Aluminothermic and Magnesiothermic Reduction of Rare Earth Compounds for Production of Alloys: Thermodynamic Evaluations

Rare earth (RE) elements can improve the properties of aluminumAluminumand magnesiumMagnesium alloys when added as an alloyingAlloying agent. A simple way to produce Al–RE or Mg–RE alloys is by adding RE metals to Al alloy or Mg alloy. However, the high pricePrice of RE metalsMetal means that an alternative route to produce the alloy is needed. An alternative way to make RE–Al/Mg alloys is by directly reducing RE compounds with Al or Mg. In this study, a systematic thermodynamic evaluation of the ability of aluminumAluminumand magnesiumMagnesium to reduce different rare earth compounds was carried out. RE oxideOxide, fluoride, and chloride systems were analyzed, with emphasis on RE chloride. The results showed that only Sc was expected to be reduced by Al in all assessed systems, while La and Ce could only be reduced by Al in the oxide form and none of the Y compounds assessed were reduced by Al. Magnesium was expected to be able to reduce La and Ce in the oxideOxide form, while not in the fluoride and chloride forms.