Redução de Óxido de Ferro: Uma Transformação Simples para Produzir Ferro Metálico a partir de Resíduo da Mineração de Ferro

Resumo

This work presents an experimental sequence, suitable for two undergraduate General Chemistry class
periods, to convert iron-mining residue rich in Fe₂O₃ into metallic iron through two complementary steps:
acid–base digestion with H₂SO₄ and aqueous electrolysis. Under teaching-lab conditions, the digestion
produced HFe(SO₄)₂·4H₂O, confirmed by X-ray diffraction (XRD), and showed that mass‑change
monitoring can be biased by the hygroscopicity of H₂SO₄, so a control setup is recommended. In the
electrolysis (graphite cathode, magnesium anode), ferromagnetic deposits of Fe⁰ were obtained and confirmed by XRD, with average yields of ~25% (1.5 V), 36% (4.5 V), and 60% (6 V) in 120 min. The setup is low-cost (including 1.5 V batteries), safe, and replicable, enabling students to investigate reaction conditions and discuss metal-extraction routes beyond traditional pyrometallurgy.