Pidgeon process

The Pidgeon process is a metallurgical method for thermally reducing magnesium oxide with silicon in externally fired retorts to produce magnesium metal. This process is an alternative to the electrolysis of magnesium chloride.1

Key Aspects of the Pidgeon Process:

• Raw Materials: It uses calcined dolomite (magnesium oxide and lime) and silicon.1
• Reaction: The core reaction involves reducing magnesium oxide (MgO) with silicon (Si) at high temperatures, producing magnesium gas and dicalcium silicate slag.1
• Conditions: The process operates under vacuum to lower the required reaction temperature, typically around 1,200 °C (2,200 °F).1
• Output: Magnesium gas is condensed into crystals, often referred to as "crowns," while the slag is removed.1

This method was notably introduced in Canada during World War II and has remained economically viable, particularly in regions with lower labor and energy costs.1