Metals
Metals
•
There are two groups of Metals
1. Ferrous –
consist mainly of IRON
2. Non Ferrous – contain NO IRON
Where do metals come from?
• Metals come from rocks
in the ground called ORE
• The ORE is mined from the ground
• The metal must then be taken from the Ore
and a big Furnace does this.
Iron
• Iron comes from Iron Ore which is
excavated from the ground.
• The furnace used to separate the Iron from
the rocks is called a
BLAST FURNACE
Blast Furnace
Blast Furnace Charge
1. Iron Ore----------------------2. Coke------------(fuel)
3. Limestone-------------------(Keeps waste bits together)
Iron Ore
• Iron ore is a rock that contains iron
combined with oxygen.
• Some of the world's highest quality iron ore
comes from Australia.
Coke
• Coke is made from coal. Once mined, the
coal is crushed and washed.
• Coal is then baked in coke ovens for about
18 hours.
• During this process, by-products are
removed and coke is produced.
Flux
• Flux is a term for minerals used to collect
impurities during iron and steelmaking.
• Limestone and dolomite are fluxes.
• The flux causes a chemical reaction and
elements not needed for steelmaking join
together to form slag.
Blast Furnace
Tuyeres are the
nozzles that the hot
air is blown through
Tuyeres
Blast Furnace operation
• The Charge is fed in at the top,
• Bell Doors open (One at a time)
• Coke burns & makes Carbon Monoxide,
• The Carbon Monoxide mixes with the Oxygen in
the Iron Ore (leaving Iron),
Blast Furnace
• The Molten Iron falls to the bottom of the
Furnace,
• The limestone joins with the impurities to
make Slag and floats on top of the Molten
Iron.
Blast Furnace
• The slag and the Molten Iron are tapped off
regularly,
Blast Furnace Waste
• Slag, Ammonia, Light Oils and Coal Tars
are waste from the Furnace,
• They make raw
materials for cements,
plastics and fertilisers.
Blast Furnace Iron
• Special rail cars bring the Molten Iron away,
• The liquid iron typically flows into a
channel and indentations in a bed of sand.
• Once it cools,
this metal is known
as pig iron.
Why is Pig Iron called Pig Iron ?
• PIG IRON is raw iron in an ingot form.
• It is the result of smelting Iron Ore, Coke and
Limestone in a blast furnace.
• It is a hard but brittle mix of iron (90% or more) and
carbon (typically 4-5%), manganese, sulfur,
phosphorus, and silicon (roughly 3% in total).
• The name is derived from the time when the iron ran
into moulds. A row of moulds was said to resemble a
litter of suckling pigs, so the single ingots were
referred to as pigs.
To create a ton of pig Iron
We start with 2 tons of ore,
1 ton of coke and
½ ton of limestone.
The fire consumes 5 tons of air.
The temperature reaches almost 3000 deg F
(about 1600 degrees C) at the core of the
blast furnace!
• Pig iron contains 4 percent to 5 percent carbon
and is so hard and brittle that it is almost
useless.
We do one of two
things with pig iron:
• You melt it, mix it with slag and hammer it to
eliminate most of the carbon (down to 0.3
percent) and create wrought iron.
Wrought Iron
• Wrought iron is the stuff a blacksmith
works with to create tools, horseshoes and
so on. When you heat wrought iron, it is
malleable, bendable, weldable and very
easy to work with.
• Or we can create steel.
Steel
• Steel is iron that has most of the impurities
removed.
• Steel also has a consistent concentration of
carbon throughout (0.5 percent to 1.5 percent).
• Impurities like silica, phosphorous and sulfur
weaken steel tremendously, so they must be
eliminated.
• The advantage of steel over iron is greatly
improved strength.
Blast Furnace Iron
• The Iron must go into a second furnace to
make it into a better quality metal (Steel)
• At the Steel making factory, it is mixed with
recycled steel and other alloys to make new
steel
Iron into Steel
• The Iron that comes from the Blast Furnace
requires further treatment to produce Steel,
• This is done in:
1. The Bessemer Converter or
2. The Basic Oxygen furnace.
To recap