Carbochlorination of YOCl for Synthesis of YCl3

Abstract

AbstractAs 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 YCl3 from YOCl via carbochlorination at 973 and 1073 K and confirmed that YCl3 can be regenerated from YOCl at a high conversion rate (82.7 pct at maximum). YCl3 was also formed even in the presence of MgCl2; however, MgCl2 decreased the conversion rate (49.8 pct at minimum). The conversion rate in the temperature region where YCl3 is a liquid (1073 K) was lower than that in the temperature region where YCl3 is a solid (973 K). Therefore, an operation with temperature cycling, in which YCl3 is formed at a temperature where YCl3 is a solid and then the temperature is increased to a temperature where YCl3 is a liquid to drain the molten mixed salt, is efficient.