Rusting
Rust is a form of iron oxide. It has water bonded loosely to it. It is called hydrated iron oxide
Learn!
In order for iron to rust
Both air and water’s a must,
Air alone won’t do
Without water there too,
So protect it, or get a brown crust!
It’s actually the oxygen in air
Learn too!
Sacrificial protection
Zinc is electrically connected to the iron. Any water or oxygen reacts with the zinc (or magnesium) instead of the iron. Coating in zinc is called galvanization and it works even when the zinc coating is scratched.
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Today’s lesson
• The extraction of iron from iron ore using a blast furnace
• Extraction method and position in the reactivity series
Ores
Most metals are found naturally in rocks called ores. They are in compounds, chemically bonded to other elements
iron ore
Roasting
Some unreactive metals can be extracted from a compound simply by heating. This is called roasting.
Roasting copper sulphide
Copper sulphide + oxygen copper + sulphur dioxide
Cu2S(s) + O2(g) 2Cu(s) + SO2(g)
Mr Porter will give you some slides to stick in
Roasting lead sulphide
Roasting lead sulphide produces lead oxide, NOT lead.
The more reactive a metal is, the more difficult it is to extract from its ore.
Can you copy please?
Extracting metals with carbon
Carbon is higher than some metals in the reactivity series. It can be used to extract medium reactive metals.
Extracting metals with carbon
lead oxide + carbon lead + carbon dioxide
2PbO(s) + C(s) 2Pb(s) + CO2(g)
Reduction and oxidation
lead oxide + carbon lead + carbon dioxide
2PbO(s) + C(s) 2Pb(s) + CO2(g)
carbon is oxidised
lead oxide is reduced
Reduction and oxidation
lead oxide + carbon lead + carbon dioxide
2PbO(s) + C(s) 2Pb(s) + CO2(g)
carbon is oxidised
lead oxide is reduced
Oxidation is the gain of oxygen, reduction is the loss of oxygen
Mr Porter will give you some slides to stick in
The Blast furnace
1000°C
1500°C
1900°C
Iron ore (haematite), coke (carbon) and limestone (calcium carbonate)
Hot waste gases (recycled to heat furnace)
Blasts of hot airBlasts of hot air
Molten iron
YouTube - Steelmaking: Blast Furnace
Reactions in the furnace
The coke (carbon) reacts with oxygen in the hot air to make carbon dioxide
C(s) + O2(g) CO2(g)
Reactions in the furnace
The carbon dioxide reacts with more hot coke to form carbon monoxide
CO2(g) + C(s) 2CO(g)
Reactions in the furnace
The carbon monoxide then reduces (takes oxygen away) the iron oxide to iron
Fe2O3(s) + 3CO(g) 2Fe(l) + 3CO2(g)
Reactions in the furnace
Limestone reacts with the impurities to form slag.
CaCO3(s) + SiO2(s) CaSiO3(s) + CO2(g)
YouTube - Steelmaking: Blast Furnace
YouTube - Blast furnace