Inventions - Pidgeon process: smelting magnesium in a vacuum

Smelting metallic magnesium often relies on the Pidgeon process, a practical reduction method utilizing raw dolomite ore. After the dolomite undergoes calcination, grinding, and pelleting, it is heated in a vacuum reduction tank alongside seventy-five percent ferrosilicon, which acts as a reducing agent. Historically, Canadian facilities utilized sulfur hexafluoride to shield the reaction from stray oxygen. Producing a single kilogram of magnesium required seventeen to twenty kilowatt-hours of energy, with China eventually producing the majority of primary magnesium using this process.

Source: Wikipedia