Symbol: Cu- short for the Latin word, cuprum.
Atomic number: 29
Atomic Weight: 63.546
Melting Point: 1984.32°F or 1084.62°C
Boiling Point: 4644°F or 2562°C
Density: 8.933 grams per cubic centimeter
Phase at Room Temperature: Solid
Element Classification: Metal
It is a ductile metal with very high thermal and electrical conductivity.
The metal and its alloys have been used for thousands of years.
Its compounds are commonly encountered as copper salts, which often impart blue or green colors to minerals such as azurite and turquoise. These salts have been ground and used for pigments for hundreds of years. Today, copper is primarily obtained from the ores cuprite (CuO2), tenorite (CuO), malachite (CuO3·Cu(OH)2), chalcocite (Cu2S), covellite (CuS) and bornite (Cu6FeS4).
Used in large amounts by the electrical industry in the form of wire, copper is second only to silver in electrical conductance. Since it resists corrosion from the air, moisture and seawater, copper has been widely used in coins. Although once made nearly entirely from copper, American pennies are now made from zinc that has been coated with copper. Copper is also used to make water pipes and jewelry, as well as other items. Pure copper is usually too soft for most uses. People first learned about 5,000 years ago that copper can be strengthened if it is mixed with other metals. The two most familiar alloys of copper are bronze and brass. Bronze, the first alloy created by people, is a mix of copper that contains as much as 25% tin. Early people used bronze to make tools, weaponry, containers and ornamental items. Brass, a mix of copper that contains between 5% and 45% zinc, was first used about 2,500 years ago. The Romans were the first to make extensive use of brass, using it to make such things as coins, kettles and ornamental objects. Today, brass is also used in some musical instruments, screws and other hardware that must resist corrosion.
Hydrated copper sulfate (CuSO4·H2O), also known as blue vitriol, is the best known copper compound. It is used as an agricultural poison, as an algaecide in water purification and as a blue pigment for inks. Cuperic chloride (CuCl2), another copper compound, is used to fix dyes to fabrics. Cuprous chloride (CuCl) is a poisonous white powder that is chiefly used to absorb carbon dioxide (CO2). Copper cyanide (CuCN) is commonly used in electroplating.
Traditional methods of mining copper was to mine the native copper if possible. Many times, that was done in small dank caves that were dug by hand, a foot at a time, using stone or crude metal implements. This was laborious and tedious not to mention dangerous. Many a miner was buried, along with his candle after his mine collapsed. Some of the more primitive tools was an axe where they had a small chip of a stone for the head. This would allow them to chip away the matrix exposing the native copper. They learned to cold working of the metal which gave way to annealing which gave way to smelting and eventually lost wax methods of working the copper. This all occurred somewhere around 7500BCE in Anatolia, now part of what we call Turkey. But when looked at globally, it is observed that the invention of these techniques occurred about the same time around the globe. So, no one culture can lay claim to having invented or created the techniques used.
Around 4500BCE, it was discovered that by the addition of other metals (usually tin) and sometimes arsenic, phosphorus, aluminum, manganese, and silicon. These additions produces an alloy much harder than copper alone. This alloy of copper and tin is called bronze. If the alloy is made of copper and zinc, it is called brass. They would add lead to the zinc and copper to make it easier to melt and it would be centuries before the concept of lead poisoning would come to light. The study of copper and what metals would make it stronger went on to push us into the iron age around 1200BCE. The techniques of forging copper where then applied to other metals and they discovered the art of iron. They used copper as hull plating for the sea going ships because it was resistant to barnacles and other marine organisms. In 1832, George Frederick Muntz, a metal roller in Birmingham, England, devised a metal flashing for ships that was 60% copper, 39.9% zinc and .1% iron. This proved to be resistant and cheaper for protecting ships from mussels and barnacles. It is known as Muntz Metal and Yellow Metal and is still used to this day.
Today, copper is used in the electrical industry due to the fact it is very conductive of electricity. Everything from wires to printed circuits are reliant on copper for its conductivity. Cheaper methods of transporting high voltages are done however with aluminum alloys instead of copper.
Copper has been used for the past few hundred years as roofing, gutters, downspouts on your more prestigious buildings. More common but not seen are the copper pipes that run through the inside of the buildings. Because of its thermal conductivity, it used in the HVAC (heating, ventilation and air conditioning) trade. The condensers and evaporators are made of copper tubing while being surrounded by aluminum sheeting.
Whereas copper was mined in tunnels years ago, it is now mostly strip mined from giant open pits. By using large excavating machines, they are able to remove vast amounts of material with minimum efforts. The ore must usually be beneficiated (concentrated). To do this, the ore is crushed. Then it must be roasted to convert sulfides to oxides, which are smelted to produce matte. Finally, it undergoes various refining processes, the final one being electrolysis. For economic and environmental reasons, many of the byproducts of extraction are reclaimed. Sulfur dioxide gas, for example, is captured and turned into sulfuric acid — which is then used in the extraction process. There are numerous methods of reducing the ore to a usable or refinable form.
Solvent extraction is a hydrometallurgical process. The process entails:
- Dissolution of the metal in an aqueous, typically acid, solution
- Transfer of the dissolved metal to an organic solution
- Transfer of the dissolved metals to a second aqueous solution
- Production of a product
The product is usually electroplated to produce the pure metal or precipitated from the solution to produce a metal salt.
Worlds largest float copper,
28.5 tons in Marquette, Michigan
Photo by Lucy Hough
9392 pounds- Calumet, Michigan
Leonard Mine, Montana
Geevor Tin Min
Mammoth Mine, Australia
Chuquicamata mine, Chile
Leonard Mine, Montana
Summitville District, Colorado
Red Dome Mine
Chillagoe Queensland, Australia
Tenorite with Malachite
Bisbee Mine, Arizona
Tinorite with Cuprite
Milpillas mine Mexico
(Photos on this page used with permission)