Thermite – A Redox Reaction Between Aluminium Powder and Iron Oxide

A redox reaction occurs when a mixture of powdered aluminium and iron oxide is ignited. The result is liquid iron and aluminum oxide. This is commonly called thermite and has many uses in industry.

Aluminium is one of the most reactive metals and it displaces the lesser reactive metal, iron oxide in this reaction. The resulting product is Aluminium oxide which can be used as a passivation layer to make the aluminium more safe to handle.

Thermite reactions are very common and have a number of practical uses, including welding rails and axle-frames together without the need for complex and heavy equipment. The heat generated is a large factor in the successful welding of rails, so thermite is commonly used to generate the heat needed for the welding to take place.

When the reaction is done correctly, the molten iron is easily poured out of the bottom of the pot. It can also be melted into small pieces that can be separated with the help of a spatula.

The iron can be of two different types depending on how quickly the molten iron is cooled down. A slow cooling of the molten iron results in better formed crystalline iron that is magnetic, while a rapid cooling leads to a more random crystalline state. It is important to note that both forms can be dangerous and may cause burns if they come into contact with water. Ensure that you have a containment system in place before attempting this experiment!

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