The reactions of some compounds of manganese with molten lithium carbonate-sodium carbonate-potassium carbonate eutectic

Abstract

The reactions of MnO, MnCl₂, MnCO₃, MnSO₄, Mn₂O₃, Mn3O₄, MnO₂ and KMnO₄ with molten lithium carbonate-sodium carbonate-potassium carbonate eutectic were studied under argon as well as carbon dioxide atmospheres. Final products for MnCl₂ reaction consisted of a mixture of oxy anions, MnO₂- and MnO₃^2-, and those for MnCO₃ were MnO₃^2- and Mn₂O₅^2- as were for the reactions of MnSO₄ and MnO₂. Mn₂O₃ and Mn₃O₄ reacted to form the oxy anion, MnO₂-. KMnO₄ decomposed to form initially a mixture of Mn₇O₁₆^4- and MnO₄^2-. These oxy anions reacted further with the eutectic to produce the oxy anion, MnOS₃^2-. Three alkali metals were present as cationic species with the above manganese oxy anions in different ratios.

The carbonate melt acted both as a reaction medium and as a Lux-Flood base, that is a donor of oxide ions evolving carbon dioxide which was partly reduced to carbon monoxide in the reactions involving manganese(II) compounds. The stoichiometries of these reactions have been suggested. Manganese(II) oxide was found to be unreactive with the carbonate eutectic.