Sustainable recycling of titanium from TiO2 in spent SCR denitration catalyst via molten salt electrolysis

Spent catalyst used for denitration by selective catalytic reduction (spent SCR denitration catalysts) is one of the important urban mines due to the high content of TiO2 (~85 wt%) and the massive accumulation amount (over 100, 000 tons), therefore, value-added reutilization of titanium in spent SCR catalysts is considerably meaningful. In this paper, a novel method is proposed for converting the titanium oxide in spent SCR denitration catalysts to metallic titanium. Specifically, titanium dioxide (TiO2) was firstly obtained from spent SCR denitration catalysts after removing the impurities by hydrometallurgy process. Then, TiO2 is converted to Ti2CO by carbothermic reduction method, and Ti2CO was further purified by oleic acid capture. Finally, by utilizing the as-prepared Ti2CO as the consumable anode in the NaCl-KCl molten salt, high-purity metallic titanium was deposited at cathode, all confirming the feasibility for the conversion of low–grade TiO2 in the spent catalysts, from 60 wt% to high–purity metallic Ti (99.5 wt%), furthermore, the energy consumption of this process is 3950 kWh tonne−1 Ti, which is lower than that of most traditional titanium metallurgy methods. The method herein can provide new insights for the value-added recycling of titanium resources in urban mines.