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

Abstract

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.