Extraction and uses of metals

the method used to extract a metal from its ore depends on

the metal's position in the reactivity series

What is used to extract iron?

blast furnace

What raw materials are added to the blast furnace

iron ore, coke, limestone (mainly CaCO3)

What is limestone used for?

To remove sandy impurities such as molten slag

Extraction of Iron

• Is a continuous process

• Iron is below C in the reactivity series and therefore can be used to extract iron from its ores such as HAEMATITE which contains iron oxide

• A blast furnace is used to extract Iron

What are the reactions in the blast furnace?

carbon + oxygen -> carbon dioxide

carbon dioxide + carbon -> carbon monoxide

iron oxide + carbon monoxide -> iron + carbon dioxide

Is the temperature inside the blast furnace high than the mpt of iron?

yes, it is so the iron is formed as a liquid. this allows it to trickle down through the blast furnace and collect at the bottom.

At the top of the blast furnace ...

the heat energy in the blast blast furnace is high enough for thermal decomposition

What happens to the iron produced in the blast furnace?

• Iron at the bottom is cast iron (contains about 4% carbon + it is hard, but brittle, so had limited uses)

-Nearly all the iron is transported to the steelworks

• Oxygen is bubbled through molten iron to remove all carbon

• Controlled amounts of carbon and other elements are then added to make many different steel alloys

What are uses of steel?

• High carbon steel is used to make tools

• Stainless steel (30% chromium) is used for cutlery, kettles etc. Where it is important that the steel doesn't rust.

• Manganese steel (15% manganese) is used for railway points

What is an alloy?

Alloys are mixtures of metals that tend to be stiffer and stronger than pure metal.

Why are alloys harder than pure metals?

the different sized atoms of the metals distort the layers in the structure, making it more difficult for them to slide over each other. Therefore the alloy is stiffer and stronger.

Is rusting an oxidation or reduction reaction?

Oxidation reaction

What conditions cause Iron to rust.

Iron rusts in the presence of oxygen and water. It is accelerated in the presence of electrolytes such as salt.

How can rusting be prevented by busing barriers?

• To prevent rust you must keep water and oxygen away from the iron.

• Eg - painting the iron/ coating the iron in grease or oil/ covering the iron in plastic

How can rusting be prevented by alloying the iron?

Alloying the iron with chromium and nickel to produce stainless steel prevents the rusting of iron. If stainless steel is scratched, it still won't rust.

How can rusting be prevents by using sacrificial metals?

• Galvanised Iron -> Iron coated with a layer of zinc, which acts as a barrier to air and water

• Zinc is more reactive than Iron and so corrodes instead of the Iron. During the process, zinc loses electrons to form zinc irons. The electrons flow into the iron. Any iron atom which has lost electrons to form an ion immediately regains them. If the iron can't form ions, it can't rust.

What are the uses of copper?

• In electrical cables because it is a good conductor of electricity

• Water pipes because it does not corrode easily

What is an ore?

An ore is a rock from the ground that contains enough of a metal to make it worthwhile extracting the metal from its compound.

What the steps to obtain aluminium?

• Geologists test rocks to see how much Bauxite there is, if it is satisfactory, mining begins

• Bauxite is near the surface and easy to dig up

• From the mine, ore is taken to bauxite plant and treated to remove impurities - result is alumina

• alumina is taken to another plant for electrolysis to give aluminium (purification)

What are the uses of aluminium?

• drink cans because it doesn't corrode

• cooking foil

• bikes

• televisions

• ships

• trams/ trains

• planes

• rockets

• buildings