value of 1.2 and stirring speed of 200 r/min for 6 min,in which a good separation effect of scandium and iron was obtained.The vibration absorption peak Sc─O was contributed to the extraction of scandium with P204.The complex[FeCln]^(3−n) existed in the solution with adding NaCl into the acid leaching solution.The value of n was higher and the valence state of the complex[FeCln]^(3−n) was lower with an increase of chloride concentration,which restricts the extraction efficiency of iron with P204.The extraction of three stages in the counter-current simulation experiments was carried out according to the McCabe-Thiele diagram.Gibbs free energy change(ΔG)of−5.93 kJ/mol,enthalpy change(ΔH)of 23.45 kJ/mol and entropy change(ΔH)of 98.54 J/(mol·K)were obtained in the solvent extraction proces,which indicate that the extraction reaction is easily spontaneous and endothermic and a proper increase of temperature is conducive to the extraction of scandium.
基金Project(2015BAB19B03)supported by the National Science and Technology Supporting Plan of China
文摘A process of removing impurities,such as Fe,Zr,Ti,Al,Si,from scandium solution by ion exchange was proposed.Various resins’selectivity was studied in scandium chloride solution.The results indicated that D851resin had high selectivity of Sc at low acidity,and high selectivity of Zr at high acidity;D370resin had high selectivity of Fe and Si in high acidity.A new technical process of removing impurities from scandium chloride solution was proposed,which includes D370resin adsorbing Fe in high acidity,D851resin adsorbing Zr in medium acidity and D851resin adsorbing Sc at low acidity.Flow experimental results show that removal rates of Al,Ca,Fe,Zr,Ti and Si,were100%,99.6%,100%,100%,99.5%and100%respectively.
