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how aluminum ingots be made?

Aluminum ingot is piece of aluminium that has been cast into a long cylindrical shape for future processing. An ingot may be either an alloy or pure aluminium metal. It is usually made by heating the molten aluminium past its melting point at about 800 degrees, and then casting it into a mould before it is cooled into a solid shape.

Aluminium ingots come in different shapes and sizes. The smallest aluminium ingots are usually called pigs. They have a weight of about 6 to 22.5 kg. Generally, small ingots are melted and then various alloy components are added before they are recast into the desired shape for extrusion and further processing.

Larger ingots are used to make aluminum profiles. For instance most of the 6 meter profiles are made from billets that are 7 meters long. Other large ingots are also available in lengths of over 11 meters. These ingots are made from special moulds buried into the ground.

Generally, aluminium ingots are produced from recycled aluminum scraps. Recycling is the most economical way to produce them because it saves up to 90 percent of the energy used to produce ingots from bauxite. The recycling process is straightforward and its main raw material is the shredded aluminium beverage can.

After the used beverage cans have been gathered, they are cleaned in preparation for processing. These cans are taken to the shredder where they are chopped into small pieces. Shredding makes it easy to take off the coatings on the can and it also makes it easier for the aluminium to melt in the furnace. 

From the shredder, the pieces of metal are passed under a magnet to remove all the steel or iron impurities. Since the steel impurities are magnetic, they will be attracted to the magnet and taken out of the aluminium. From the magnetic separator, the shreds are taken to the decoater.

At the decoater, the paint is taken off the shredded cans. The decoater passes very hot air through the metal shreds and the paint on them evaporates. During the de-coating process, the shreds attain a temperature that makes it easier for them to melt inside the furnace.

Then the de-coated cans are carried in a special bin and poured at the opening of the smelting furnace, which is heated to a temperature of 800 degrees centigrade. These metal shreds are fed into the furnace gradually. In the furnace, they are turned into molten aluminium. From the furnace, the molten metal is moved in buckets to the cast house where the impurities are removed and the molten metal is poured into moulds to solidify.

Different sizes and shapes of ingots may be produced via this process. But most of the ingots produced are usually used for aluminium profiles. The metal flows gently into moulds, which are attached to a conveyor. As the molten metal comes into the mould, it is cooled with finely vaporized water. As the aluminium hardens, it gains weight and eventually the ingot is formed. Then aluminum profile manufacturer melt the ingots to get rods for extrusion.