A Novel Activated Vanadium Extraction Tailing Catalyst for NOX Removal in NH3-SCR

Abstract

In this paper, the vanadium extraction tailings (VT) by sodium roasting—water leaching were used to prepare the active catalyst by activate treatment to explore denitrification. The influence of activating parameters and denitrification conditions on NO_X removal of the catalyst were analyzed with selective catalytic reduction (NH₃-SCR). The surface behavior was characterized by BET, SEM, XPS, H₂-TPR, and NH₃-TPD. The results show that optimal catalyst was prepared under the conditions that acid medium was 12% (volume fraction) HNO₃, particle size of VT was less than 38 μm, and calcination temperature was 500 °C; its NO conversion rate reached 95% under the denitrification conditions of 5% O₂, 500 ppm NO, 500 ppm NH₃, and gas hourly space velocity 50000 h⁻¹. The optimal catalyst performed well for against SO₂ poisoning but bad for H₂O. The specific surface area and specific pore volume of optimal catalyst increased by 11.10 and 7.95 times compared with VT. The optimal catalyst featured a greater ratio of Fe³⁺, Mn⁴⁺, V⁵⁺, and chemisorbed oxygen, lower temperature of iron reduction, and higher H₂ adsorption peak, which were in favor of NO_X removal. Moreover, its surface acidity was enhanced reflecting in a larger NH₃ desorption peak area and a 43 °C higher desorption temperature than VT.

Graphical Abstract