Thermal Analysis Of Magnesium Ferrite Synthetic Process

The synthesis process of magnesium ferrite is always concerned during preparing metallurgy materials and inorganic materials. In this paper the synthesis process of magnesium ferrite was researched by using samples of active magnesia and iron, active magnesia and magnetite, active magnesia and Fe₂O₃(analytically pure) with thermal analysis, XRD, SEM, and petrographic analysis. Meanwhile the kinetics of the magnesium ferrite reaction has been carried out. The results are as follow:1. Solid state reaction between active magnesia and iron, active magnesia and magnetite, active magnesia and Fe₂O₃ occurred as revealed by the exotherm in DSC which is resulted in magnesium ferrite.2. The formation of the magnesium ferrite in samples of the mixture of active magnesia and iron has been proved indirectly by comparing the conversion rate of TG —DSC curves from 900K to 1250K. The existence of the magnesium ferrite has been determined from XRD and petrographic analysis directly.3. According to the method of Achar—Brindley—Sharp— Wendworth, thekinetics equation —da/dT= βk(1-α)^1.25 has been established at the apparent stage ofsynthesis magnesium ferrite with the data of the heat flow curve of the mixture of active magnesia and Fe₂O₃, and mechanism function is fit for the model of nucleation forming and growing at random.4. The results of XRD of the mixture of magnetite and active magnesia show that the magnesium ferrite was formed at 1173K. With temperature increasing the yield of magnesium ferrite increased and it got the maximum at 1523K. There are parts of magnesium ferrite decomposed at 1723K. The kinetics equation has been established in the process of synthesizing magnesium ferrite using XRD data. According to the equation, the activation energy of formation (Ea) of magnesium ferrite was determined as 58KJ/mol at 1173-1523K for the samples of active magnesia and magnetite.