Effects of manganese content and calcination temperature on Mn/Zr-PILM catalyst for low-temperature selective catalytic reduction of NOx by NH3 in metallurgical sintering flue gas.

The effects of manganese content, carrier calcination temperature, and catalyst calcination temperature of manganese-based zirconium pillared intercalated montmorillonite (Mn/Zr-PILM) catalysts were investigated for low-temperature selective catalytic reduction of NOx by NH3 (NH3-SCR) in the metallurgical sintering flue gas. The physicochemical properties of these catalysts can be characterized by X-ray diffraction (XRD), N2 adsorption-desorption isotherm, and temperature-programmed desorption of ammonia (NH3-TPD). The 10Mn/Zr400-PILM(300) catalyst had the highest NOx conversion under excess oxygen conditions (15 vol% oxygen) and reached 91.8% NOx conversion at 200 °C. It was found that when the loading of manganese was 10 wt.%, the catalyst had the highest catalytic activity and the manganese-active component was highly dispersed on the Zr-PILM surface. The optimal calcination temperature of the Zr-PILM was 400 °C because the catalyst pore size was concentrated at 1.92 nm and the catalyst had the most acidic sites. And the optimum calcination temperature of the catalyst was 300 °C. This was because excessive calcination temperature promoted the manganese oxide polymerization and reduced the catalytic activity of the catalyst.