About Iron Ore

About this Website

In this website I will outline what iron ore is, what is is used for, who the large suppliers are, where it can be found and update with some iron ore prices and iron ore trade news.

What is Iron Ore?

Iron Ore is the base material which can be used to make Pig Iron, which itself is used to make Steel.  The iron is usually present in the form of iron oxide (known as hematite and magnetite) but can also be present as other compounds.  Iron ore is one of the most important minerals in the world and, along with coal is also one of the most widely transported.  It is often mentioned that steel production, and by inference iron ore shipment levels are a great barometer for the health of the world economy. The vast majority of iron ore is mined in a very small number of countries – notably Brazil, Australia and India and is generally transported to other parts of the world, particularly China and East Asia, North America and Europe – more information of the main suppliers of iron ore can be found here – iron ore producers.

Iron Ore Smelting

As mentioned previously, iron is present in iron ore as an Iron Oxide so somehow the iron and oxygen bonds need to be broken to create pure iron.  The way this is done is by introducing carbon for the Oxygen to bond with instead of the iron.  The reduction agent used is Carbon Monoxide (CO) which bonds with an Oxygen atom at each stage of the reduction process to produce a reduced Iron Oxide and Carbon Dioxide at each stage until finally just Iron and Carbon Dioxide is produced at the last stage.

To obtain Carbon Monoxide, coke is oxidised in a low oxygen environment (to prevent the production of Carbon Dioxide).  Iron Ore also contains many trace elements which are genereally undersirable in steel, and these elements are generally removed in the form of slag, which is produced as a waste material and can have some uses in industries such as the cement industry.

In order for this process to work, the ore has to be in a form that will allow air flow through the particles which means that it has to either be in the form of fairly large chunks or in the form or iron ore pellets.

Impurities and Trace elements

As mentioned, there are a number of impurities in iron ore, some of the more common ones are:

  • Silica – Silica is nearly always present in iron ore, most is removed as slag but some is reduced down to Silicon as this can have some beneficial properties in steel
  • Aluminium – Aluminium is sometimes present and is quite hard to reduce
  • Sulphur – Sulphur in iron and steel causes it to be brittle when hot, which is very undesirable.  There are a number of ways to remove Sulphur, including roasting the ore to form Sulphur Dioxide, the addition of Manganese to bond with the Sulphide or, more commonly, the addition of desulphurizing agents (typically Calcium or Magnesium) which bond with the Sulphur when added in the form of powder, transported with an Argon blast into the molten steel.
  • Phospherous – Phospherous in iron and steel can make it brittle at low temperatures, and therefore needs to be removed or controlled.  This is done by the addition of Iron Oxide to oxidise the Phospherous.

Once these impurities have been removed, the liquid iron can be removed in batches to make what is known as pig iron.  The pig iron is then further worked to remove more impurities, to carefully control the carbon content and to add alloying metals such as Chrome and Molybdenum.  The main process for the continued refining of pig iron into more usable steel is known as the Basic Oxygen Furness (BOF) process and this method can be used to create steel ingots, billets or other semi finished products.

 

 


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