What are the methods by which bauxite ore is extracted from aluminium?

Answer 1

Bauxite is usually strip mined because it is almost always found near the surface of the terrain, with little or no overburden. Approximately 70% to 80% of the world's dry bauxite production is processed first into alumina, and then into aluminium by electrolysis as of 2010. Bauxite rocks are typically classified according to their intended commercial application: metallurgical, abrasive, cement, chemical, and refractory.

Usually, bauxite ore is heated in a pressure vessel along with a sodium hydroxide solution at a temperature of 150 to 200 °C. At these temperatures, the aluminium is dissolved as an aluminate (the Bayer process). After separation of ferruginous residue (red mud) by filtering, pure gibbsite is precipitated when the liquid is cooled, and then seeded with fine-grained aluminium hydroxide. The gibbsite is usually converted into aluminium oxide, Al2O3, by heating. This mineral becomes molten at a temperature of about 1000 °C, when the mineral cryolite is added as a flux. Next, this molten substance can yield metallic aluminium by passing an electric current through it in the process of electrolysis, which is called the Hall--Héroult process after its American and French discoverers in 1886.

Prior to the Hall--Héroult process, elemental aluminium was made by heating ore along with elemental sodium or potassium in a vacuum. The method was complicated and consumed materials that were themselves expensive at that time. This made early elemental aluminium more expensive than gold.[4]

Answer 2

It's the other way around: How is aluminum extracted from Bauxite ore? The ore is heated in a blast furnace, to about 1225 degrees. The aluminum in the ore melts, and flows out the bottom of the furnace into ingots.

Answer 3

Bauxite is refined to alumina (aluminum oxide) by heating while mixed with sodium hydroxide, where the resultant soluble compound sodium aluminate can be removed from the ore. The aluminum hydroxide can be removed by neutralization or by seeding with Al(OH)3 crystals.

This is called the Bayer process.

The aluminum metal is separately removed from the alumina by electrolysis, where alumina is dissolved in molten cryolite and aluminum ions are removed at the cathode of a very large processing cell.

This is called the Hall-Heroult process.

Answer 4

The process by which alumina is extracted from bauxite is called the Bayer Process.

Answer 5

Bauxite is an ore. Aluminium, a metal, is extracted from it.

Answer 6

Got that backwards. Aluminum is extrated from Bauxite. To do so requires chemical treatment and electrolytic conversion.