Phase transitions and deoxidizing effect in the thermal decomposition of hydrous ferrous oxalate

Article abstract of DOI:10.1002/pssa.2211540208

Powder of hydrous ferrous oxalate is annealed in non-oxidizing atmosphere of Ar, and the solid decomposition products obtained at various temperatures are studied by Moessbauer effect (ME) and X-ray diffraction (XRD). The results indicate that in Ar the initial product which is wustite changes into magnetite and α-Fe with increasing annealing temperature, at the same time a small amount of Fe₄C appears. Annealing the oxalate at higher temperature, the magnetite in the solid products begins to transform into non-stoichiometric FeO (Fe_1-xO or FeO_x), and so an obvious deoxidizing effect of magnetite is indicated. At about 600 °C, the transition from magnetite to Fe_1-xO is already completed. Further results show that the deoxidizing effect does not result from the action of Ar and suggest that the deoxidizing effect of oxide is a general phenomenon.