Synthesis of active goethite and maghemite from scrap iron sources

摘要

Investigations have been carried out on the oxidative hydrolysis of iron(Ⅱ) chloride using Na_2CO_3 or NaOH. The products were subjected to hydrothermal agitation before being filtered and dried at 110℃. The samples were characterised by chemical analysis, surface area by nitrogen adsorption, thermal analysis and XRD. The studies indicate that samples prepared by different procedures and at different temperatures result in the formation of mixtures of goethite (α-FeOOH), maghemite (γ-Fe_2O_3), ε-Fe_2O_3 and Fe_3O_4 in varying compositions. All the samples, when heated to 400℃ or above, are converted to α-Fe_2O_3.