Copper
Also: Cu, Cuprum, Red metal
Copper (Cu, atomic number 29) is a reddish transition metal with outstanding electrical and thermal conductivity, regarded as the oldest metal deliberately used by humans and today an indispensable industrial raw material.
Copper is one of the oldest useful metals of humankind: more than 10,000 years ago it was cold-hammered in Anatolia and Mesopotamia, and its alloying with tin ushered in the Bronze Age. Today copper is a global leading indicator for the economy and industrial development – which is why traders like to speak of "Dr Copper", because the copper price often signals economic turning points early. You can find the current copper price and historical price developments on the relevant overview pages.
Properties and occurrence
Copper is a soft, ductile metal with a characteristic reddish colour. Its most important physical features:
| Property | Value |
|---|---|
| Density | 8.96 g/cm³ |
| Melting point | 1,085 °C |
| Electrical conductivity | 58.1 MS/m |
| Thermal conductivity | 401 W/(m·K) |
| Mohs hardness | 3.0 |
Only silver conducts electricity better than copper – at a fraction of the cost. This property makes it the preferred material for cables, windings and electronic components worldwide.
Copper occurs both native (as pure metal in nature) and in numerous ores. The most important copper ores are chalcopyrite (CuFeS₂), malachite (Cu₂(CO₃)(OH)₂) and bornite (Cu₅FeS₄). Chile is by far the world's largest producer, accounting alone for around 25–28% of the global annual amount.
Extraction and processing
Primary extraction takes place predominantly in open-pit mining. The mined ore passes through several processing stages:
- Flotation – enrichment of the copper ore to 25–35% Cu content (concentrate)
- Smelting and converting – production of raw copper (blister copper, ~98–99% Cu)
- Electrolytic refining – purification to electrolytic copper (≥ 99.99% Cu, cathode)
The formula for the copper content in ore (ore grade) is:
Ore grade (%) = (mass of Cu in ore / total ore mass) × 100
Modern copper mines often work with ore grades of only 0.5–1.5% Cu; economic minimum grades lie, depending on the project, at around 0.3–0.5%.
Important alloys
Copper is one of the most-used alloying partners in metallurgy:
| Alloy | Composition | Properties |
|---|---|---|
| Bronze | Cu + Sn (tin) | hard, corrosion-resistant |
| Brass | Cu + Zn (zinc) | easily machined, decorative |
| Gunmetal | Cu + Sn + Zn + Pb | pressure-tight, for fittings |
| Nickel silver | Cu + Ni + Zn | silver-like, corrosion-resistant |
| Tombac | Cu + Zn (10–20%) | gold-coloured, for medals |
Copper also plays a central role in precious-metal processing: in 585 gold (14 carat) and in red gold, copper is the most important alloying partner, determining strength and colour.
Use and markets
About 65% of global copper consumption goes to the electrical industry – from power cables through transformers to electric motors. Other significant customer sectors are:
- Construction (water pipes, roofing, heating pipes)
- Mechanical engineering and automotive (radiators, brake lines, wiring harnesses)
- Renewable energy (wind turbines, photovoltaic installations require considerably more copper than conventional power plants)
- Electronics and telecommunications (circuit boards, semiconductor bonding)
Rising demand from electromobility and the energy transition is considered a structural demand driver: an electric car contains on average three to four times as much copper as a combustion vehicle.
Copper as a traded good
The global copper price is traded primarily on the London Metal Exchange (LME) and on COMEX in New York, quoted in US dollars per tonne. Common trading units are:
- LME lots: 25 tonnes (standard contract)
- Cathodes, granules, wire in physical trading
As an industrial metal – and therefore not a precious metal in the narrower sense – copper is subject to standard VAT (20%) on purchase in the United Kingdom under HMRC rules. Its price development depends strongly on global economic cycles, the Chinese construction sector and the pace of energy-infrastructure expansion. On the exchange-rate page current USD/GBP rates can be retrieved, which are relevant for price conversion.
Note: this article does not constitute investment or tax advice.
Recycling
Copper is almost infinitely recyclable without loss of quality. Around 35% of global copper demand is already met by secondary copper (recycling). So-called urban mining – recovery from electronic scrap, old cables and fittings – is gaining importance in view of declining ore grades and rising extraction costs.
In brief
Copper connects history and future like almost no other metal: as the material of the first human metalworking and at the same time as a key raw material for electrification and the energy transition, it remains an indispensable material. Economists regard the copper price as a reliable early indicator of global economic development.