Cyprus context
These are not stand-alone pages, but
complements to the above ones.
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Recycling aluminium is amongst the most useful and profitable of all
recycling. To understand this, it can be stated that the production of
virgin metal from ore (bauxite) is done in electrolytic graphite
furnaces with a fluorspar flux. This requires enormous quantities of
electrical energy to produce the raw and impure metal, which has to be
further purified in energy-intensive processes.
On the other hand, the energy required for recycling used aluminium is only
about 1/10 that of obtaining the virgin metal. It is for this reason that scrap
aluminium is quoted on both the London and Chicago metal exchanges. Before
re-smelting the scrap aluminium, any organic material such as printing inks,
food residues, drink residues etc are oxidised, producing a flammable gas which
is used to help the smelting process. This means that there is no need to
pre-clean the aluminium in order to recycle it.
All kinds of aluminium are suitable for recovery, including drinks cans,
kitchen foil, old saucepans (of course, only aluminium!), industrial machining swarf, all the way up to
aircraft wings and fuselages. In most countries, scrap merchants will pay well
for aluminium, provided that the quantities make it worthwhile to process it. In
some countries, used drink cans are collected for charitable purposes or to help
pay for less profitable waste collection.
A question which is sometimes asked is whether aluminium alloys are also
suitable for recycling. The answer is yes, because the alloying metals are
removed or diluted during the re-smelting process. The actual purifying process
varies according to the alloys and the relative quantity in the total process.
In my opinion, there is absolutely no excuse for disposing of any aluminium
other than by recycling.
Slightly off-topic, there is another reason why recycling is preferable to
reducing aluminium ore to virgin metal. As mentioned above, the crucibles used
for smelting aluminium are made from graphite, which is a form of carbon. At the
temperatures used for smelting, some of this graphite reacts with the fluorspar
flux to form carbon tetrafluoride. This is emitted as a gas which happens to be
one of the most powerful greenhouse gases in the world with a global warming
potential of about 10,000 times that of carbon dioxide. To be quite fair,
aluminium smelters have done everything possible to reduce the quantity of
carbon tetrafluoride which is emitted, over the past 20 years, but there is
still nevertheless a certain quantity which may influence climate change over a
period of thousands of years. The more aluminium that is recycled, the less will
be the quantity of carbon tetrafluoride which will be emitted.
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