Unit 2: Extraction Of Metals (AQA)

A brief summary on extraction of metals for the AQA unit two Chemistry exam.

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  • Created by: Lauren
  • Created on: 19-12-11 12:07

Iron Extraction.

Haematite (Fe2O3), limestone (CaCO3) coke (C) and hot air are added to the blast furnace.

Firstly, the coke reacts with the oxygen in the hot air to produce carbon dioxide.

The carbon dioxide then reacts with the coke to produce carbon monoxide.

The carbon monoxide then reacts with the haematite to form iron and carbon dioxide.

The haematite contains silicon dioxide which is reacted with calcium oxide to form calcium silicate (****.) This floats to the top of the blast furnace where it can be removed.

Adding magnesium reacts with the sulphur impurities, preventing the formation of sulphur dioxide, which causes acid rain to form.

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Aluminium Extraction.

The ore of aluminium is called bauxite. This bauxite is firstly purified so an aluminium oxide powder is formed.

In order to lower its melting point, cryolite is added to the aluminium oxide. Once the aluminium oxide is melted, its ions are free to move and carry an electrical charge.

During electrolysis, the oxygen anions move to the positively charged anode and lose two electrons, forming oxygen gas (Which reacts with the carbon anode, forming carbon dioxide.) The aluminium cations move to the negatively charged cathode, gain three electrons and sink as molten aluminium.

This process is very costly because of the energy required to melt the aluminium oxide.

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Extraction of Titanium.

The extraction of titanium is done as a batch process.

Titanium oxide is reacted with chlorine and coke. This reaction takes place at 900oC. This produces titanium chloride (TiCl4) and carbon dioxide.

The titanium chloride is then reacted with either sodium or magnesium in an inert argon atmosphere (to prevent oxidation,) at 500oC. This forms titanium and sodium chloride.

This mixture is left to cool for a few days before HCl is used to wash away the sodium chloride.

This process is also very expensive due to the energy used to produce the high temperatures and because it is produced using a batch process.

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Extraction Of Tungsten

Tungsten oxide is reacted with hydrogen gas at very high temperatures. This produces very pure tungsten and water.

However, using large amounts of a hydrogen is dangerous because it is extremely flammable.

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Comments

Moonman

Really helpful but would be better if the equations were included becuase we need to know that :)

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