ABSTRACT
The use of light metals is essential for aerospace, space and transportation industries because lighter components allow reaching long distances by using less fuel. Magnesium (Mg) is the lightest structural metal with a density of 1.738 g∙cm−3, and its alloys have promising mechanical properties with its moderate availability and price between all light metals. The selection of primary magnesium production depends on the raw material (magnesium containing ores or salts solved in salty lakes). Vacuum silicothermic production process, called the Pidgeon Process after its inventor L. M. Pidgeon, is the dominant primary production method among all processes. It is based on the reduction of Mg in calcined dolomite ore by using ferrosilicon as a reductant in air-sealed retorts under vacuum atmosphere at temperatures between 1200°C and 1250°C. This process must be realized under vacuum due to the thermodynamical obligation. The reduction reaction is only feasible over 1870°C under 1 bar atmospheric pressure, thereby process costs would dramatically increase whereas production capacity slightly increases. In this chapter, historical development, fundamental principles, theoretical background, industrial application and disposal of wastes of the process are comprehensively explained with theoretical and industrial examples.
