Pore network structure of ore body is a diffusion channel of leaching agent solution that exerts a significant influence on seepage.The ore body structure,pore distribution,pore and throat size,and pore network charac...Pore network structure of ore body is a diffusion channel of leaching agent solution that exerts a significant influence on seepage.The ore body structure,pore distribution,pore and throat size,and pore network characteristics of topsoil,weathered,and semiweathered layers of ionic rare earth ore in southern Jiangxi Province were explored in this study.The effect of leaching operation on the pore structure was investigated,and main factors affecting the seepage were analyzed.Results showed that the semiweathered layer presents a dense structure and a small number of unconnected pores.Pores of topsoil and weathered layers are mainly long and narrow column openings with some planar fractures.Even pore distribution and large size span were observed.Compared with the weathered layer,the topsoil layer demonstrates larger voids,smaller average pore volume and equivalent radius,and fewer coordination throats;however,the average equivalent radius of the throat in the topsoil layer is larger and largescale channels exist through ore body vertically.Hence,permeability of the topsoil layer is significantly higher than that of the weathered layer.Colloidal clay minerals migrate easily and the occurrence of silting in the small porosity blocks the throat and significantly decreases the permeability of the ore body in the leaching process.The equivalent radius of the throat is the key to the seepage.Reducing the migration of fine particles is an effective measure to protect the throat and shorten the leaching period.展开更多
A novel bifunctional task-specific ionic liquid(TSIL),i.e.[trialkylmethylammonium][sec-nonylphenoxy acetate]([A336] [CA-100]) was impregnated on intermediate polarized XAD-7 resin,and the prepared solvent impreganated...A novel bifunctional task-specific ionic liquid(TSIL),i.e.[trialkylmethylammonium][sec-nonylphenoxy acetate]([A336] [CA-100]) was impregnated on intermediate polarized XAD-7 resin,and the prepared solvent impreganated resin(SIR) was studied for rare earth(RE) separation.Adsorption ability of the SIR was indicated to be obviously higher than that prepared by [A336][NO3] because of the functional anion of [A336][CA-100].Adsorption kinetics,adsorption isotherm,separation and desorption of the SIR were also studied.展开更多
The electrodeposition and electrochemical behaviors of rare earths in different ionic liquids are summarized. It is demonstrated that most of the rare earths can be electrodeposited in ionic liquids except cerium. Ani...The electrodeposition and electrochemical behaviors of rare earths in different ionic liquids are summarized. It is demonstrated that most of the rare earths can be electrodeposited in ionic liquids except cerium. Anion of ionic liquids appears to play a significant role in determining the electrochemical windows, and then deciding whether the corresponding ionic liquids can be used for rare earths electrodeposition. The electrochemical behaviors of the reduction process in ionic liquids are similar to those in high-temperature molten salts. The reduction of RE(III) to RE(II) has different reversibility, but the reaction of rare earths to their zerovalent state is irreversible.展开更多
It is indicated from a study of transport of rare earth ions through the emulsion liquid mem-brane of bis（2,4,4-trimethylpentyl）phosphinic acid-Span 80-toluene that transporting rare earth ions com-pletely and rapid...It is indicated from a study of transport of rare earth ions through the emulsion liquid mem-brane of bis（2,4,4-trimethylpentyl）phosphinic acid-Span 80-toluene that transporting rare earth ions com-pletely and rapidly was realized under the optimum experimental conditions:1.0×10<sup>-3</sup>～3.0×10<sup>-3</sup>mol/Lbis（2,4,4-trimethylpentyl）phosphinic acid and 2%～4%（W/V）Span 80 in toluene solution as membranephase,0.50～2.0 mol/L HCl as inner phase,rare earth ion solutions with pH 3.5～5.0 as outer phase.Ac-cording to the differences of transport behavior for rare earth ions,it is possible to separate rare earth ionsfrom mixed solutions of rare earth ions by this liquid membrane system.展开更多
Ce0.85Sm0.15O1.925 (SDC) and La0.9Sr0.1Ga0.8Mg0.2O2.85 (LSGM) were synthesized using Glycine-Nitrate Process (GNP), and the composite electrolytes were prepared by mixing SDC and LSGM. An X-ray diffraction pattern ind...Ce0.85Sm0.15O1.925 (SDC) and La0.9Sr0.1Ga0.8Mg0.2O2.85 (LSGM) were synthesized using Glycine-Nitrate Process (GNP), and the composite electrolytes were prepared by mixing SDC and LSGM. An X-ray diffraction pattern indicated that the mixture of SDC and LSGM consisted of their original phases after heating at 1450 oC for 10 h. The electronic conductivity of SDC-LSGM composite electrolytes were measured by direct current polarization method using Hebb-Wagner ion blocking cell at 700-800 oC in the oxygen partial pressure range of 10-6-10-20 MPa and compared with the results of SDC. Typical polarization curves, which were theoretically predicted, were observed on all the samples. The slopes of lgσe-lgPo2 plot for all the composite electrolytes agreed with the theoretically predicted value of -1/4 at some in- termediate oxygen partial pressures and -1/6 at low oxygen partial pressure. The electronic conductivity of SDC-LSGM composite electro- lytes decreased with the increase in LSGM content, whereas the ionic transport number ti of all the samples increased with the increase in LSGM content.展开更多
A series of compounds, La 2/3- x Li 3 x MoO 4, were first prepared. Their structures are tetragonal scheelites with the cationic defects. The cell parameters a, c and values of c/a decrease with the increasing of the ...A series of compounds, La 2/3- x Li 3 x MoO 4, were first prepared. Their structures are tetragonal scheelites with the cationic defects. The cell parameters a, c and values of c/a decrease with the increasing of the substitution amount (3 x ) of lithium ion. Cationic vacancies are getting more as Li + concentration is lower. The diffusion of lithium ion is predominant. The concentration of charge carriers increases with increasing the substitution amount (3 x ) of lithium ion, meanwhile, the concentration of cationic vacancies decreases. The conductivity approaches the best when the substitution amount (3 x ) of lithium ion is about 0.3. The conductivity of La 0.567 Li 0.3 MoO 4 is 6.5×10 -6 S·cm -1 at room temperature.展开更多
Nanocrystalline powder of LaF3 was synthesized by a method of direct precipitation from water solution. Particle size and shape of LaF3 nanocrystalline powder was analysed with TEM. Particles were mainly spherical wit...Nanocrystalline powder of LaF3 was synthesized by a method of direct precipitation from water solution. Particle size and shape of LaF3 nanocrystalline powder was analysed with TEM. Particles were mainly spherical with narrow particle size distribution （10～20 nm）. The average particle size analysed with XRD is 16.7 nm. Nano-LaF3 bulk material was prepared by compacting the powder to 1 GPa at room temperature and a vacuum of 10 -4 Pa. The ionic conductivity of nano-LaF3 bulk material was studied with complex impedance spectra at room temperature. The ionic conductivity of nano-LaF3 bulk material （1×10 -5 S·cm -1 ） at room temperature is significantly increased compared to that of single crystal LaF3 （1×10 -6 S·cm -1 ）. A special phenomenon was observed firstly time that the ionic conductivity increased gradually with multiple testing in result of relaxation.展开更多
BaxCe0.8Pr0.2O3-α (x=0.98-1.03) ceramics were prepared by high temperature solid-state reaction. X-ray diffraction (XRD) patterns showed that the materials were perovskite-type orthorhombic single phase. By using gas...BaxCe0.8Pr0.2O3-α (x=0.98-1.03) ceramics were prepared by high temperature solid-state reaction. X-ray diffraction (XRD) patterns showed that the materials were perovskite-type orthorhombic single phase. By using gas concentration cell and AC impedance spectroscopy methods, the electrical conduction behavior of the materials was investigated in different gases at 500-900 °C. The influence of non-stoichiometry in the materials with x≠1 on conduction properties was studied and compared with that in the material with x=1. The results indicated that Ba1.03Ce0.8Pr0.2O3-α was a pure protonic conductor, and Ba0.98Ce0.8Pr0.2O3-α was a mixed conductor of protons and electrons in wet hydrogen at 500-900 °C. BaCe0.8Pr0.2O3-α was a pure protonic conductor in 500-600 °C, and a mixed conductor of protons and electrons above 600 °C in wet hydrogen. In 500-900 °C, they were all mixed conductors of oxide ions and electronic holes in dry air, and mixed conductors of protons, oxide ions and electronic holes in wet air. Both the protonic and oxide ionic conductivities increased with increasing barium content in the materials in wet hydrogen, dry air and wet air, respectively.展开更多
The title compound, [Nd(dmso) 7Cl][Bph 4] 2(dmso=dimethylsulfoxide, Bph 4=tetraphenylboron anion) was synthesized in organic solvent acetone/EtOH and the structure was determined by single crystal X ray diffraction. T...The title compound, [Nd(dmso) 7Cl][Bph 4] 2(dmso=dimethylsulfoxide, Bph 4=tetraphenylboron anion) was synthesized in organic solvent acetone/EtOH and the structure was determined by single crystal X ray diffraction. The crystal is triclinic with space group P 1, and the crystal data are as follows: a =1 2554(1) nm, b = 1 2799(1) nm, c =2 4598(3) nm; α =93 53(1)°, β =104 50(1)°, γ =112 77(1)°, V =3 4722(6) nm 3, Z =2, M r=1365 01, D c=1 306 g·cm -3 . The crystal is composed of a big cation [Nd(dmso) 7Cl] 2+ and two big anions [BPh 4] -. The Nd 3+ is coordinated by a chlorine atom and seven oxygen atoms from seven dimethylsulfoxides forming a distorted square antiprism coordination polyhedron,while the BPh - 4 anion is charge equilibrium ion.展开更多
A series of solid solution material based on ceria, Ce 0.9 Ca 0.1- x Sr x O 1.90 ( x =0, 0 04, 0 05, 0 06), were synthesized by a solid reaction method. Ceria doped with two alkali earth elements has cubic fluorite st...A series of solid solution material based on ceria, Ce 0.9 Ca 0.1- x Sr x O 1.90 ( x =0, 0 04, 0 05, 0 06), were synthesized by a solid reaction method. Ceria doped with two alkali earth elements has cubic fluorite structure. The ionic conductivity of these materials at high temperature was studied by impedance spectra, and an increasing effect of ionic conductivity was found. A maximum conductivity is achieved when the effective ionic radius is near to the critical radius (0 1106 nm). Some fuel cells were made using these materials as electrolyte. The output power and current of the SOFC with the electrolyte of double doped ceria are better than those of YSZ and single doped ceria, and the open circuit voltage of the double doped ceria is also higher than that of the single doped ones.展开更多
基金supported by the National Natural Science Foundation of China(Nos.51774153,92062110)National Key Research and Development Program of China(No.2021YFC2901702)。
文摘Pore network structure of ore body is a diffusion channel of leaching agent solution that exerts a significant influence on seepage.The ore body structure,pore distribution,pore and throat size,and pore network characteristics of topsoil,weathered,and semiweathered layers of ionic rare earth ore in southern Jiangxi Province were explored in this study.The effect of leaching operation on the pore structure was investigated,and main factors affecting the seepage were analyzed.Results showed that the semiweathered layer presents a dense structure and a small number of unconnected pores.Pores of topsoil and weathered layers are mainly long and narrow column openings with some planar fractures.Even pore distribution and large size span were observed.Compared with the weathered layer,the topsoil layer demonstrates larger voids,smaller average pore volume and equivalent radius,and fewer coordination throats;however,the average equivalent radius of the throat in the topsoil layer is larger and largescale channels exist through ore body vertically.Hence,permeability of the topsoil layer is significantly higher than that of the weathered layer.Colloidal clay minerals migrate easily and the occurrence of silting in the small porosity blocks the throat and significantly decreases the permeability of the ore body in the leaching process.The equivalent radius of the throat is the key to the seepage.Reducing the migration of fine particles is an effective measure to protect the throat and shorten the leaching period.
基金supported by ‘Hundreds Talents Program’from Chinese Academy of Sciences, National Natural Science Foundation of China (50574080, 20901073)National Key Technology R&D Program of China (2006BAC02A10)Distinguished Young Scholar Foundation of Jilin Province (20060114)
文摘A novel bifunctional task-specific ionic liquid(TSIL),i.e.[trialkylmethylammonium][sec-nonylphenoxy acetate]([A336] [CA-100]) was impregnated on intermediate polarized XAD-7 resin,and the prepared solvent impreganated resin(SIR) was studied for rare earth(RE) separation.Adsorption ability of the SIR was indicated to be obviously higher than that prepared by [A336][NO3] because of the functional anion of [A336][CA-100].Adsorption kinetics,adsorption isotherm,separation and desorption of the SIR were also studied.
基金Funded by National Natural Science Foundation of China (Nos. 50864009 and 50904031)
文摘The electrodeposition and electrochemical behaviors of rare earths in different ionic liquids are summarized. It is demonstrated that most of the rare earths can be electrodeposited in ionic liquids except cerium. Anion of ionic liquids appears to play a significant role in determining the electrochemical windows, and then deciding whether the corresponding ionic liquids can be used for rare earths electrodeposition. The electrochemical behaviors of the reduction process in ionic liquids are similar to those in high-temperature molten salts. The reduction of RE(III) to RE(II) has different reversibility, but the reaction of rare earths to their zerovalent state is irreversible.
基金Supported by the National Natural Science Foundation of China
文摘It is indicated from a study of transport of rare earth ions through the emulsion liquid mem-brane of bis（2,4,4-trimethylpentyl）phosphinic acid-Span 80-toluene that transporting rare earth ions com-pletely and rapidly was realized under the optimum experimental conditions:1.0×10<sup>-3</sup>～3.0×10<sup>-3</sup>mol/Lbis（2,4,4-trimethylpentyl）phosphinic acid and 2%～4%（W/V）Span 80 in toluene solution as membranephase,0.50～2.0 mol/L HCl as inner phase,rare earth ion solutions with pH 3.5～5.0 as outer phase.Ac-cording to the differences of transport behavior for rare earth ions,it is possible to separate rare earth ionsfrom mixed solutions of rare earth ions by this liquid membrane system.
基金the National Natural Science Foundation of China (10674034)
文摘Ce0.85Sm0.15O1.925 (SDC) and La0.9Sr0.1Ga0.8Mg0.2O2.85 (LSGM) were synthesized using Glycine-Nitrate Process (GNP), and the composite electrolytes were prepared by mixing SDC and LSGM. An X-ray diffraction pattern indicated that the mixture of SDC and LSGM consisted of their original phases after heating at 1450 oC for 10 h. The electronic conductivity of SDC-LSGM composite electrolytes were measured by direct current polarization method using Hebb-Wagner ion blocking cell at 700-800 oC in the oxygen partial pressure range of 10-6-10-20 MPa and compared with the results of SDC. Typical polarization curves, which were theoretically predicted, were observed on all the samples. The slopes of lgσe-lgPo2 plot for all the composite electrolytes agreed with the theoretically predicted value of -1/4 at some in- termediate oxygen partial pressures and -1/6 at low oxygen partial pressure. The electronic conductivity of SDC-LSGM composite electro- lytes decreased with the increase in LSGM content, whereas the ionic transport number ti of all the samples increased with the increase in LSGM content.
文摘A series of compounds, La 2/3- x Li 3 x MoO 4, were first prepared. Their structures are tetragonal scheelites with the cationic defects. The cell parameters a, c and values of c/a decrease with the increasing of the substitution amount (3 x ) of lithium ion. Cationic vacancies are getting more as Li + concentration is lower. The diffusion of lithium ion is predominant. The concentration of charge carriers increases with increasing the substitution amount (3 x ) of lithium ion, meanwhile, the concentration of cationic vacancies decreases. The conductivity approaches the best when the substitution amount (3 x ) of lithium ion is about 0.3. The conductivity of La 0.567 Li 0.3 MoO 4 is 6.5×10 -6 S·cm -1 at room temperature.
文摘Nanocrystalline powder of LaF3 was synthesized by a method of direct precipitation from water solution. Particle size and shape of LaF3 nanocrystalline powder was analysed with TEM. Particles were mainly spherical with narrow particle size distribution （10～20 nm）. The average particle size analysed with XRD is 16.7 nm. Nano-LaF3 bulk material was prepared by compacting the powder to 1 GPa at room temperature and a vacuum of 10 -4 Pa. The ionic conductivity of nano-LaF3 bulk material was studied with complex impedance spectra at room temperature. The ionic conductivity of nano-LaF3 bulk material （1×10 -5 S·cm -1 ） at room temperature is significantly increased compared to that of single crystal LaF3 （1×10 -6 S·cm -1 ）. A special phenomenon was observed firstly time that the ionic conductivity increased gradually with multiple testing in result of relaxation.
基金Project supported by the National Natural Science Foundation of China (20771079)Qing Lan Project and the Natural Science Foundation of Education Department of Jiangsu Province (07KJB150126 and 08KJD150008)
文摘BaxCe0.8Pr0.2O3-α (x=0.98-1.03) ceramics were prepared by high temperature solid-state reaction. X-ray diffraction (XRD) patterns showed that the materials were perovskite-type orthorhombic single phase. By using gas concentration cell and AC impedance spectroscopy methods, the electrical conduction behavior of the materials was investigated in different gases at 500-900 °C. The influence of non-stoichiometry in the materials with x≠1 on conduction properties was studied and compared with that in the material with x=1. The results indicated that Ba1.03Ce0.8Pr0.2O3-α was a pure protonic conductor, and Ba0.98Ce0.8Pr0.2O3-α was a mixed conductor of protons and electrons in wet hydrogen at 500-900 °C. BaCe0.8Pr0.2O3-α was a pure protonic conductor in 500-600 °C, and a mixed conductor of protons and electrons above 600 °C in wet hydrogen. In 500-900 °C, they were all mixed conductors of oxide ions and electronic holes in dry air, and mixed conductors of protons, oxide ions and electronic holes in wet air. Both the protonic and oxide ionic conductivities increased with increasing barium content in the materials in wet hydrogen, dry air and wet air, respectively.
文摘The title compound, [Nd(dmso) 7Cl][Bph 4] 2(dmso=dimethylsulfoxide, Bph 4=tetraphenylboron anion) was synthesized in organic solvent acetone/EtOH and the structure was determined by single crystal X ray diffraction. The crystal is triclinic with space group P 1, and the crystal data are as follows: a =1 2554(1) nm, b = 1 2799(1) nm, c =2 4598(3) nm; α =93 53(1)°, β =104 50(1)°, γ =112 77(1)°, V =3 4722(6) nm 3, Z =2, M r=1365 01, D c=1 306 g·cm -3 . The crystal is composed of a big cation [Nd(dmso) 7Cl] 2+ and two big anions [BPh 4] -. The Nd 3+ is coordinated by a chlorine atom and seven oxygen atoms from seven dimethylsulfoxides forming a distorted square antiprism coordination polyhedron,while the BPh - 4 anion is charge equilibrium ion.
文摘A series of solid solution material based on ceria, Ce 0.9 Ca 0.1- x Sr x O 1.90 ( x =0, 0 04, 0 05, 0 06), were synthesized by a solid reaction method. Ceria doped with two alkali earth elements has cubic fluorite structure. The ionic conductivity of these materials at high temperature was studied by impedance spectra, and an increasing effect of ionic conductivity was found. A maximum conductivity is achieved when the effective ionic radius is near to the critical radius (0 1106 nm). Some fuel cells were made using these materials as electrolyte. The output power and current of the SOFC with the electrolyte of double doped ceria are better than those of YSZ and single doped ceria, and the open circuit voltage of the double doped ceria is also higher than that of the single doped ones.
