iron: Quick Facts

Iron (Fe) is a chemical element and a metal, ranking as the most abundant and cheapest metal in widespread use. It is the primary component of steel and is found in various minerals, notably hematite and magnetite. Iron constitutes about 5% of Earth's crust and is the most abundant element in Earth as a whole. In its pure form, iron is relatively soft, but its properties are significantly altered by the addition of carbon, forming steel. Iron has a melting point of 1,538 °C (2,800 °F).

Iron, a fundamental chemical element, is integral to numerous everyday applications due to its strength and versatility. It is the primary component of steel, which is extensively used in construction for buildings, bridges, and infrastructure. In transportation, iron and steel are crucial for manufacturing vehicles, trains, and ships. Everyday tools, from kitchen utensils to industrial machinery, are often made from iron or its alloys. Furthermore, iron is vital for household appliances, cookware, and even decorative items like railings and gates. Its magnetic properties also find use in various electronic components.

Iron is found in Earth's crust, making up about 5 percent of its composition, and is the fourth most abundant element overall. While the free metal is rare in the crust, iron is abundant in Earth's core, which is primarily composed of nickel-iron. Iron is also plentiful in the Sun and other stars.

In nature, iron is most commonly found combined with other elements in various minerals. The most significant iron ores are oxides, including hematite (Fe₂O₃), magnetite (Fe₃O₄), limonite (hydrated ferric oxide hydroxide), and siderite (FeCO₃). These ores are found in igneous, metamorphic, and sedimentary rocks. Major iron ore-producing countries include China, Brazil, Australia, Russia, and Ukraine.

Iron (Fe) is a dense metal with a silvery-white appearance and notable magnetic properties. It is the fourth most abundant element in Earth's crust and melts at 1,538° C (2,800° F). Iron is allotropic, meaning it exists in different crystal structures (body-centered cubic or face-centered cubic) depending on the temperature. In its pure form, iron is malleable, but it is typically used in alloys like steel to enhance its properties. Pure iron is reactive, especially in finely divided states, and readily combines with nonmetals. It is also ferromagnetic below 770° C (1,420° F), a property known as the Curie point.

Iron is crucial for living organisms, primarily for its role in oxygen transport and electron transfer reactions. In humans and many other animals, iron is a key component of hemoglobin, the protein in red blood cells responsible for carrying oxygen from the lungs to the body's tissues. Iron also functions as a cofactor for various enzymes, which are essential for catalyzing biochemical reactions necessary for life. Iron deficiency is a widespread nutritional deficiency, leading to conditions like iron-deficiency anemia, characterized by fatigue and reduced growth and development.

Iron is primarily extracted from ore using a blast furnace, a process that releases iron from its chemical combination with oxygen. Iron ore, coke, and limestone are fed into the top of the furnace. Preheated air is blown in from the bottom, causing the coke to burn and generate intense heat. This heat reduces the iron oxides in the ore to metallic iron. The molten iron and slag collect at the bottom and are tapped off separately. Alternative methods like direct reduction and smelting reduction are also employed, though less common than the blast furnace.