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Iron(III) oxide (Fe₂O₃); one of the two primary iron ore minerals used in iron smelting. Red to silver-grey in color; hardness 5–6 on Mohs scale; specific gravity ~5.26 g/cm³. The most abundant iron ore in Earth’s crust and the primary ore for the majority of global iron production historically and industrially. Contains ~70% Fe by mass when pure, though ores are typically 50–65% Fe by mass. [Sources: Klein, C. & Dutrow, B. (2007), ‘Manual of Mineral Science’, 23rd ed., Wiley, pp. 338–340; common mineralogical knowledge.]
Common forms
- Lump ore (crushed run-of-mine)
- Sintered or pelletized ore (industrial preparation)
- Powder (after roasting and crushing for bloomery use)
- Specularite (silvery platy crystals)
Common sources
- Banded iron formations (BIFs) — Precambrian sedimentary deposits; major global iron ore source (e.g., Pilbara, Australia; Carajás, Brazil; Lake Superior region, USA)
- Gossan and laterite deposits — secondary enrichment zones
- Bog iron — limonite/goethite ores that convert to hematite on roasting; historically important for small-scale bloomery smelting in Europe [Source: Tylecote (1992), ‘A History of Metallurgy’, 2nd ed., Institute of Materials, London, pp. 20–22]
Composition
Fe₂O₃ (iron III oxide); theoretical iron content 69.9 wt% Fe. Natural ores contain silica, alumina, and other gangue minerals reducing effective Fe content to typically 50–65 wt% in run-of-mine ore.
Hazards
- Fine hematite dust is a respiratory irritant; chronic inhalation associated with siderosis (iron dust pneumoconiosis). [Source: IARC, common occupational health knowledge]
- No acute chemical toxicity in bulk form; inert at ambient temperatures
Properties
- color: Red to silver-grey (specular hematite); streak always red-brown — diagnostic field test
- magnetic: Weakly magnetic in pure form (unlike magnetite); some varieties (martite) non-magnetic
- reducibility: Reduced by CO in stages: Fe₂O₃ → Fe₃O₄ → FeO → Fe; reduction begins above ~570 °C [Source: Kubaschewski & Alcock (1979), ‘Metallurgical Thermodynamics’, 5th ed., Pergamon, pp. 267–271]
- melting_point: ~1565 °C (decomposes before melting under atmospheric pressure)
- mohs_hardness: 5–6
- crystal_system: Trigonal (rhombohedral)
- specific_gravity: ~5.26 g/cm³
Purity grades
- High-grade lump ore: 60–68% Fe
- Standard ore: 50–60% Fe
- Low-grade/beneficiation feed: below 50% Fe; requires concentration before use
Connections
Incoming
- Requires input ← Bloomery Iron Smelting — Hematite is the most commonly used iron ore feedstock in bloomery smelting; charged in alternating layers with charcoal at roughly 1:1 mass ratio. May be roasted prior to charging to increase porosity and remove sulfur. Not exclusive — magnetite and other ores also used.
- Requires input ← Blast Furnace Ironmaking — Hematite (Fe2O3) is the primary iron ore feedstock; typically sintered or pelletized before charging. Standard feed grade 55–68 wt% Fe.