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 color from dark grey, bright yellow, deep purple, to rusty red (How Does Iron Ore Form?). The iron itself is usually found in the form of magnetite (Fe3O4), hematite (Fe2O3), goethite (FeO(OH)), limonite (FeO(OH).n(H2O)) or siderite (FeCO3).
Ores carrying very high quantities of Hematite or Magnetite (greater than ~60% iron) are known as “natural ore” or “direct shipping ore”, meaning they can be fed directly into iron-making blast furnaces. Iron ore is the raw material used to make pig iron, HBI, DRI and Iron Nuggets, which are the main raw materials to make steel. 98% of the mined iron ore is used to make steel. Indeed, it has been argued that iron ore is “more integral to the global economy than any other commodity, except perhaps oil”.
DRI, HBI, MPI & Iron Nuggets all have:
Known, consistent Chemistry
Hight Fe, Low residual content
And year around availability
Merchant Iron Units = Scrap and Ore-based Metallics
Iron is the world’s most commonly used metal – steel, of which iron ore is the key ingredient, representing almost 95% of all metal used per year. It is used primarily in structural engineering applications and in maritime purposes, automobiles, and general industrial applications such as machinery (How Iron And Steel Work).
The major constraint to economics for iron ore deposits is not necessarily the grade or size of the deposits, because it is not particularly hard to geologically prove enough tonnage of the rocks exist. The main constraint is the position of the iron ore relative to market, the cost of rail infrastructure to get it to market and the energy cost required to do so.
World production averages two billion metric tons of raw ore annually.
Prior to the industrial revolution, most iron was obtained from widely available goethite or bog ore, for example during the American Revolution and the Napoleonic wars. Prehistoric societies used laterite as a source of iron ore. Historically, much of the iron ore utilized by industrialized societies has been mined from predominantly hematite deposits with grades in excess of 70% Fe. These deposits are commonly referred to as “direct shipping ores” or “natural ores”. With increasing iron ore demand, coupled with the depletion of high-grade hematite ores in the United States, after World War II led to development of lower-grade iron ore sources, principally the utilization of magnetite and taconite.
Merchant Pig Iron (MPI)
Hot Briquetted Iron (HBI)
Direct Reduced Iron (DRI)
1 Wikipedia.org – Iron-Ore
2 What Are Ore Based Metallics – Alberto Hassan, May 2011, Ore-Based Metallics Seminar