A novel strategy for efficient utilization of manganese tailings: High SO2 resistance SCR catalyst preparation and faujasite zeolite synthesis

Abstract

Herein, a core-shell structure SiO₂@Mn catalyst was successfully synthesized from manganese tailings for NO removal through selective catalytic reduction with ammonia at low temperature. In the presence of 10 % H₂O and 100 ppm SO₂, the SiO₂@Mn catalyst exhibited excellent catalytic activity of 85 % NO conversion at 225 °C. This special core-shell was constructed by inert nano-SiO₂ particles, which grew and encapsulated on the surface of manganese oxide, inhibiting the reaction between SO₂ with MnOx and thus improving the SO₂ resistance. Furthermore, a filter residue was generated in the process of catalysts preparation. Under proper hydrothermal conditions, the residue comprising of Si, Al, and O was used to synthesize high-crystallinity X-type zeolite. This process fully utilized manganese tailings and inspired for Mn-based catalysts design and X-type zeolite preparation, realizing the dual benefits of atmosphere purification and solid waste disposal.

Keywords: Core–shell structure; Faujasite zeolite; Manganese tailings; NH(3)-SCR; SO(2) resistance.