Aluminium vs Alumina
Although aluminium and alumina sounds similar, they are different. Alumina is a compound, which includes aluminum element.
Aluminum or Al is an element in the group 3 and period 3, which has the atomic number of 13. The electron configuration of Al is 1s2 2s2 2p6 3s2 3p1. Al is a silvery white solid, and it is the most abundant metal in the earth crust. Al is not soluble in water at room temperature. Atomic weight of Al is about 27 g mol-1, and it is a light weighted, low density and durable metal. It is an excellent electric conductor. Al doesn’t easily ignite. Al is showing both metallic and non metallic characteristics; hence, it is amphoteric. As a metal, it reacts with acids releasing hydrogen gas a form the +3 charged metal ion. As a non metal, it reacts with hot alkali solutions and form aluminate ions. Since Al is too reactive to stay in its free form, naturally it occurs in minerals. Main Al containing mineral is bauxite. Large bauxite ores are located in Australia, Brazil, Jamaica and Guinea. It is also in the minerals such as cryolite, beryl, garnet, etc. Al is largely used in automobiles and other vehicles manufacturing, construction, paints, for household items, packaging etc, due to its low density and resistance to corrosion. Pure aluminum is soft and lack in strength to use it, but it is mixed with other elements like iron or silicon (in small amounts) to increase the strength and hardness.
Alumina is the oxide of aluminum with the formula Al2O3. This is a white color crystalline solid. Since aluminum is too reactive, it is not found in free form naturally (very rarely free Al can be found). In nature, Al is covered with an oxide layer, and this surface aluminum oxide layer protects it from corrosion. Molecular weight of alumina is about 102 g mol-1. Its melting point and boiling points are very high, which are over 2000 oC. Alumina is water insoluble, but very hygroscopic. Alumina cannot conduct electricity, but it is a thermal conductor. Since aluminum is an amphoteric element, aluminum oxide is also an amphoteric oxide. Alumina is used to produce Al by the Hall process. In this process, alumina is dissolved in molten cryolite, and the resulting salt is electrolyzed. Then the pure Al salt can be obtained. Alumina is found commonly in the form of corundum, which is s crystalline mineral. This is mainly mined in India, Sri Lanka, Russia, and Zimbabwe. Alumina is used as an abrasive due to its hardness and strength. It is also used as a catalyst to enhance chemical reaction rates. Moreover, it is used as a water absorber to purify gases, and filler for plastics.
What is the difference between Aluminum and Alumina?
• Aluminum is an element, and alumina is an aluminum containing compound. The molecular formula of alumina is Al2O3, and aluminum is shown as Al.
• Aluminum is a good electric conductor, but alumina is an electrical insulator.
• Aluminum is largely reactive with oxygen, acids or bases. But alumina is not too reactive like aluminum; thus, acts as a protective layer over aluminum.
• Alumina can be used to produce aluminum.