How is aluminum produced?
More recently (a little over a century ago)aluminum was considered one of the most expensive metals. And this was due not to the small stocks of raw materials, but to the complex process of production of this metal. Today, aluminum has become one of the cheapest metals due to both large raw materials reserves and improved production. It occupies a leading position in the production of non-ferrous metals and is widely used in many industrial sectors, both in pure form and in the form of alloys. How is aluminum produced today? Let's figure it out.
What is aluminum made of?
Depending on the raw materials used to produce this metal, aluminum is divided into primary and secondary.
For the production of primary aluminum, mineral ores containing alumina are used: bauxites, nephelines, alunites.
Bauxite is the most enriched with aluminum oxide - aluminum oxide contains more than 50%. Up to 30% of the oxide contains nephelines. And the smallest content (up to 20%) is in the alunites.
Secondary aluminum, as well as aluminum alloysare obtained by processing of aluminum waste and scrap. For its production, aluminum chips, foil and wire are remelted, and metal sheets and pipes are cut.
How is primary aluminum produced?
Primary aluminum is produced by a method thatis called "electrolysis of alumina melt in cryolite". Ore production of aluminum is a multi-stage process, which includes the production of intermediate raw materials: alumina-cryolite and fluoride salts-coal products-electrolytic aluminum.
The main links of this technological chain -alumina and electrolytic aluminum. The main device of production - electrolyzer or aluminum bath. The density of aluminum is higher than that of cryolite. Therefore, the process of electrolysis is separated from the cryolite-alumina melt. Separating, the metal settles on the bottom of the bath, where it is collected by vacuum buckets. Then the collected metal is purified by the chlorination method and ingots are cast from it.
How is aluminum made from scrap?
Secondary aluminum is produced by smelting. For this, the waste is collected and sorted, and then purified by a cold processing method. In the process of processing, all impurities (metals and non-metals) are removed from the waste, and then the scrap is melted in furnaces of fuel or electric melting. The finished product is poured into special casting pigs.
Since the production of this metal requires largeenergy, aluminum plants are built in the vicinity of hydroelectric power plants that provide the cheapest electricity. For the same reason, enterprises producing alumina are located next to deposits of aluminum ores.
More information on this and other similar topics you can find in the articles of our section Chemistry.