Iron production and steel
From furnace iron to steel
1. Iron ores and extraction of iron
2. Is steel just iron?
Car bodies, bridges and many tools are made of steel. Yet the furnaces you met so far give iron, not steel.
Pick the right answer
Predict: what is steel?
- A. Pure iron
- B. Iron exactly as it leaves the blast furnace
- C. Iron, cleaned of impurities, with some elements added
- D. A metal different from iron
Explanation
Steel is made from the iron that leaves the furnaces by two processes: removal of impurities, and addition of some elements to give the required properties.
3. The third stage
- Ore dressing → Reduction of iron ores
- Reduction of iron ores → Iron production
After the reduction of iron ores in the blast furnace or Midrex furnace comes the third step: iron production.
It produces different types of iron, such as cast iron and steel.
4. Two essential processes
The steel industry depends on two essential processes:
- Removal of impurities from iron resulting from the furnaces.
- Addition of some elements to iron to produce steel with the required properties for industrial purposes.
- Iron from the furnaces → Removal of impurities
- Removal of impurities → Addition of some elements
- Addition of some elements → Steel
5. From ore to steel
Put in order
Put the steps in order, from ore to steel.
- Roasting the ore in air
- Reducing the ore with CO (or CO + H₂)
- Removing impurities from the furnace iron
- Adding some elements to give the required properties
6. Steel furnaces
- Iron from the furnaces → Oxygen converter
- Iron from the furnaces → Open-hearth furnace
- Iron from the furnaces → Electric furnace
- Oxygen converter → Steel
- Open-hearth furnace → Steel
- Electric furnace → Steel
Steel is produced by one of three furnaces: the oxygen converters, the open-hearth furnace or the electric furnace.
7. Two mix-ups
| Iron from the furnaces | Steel | |
|---|---|---|
| Made in | Blast furnace or Midrex furnace | Oxygen converter, open-hearth furnace or electric furnace |
| Made from | Iron ore | Iron from the furnaces: impurities removed, some elements added |
8. Check yourself
Sort into groups
Which job does each furnace do?
Blast furnaceElectric furnaceMidrex furnaceOpen-hearth furnaceOxygen converter
Pick the right answer
A student removes every impurity from furnace iron and adds nothing. Has the student made steel?
- A. Yes: steel is iron with the impurities removed.
- B. No: steel also needs some elements added for the required properties.
- C. Yes, if it was done in the blast furnace.
Explanation
Removal of impurities is one of the two processes. Steel also needs some elements added to give the required properties for industrial purposes.
9. Summary
- Third stage: production of different types of iron, such as cast iron and steel.
- Steel: removal of impurities from furnace iron + addition of some elements.
- Steel furnaces: oxygen converters, open-hearth furnace, electric furnace.
Back to the hook: can you explain why steel is not the same as the iron from the blast furnace?
Reveal
The iron from the blast furnace still holds impurities. Steel is made from it in a steel furnace: the impurities are removed, then some elements are added to give the required properties.