Alumina

Aluminum originates as an oxide called alumina. Because aluminum itself does not occur in nature as a metal, the processing of aluminum took a giant leap forward with the advent of electricity.
 
Deposits of bauxite ore are mined and refined into alumina—one of the feedstocks for aluminum metal. Then alumina and electricity are combined in a cell with molten electrolyte called cryolite. Direct-current electricity is passed from a consumable carbon anode into the cryolite, splitting the aluminum oxide into molten aluminum metal and carbon-dioxide.

The molten aluminum collects at the bottom of the cell and is periodically “tapped” into a crucible and cast into ingots. While continual progress has been made over the more than 110-year history of aluminum processing to reduce the amount of electricity used, there are currently no viable alternatives to the electrometallurgical process.

However, between materials recovery and ongoing innovative research and development efforts, the industry is constantly searching for ways to reduce the amount of electricity used in aluminum production—and thus the related emissions and costs.

The worldwide alumina industry produces more than 70 million dry metric tons of bauxite residue annually. Australia is the largest alumina refiner in the world, processing nearly one-third of the global total.