Transformation of Magnetite (Fe3O4) and Maghemite (γ–Fe2O3) to a–Fe2O3 from Magnetic Phase of Glagah Iron Sand

The study of magnetite (Fe3O4) and maghemite (γ-Fe2O3) transformation to α-Fe2O3 from magnetic phase of Glagah iron sand has been done. Glagah sand was magnetised to separate magnetic and non-magnetic sand. Then, it was prepared by ball milling for 5 h (20:1 w/w) to reduce the particle size. Magnetic iron sand was roasted at 1,000°C with the addition of sodium carbonate (Na2CO3) (sand mass ratio: Na2CO3 1:2 w/w) for 2 h to reduce the silicon dioxide (SiO2) content. Characterisation of X-ray fluorescence after magnetic separation, ball milling and roasting showed an increasing percentage of Fe2O3 from 31.10% to 70.13%. Furthermore, magnetic iron sand was refluxed using hydrochloric acid (HCl) with concentrations of 3, 6, 9 and 12 M for 2 h. Then, the aqueous phase was precipitated with the addition of 3 M ammonium hydroxide (NH4OH). The obtainable sediments showed Fe2O3 optimal percentage at concentration of 12 M by 67.96%. Calcination of Fe2O3 at 400°C, 600°C and 800°C showed a phase transformation of Fe3O4 and γ-Fe2O3 to α-Fe2O3 which reached an optimum was 92.23% at a temperature calcination of 800°C was showed an optimum percentage (92.23%) of phase transformation of Fe3O4 and γ-Fe2O3 to α-Fe2O3 at a temperature of 800°C. While the thermogravimetry/different thermal analysis showed the formation of a stable α-Fe2O3 after a temperature at 707.9°C is indicated by no longer mass loss.