Aluminum Sourcing: From Bauxite to Billet

Understand the aluminum value chain so you can negotiate intelligently with extruders, foundries and rolling mills.

Aluminum sourcing requires understanding the full value chain from raw materials to semi-finished products like billets. This knowledge empowers procurement professionals to negotiate better terms with suppliers such as extruders, foundries, and rolling mills by grasping cost drivers and market dynamics

Bauxite Mining

Bauxite, containing 15-25% aluminum, serves as the primary ore and is mined mainly in equatorial regions like Australia and Africa, with global reserves estimated at 55-75 billion tons lasting 250-340 years at current rates. Approximately 6-7 tonnes of bauxite yield one tonne of aluminum, involving mining contractors, explosives, and transportation.

Alumina Refining

Bauxite is refined into alumina (aluminum oxide) via the Bayer process in refineries, requiring about 2 tonnes of alumina per tonne of aluminum. This step uses chemicals like caustic soda and lime, plus power, contributing 26% of production emissions.

Primary Smelting

Alumina undergoes electrolysis in smelters to produce molten aluminum, an energy-intensive process where oxygen bonds are broken in electrolytic baths. The resulting liquid metal, a commodity traded on the London Metal Exchange (LME), accounts for 64% of emissions and is cast into ingots or billets.

Casthouse to Billet

Molten aluminum is alloyed with elements like copper or silicon for strength and cast into billets—log-shaped forms via vertical direct chill—used by extruders, or slabs for rolling mills. Billets are homogenized to eliminate segregation before further processing.

Downstream Processing

Extruders heat billets to around 500°C and force them through dies to create profiles for construction and automotive uses. Foundries cast alloys into components, while rolling mills process slabs into sheets or foil as thin as 0.006 mm. Recycling uses just 5% of primary energy, with 75% of all aluminum still in use.

Negotiation Strategies

Know LME prices and alloy premiums to challenge markups from extruders on billet costs. For foundries and rolling mills, request transparency on recycled content, certifications, and capabilities via detailed drawings specifying alloy, tolerances, and volumes. Avoid cheapest bids; prioritize integrated producers for cost efficiency and verify supplier websites for press sizes or industry focus.