AS Chemistry Unit 2 Metal Extraction

Principles of metal extraction & Environmental aspects of metal extraction.

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Extracting Iron

Main Ore:- Haematite. Fe2O3 - Iron Oxide. Method used - reduced using carbon, in a blast furnace. Raw materials - Iron Ore (Fe2O3), Coke & Limestone (CaCO3). At the side of the blast furnace you have air. So what happens?

Stage 1:- C + O2 -----> CO2. Stage 2:- CO2 + C -----> 2CO

Stage 3:- Fe2O3 + 3CO -----> 2Fe + 3CO2

Conversion of Iron into Steel: Use a basic oxygen converter (BOC). Blast O2 into impure iron. C reacts to give CO2: C + O2 -----> CO2. To make steel add back controlled amounts of carbon and/or other metals.

Equation for **** formation/use. Iron ore will contain impurities: Silicon Dioxide SiO2 (sand) removed by Limestone CaCO3.

1. SiO2 --heat--> CO2 + CaO. 2 CaO + SiO2 -----> CaSiO3. Calcium Silicate - SLAG. Slag is the waste material from the blast furnace, which is used in road building.

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Extracting Titanium

Main Ore:- Rutile, TiO2. Titanium is a very expensive metal to extract:- Produced by BATCH PROCESS. Relies on extraction of other reaction metals. The intermediate in the production is hazardous and explosive. Batch Process:- assemble and take apart a site for the extraction on a regular basis.

Stage 1:- TiO3 + C + 2Cl2 --900*C/Heat---> TiCl4 + 2CO. TiCl4 is both explosive and hazardous, with water give HCl fumes.

Stage 2:- TiCl4 is reduced using sodium or magnesium.

Sodium:- TiCl4 + 4Na ---ArAtmos/Heat---> Ti + 4NaCl

Magnesium:- TiCl4 + 2Mg ---ArAtmos/Heat---> Ti + 2MgCl2

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Issues with and uses of titanium extraction

Issues with titanium extractions

1. Expense:- Na/Mg are both reactive metals. They have to be extracted this involves electrolysis. Chlorine has to be produced.

2. Use of Carbon:- In theory titanium could be extracted using carbon; but it forms a stabe compound with carbon.

3. Argon Atmosphere:- Inert atmosphere needed because oxygen can react with titanium to give TiO2 which makes Ti brittle.

Uses of Titanium

  • Aircraft Wings - lightweight and has high melting point.
  • Replacement Surgery - not rejected by the body.
  • Nuclear Industry for paperwork - doesn't rust.
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Extracting Aluminium

Man Ore:- Impure Bauxite (Al2O3). Extracted using electrolysis. Raw materials:- bauxite dissolved in molten cryolite. Conditions need for the extraction of aluminium from its ore- High temperature.

Extraction equations: Graphite.

At Anode (+):- O2- ions attracted. 2O2- + 4e ---> O2.

Problems:- Anode needs to be replaces regularly. Graphite reacts with O2 to give CO2.

C + O2 ---> CO2.

At Cathode (-):- Al3+ ions attracted. Al3+ + 3e ----> Al

Uses of Aluminium:- Aeroplane wings, drinks cans, wrapping foil & cooking foil.

*ALL METAL EXTRACTIONS INVOLVE REDUCTION*

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Comments

Moggerfrog

Great - could you add Manganese, Copper and Tungsten as well? Thanks very much though! :D

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