Molten eutectic mixture

Downs A process for making sodium by electrolyzing a molten eutectic mixture of sodium chloride and calcium chloride at 580°C. Invented in 1922 by J. C. Downs at Du Pont, and widely used ever since. In the United Kingdom it was first used in 1937. 

Molten single salts or molten eutectic mixtures are generally characterized by very high ionic conductivities (> 100 S/m). This property makes them desirable media as battery electrolytes since it permits operation at high... 

Magnesium electrochemistry in molten salts media is especially important for the mass production of the pure metal. Magnesium is frequently produced and refined by electrolysis of high-temperature, molten eutectic mixtures of anhydrous MgCl2 with various salts, such as KC1, CaCl2 etc. High-temperature molten salts baths, with similar compositions, with the addition of borate are also studied for the production of MgB2. 

In the molten carbonate process a molten eutectic mixture of lithium, sodium, and potassium carbonates removes sulfur oxides from power plant stack gases. The resulting molten solution of alkali metal sulfites, sulfates, and unreacted car bonate is regenerated in a two-step process to the alkali carbonate for recycling. Hydrogen sulfide, which is evolved in the regeneration step, is converted to sulfur in a conventional Claus plant. A 10 MW pilot plant of the process has been constructed at the Consolidated Edison Arthur KiU Station on Staten Island, and startup is underway. 

In the molten carbonate process, a molten eutectic mixture of lithium, sodium, and potassium carbonates is used to scrub the power plant gas stream. The sulfur oxides in the gas stream react with the carbonates to form sulfites and sulfates which remain dissolved in excess unreacted carbonate melt. The molten carbonate-sulfite-sulfate mixture is then... 

Kaneko and Kojima studied the oxoacidic properties of Na2S207 and Na202 in the molten eutectic mixture K2S04-Li2S04-Na2S04 at 550 °C [124, 125]. The difference of pO values in their 0.01 mol kg-1 solutions is equal to 10 pO units. This value allows us to determine that the width of the acid-base range for the standard solutions in this melt is equal to 14 pO units. The acid-base range of stable existence of V02+ ion is found to lie within the interval of pO = 8.5-10.6. 

The investigations of MgO solubility in the molten eutectic mixtures make it possible to trace the thermal dependence of the MgO solubility product in ionic melts possessing quite different acidic properties. These dependences are presented in Fig. 3.7.17. They are practically linear, although in both dependences there is a bending towards the inverse-temperature axis near 700 °C. Nevertheless, both plots can be approximated by the following equations (on the molar-fraction scale) ... 

V.L. Cherginets and T.P. Rebrova, Studies of Some Acid-Base Equilibria in the Molten Eutectic Mixture KCl-LiCl at 700°C, Electrochim. Acta 45 (1999) 469-476. 

T.P. Boyarchuk, E.G. Khailova and V.L. Cherginets, Potentiometic Investigation of Solubilities of Oxides in Molten Eutectic Mixture of Caesium, Potassium and Sodium Chlorides, Preprint of Institute for Single Crystals, IMK-91-17 (Kharkov, 1991) p. 14. 

Maslov, S.V, Volkovich, VA. and Vasin, B.D. (1994) Dissolution of niobium metal in molten eutectic mixture of sodium and cesium chlorides (in Russian). Rasplavy (Melts), 4, 37-40. 

Environment Molten eutectic mixture of sodium, potassium and lithium chloride at melt temperatures ranging from 500 to 600°C. The pot used was a weld cylinder with 3 mm thick steel walls and 305 mm in height. 

The process operates with a closed absorbent cycle in which a molten eutectic mixture of sodium, potassium, and lithium carbonate is circulated to react with the sulfur oxides in the flue gas. The sulfur compounds are absorbed at about 800°F, forming sulfites and sulfates in the melt. The molten salt is next processed in a reducer, operating at about 1,400°F, which uses petroleum coke to convert oxidized sulfur species to the sulfide form. Heat is provided in the reducer by oxidation of a portion of the coke with air. 

Lux reported the oxygen electrode reversibility investigation and constmction of empirical acidity scale for the molten eutectic mixture K2S04-Na2S04 at 800°C. The thermal stability of pyrosulfates has been shown by Flood et to decrease with the... 

We investigated reactions of Be and Mg cations with in the molten eutectic mixture of CsCl-KCl-NaCI at 783°C by potentiometric method using Pt(02) YSZ indicator electrode. Addition of 0 ions to the melt containing Mg results in precipitation of MgO (pKj Mgo = 11.89 0.3, molality) whereas interaction of Be with 0 is accompanied by sequential formation of Be20 (pK = 15.68 0.5, molality) and precipitation of BeO (pKg Beo " 9.62 0.3, molality). On the basis of the obtained and known data pK ... 

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