Extraction of Aluminum

• Aluminum is extracted from bauxite (aluminum oxide)
• Most metals are extracted by reducing with carbon, but aluminum is more reactive than carbon
• All metal oxides are bases except for Al2O3, which is amphoteric meaning it can react with an acid and a base. This means that Al2O3 can be separated using the reaction with a base.
• Al2O3 has a high mpt due to strong electrostatic forces and strong charges
• Al2O3 must be a liquid for electrolysis to work, but a lot of energy would be required to melt the ore, so cyrolite (Na3AlF6) is added to lower the mpt and increase the conductivity
• Cryolite is not a catalyst
• A graphite anode is used to get the O2 ions out of the Al2O3 electrolyte, but at high temps the O2 reacts with the electrodes causing it to burn meaning that the anodes erode over time and must be replaced
• A steel cathode is used to collect the Al liquid
• Al is used for tin cans (doesn't rust)
• Al is used for airplanes (low density)
• Electrolyte with Al2O3 and cryolite must be heated to 1000 c
• An environmental problem of this process is that CO2 is released from the anode which contributes to climate change
• An environmental problem of this process is that it has a high energy demand and electricity is generated from fossil fuels which are a non-renewable resource and produces CO2
• Graphite is made from carbon atoms, so when the O2 reacts with it, CO2 is produced
• An environmental problem of this process is that mining bauxite destroys forests
• A way to help the environmental problems is to recycle aluminum to reduce energy demands and avoid mining