Why is aluminum so expensive?

[lolitahe69]

The price of aluminum spiked this week to $2,740 a ton, a 10-year high, compared to $1,756 a year ago, in part because of the unrest in Guinea — the source of some material important to aluminum production. Beyond the recent hike, however, aluminum prices have mostly been rising all year.
Why is aluminium so expensive?

[Keganhirl]

Even though aluminium is more abundant than iron in the Earth's crust , aluminium is more expensive than iron. This is mainly because of the large amounts of electrical energy used in the extraction process.