Copper, known to mankind since the ancient times, is widely distributed
as sulfides, asenides, chlorides, and cabonates, in combination with iron
and other transition elements. Copper is a reddish metal with a high luster. It
and gold are the only two coloured metals. The metal is soft, ductile and it is
very high thermal and electrical conductivity. The surface of copper is often
dulled by oxide formation.
The two main classes of copper ores are:
the mixed sufides of copper and iron, such as chalcopyrite CuFeS2,
and bornite Cu5FeS4.
the basic carbonates such as azurite Cu3(CO3)2(OH)2,
and malachite, Cu2CO3(OH)2.
In Canada, the main deposits of copper ore are found, associated with nickel,
in the Sudbury region of Ontario. Copper is also found in various parts of British
Columbia and in many other provinces. It is usually associated with other metals
such as: gold, silver, zinc,
molybdenum and lead.
In Canada, copper is refined by Noranda
Ltd. in Montreal and INCO in Sudbury.
The combined capacity of these two refineries is over 600,000 tonnes per year
(worth about $1.3 billion/year). Impure copper is refined electrolytically.
The electrolytic copper is 99.96 ot 99.99% pure.
Treatment of azurite and malachite with sulfuric acid produces copper sulfate,
which has a characteristic blue colour. The most common form of copper sulfate
is the pentahydrate, CuSO4.5H2O, and has a wide variety
of uses such as:
providing a source of trace amounts of copper when mixed with
superphosphate to improve crop yield,
an algicide (in quantities of <1 part per million) as it is toxic to micro-organisms
in reservoirs and swimming pools,
the use of weapons made with bronze
in ancient times,
coins such as "copper" pennies are made of bronze,
coins such as dimes, nickels, and quarters contain an alloy of 30% nickel
and 70% copper,
the manufacture of ornaments, ultensils made of brass,
alloys of copper used in 14-carat gold, sterling silver jewelry and silverware,
the manufacture of electrical wires and electrical components,
roofing, the chalky green color of weathered copper (remember the green
rooftop of Vancouver Hotel?) is due to the formation of the basic carbonate,
Cu(OH)2.CuCO3,
water pipes in plumbing as it does not react with hot or cold water in an
appreciable rate, and
the need of trace amounts of copper by human. Current theories suggest that
copper deficiency causes anemia because copper is needed for the absorption
and mobilization of iron required to make hemoglobin. Important dietary sources
of copper are nuts, liver and shellfish.
the need of copper in certain marine animals. Copper serves ths same oxygen-carrying
function in the fluids of marine animals much the same way that iron is needed
in higher animals.
