Chapter 2.7 - Rare Earth, Titanium Group Metals, and Reactive Metals Production

Abstract

Metallurgy for the production of rare earth metals, titanium group metals, and reactive metals is comprehensively reviewed. For rare earth metals, the physicochemical properties of rare earth metals and their chemicals, the raw materials for metallurgy, and the outline of the metal production are summarized. Particularly, the thermodynamic characteristics of rare earth chemicals are described in detail. The characteristics of reduction and refining processes are summarized based on the literature on the industrial process and lab-scale research. High-purity refining methods for rare earth metals, including processes under study, are further introduced. For titanium group metals, the history of titanium production, the current production process of titanium metal (the Kroll process), and other commercialized production processes (the Hunter process, Iodine process) are summarized. Past and recent research for new titanium production processes are reviewed by classifying the processes according to the types (electrolysis and metallothermic reduction). Additionally, the entire production process of zirconium and hafnium metals, including the separation process for elemental zirconium and hafnium, is summarized. For reactive metals, the thermodynamic properties of lithium, sodium, magnesium, and calcium metals and their chemicals are summarized. The entire production processes are briefly explained. The raw materials and certain types of smelting processes with a central focus on molten salt electrolysis are reviewed. Bipolar electrolysis for magnesium metal production advanced in Japan is introduced. Metallothermic reduction processes for producing magnesium and calcium as the industrial production method are briefly summarized.