Depending on the distance and localization between the mine and the refinery, several means of transportation can be used: conveyor belts, trucks, trains, barges and ships. In recent years, the transport of bauxite slurry is used to feed the alumina refinery. The process of bauxite extraction is a classic strip mining activity with prospection, surface stripping (sometimes using explosives) and possible treatment of the ore; mainly crushing and washing.
The first step in the commercial production of aluminum is the separation of aluminum oxide from the iron oxide in bauxite. This is accomplished in a refinery or alumina plant using a technique developed by Karl Joseph Bayer, an Austrian chemist, in 1888. In the Bayer Process, bauxite is mixed with caustic soda, or sodium hydroxide, and heated under pressure. The sodium hydroxide dissolves the aluminum oxide, forming sodium aluminate. The iron oxide remains solid and is separated by filtration. Finally, aluminium hydroxide introduced to the liquid sodium aluminate causes aluminium oxide to precipitate, or come out of solution as a solid. These crystals are washed and heated to get rid of the water. The result is pure aluminum oxide, a fine white powder also known as alumina.