All metals are extracted from ores or binding non-valuable materials. Metallic elements scatter on the Earths crust and deposit in large amount in different places. Miners have to dig out and collect them primarily as a raw material to be subject to several metallurgical processes before obtaining their pure solid valuable substance.
There are many metallurgical ways of extracting metals from ores. The most popular and adopted ways include mineral processing, hydrometallurgy, pyrometallurgy and electrometallurgy. Each of these methods leads to collecting the metallic element from an ore and purifying to achieve its ultimate use. However, they all differ in mechanisms, substances and chemicals used to treat the ore.
Mineral processing is the simplest metallurgical method of extracting metals from ores. In this method, the particle size of the raw material is manipulated, usually reduced, until only the valuable materials are left. Particle size reduction can be done by breaking the ore to create enough space for the extraction of the needed element. After removing the gangue (non-valuable material, the metallic element left will be processed to become pure.
Hydrometallurgy, on the other hand, uses a different treatment of the ore. Instead of removing the gangue by mechanical force, extraction is done through application of aqueous solution. Aqueous solution involves liquid to soften the bond between the pure metal element and the gangue. A very good example of metal usually drawn from an ore through this method is nickel, which forms most useful nickel alloys
seen today, such as coins, medals and stainless steel.
Increasing the temperature can also result in efficient extraction of a metal element from an ore.
Pyrometallurgy is a method that uses fire (pyro) to separate the valuable material from a melted gangue. Although not usually applied for extracting elements comprising nickel alloys
, this method is attempted for it gives purer yield.
Lastly, electrometallurgy is a method that involves the process called electrolysis to disintegrate hard bonded elements. By applying significant amount of electricity, extraction can take place very easily. Electrolysis is so powerful that it can separate even elements of diatoms in a non ferrous metal
. Such a power can instantly lead to purification without further procedure.