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# Electrolytic refining: The copper from smelting is moulded into anodes, and the cathode is created from a pure sheet of copper. At the cathode a pure layer of copper is formed due to the oxidation that occurs at the anode and this decreases the cathode occurring. A sludge (muddy type of mixture) is created which form valuable metals such as gold and silver, which are less active than copper. The impurities which are left behind in the solution eg.iron are usually more active than the copper. Chemical Reactions:

# Roasting: 2Cu2S(l) + 302 (g) → 2Cu2O(l) + 2SO2 (g)

# Smelting: 2Cu2O(l) + Cu2S(l) → 6Cu(l) + SO2 (g)

# Slag Formation: CaO(s) + SiO2 (s) → CaSiO3 (l) . FeO(s) + CaSiO3 (l) → FeSiO3 (l) + CaO(s)

# Transportation- The transportation of the ores to the refinery is expensive
# Exports- in order to transport the goods to foreign countries special equipment is needed.
# Environmental cost- due to land degradation large sums of money are payed towards the environment.
# Bayer process- it is the conversion of bauxite into alumina which needs heaps of amounts of chemicals such as, sodium hydroxide, which creates additional costs to the extraction.
# Waste – created waste is expensive to get rid of and dispose example, Fe2O3 is formed in the refining process and it is transported to ponds in order to dispose it there.
# 10 tonnes of bauxite are required to produce 1 tonne of aluminium, using this process. Total cost – AU$1 632 per tonne.

Energy:
# Bayer process – when bauxite is refined to create alumina it requires 15 000 MJ of energy per tonne.
# Electrolytic reduction - when alumina is refined to create aluminium it request 100 000 amps per tonne.
# Refineries and smelting factories they need their own power plant because of the amount of energy they need.
# The amount of energy that they require in