Resources Recycling ISSN:2765-3439(Print) 2765-3447(Online) 자원리싸이클링

Spent SCR (Selective catalytic reduction)catalysts used to remove nitrogen oxides in the atmosphere contain valuable metals, so efficient recovery technology is required. Therefore, this study compared and evaluated the experimental data on vanadium and tungsten leaching tested in previous research on spent SCR catalysts. All of the research applied NaOH-based direct leaching, and two of those utilized pressurized leaching to improve the leaching effect. As a result of regression analysis for the evaluation, mostly a high linear correlation was found between the predicted and the experimental leaching efficiencies (coefficient of determination of 89%-99%). The overall leaching efficiency levels according to the component and pressurization could roughly be recognized through the Y-intercept in the regression equation. The effects of the significant factors could be evaluated through the coefficients of the first degree terms of independent variables related to the factors. As a result, such coefficients on leaching temperature among the significant factors generally ranged 10^-3‒6.23×10^-3. In addition, the coefficients on leaching agent ranged 2.6×10^-2‒5.1×10^-2 for V₂O₅ leaching and 0.1-0.21 for WO₃, implying that increasing the concentration of the leaching agent may be effective for selective enhancement of WO₃ leaching. Meanwhile, the coefficients of the leaching time ranged 1.8×10^-4‒3×10^-3, and those of liquid-solid ratio generally ranged 10^-2‒1.9×10^-2, indicating that an increase in the corresponding factor may lead to improved leaching efficiency.