Gold is the ONLY metal that is found in a usable form, all others are found as ores.
Metal: Ore:
Iron Magnetite,Haematite
Copper Chalcopyrite
Aluminium Bauxite
Lead Galena
Tin Cassiterite
Zinc Zinc Blende
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The Structure Of Metals
Made up of crystals.
Each crystal has a boundary that is firmly bonded to the boundary of the neighbouring crystal.
The nature of the crystal depends on the material.
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Ferrous Metals: Iron and Steel
Iron is produced directly from its ore through the use of a blast furnace. The material produced is called 'pig iron' and is not of sufficient high quality to be of any commercial use.
Pig iron is converted into steel by the introduction of carbon into its structure. This is carried out in an oxygen furnace.
An alternative steel-making process is the electric arc furnace- more often used in the production of specialist steels.
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Iron and Carbon
Iron
Soft
Ductile
Carbon
Hard
Brittle
When mixed together the properties of iron are greatly improved.
Increasing carbon content:-
Becomes harder
Toughness reduces
Both medium and high carbon steel can be heat-treated to make then stronger and harder.
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Mild Steel
Base Material Iron
Additional element,carbon <0.3%
Ductility High
Hardness Low
Toughness High
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Medium Carbon Steel
Base Material Iron
Additional element, carbon 0.3-0.6%
Ductility Lower than mild steel
Hardness Higher than mild steel
Toughness Lower than mild steel
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High Carbon Steel
Base Material Iron
Additional element, carbon 0.6-1.7%
Ductility Lower than medium carbon steel
Hardness Higher than medium carbon steel
Toughness Lower than medium carbon steel
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Cast Iron
Base Material Iron
Additional element, carbon 3.5%
Ductility Low
Hardness High
Toughness Brittle
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Typical Uses Of Steels
Mild Steel
Nuts, bolts, washers, car bodies, panels for cookers and other white goods
Medium Carbon Steel
Springs and general gardening tools
High Carbon Steel
Hand tools, scribers, dot punches, chisels and plane blades
Cast iron
Machine parts, brake discs and engines
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Bauxite
The most common metal in the Earth's crust- can be made into aluminium using electrolysis.
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Aluminium
Melting Temperature - 660
Properties -
Excellent conductor of electricity
Uses -
Kitchenware e.g. saucepans
When drawn into wire used in overhead power cables
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Copper
Melting Temperature - 1083
Uses -
Electrical contacts
Domestic pipework
In wire form it is used for electrical cable and wire
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