Selective hydrolysis of trace TiCl4 from VOCl3 for preparation of high purity V2O5

Given the strong demands for high purity vanadium products dedicated for all-vanadium redox flow battery (VRFB), numerous preparation technologies have been developed. One of them, the chloride process that using vanadium oxytrichloride (VOCl 3 ) as purification intermediate presents distinct technical advantages. The intermediate is readily purified via distillation process to remove most of the impurities. However, the trace titanium tetrachloride (TiCl 4 ) is difficult to be removed, due to close saturated vapor pressures. In present work, based on thermodynamic calculation and analyses, we found that TiCl 4 reacts with water significant preferentially to form the corresponding oxide, compared with VOCl 3 . Then we proposed a novel method to remove trace TiCl 4 from VOCl 3 by selective hydrolysis – distillation. The related experiments were conducted and validated the feasibility of the innovative process. Vanadium pentoxide (V 2 O 5 ) with purity higher than 99.99   wt% (4N) was further prepared from the purified VOCl 3 by precipitation – calcination .