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 MnO32-, and those for MnCO3 were MnO32- and Mn2O52- 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 Mn7O164- and MnO42-. These oxy anions reacted further with the eutectic to produce the oxy anion, MnOS32-. 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.