Transformation of Goethite into Hematite

Goethite (α-FeOOH) is one of the most common iron oxyhydroxides found in lateritic iron ores, bauxite residues, and sludges from hydrometallurgical processes. It presents significant challenges due to its high structural water content, fine particle size, and low thermal stability, affecting mineral processing, filtration, and metallurgical operations. Converting goethite into hematite (α-Fe₂O₃) is crucial for enhancing material handling, improving process efficiency, and facilitating the production of high-value products, such as iron ore pellets and pigments. This review provides a comprehensive analysis of the mechanisms, thermodynamics, and kinetics that govern the dehydration of goethite through thermal, hydrometallurgical, and hybrid methods. It highlights recent advances (2020–2025) in process technologies, such as low-carbon heating techniques, controlled precipitation, and integrated circular economy strategies for residue valorization. Characterization methods, such as X-ray diffraction (XRD), Mössbauer spectroscopy, and thermogravimetric analysis (TGA), are examined for their roles in monitoring phase transformations. The review critically assesses industrial applications, process optimization strategies, and future perspectives, emphasizing the importance of goethite transformation for sustainable iron production and waste management.