calciothermic process

The calciothermic process is a metallurgical technique used to extract high-purity rare-earth metals. In this method, a rare-earth fluoride is heated with calcium metal at high temperatures, typically above 1,450 °C. This reaction produces calcium fluoride and the desired rare-earth metal. The calcium fluoride floats on the molten metal, allowing for easy separation. The metal is then further purified by heating in a vacuum to remove excess calcium, followed by sublimation or distillation. This process is effective for most rare-earth metals, excluding those with very high vapor pressures. This method is a form of reduction, a key process in extractive metallurgy where a metallic oxide compound is heated with a reducing agent to release the metal.12