Electromotive Force Series of Metals in Fused Salts and Activities of Metal Chlorides in 1:1 Molar KCl-NaCl Solutions

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Section: Discussionmentioning

confidence: 65%

“…The poteiltials of the chlorine electrode which were measured against the silver -silver chloride reference electrode in a previous investigation (6) are also included in this table.…”

Section: Discussionmentioning

confidence: 99%

Electrode Potentials of the Uranium Chlorides in Fused Alkali Chloride Solutions

Flengas¹

1961

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“…Weighing, handling, and transfer of all chemicals were conducted in a drybox filled with anhydrous argon gas. All graphite used in the experiments was high density, research grade graphite (Aremco), and it was purified by chlorine treatment at 1273 K, as described previously (16,17).…”

Section: Methodsmentioning

confidence: 99%

“…For the AgCl experiments, the cell consisted of the Ag indicator electrode and the Cl, gas reference electrode. The half cell compartments were separated by a diaphragm consisting of an asbestos fibre fused in quartz (16). The A1CI3 cell contained the A1 indicator electrode and the Ag/AgCl secondary reference electrode.…”

Section: Methodsmentioning

confidence: 99%

Thermodynamic properties of the dilute solutions of silver chloride and aluminum trichloride in alkali chlorides by electromotive force measurements

Tumidajski¹,

Flengas²

1985

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P. J. TUMIDAJSKI and S. N. FLENCAS. Can. J. Chem. 63, 1080 (1985.'Thermodynamic data for dilute solutions of AgCl and AlCl, in molten alkali chlorides were derived from the emf's of formation and of galvanic cells, respectively, given as, Ag/AgCI -ACI/C,C12 and Ag/AgCl -ACI//AIC13 -ACI/AI. ACI represents NaCI, KC1, CsC1, or the equimolar mixtures of NaCI-CsCI and KC1-CsCI. It was found that the thermodycmic properties o m e ternarymelts could be predicted from the results of the binary melts using the relationship (17,20,21), (AZ),,, = (1 -t) (AZ),, + t(AZ),,, where Z represents any partial molar property. The ternary solution is denoted by the subscript 1, 2, 3 while the two binaries are denoted by 1, 2 and 1, 3; t is a concentration variable given as t = X3/(X2 + X,). These expressions are valid when the binary and the ternary solutions have the same content of either AgCl or AlCI,, respectively. P. J . TUMIDAJSKI et S. N. FLENCAS. Can. J . Chem. 63, 1080Chem. 63, (1985.En se basant sur les fem de formation et des cellules galvaniques Ag/AgCl -ACI/C, C12 et Ag/AgCI -AC1//AIC13 -ACl/Al dans lesquelles ACI reprtsente NaCI, KC1, CsCl ou des mtlanges Cquimolaires de NaCI-CsC1 ou de KCI-CsCI, on a tvalut les donntes thermodynamiques de solutions dilutes de AgCl et de AlC13 dans des chlorures alcalins fondus. On a trouvC que l'on peut prtdire les proprittts thermodynamiques des selsgrnaires fondus e n s b a s a n t s~l e s rtsultats obtenus avec des sels binaires fondus et en utilisant la relation (17, 20, 21) (AZ)123 = (1 -t) (AZ),? + t(AZ)13, oh Z reprtsente n'importe quelle propriktt molaire partielle. On utilise les indices 1, 2, 3 pour dtsigner la solution ternaire et les indices 1, 2 et 1, 3 pour designer les deux solutions binaires; t est une variable de concentration que l'on reprtsente par t = X3/(X2 + X,). Ces expressions sont valables quand les solutions ternaires contiennent chacune des quantitts semblables de AgCl ou de AICI,. [Traduit par le journal]Introduction The thermodynamic properties of the solutions of AgCl or AlCl, in alkali chloride melts have been the subject of several studies. For the former, the systems investigated include the binary solutions of AgC1-NaCl (1 -3), AgCl-KC1 (1, 3, 4), AgCI-CsCl (1, 3) and AgCl-RbCl (3), and the ternary solutions of AgCl-LiCl-KC1 (5, 6 ) , AgCl-NaCI-KC1 (3), and AgC1-NaC1-CsC1 (3). For the case of AlCl,, the following systems have been studied: AlC1,-NaCI (7-12), AlC1,-KC1 (7), AIC1,-RbCl (7), AlC1,-CsCl (7), and AlC1,-NaCl-KC1 (13). These measurements were taken with concentrated solutions of AgCl or AlCl,. The behaviour of dilute solutions of AgCl or AlCl, where Henry's law is expected to be valid have not yet been investigated. The thermodynamic properties of the dilute solutions of AgCl in the binary systems AgCl-NaCl, AgCl-KCl, AgCl-CsCl, and in the ternary systems AgC1-NaC1-CsC1 and AgCl-KCl-CsCl have been obtained from emf measurements on formation cells of the type, Ag/AgCl -ACl/C,CI,. The thermodynamic properties of the dilute solutions of AlCl,...

“…AIeasurernents of the "apparent standard potentials" of several metal -metal chloride systems in dilute solutions in fused alkali chlorides have been reported in previous investigations (1,2,3). Sucll measurements provide data on activities, help determine the equilibrium constants of chemical reactions in fused salts, and provide some of the necessary information for the recovery of metals by fused salt electrolysis.…”

mentioning

confidence: 84%

Thermodynamic and Electrochemical Properties of Zirconium Chlorides in Alkali Chloride Melts

Swaroop¹,

Flengas²

1966

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The liquidus curves in the binary equilibrium phase diagrams of the systems, ZrCI,MCI, and ZrCIJ-hIC1, where M is potassium or sodium, have been determined where possible. The electroche~nic~l properties of the clilute solutions of zirconium di-, tri-, and tetra-chlorides, in the teriiperature range 670 OC to 750 'C, mere investigated by reversible electromotive force measurements. From the results various equilibria between zirconiun~ metal and the soltitions of zirconium tri-and tetra-chlorides, respectively, were determined. Activity calculations indicate that zirconiu~n tetrachloride is heavily complexed in these melts.AIeasurernents of the "apparent standard potentials" of several metal -metal chloride systems in dilute solutions in fused alkali chlorides have been reported in previous investigations (1, 2, 3). Sucll measurements provide data on activities, help determine the equilibrium constants of chemical reactions in fused salts, and provide some of the necessary information for the recovery of metals by fused salt electrolysis. An equimolar melt of potassiuin and sodium chlorides was used as the solvent melt in all these studies, and a silver -silver chloride electrode developed earlier in this work (1) was the reference electrode.In this investigation, the technique has been applied to the determination of the reversible potentials of the zirconium chlorides in the temperature range 670 OC t o 750 "C. Three zirconium chlorides arc known to exist a t room temperature: zirconium dichloride, zirconium trichloride, and zirconiulm tetrachloride.Pure solid zirconiutm trichloride disproportiorlates a t high temperatures by the reaction:Turiibull and Watts (4) have shown that the reaction pressure of zirconiunl tetrachloride vapor in equilibriunl n ith the two solid phases reaches 1 atin at about 450 OC. Solutions of zirconium trichloride in alkali chloride inelts have also been considered to be thermally unstable and recent measurelnents of the zirconium potential have been conducted in nlelts containing zirconiui~l tetrachloride (3, G). Preliminary experiments in this laboratory have indicated that a t 700 OC zirconium metal is soluble in an equiinolar melt of potassiuln and sodium chlorides co~itaining either zirconium trichloride or zirconiun~ tetrachloride. Solidified material from these solutions had a dark blue color, indicating the presence of reduced zirconium species.In the experimental 1)-ork reported herein, the thermal stabilities of zirconium dichloride a i d of zirconiunl trichloride in solutioi~ were investigated by cryoscopic measureinents and by X-ray analysis.The liquidus curves of the binary s y s t e i~~s hIC1-ZrClz and IICI-ZrC13, xvl~ere &I is potassiun~ or sodium, were determined. The potentials of a zirconiuin electrode iminersed in a solution containing zirconium dichloride and thc redox potentials of the systems ZrCl2jZrCl8 and ZrClalZrCll nere also investigated. Froin the results, the equilibriu~n For personal use only.