Steel Story

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  • Created by: Natasha
  • Created on: 17-04-12 15:29
  • To make iron, it is first nece**ary to mine iron ore.
  • Iron ore is simply rock with a high concentration of iron within it. Usually the ores are mixed into rocks which contain silica. (http://www.4college.co.uk/a/**/ironextraction1.gif)
  • From the table above, it is evident that the iron ores contain oxygen.
  • In order to make the iron from the ore, the oxygen must first be removed. This can be achieved using a blast furnace in which a series of reduction reactions occur.
  • Ores of iron greater than 5mm can be placed straight into the blast furnace; however these are in short supply and so the iron first goes through agglomerating proce**es (fuse together the smaller lumps of ore) such as sintering or pelletising. These proce**es involve mixing together the iron with controlled quantities of fluxes. (http://www.4college.co.uk/a/**/ironextraction2.gif)
  • Iron, limestone and coke are fed into the top of the blast furnace. The limestone is melted to become the ****, which removes impurities such as sulphur.
  • The main fuel used in the blast furnace is coke. This is made by heating carbon in the absence of oxygen. The coke is burnt in heated air (1,100 K to 1,600K) and then blown into the furnace at the bottom. The coke reacts with oxygen in the hot air blast to form carbon monoxide:
    2C(s) + O2(g) (http://www.4college.co.uk/a/**/arrow.gif) 2CO(g)
  • Hydrocarbons can also be used as a fuel, and these react similarly to produce carbon monoxide and hydrogen.
    CH4(g) + 0.5O2(g) (http://www.4college.co.uk/a/**/arrow.gif) CO(g) + 2H2(g)
  • The gases move up the blast furnace where they reduce the iron oxides (at different temperatures):
    Fe2O3(s) + 3CO(g) (http://www.4college.co.uk/a/**/arrow.gif) 3CO2(g) + 2Fe(s)
    Fe2O3(s) + 3C(s) (http://www.4college.co.uk/a/**/arrow.gif) 2Fe(s)+ 3CO(g)
  • The products formed from the reactions above begin to melt and trickle down to the bottom of the blast furnace.
  • The limestone also descends to the bottom of the blast furnace where it is thermally decomposed:
    CaCO3(s) (http://www.4college.co.uk/a/**/arrow.gif)CaO(s) + CO2(g)
  • The basic calcium oxide produced in this reaction then goes on to react with acidic impurities in the iron:
    FeS(s) + CaO(s) + C(s) (http://www.4college.co.uk/a/**/arrow.gif) CaS(s) + FeO(s) + CO(s)
    CaO(s) + SiO2(g) (http://www.4college.co.uk/a/**/arrow.gif) CaSiO3(s)
  • The CaS and CaSiO3 become the ****, which also contains other impurities such as MgO, CaO, SiO2and Al2O3. The liquid **** is le** dense than iron and so it floats on top of the molten iron at the bottom of the furnace.
  • The molten iron and liquid **** are removed from the furnace through the tap holes at the base.
  • The **** can be used to make bi-products such as cement. The hot gases produced are cleaned and are then burned as a fuel in the hot blast stoves that are used to preheat the air that is blown into the furnace.

The Basic Oxygen Steel making (BOS) Proce**

  • In the UK, steel is made using the BOS proce**…

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