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Useful metal properties
- Strength and hardness
- Cheap cost of production
- Versatility of shapes
- Durable
- Conductivity and magnetisim
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Important Metal groups (5)
Structural Metals (strong)
Workable metals (ductile)
Heavy Metals (toxic)
Radioactive Metals (unstable)
Noble metals (non- corroding
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Extraction of ore
Metals Require energy intensive extraction techniques and generate greenhouse gases
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Steel Production Steps 1.2.3
1. Reduction of iron ore to pig iron (high carbon content)
2. Refining pig iron into steel
3. Forming steel into products
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Reduction of Iron ore to Pig Iron
- Blast furnance with carbon (coke) ,limestone and iron ore
- Lime stone removes impurities in from iron ore
- Slag (stuff left ontop of pig iron) is non metallic and contains silicates
- Molten iron with carbon is collected at the bottom
- Pig iron is not pure iron, but has high carbon content, manganse, silicon
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Cast Iron Properties
- Made directly from re smelting pig iron with coke in smaller furnance
- Carbon Content between 2 to 4.5%
- Brittle material
- Does not soften when heated metls at 1232 degrees
- Easy to cast
- Reasonably corrosion resistant in water
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Types of cast iron 5
- Gray iron
- Ductile iron
- White Iron
- Malleable Iron
- Wrought Iron
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Gray Iron characteristics
- Graphic flakes
- Weak and brittle under tension
- Stronger under compression
- Excellent Vibrational dampening
- Wear resistant
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Ductile iron
- Add Mg or Ce
- Graphite in modules not flakes
- Matrix often pearlite - better ductility
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White iron
- 1% Si so harder but brittle
- More cementitie
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Malleable Iron
- Heat treat 800-900 degrees
- Graphite in rosettes
- More ductile
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Wrought Iron
- Made from further smelting of cast iron
- almost pure iron
- Produced by combining molten metal with small amounts of hot slag
- Becomes soft when heated Melts at 1538
- Ductile
- Not easily cast
- Cold worked, forgerd, welded
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Refining Pig iron and scrap to metal process
Kelly Bessemer Process (1855)
- Air blast used to refine pig iron. Burns up impurities such as carbon, silicon and manganese
- Produces steel then wrought iron
- Robert Mushet and Goren Goranson modified the process to produce steel
- Basic oxygen furnace - 300tons in 25 mins
- Electric arc - melts steel uses a lot of energy
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