The oxidation of FeV2O4 by oxygen in a sodium carbonate mixture

The oxidation of FeV2O4, synthetic coulsonite, in a sodium carbonate mixture was studied by using thermal analysis and X-ray powder diffraction techniques. The vanadium is converted to water-soluble sodium vanadates in the temperature range 300°C to 800°C. Product formation is dependent on the amount of sodium carbonate present in the mixture. Na3VO3 and Fe2O3 were formed in a stoichiometric mole ratio of FeV2O4:Na2CO3 of 1:1 whereas Na3VO4, Na4V2O7 and Fe2O3 were formed in a 2:5 mole ratio mixture and Na3VO4 and NaFeO2 in a 1:5 mole ratio mixture. This temperature is much lower that the processing temperature of ∼1050°C currently used for the roasting of a titaniferous magnetite ore.