Transcript here - Summerhill College
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: