Solubility of Li[sub 2]O in Molten LiCl–MCl[sub x] (M=Na, K, Cs, Ca, Sr, or Ba) Binary Systems

The solubility of oxide ions in LiCl-rich (, K, Cs, Ca, Sr, or Ba) melts was measured in the temperature range 723–923 K as part of the development of an electrolytic reduction process for spent nuclear fuel because the solubility of oxide ions strongly affects the rate of oxide reduction. With the exception of the system, the precipitate was under an oversaturated condition. The solubility of in molten LiCl at 923 K was determined to be . The solubility significantly decreased when alkali metal chlorides (NaCl, KCl, and CsCl) were added to LiCl and slightly decreased when was added. In contrast, the addition of increased the solubility. Empirical formulas for the relationship between solubility and salt composition were derived. The logarithm of solubility plotted against the reciprocal temperature gave an approximately linear relationship in the LiCl–KCl system. The addition of to LiCl saturated with gave a CaO precipitate.