Countercurrent Electromigration Research Articles

Anomalous Behavior of Ag(I) and Tl(I) Ions in Mobilities of Molten Nitrates

The data on internal cation mobilities, u, in the molten binary nitrate systems (M, Ag)NO3 and (M, Tl)NO3 (M=alkali metal ion) determined by Klemm's countercurrent electromigration method are reexamined. In binary alkali nitrates u is well expressed by an empirical equation u={A/(Vm – Vo)}exp(-E/RT), where Vm is the molar volume; A, Vo and E are constants nearly independent of coexisting cations. If Ag+ is contained, the uM of coexisting cations M negatively deviates from such an equation, and, on the contrary, if Tl+ is contained, the uM positively deviates. Thus, Ag+ and Tl+ having relatively high polarizabilities have the opposite effects on uM, that is tranquilization effect and agitation effect, respectively. The reason has been interpreted in terms of the high polarizabilities and the difference in the sizes of Ag+ and Tl+.

The Chemla effect in the mobilities in the molten binary system of lithium chloride and caesium chloride

Relative differences in internal mobilities for the binary molten system (Li,Cs)Cl were measured by a countercurrent electromigration method at 913 K and 973 K. The internal mobilities of Li+ and Cs+ were calculated from these data and from those available for the electrical conductivities and densities of the mixtures. The Chemla effect occurs, i.e. the isotherms of the mobilities plotted as a function of concentration cross each other. The internal mobilities uic are found to be well described by the expression uic = [A/(Vm − V0)]exp(−E/RT), where Vm is the molar volume and A, V0 and E are constants which are different at two ranges of Vm. The present data are compared with those obtained previously by the emf method.

Transport property of cations Li+and K+in the molten salt electrolyte

Abstract With the countercurrent electromigration method, the ionic mobility differences of Li+ and K+ in molten binary electrolyte LiCl‐KCl have been measured over a widely concentration and temperature range. Except at a region of high concentration of LiCl, the mobility of the large cation, K+ (bk ), is greater than that of the smaller Li+ (bu ) cation. The crossing points of the isotherm mobility shifts with the temperature with a higher concentration of LiCl. When the Coulombic attraction force is expected to be the dominant factor for ruling the cation mobilities, both bu and bK have been found to be well expressed by the empirical equation b = [A/(V— Vo ) ] exp(—E/RT), where A, Vo and E are characteristic constants of the cation, V is the molar volume of mixtures, and R is the gas constant.

Internal Cation Mobilities in the Molten Systems (Ag, Rb)NO3 and (Ag,Cs)NO3 Remeasured by the Klemm Method

Abstract Internal mobility ratios in the molten binary systems (Ag,Rb)NO3 and (Ag,Cs)NO3 have been measured by Klemm's countercurrent electromigration method at various temperatures and compositions. From these and the available data on the densities and conductivities, the cation internal mobilities b have been calculated. Over the investigated regions of temperature and composition bAg is greater than bRb and bCs . The internal mobility of Ag+ is well expressed by bAg = [A/(V - V0)] • exp(-E/RT), where V is the molar volume of the mixtures, A, V0 , and E being constants nearly independent of the coions. A comparison of the present data with those previously obtained by the EMF method certifies that the Klemm method yields more precise data.

ChemInform Abstract: Enrichment of 6Li by Countercurrent Electromigration in Molten LiNO3

ChemInformVolume 20, Issue 33 Preparative Inorganic Chemistry ChemInform Abstract: Enrichment of 6Li by Countercurrent Electromigration in Molten LiNO3 T. HAIBARA, T. HAIBARA Dep. Electron. Chem., Tokyo Inst. Technol., Midori, Yokohama 227, Jap.Search for more papers by this authorO. ODAWARA, O. ODAWARA Dep. Electron. Chem., Tokyo Inst. Technol., Midori, Yokohama 227, Jap.Search for more papers by this authorI. OKADA, I. OKADA Dep. Electron. Chem., Tokyo Inst. Technol., Midori, Yokohama 227, Jap.Search for more papers by this authorM. NOMURA, M. NOMURA Dep. Electron. Chem., Tokyo Inst. Technol., Midori, Yokohama 227, Jap.Search for more papers by this authorM. OKAMOTO, M. OKAMOTO Dep. Electron. Chem., Tokyo Inst. Technol., Midori, Yokohama 227, Jap.Search for more papers by this author T. HAIBARA, T. HAIBARA Dep. Electron. Chem., Tokyo Inst. Technol., Midori, Yokohama 227, Jap.Search for more papers by this authorO. ODAWARA, O. ODAWARA Dep. Electron. Chem., Tokyo Inst. Technol., Midori, Yokohama 227, Jap.Search for more papers by this authorI. OKADA, I. OKADA Dep. Electron. Chem., Tokyo Inst. Technol., Midori, Yokohama 227, Jap.Search for more papers by this authorM. NOMURA, M. NOMURA Dep. Electron. Chem., Tokyo Inst. Technol., Midori, Yokohama 227, Jap.Search for more papers by this authorM. OKAMOTO, M. OKAMOTO Dep. Electron. Chem., Tokyo Inst. Technol., Midori, Yokohama 227, Jap.Search for more papers by this author First published: August 15, 1989 https://doi.org/10.1002/chin.198933029Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume20, Issue33August 15, 1989 RelatedInformation

Internal Cation Mobilities in the Molten Binary System(Na,NH4)NO3

Relative differences in the internal cation mobilities in the molten binary system (Na, NH4)NO3 have been measured by Klemm's countercurrent electromigration method at NaNO3 mole fractions 0 0.3 and temperatures 433-453 K. Also the densities and electric conductivities of this system have been measured. From these data the internal cation mobilities, bNa and bNH₄, were calculated. Under all accessible conditions, bNH₄ is greater than bNa. The results are discussed in terms of the interaction between unlike ions and free space.

Enrichment of Li‐6 by Countercurrent Electromigration in Molten LiNO3

High enrichment of 6Li was attempted by improvement a previously used countercurrent electromigration method in molten . In order to prevent a possible outflow of Li+ ions into a large cathode compartment which contained melt by electromigration, a small zone of was formed between molten and in a separation tube. The electromigration cell was reformed so that the temperature in the separation tube could be kept at an intended value. 6Li was enriched from 7.4 to 91.2% in 39 days without any trouble with material corrosion.

Anomalous Distribution of K-lsotopes During Countercurrent Electromigration in Molten ( L i,K )NO3

Abstract The previously presented theory that, in countercurrent electromigration of molten common anion binary mixtures, the lighter isotope of the less mobile cation should anomalously enrich in a zone next to the anode, has been substantiated for the K isotopes in molten (Li, K)NO3.

The Isotope Effect of Li-Ions in Countercurrent Electromigration of Molten LiOH

Abstract The relative difference, ε, in the internal mobilities of 6Li and 7Li ions in molten LiOH has been measured with the Klemm method. In the investigated range of temperature from 763 K to 873 K, ε has been determined to be 0.0068-0.0080 and seems to increase slightly with temperature.

The Isotope Effect of Li+ Ions in Electromigration of Molten LiNO3

The relative difference in internal mobilities o f 6Li and 7Li, ε, in molten LiNO3 has been remeasured in the temperature range from 559 K to 726 K by countercurrent electromigration (Klemm 's method). As temperature increases, the isotope effect increases, although the increasing rate decreases: it is practically constant above 650 K. The ε values are lower than those measured by Lundén and Ekhed [5] by 15-25% . The effective diffusion coefficients have been estimated from the distribution of the isotopes in the separation tube by numerical simulation.

Enrichment of Li-6 by Countercurrent Electromigration of Molten LiNO3

Enrichment of Li-6 by Countercurrent Electromigration of Molten LiNO3

High Enrichment of Li-6 by Countercurrent Electromigration in Molten LiNO3 with Molten NH4NO3 at the Cathode

Based on a previously proposed principle, 6Li was enriched from the original abundance 7.4% to 82% with a cell of a new type. Ammonium nitrate melt was used in the relatively large cathode compartment. The enrichment took place around the rather sharp boundary between LiNO3 and NH4NO3 near the end of a nearly horizontal separation tube opening to the cathode compartment. In 31 days’ electromigration no serious corrosion problem was encountered.

Changes in Composition by Countercurrent Electromigration in a Gradient of Temperature and/or Composition

Unexpected previous findings in countercurrent electromigration experiments are explained and a new measuring technique based on dual temperature or dual composition experiments is proposed.

On the Distribution of Isotopes in a Separation Column in Countercurrent Electromigration of Molten Binary Mixtures

Abstract In countercurrent electromigration of molten binary mixtures with a common anion in which each cation is composed of two isotopes, the less mobile cation is enriched toward the anode, and, at the same time, the isotopes of this cation become distributed in a complicated way. Thus, the zone next to the anode where the heavy isotope is enriched is immediately followed by a region where a slight enrichment of the light isotope occurs, while for the more mobile cation the heavy isotope is enriched in both these regions. This phenomenon has been observed in experiments with the systems (Li-K)NO3 and (Li-K)Cl and it has also been reproduced by analyzing the flow equations for the constituent components numerically with a computer. It is verified that the existing formulation for the calculation of the elementary separation factor holds independent of whether there is such an anomaly in the isotope distribution for the less mobile cation.

Calcium isotope enrichment by means of counter-current electromigration using an ion-exchange resin as migration medium

A new apparatus was designed and constructed for calcium isotope enrichment by means of counter-current electromigration. Experiments have been carried out under conditions where the temperature and migration length were varied. The separation coefficient per unit mass was found to vary from 1.3.10 −4 to 8.7· 10 −4 depending on the conditions, however, most values were larger than those obtained by ion-exchange chromatography. The mass effect was also observed clearly, −μ +  0.0035. The atomic fraction of 48Ca increased from its original value of 0.185% to 0.226% after 5 weeks of migration under moderate conditions, yielding 144 mg of the enriched calcium.

Internal Cation Mobilities in the Molten Systems (Li-Rb)N0 3 and (Li-Cs)NO s

The relative differences in internal cation mobilities are measured for the molten systems (Li-Rb)NO3 and (Li-Cs)NO3 over a wide range of temperatures and concentrations with a countercurrent electromigration method, and the internal mobilities are calculated from these results and the available data on the electrical conductivity. The following phenomena are observed: (a) under some conditions the electrical mobility of Li+ is lower than that of the larger cation, (b) at a given temperature the mobility of Li+ decreases with increasing molar volume of the mixture, and (c) at low temperatures the isotherms of the mobility of the large cation show a maximum at some low concentration of that ion. These phenomena are interpreted in terms of the free space and the pair potential between cation and anion

A Cell for Countercurrent Electromigration Experiments for Molten Nitrates

A new type of cell for countercurrent electromigration of molten nitrates is proposed, in which molten NH4NO3 is employed just above its melting point in a large cathode compartment. This cell can be used effectively without trouble of corrosion for the purpose of (1) enrichment of 6Li, (2) enrichment of heavier isotopes such as 7Li, and (3) measurements of relative internal mobility differences of cations and/or isotopes.

Internal Cation Mobilities in the Molten Systems LiNO3-TlNO3 and RbNO3-TlNO3

Abstract The relative differences in internal cation mobilities are measured for the molten systems LiNO3-TlNO3 and RbNO3-TlNO3 over a wide range of temperature and concentration by means of counter-current electromigration technique (Klemm's method), and the internal mobilities are calculated from the existing data on the electric conductivity for these systems. For the system LiNO3-TlNO3 , a marked dependence of the relative internal mobility differences on temperature is found particularly in the Li+ rich region, and a considerable concentration dependence is found over the investigated temperature range. This is qualitatively explained in terms of a model which takes into account mainly the differences of the cation-anion pair potentials and of the sizes of the two cations. On the other hand, for the system RbNO3-TlNO3, only a slight temperature dependence is observed and no concentration dependence, if present, is detected within the experimental accuracy.

Enrichment of Li-6 by Countercurrent Electromigration with Molten LiNO3-NH4NO3System

Enrichment of Li-6 by Countercurrent Electromigration with Molten LiNO₃-NH₄NO₃System

Enrichment of Li-6 by Countercurrent Electromigration with Molten LiNO3-NH4NO3 System

(1974). Enrichment of Li-6 by Countercurrent Electromigration with Molten LiNO3-NH4NO3 System. Journal of Nuclear Science and Technology: Vol. 11, No. 7, pp. 314-316.