Aluminium — material dossier
Aluminium is the inverted-chokepoint critical metal: the ore (bauxite) is genuinely diversified, but the energy-intensive smelting step is China-dominant. The risk lives in electricity and processing concentration, not in the rock.
What it is
Light structural metal (atomic number 13; density 2.70 g/cm³; melting point 660°C). Produced in three stages: bauxite ore → alumina (Al₂O₃, Bayer process) → primary aluminium (Hall-Héroult electrolysis, ~14 MWh per tonne). Roughly 4 t bauxite → 2 t alumina → 1 t aluminium.
Traded as: LME primary ingot/billet; alloyed wrought and cast products; secondary (recycled) metal, which meets a large and growing share of demand at ~5% of the energy of primary.
Where it comes from
Bauxite mining (~440 Mt/yr, 2025 — USGS MCS 2026)
Diversified across Guinea (~34%), Australia (~22%), China (~20%), Brazil (~7.5%) and India (~5.7%). Guinea overtook Australia as the world's largest bauxite source. Indonesia's 2023 export ban pushed it toward domestic alumina; Guinea revoked and reallocated licences to a state-backed miner in August 2025.
Primary smelting (~74 Mt/yr, 2025 — the binding stage)
- China ~61% — Hongqiao, Chalco, Xinfa. The dominant
chokepoint; concentration tracks cheap (often coal) power.
- India ~6%, Russia ~5% (Rusal Siberian hydro), **Canada
~4.5% (Rio Tinto hydro), UAE ~3.6%, Bahrain ~2%, Norway ~2%** (Hydro). Western smelting is hydro-anchored but small.
Why it matters
Used everywhere weight matters: transport (auto, aero, rail), packaging, building, electrical conductors and heat exchange. For wind turbines (Vestas), aluminium goes into nacelle components, castings, heat sinks and cabling.
Supply-risk read
Smelting concentration is the binding constraint, but USGS lists broad substitutes — copper in electrical/heat-exchange uses; composites, magnesium, steel and titanium in transport; steel, glass and plastics in packaging — which keeps aluminium at Elevated rather than High. The live policy overhang is trade measures: the US March 2025 Section 232 tariff (25%, doubled to 50% by June 2025 ex-UK) is the defining 2025 event, plus the embedded carbon/energy-price exposure of coal-based smelting.