Solubilities of alkali earth metal carbonates in KCl-NaCl eutectic

3 SOLUBILITIES OF ALKALI EARTH METAL CARBONATES IN KCl-NaCl EUTECTIC 

Carbonates are often used for studies in molten halides, which is connected with their basic character, i.e. they are donors of O2-. Since alkaline carbonates are suitable for Lux acid neutralization they are often used as Lux bases (oxide ion donors) in molten halide melts to study the acid-base equilibria [165, 178, 185]. Quantitative estimations of the carbonate ion s basicity in different melts are performed on the assumption of its dissociation according to equation (2.3). 

Known investigations of the reaction (2.3) in molten chlorides were performed both under equilibrium (i.e. with a constant C02 pressure over the melt in the process of the experiment) [310, 312] and non-equilibrium 

Equilibria in solid oxide-ionic melt systems 

All the above-said concerns alkali-metal carbonates dissolved in melts based on alkaline- and alkaline-earth metal halides. It should be mentioned that there is a lack of data on the behaviour of alkaline-earth carbonates, in high-temperature alkaline halide melts. Nevertheless, these data are necessary, in particular, for the purification of halide melts. For example, it is known that alkaline-earth oxides possess appreciable solubilities in molten alkaline halides, and that they can be used for precipitation of less soluble transition metal-oxides. After such a precipitation, the excess of alkaline-earth oxide remains in the dissolved state. The question arises, therefore, whether it can be removed from the halide melt by passing C02 according to the conventional reaction 

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Solubilities of alkali earth metal carbonates in KCl-NaCl eutectic... 

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