188 results about "Iron ore" patented technology

Iron ores are rocks and minerals from which metallic iron can be economically extracted. The ores are usually rich in iron oxides and vary in colour from dark grey, bright yellow, or deep purple to rusty red. The iron is usually found in the form of magnetite (Fe₃O₄, 72.4% Fe), hematite (Fe₂O₃, 69.9% Fe), goethite (FeO(OH), 62.9% Fe), limonite (FeO(OH)·n(H₂O), 55% Fe) or siderite (FeCO₃, 48.2% Fe).