Carbochlorination of YOCl for Synthesis of YCl3

Abstract As the production of high-quality titanium (Ti) metal increases significantly, the generation of low-quality Ti scraps increases and exceeds the demand for current cascade recycling in ferrous metallurgy. Therefore, the development of an upgrading recycling technology, in which scraps are refined and reutilized, is required. The magnesium (Mg) deoxidation assisted by the formation of oxychlorides of rare earth metals is currently considered a promising process for upgrading recycling technology, during which YOCl is formed as a byproduct. In this study, we investigate the synthesis and separation of YCl 3 from YOCl via carbochlorination at 973 and 1073 K and confirmed that YCl 3 can be regenerated from YOCl at a high conversion rate (82.7 pct at maximum). YCl 3 was also formed even in the presence of MgCl 2 ; however, MgCl 2 decreased the conversion rate (49.8 pct at minimum). The conversion rate in the temperature region where YCl 3 is a liquid (1073 K) was lower than that in the temperature region where YCl 3 is a solid (973 K). Therefore, an operation with temperature cycling, in which YCl 3 is formed at a temperature where YCl 3 is a solid and then the temperature is increased to a temperature where YCl 3 is a liquid to drain the molten mixed salt, is efficient.