Metals Flashcards
What’s the most common ore ?
Aluminium is the most common ore followed by iron
In general, the more rare a material is the more…
expensive it is
however a common ore like aluminium is still expensive because its expensive to process as you have to use electrolysis rather than heat to extract it from the ore
Where do metals come from ?
ores which are found in the ground
What percentage of the earths crust is made up of metal ores ?
25% of the earths crust is made up of metal ores
The ores do not re-grow when we dig them up meaning that they are …
Non-renewable and unsustainable
What ore does iron come from ?
Magnetite, haematite
What ore does copper come from ?
Chalcopyrite
What ore does aluminium come from ?
Bauxite
What ore does Lead come from ?
Galena
What ore does Tin come from ?
Cassiterite
What ore does Zinc come from ?
Zinc blende
What are the 3 categories of metals ?
Ferrous, non-ferrous and alloys
What is the structure of the metal ?
All metals are made up of crystals. Each crystal has a boundary that is firmly bonded to the boundary of a neighbouring crystal
What does the nature of the crystal depend on ?
The nature of the crystal depends very much on the material
for e.g. steel is made up from iron and carbon so these elements will be seen within the microstructure of the material
How do you extract iron ?
We extract iron from magnetite ore using a blast furnace.
How does a blast furnace work ?
1) Solid raw materials - iron ore, coke, limestone - are added from the top of the blast furnace
2) Hot air is blown in to the bottom of the blast furnace and provides the oxygen for the coke (carbon) to burn
3) Iron oxide in the iron ore reacts and changes to iron - molten iron trickles to the bottom of the furnace
4) Limestone reacts with impurities to form a slag that floats on the iron
5) Waste gases are removed to a treatment plant
What are the properties of ferrous metals ?
- Ferrous metals contain iron
- They will corrode if unprotected
- Ferrous metals are magnetic
What happens if you add carbon to iron ?
It forms steel
Why is iron not commercially viable ?
Because iron is generally soft and ductile which makes it not commercially viable
How do the properties of iron change when carbon is added to it ( when is becomes steel ) ?
When carbon ( a very hard and brittle element ) is mixed with iron the characteristics of iron are greatly improved - it becomes more harder and tougher
What does increasing carbon content do to a material ?
- the material becomes harder
- toughness reduces - cast iron is brittle under impact
- Both medium and high carbon steel can be heat treated to make them harder and stronger
What’s the most plentiful metal found in the earths crust
Aluminium
Why is aluminium high in demand
Because its both light and strong
How is aluminium extracted from aluminium oxide ( bauxite )
It is extracted by electrolysis - electricity passes between the electrodes and pure aluminium forms at the cathode
Name some ferrous metals
- cast iron
- high speed steel
- low carbon steel
- medium carbon steel
Name some Non-ferrous metals
- Aluminium
- Zinc
- Copper
- Sliver
- Gold
- Titanium
- Tin
Name some ferrous alloys
- Stainless steel
- Die steel ( tool steel )
Name some Non-ferrous alloys
- Brass
- Bronze
- Pewter
- Duralumin
Name all the performance characteristics of metals
- hardness
- toughness
- malleability
- elasticity
- tensile strength
- density
- resistance to corrosion
- thermal conductivity
- electrical conductivity
- melting points
- ability to be alloyed
- ability to be joined with heat processes
- ability to take applied coating and finishes
