Copper has been used by humans for about 9000 years in its naturally occurring metal persona and has been smelted from ores in kilns for about 5000 years. Soon after that it was alloyed with tin and kick started the amazing transformation of the world in the Bronze Age. If you mix, or alloy copper with zinc you get brass or if you create an alloy with tin and antimony you get pewter, but we never managed to have a Brass or a Pewter Age as iron and steel took over about 3000 years ago.
Copper is on the bounce once again as a metal for the modern age, due to its heat and electrical conductivity properties. It is a prime metallic component of an electric motor and as such is one of the major beneficiaries of the EV era, following the amount of aluminium used in EV car bodies. As the demand for copper increases, its price is likely to as well and that may cause some problems for our mate Elon.
Chile is by far the largest copper producer and Australia comes in at number five in the world, with Mt Isa and Olympic Dam our biggest mines at the moment. While open cut mining is often possible, in Australia our largest mines are underground and are associated with the fracturing (fracking anyone?) of a lot of rock, as all mining is. Copper mines are also associated with increased seismicity, again as all mining, quarries and dams are.
The processing of copper involves either leaching with sulphuric acid (Mt Isa) or flash smelting (Olympic Dam) with the latter using diesel to fuel the smelter. While all efforts are taken to keep waste gases and particulates under control there are inevitably CO2 emissions, either from the fuel or the breakdown of the carbonate material associated with the ore.
Copper is one of the best conductors of heat and electricity and is also highly ductile, which allows it to be drawn into long wires without breaking. It is a better heat conductor than gold and about twice as good as aluminium for that purpose. It has the property of having “a sea of free electrons” which allow it to somewhat freely conduct both heat and electricity.
While understanding the workings of electromagnetic fields is horrendously complex and difficult to visualise, the sea of free electrons analogy is not a bad start. You can review my maths blogs if you want to delve more deeply, but it does involve imaginary numbers. If I compare electricity transmission to sound transmission then let’s start with sound moving through air. Our air can be thought of as a sea of gaseous atoms floating relatively freely in an otherwise vacuum. When I impart energy to the pigskin covering of a drum kit, it makes the cover vibrate and sets the air gases vibrating in sympathy. In doing so it passes the message from particle to particle until it reaches your ears where your brain deciphers the sensation. We call this sound or if it travels through the earth, seismic energy. In a vacuum, no one can hear you scream.
With electricity, a source of energy, eg a battery or a dynamo sets the sea of free electrons vibrating and passes the electrical signal along creating an electric current. So it is the copper wire that supplies the electrons, not the battery. And while that is not a bad starting point, it is not strictly correct. Electrons do “flow” to some degree and do oscillate, but while the electrical signal can travel as fast as the speed of light, any electron flow certainly doesn’t. Any charged particle can cause an electrical current, including protons and even electron “holes” can be considered to flow!
Enough of the complex stuff, simply put, the transmission of energy for example, by sound through air, or by water waves, or electricity does not require a particle to flow, just the energy or message. Anything travelling at the speed of light has no rest mass, examples being a photon or a message. If an electron were to travel at the speed of light, it would obtain infinite mass, according to Albert.
As with aluminium, copper is easy to recycle, with a huge energy and material saving if we do, making its use sustainable. With the amount of thieving of copper pipes and wiring from building sites I guess everyone already knows that.
Copper can be toxic to humans in large enough doses, so don’t drink water out of the hot water pipes. Fill your kettle from the cold tap. Copper cookware is toxic if uncoated or the coating is scratched. Such cookware is generally coated with stainless steel, tin or enamel. Copper and gold are the only coloured metals.