What is Copper?

Copper is the eighth most abundant metal in the Earth’s crust. It occurs in at least 160 minerals and is one of the few metals that occur naturally in commercially workable quantities.

Since the beginning of history, copper has played an important part in human development. Ancient civilizations made crude weapons and tools from copper and later civilizations developed this knowledge to hammer copper into sheets to make ornaments, household utensils, tools and water pipes.

Today copper appears everywhere in our everyday lives. It is hidden away in many objects that we use in our homes and offices on a daily basis like telephones, computers, radios, TVs and motor vehicles.

One of the reasons copper is so important is that it can be made into alloys. That means it can be combined with other metals to make new alloys, like brass and bronze. These are harder, stronger and more corrosion resistant than pure copper.

Uses for Copper 

Electrical conductor: Copper is an excellent conductor of electricity. For the past 50 years about half the world’s copper consumption has been used for this purpose. It is used in electric generators and motors, lighting fixtures and wiring, radio and TV sets, computers and almost everything electrical.

Heat conductor: Because of copper’s ability to conduct heat it is used for motor vehicle radiators, air conditioners and home heating systems.

Industry: Copper’s corrosion resistance and ease with which it can bejjjoinedhave madee copper the choice fooor plumbing and piping systems, automotive fuel lines, sea water desalination plants and hydraulic systems. It is also used in the manufacture of motor vehicles, aircraft, coins, scientific instruments and as a trace element in fertilizer.

Copper Facts  

· The word copper comes from the Latin word "cuprum", which means "ore of Cyprus". This is why the chemical symbol for copper is Cu.

· Copper is believed to be the first metal to be used in quantity by early humans and it combines more useeeeeful properties than any other metaal.

· Copper is the onlyy naturally occurring metal other than gold that has a distinctive colour. Like gold, copper is an excellent conductor of heat and electricity.

· Copper is the eight most abundant metal in the earth’s crust. It is mined in at least 63 countries, including Chile, USA, USSR, Canada, Zambia, Poland, China, Uganda, Nicaragua, Australia and Mexico.

· Copper is easily mixed with other metals to form alloys such as bronze and brass. Bronze is an alloy of tin and copper, and brass is an alloy of zinc and copper.

· Copper melts at 1083 C and boils at 2567 C

· Copper is tough, ductile and malleable and is resistant to corrosion (it does not rust very easily).

·&ammp;ammp;nbbsp;Copper is classified as a Transition Element and occurs as a native metal and in a variety of compounds.

How copper deposits form …

because copper reacts readily with other substances, it can be found in a variety of ways in the Earth's crust. It is often found in deposits with other metals such as lead, zinc, gold and silver.

By far the largessst amounts of copper are found in the crust in bodies known as ‘porphyry’ copper deposits. These deposits were oncelarge masses of molten rock that cooled and solidified deep in the Earth's crust. As they cooled, some large crystals grew, which were then surrounded by smaller crystals — geologists call these rocks porphyries

At first, the molten rock contained a small amount of copper. As it cooled and crystals began to form the amount of fluid became smaller. The copper remained in the fluid, becoming more and more concentrated. When the rock was almost completely solid, it contracted and cracked and the remaining copper-rich fluid was squeezed into the cracks, where it too finally solidified.

Over many millions of years the rocks covering these deposits eroded away and the deposits eventually appeared at the surface.
These deposits can contain 2 billion tonnes of rock which, when processed, gives 30 million tonnes of copper metal.

Copper production

From ore to finished product
From its original home buried underground in a mine to its use in a finished product such as wire or pipe, copper passes through the stages outlined below. When it is recycled it can pass through some over and over again.

1. Mining and crushing
The beginning for all copper is to mine sulfide and oxide ores through digging or blasting and then crushing it to walnut-sized pieces.
2. Grinding
Crushed ore is ball or rod-milled in large, rotating, cylindrical machines until it becomes a powder usually containing less than 1% copper. Sulfideores are moved to a concentrating stage, while oxide ores are routed to leaching tanks.
3. Concentrating
Minerals are concentrated into a slurry that is about 15% copper. Waste slag is removed. Water is recycled. Tailings (left-over earth) containing copper oxide are routed to leaching tanks or are returned to the surrounding terrain. Once copper has been concentrated it can be turned into pure copper cathode in two different ways: leaching and electrowinning or smelting and electrolytic refining.
4a. Leaching
Oxideore and tailings are leached by a weak acid solution, producing a weak copper sulfate solution.
5a. Electrowinning (SX/EW)
The copper-laden solution is treated and transferred to an electrolytic process tank. When electrically charged, pure copper ions migrate directly from the solution to starter cathodes made from pure copper foil. Precious metals can be extracted from the solution.

OR

4b. Smelting
Several stages of melting and purifying the copper content result, successively, in matte, blister and, finally, 99% pure copper. Recycled copper begins its journey by being resmelted.
5b. Electrolytic-refining
Anodes cast from the nearlypure copper are immersed in an acid bath. Pure copper ions migrate from the anodes to "starter sheets" made frompure copper foil where they deposit and build up into a 300-pound cathode. Gold, silver and platinum may be recovered from the used bath.
6. Pure copper cathodes
Cathodes of 99.9% purity may be shipped as melting stock to mills or foundries. Cathodes may also be cast into wire rod, billets, cakes or ingots, generally as pure copper or alloyed with other metals.
7. Cathode is converted into:
§ Wire rod - coiled rod about 1/2" in diameter is drawn down by wire mills to make pure copper wire.
§ Billet – 30’ logs, about 8" diameter, of pure copper are sawed into these shorter lengths which are extruded and then drawn as tube, rod and bar stock of many varied sizes and shapes. Rod stock may be used for forging.
§ Cake - slabs of pure copper, generally about 8" thick and up to 28' long, may be hot-and cold-rolled to produce plate, sheet, strip and foil.
§ Ingot - bricks of pure copper may be used by mills for alloying with other metals or used by foundries for casting.

To download a PDF that illustrates the above process as a flowsheet, click on the link below:

copperproductionprocess.jpg

Australian Copper Deposits

In Australia copper is mainly found as the mineral chalcopyrite in rocks that are more than 250 million years old. Other less commonly occurring minerals that contain copper are azurite and malachite. Copper is sometimes found in its pure form, which is called "native copper".

Australia and its surrounding area has many rich mineral deposits and of these there are several copper mines that are of world significance.

The Mount Isa Mine (MIM Holdings) in the Northern Territory accounts for around 75% of Australian copper production and is on the of the 10 largest producers in the world.It isone of thefew areas where significant quantities of copper, silver, lead and zinc occurin close proximity.

Silver-lead ore was discovered outcropping in a creek bed at Mount Isa in 1923. Deep drilling during the 1930s revealed large quantities of copper ore beneath the silver-lead-zinc ore, however except for a period during World War II, copper production did not commence until 1953.

Modern exploration methods now allow deposits of metal ores which may not outcrop at the Earth’s surface to be detected.  The Olympic Dam (WMC Limited) deposit in South Australiawas discovered by drilling over ananomaly revealed by aerial geophysical measurements. Olympic Dam was discovered in 1975 and drilling commenced in 1988.  It is one of the largest copper-gold-uranium-silver accumulations in the world.

Environmental responsibility

The copper mining industry is committed to protecting the environment wherever they explore for new resources or develop, operate or close mines.

Early in the project planning of a mine, baseline studies of flora and fauna, water and air quality, and cultural sites are conducted to ensure that development proceeds, and management systems are designed, with their protection in mind.

Mining inevitably disturbs land, which is whyland is reclaimed after mining is completed. Land reclamation involves returning the land to a productive alternative use, a process thatincludes recontouring and stabilising soil, constructing rainwater drainage systems and replanting trees and vegetation.

Copper – the future

Copper’s role in industry and society will grow through continuing research and the demands of the 21st century. Its historic advantages will be expanded in many ways, including a wider range of architectural applications and in the Smart Wiring of our homes of the future. It will be applied in powder form in new-generation super-conductors and as a wrapper for co-axial fibre optic cables.

Advances in medical, biological and agricultural sciences, and a greater understanding of the role of copper compounds in animal and plant health will boost copper’s role in the environmental, health and agricultural industries.

Click here:  http://www.copper.com.au/cdc/category.asp?category_id=55 for a link to Copper and Tomorrow’s Technology articles.

Also, to read an excellent article about "Bioleaching", please click on the link below:

http://www.copper.org/innovations/2004/May//producing_copper_natures_way_bioleaching.html

Learn more
Still have further questions about copper?

Contact our office on 1800 075 060 to ask for a copy of our complimentary school education pack outlining the history, facts and figures of copper.

The UK and US Copper Development Associations also have education material available on their web sites:
www.copper.org
www.cda.org.uk

Alternatively, send an email query toour resident copper expert on technical@copperdev.com