Did you know what the third most common element on our planet is? You will most likely be surprised to know that it is Aluminium. And while this is true, aluminium is not found on earth in its natural state, but as various compounds. Let us learn more about the occurrence of metals on earth.
Occurrence of Metals
So, we obtain metals from the earth’s surface, or from below earth’s surface. However, not all metals are in their pure form. Some are mixed with impurities and some are a mixture of various other elements. We can actually classify the three basic ways of occurrence of metals in our lithosphere.
(Source: 911 metallurgist)
A native metal is one that exists in nature (on earth’s surface) in its actual metallic form. It can either exist in pure form or as an alloy. Some such native metals that we can identify as such are iron, tin, tungsten, antimony, arsenic and zinc. Native metals also include two specific groups, namely the Gold group and the Platinum group.
- The Gold group consists of Gold, Silver. Aluminium, Mercury and Lead
- The Platinum group consists of Platinum, Palladium, Rhodium, Iridium, Osmium and Ruthenium
Relatively very few native metals are in existence. Only metals that are generally less reactive can be found in their native state since they can resist naturally occurring chemical reactions such as oxidation and reduction. Gold, Silver and Platinum are the metals that occur in their true native form in large quantities around the world.
An alloy is a mixture of two metals or even one metal and another substance, but the major component being metal. Metals usually have some excellent properties for commercial use such as high strength and electrical conductivity. To enhance them even further we mix metals with another component to give them extra advantages.
Steel is an excellent example. Here Iron is mixed with a very small amount of carbon. This gives a substance that is stronger and lighter than just pure metal. Other such alloys are Brass ( Copper and Zinc), Bronze (Copper and Tin), Stainless Steel ( Iron, Nickel and Chromium) and countless more.
Now as the case may we find very few metals in our atmosphere in their natural form. Most metals are found mixed together with other materials and minerals. Some such materials from which we can extract metals that we desire are known as Ores.
Hence it is important to know the most abundantly occurring ores and the metals we extract from them. Let us take a look at some of the most common ones found on earth and the primary metals we extract from these ores
- Bauxite AlOx(OH)3-2x
- Kaolinite Al2(OH)4Si2O5
- Haematite Fe2O3
- Magnetite Fe3O4
- Iron Pyrites FeS2
- Copper Pyrite CuFeS2
- Cuprite Cu2O
- Malachite CuCO3.Cu(OH)2
- Zinc Blende ZnS
- Zincite ZnO
- Calamine ZnCO3
Now, these ores need to be processed so metals can be extracted from them. This entire process of extracting metals from ores is metallurgy. On a basic level, this involves three main steps, which are
- The concentration of the ore
- Isolation of the metal from the ore
- Purification process to obtain pure metal
Solved Questions for You
Q: Name which one of these is a mineral of manganese?
- All of the above
Ans: The correct answer is “C”. Pyrolusite is a black amorphous mineral which consists of manganese oxide.