Slide 1IRON: An abundant MetalMajor Producers in 2006U.S. Production and UseU.S. versus World Production Fe ore (metric tons)What are the two most important Fe ore minerals?What are other Fe ore minerals?How are they concentrated in a large enough amount to mine?Slide 9Bog IronIron StonesSlide 12BIF: World’s Major Fe SourceA BIFAn Example: Carajas, BrazilBIFWhat is common to all?Where were they formed?How exactly did they form?Here come the algae!Modern StromatolitesMore Modern StromatolitesWhy cycles of Fe and Si?Natural OreBrazilWhat is the dominant type of Mining?WHY?Open Pit MiningU. S. Iron open pit minesComparisonBeneficiationConcentrationTaconite ProcessBlast FurnaceBlast Furnace SimplifiedThe Charge for 1 Ton of FeThe ReactionPig IronNot QuiteReserves 2006China: the beast driving the systemIRONIRON: An abundant Metal•Makes of 5 wt% of the crust; 0.48 vol %•Accounts for 95% of all metals consumed•2006: 1.69 x 109 metric tons of iron ore were produced in the worldMajor Producers in 2006•China 520 million metric tons•Brazil 300 million metric tonsU.S. Production and Use•In 2006, the U.S. produced 54 million tons of iron ore•In 2006, the U.S. used 57 million tons of iron oreU.S. versus World ProductionFe ore (metric tons)What are the two most important Fe ore minerals?•Magnetite–Contains both Fe +2 and Fe +3•Hematite–Contains only Fe +3What are other Fe ore minerals?•Fe hydroxides•Fe silicatesHow are they concentrated in a large enough amount to mine?•A. Igneous–Intrusive, layered•One of our sources of Vanadium (V)–Contact Metamorphic–VolcanicHow are they concentrated in a large enough amount to mine?•Sedimentary–Residual (those laterites again)–Bog Iron–Iron Stones–Banded Iron Formations (fondly known as BIF)Bog Iron•Swamps•Very small•Fe hydroxidesIron Stones•Deposits extend from 10’s to 100’s km, up to 10 m thick•Form in a shallow marine environment •Common in rocks aged in the last 600 million years as a result of direct sedimentationIron Stones•Initially were the major Fe supply, especially during the Industrial Revolution•Names that apply to them include:–Phanerozoic–Minette (Germany, France, England)–Clinton (U.S.)BIF: World’s Major Fe Source•Taconite•Jaspilite•ItabiriteA BIFAn Example: Carajas, Brazil•CARAJÁS is an integrated mine-railroad-port system, built and operated by Companhia Vale do Rio Doce-CVRD, and it is today the backbone of the economic and social development of a huge area of north/northeastern Brazil. Today at Carajás, CVRD mines and processes 45 million tons of iron ore annually, as well as 1.5 millions tons of manganese, and 10,000 kilograms of gold. It is also preparing to produce copper, bauxite and other metals. All these activities are constantly monitored by an environmental policy that strives to conserve and recuperate delicate Amazon ecosystems. •http://www.ctc.puc-rio.br/icee-98/carajas.htmBIF•All around the world, all formed during a period 2.6 to 1.8 billion years agoWhat is common to all?•All banded, composed of iron ore and quartz•All are low in Al•All are free of cobbles/pebbles i.e. detritus•Do not appear to be related to volcanismWhere were they formed?•Broad sedimentary basins•Following long periods of continuous weathering and erosion•Land was inundated by shallow seasHow exactly did they form?•Chemical Precipitation•Fe was held in solution (water)•Atmosphere was rich in carbon dioxide and methane•There was no free oxygenHere come the algae!Modern StromatolitesMore Modern StromatolitesWhy cycles of Fe and Si?•Climatic changes (water turn over)•Micro-organisms•Cyclical evaporationNatural Ore•Or Direct Shipping ore•How was it formed?BrazilWhat is the dominant type of Mining?•Surface Mining: Open PitWHY?•Larger production capacity•Cheaper to operate/ton•Easier and safer to maintainOpen Pit MiningU. S. Iron open pit mines•Operate at a disadvantage in comparison to those in Brazil•For each metric ton of iron-oxide we must remove–5 to 6 tons of rock–3 tons of ore–2-3 tons of overburdenComparison•That’s about 12 ton of material in comparison to a comparable mine in Brazil which only has to remove 1.5 to 2 tones of rock for each ton of iron oxideBeneficiation•What does this mean?Concentration•Just another word!Taconite Process•I will talk about this!!!Blast FurnaceBlast Furnace SimplifiedThe Charge for 1 Ton of Fe•1.6 ton ore•0.7 ton coke•0.25 ton limestone•3.6 ton AIR at 1600 degrees CThe Reaction•C + ½ O2 yields CO•3CO + Fe2O3 yields 2 Fe + 3CO2•Limestone does two things. It works as a flux (lowers the melting temperature) and it aids in making a slag that absorbs undesirable elementsPig IronNot Quite•Pig iron is used in the manufacture of SteelReserves 2006•When will we run out?•160,000,000,000 Reserves•370,000,000,000 Reserve Base•World Production 1,690,000,000China: the beast driving the