Where Do Metals Come From?

Metal is one of the most important materials that mankind has discovered, enabling incredible advancement in everything from hunting for food, to creating microchips and nano-technology. But where exactly do metals come from, and how are they made?

What are Metals?

In physics, a metal is something that can conduct electricity at extremely cold temperatures, metals are generally a crystalline solid with a lustrous appearance when polished.

There are 6 main types of metals, Gold, Silver, Copper, Iron, Tin and Lead, but there are many more metallic elements in addition to these. Most metals conduct electricity and heat well.

Where do Metals Come From?

Many metals are extracted from the Earth’s Crust, usually mixed in with rocks and minerals in deposits underground, also commonly called Ore. These need to be extracted and refined before being useful materials.

Some metals can be found almost anywhere, with Iron Ore being the most commonly found. Iron Ore has been mined in almost every continent, from East and West Europe, South America and Australia.

Precious metals such as Gold and Silver are much less easy to come by but are still spread evenly around the world. Some places however have much more than others, South Africa, Australia and China top the world ranking for Gold deposits.

How are Metals Made?

After mining the ore, the metals need to be refined, this process varies greatly depending on the type of metal in question.

How is Steel Made?

Iron is made by the extraction and refining of Iron Ore, the main types of Iron Ore being Hematite and Magnetite. Both are crystalline ores found in rocks and mineral deposits, the former being known for its distinctive red color.

Once the ore is extracted – the method of which depends on the depth and location of the ore – it is refined using multiple stages, the first being in a blast furnace.

From this ‘Pig Iron’ is created, further processing such as decarburization, refining and alloying are carried out, in order to produce steel.

How is Copper Made?

As copper is found in its elemental form, it does not need chemically altering to be used as a metal, instead multiple stages of filtering and refining are carried out, often by way of floatation tanks that separate the ore in solution into copper, sediment and rock.

From there the copper is smelted into usable bars, and then alloying elements are added as necessary, to create the various types of Copper available, including brass and bronze.

How is Aluminium Made?

Aluminium is a complex metal to produce, involving multiple stages and a large amount of raw material compared to the end product. This is why aluminium was so expensive when it first became commercially available.

The first step to producing aluminium is the mining of Bauxite, which is a clay mineral that is the main raw material used in making the metal. Approximately 5 tonnes of Bauxite are required to produce 1 tonne of Aluminium.

Bauxite is crushed and washed to separate the clay, from there multiple chemical processes including digesting, settling and precipitation are carried out to produce Alumina, or Aluminium Oxide.

From there the Alumina is smelted at over 950 degrees celsius to break the bond between the Aluminium and oxygen. The resultant aluminium is then purified further, and alloyed to create the many derivatives used commercially.

How Were Metals Made 100 Years Ago?

Metal production has seen extensive development in the last century, in some cases going from experimental trials, to billion dollar industries in less than 50 years.

The Oxygen Steelmaking Process was commercialized in the 1950’s, involving blowing oxygen through the molten pig iron to reduce its carbon content dramatically. Before this process was developed, the Open-Hearth Furnace method was used.

Not only was the open hearth process less efficient, using much more heating gas than the basic oxygen system, but the economies of scale were far beneath too, with open hearth processes taking much longer per charge to complete.

Open hearth steelmaking is still used in some parts of the world, namely India and the Ukraine, where energy and labor costs are lower.

Other processes such as those used to refine Aluminium, were much more rudimentary until the technologies were mass-commercialized in the latter parts of the 20th century, the processes devised then are relatively unchanged today.

Where in the World do Metals Come From?

The various metals in common usage are mined from all over the globe, with some areas being more prominent than others for certain ore.

Where is Iron mined for steel?

• China
• Australia
• Brazil
• India
• Russia

Where is Aluminium ore Mined?

• China
• Russia
• India
• Australia
• Guinea

Where is Copper mined?

• Chile
• Peru
• Canada
• Russia
• Africa

How Long Do Metals Take to Refine?

Thanks to innovations in both the processes and equipment, metals such as steel and aluminium can be produced from their ore faster than ever before.

How long does it take to make Steel?

Electric arc furnaces melt the pig iron used to create steel by way of electric arc, created by high amperage electric currents, in a similar way to how arc welding does, albeit on a much larger scale.

Because of the tremendous amount of energy put into the system, the process can be performed quite quickly, with furnaces typically producing 150 tonnes of steel per melt, in around 1 and a half hours.

How long does it take to make Aluminium?

The process of creating aluminium is much more complicated than that of steel, involving multiple chemical processing steps after the ore has been mined and purified.

One such step, known as the Bayer process, converts the aluminium ore Bauxite into Alumina; aluminium oxide. This process can take in excess of 24 hours to complete and involves numerous steps of controlled heating and the inclusion of chemicals.

Metal Fun Facts

• Of the 118 elements on the periodic table, 95 are considered ‘metallic’
• After its discovery, Aluminium was one of the most expensive metals in the world, costing more than gold or silver, due to the complexity of the refining process.
• Alumina (aluminium oxide) is sometimes found contaminated with chromium, iron, magnesium and other elements, these form as crystals, commonly known as Rubies and Sapphires.
• The rarest metal on Earth is Francium, a radioactive element that is highly unstable. It has a very short half-life, meaning it will decay into radium after just 22 minutes. It is predicted that less than 30 grams are present on earth at any one time.