Effect of Various Electrolyte Compositions on the $NiO$ Degradation in Molten Carbonates

In the present paper we report the $NiO$ solubility in a variety of alkali carbonate compositions in the presence of $MgO$⁠, $CaCO3$⁠, $BaCO3$⁠, and $La2O3$ additions under different conditions of gas composition and temperature. Two types of binary eutectic melts were chosen, namely, the standard electrolyte (62-38) $(Li-K)2CO3$ and (52–48)% $(Li-Na)2CO3$ mixtures. The ternary eutectic melt chosen was $(43.5-31.5-25.0)mol%$$(Li-Na-K)2CO3$⁠. The observed reduction of $NiO$ solubility induced by the additives can be explained in terms of a higher basic character of all the modified electrolytes, although the $NiO$ dissolution still follows an acidic dissolution mechanism in all the conditions under study.