Such metal is frequently stored outdoors and can be wet. Charging of damp aluminium to hot furnaces results in the generation of large volumes of steam, and can cause steam explosions, in the worst cases blasting molten aluminium around the casthouse.
Traditionally, scrap metal has been heated with a gas flame to remove moisture, but such localised heating can never fully remove water, and steam explosion can still occur.
Iceland's VHE has completed the fabrication and installation of a preheating furnace for the Rio Tinto Alcan smelter at Straumsvík in Iceland.
The furnace, which is semi-automatic, is able to heat 15t of scrap to 200°C within two hours. At this temperature all water and many low-boiling point organics are fully removed.
The oven is electrically heated and uses the recirculating air principle for best efficiency.