Glass phase extraction for one-step separation and recovery of strategic metals from spent hydrofining catalysts

Abstract

Spent hydrofining/selective catalytic reduction catalysts generated during the production of ultra-low-sulfur/nitrogen fuel are considered to be hazardous wastes. Furthermore, the sustainable supply of critical metal resources such as molybdenum (Mo), tungsten (W), nickel (Ni) and vanadium (V), which are present in high concentrations in spent catalysts, is challenged by the climate emergency, ore depletion and inefficient technologies for separating metals. Here, glass phase extraction is proposed as a novel approach for simultaneously separating metals and obtaining recovered products from spent hydrofining catalysts in one step. By constructing a glass network structure that satisfied a stable coordination environment for the target metal ions, 99.82 % of the Mo6+ was “melt-melt” separated with the glass phase as Na2MoO4, while the extraction efficiencies of Ni2+ and Al3+ were >99.16 %. The separation factors βMo/Ni and βMo/Al were as high as 65812.95 and 71944.85, respectively. The obtained results verify this method as a valuable synthetic route for refractory metal salts and transition metal ion-doped glass–ceramic materials, enhancing the prospect of achieving full-component resource recovery from hazardous wastes.