Catalytic effect of rare earth tailing on NOx reduction in CO reburning

Abstract

The effect of catalytic denitration performance of rare earth tailing was experimentally investigated at 300–900 °C. The rare earth tailing was separated to magnetic separation tailing and magnetic separation concentrate by high intensity magnetic separation. A fixed-bed reactor was used to evaluate the catalytic denitration performance of rare earth tailing, magnetic separation tailing, and magnetic separation concentrate. The X-ray Diffraction (XRD), Advanced Mineral Identification and Characterization System (AMICS), Scanning Electron Microscope (SEM) and H2 Temperature Programmed Reduction (H2-TPR) were used to characterize the three tailing. The results showed that it was difficult for CO to react directly with NO. When the temperature was 900 °C, the NO conversion rate was only 6.4%. After adding three minerals, the NO conversion rate increased significantly. When the reaction temperature was 500 °C–700 °C, the NO conversion rate of magnetic separation tailing was higher than that of rare earth tailing and magnetic separation concentrate. With the increase in the CO volume fraction, the NO conversion rate of the three minerals increased first and then decreased. The increase in the volume fraction of CO2 and SO2 had little effect on the conversion rate of NO, the incorporation of O2 seriously affected the conversion rate of NO.

Keywords

• Catalytic denitration
• Rare earth tailing
• NO reduction
• CO reburning