Ferrite grade iron oxides from ore rejects

[摘要] Iron oxyhydroxides and hydroxides were synthesized from chemically beneficiated high SiO₂/Al₂O₃ low-grade iron ore (57.49% Fe₂O₃) rejects and heated to get iron oxides of 96â€�??99.73% purity. The infrared band positions, isothermal weight loss and thermogravimetric and chemical analysis established the chemical formulas of iron-oxyhydroxides as ð›�?-FeOOH.0.3H₂O; ð›�?-FeOOH.0.2H₂O and amorphous FeOOH. The thermal products of all these were ð›�?-Fe₂O₃ excepting that of ð›�?-FeOOH.0.3H₂O which gave mainly ð›�?-Fe₂O₃ and some admixture of ð›�?-Fe₂O₃. The hydrazinated iron hydroxides and oxyhydroxides, on the other hand, decomposed autocatalytically to mainly ð›�?-Fe₂O₃. Hydrazine method modifies the thermal decomposition path of the hydroxides. The saturation magnetization, 𝐽_s, values were found to be in the range 60â€�??71 emu g^â€�??1 which are close to the reported values for ð›�?-Fe₂O₃. Mechanism of the ð›�?-Fe₂O₃ formation by hydrazine method is discussed.

[学科分类] 材料工程

[关键词] Ore rejects;chemical beneficiation;iron hydroxide;iron oxyhydroxide;ferrite.