Study on the Denitration Performance of Sulfuric Acid-Modified Columnar Catalysts Derived from Rare Earth Tailings

¹ School of Energy and Environment, Inner Mongolia University of Science and Technology, Baotou 014010, China
² Key Laboratory of Efficient and Clean Combustion in Inner Mongolia Autonomous Region, School of Energy and Environment, Inner Mongolia University of Science and Technology, Baotou 014010, China

^* Corresponding author: Junmao Qie, E-mail: 907360382@qq.com

Abstract

Currently, the massive accumulation of Bayan Obo rare earth tailings in Baotou City, Inner Mongolia, has imposed significant pressure on the local ecological environment. The Fe and Ce elements contained in these tailings possess potential as active components for denitration catalysts. However, their inherent denitration efficiency remains relatively low, necessitating integration with other treatment processes for performance enhancement. This study employed sulfuric acid activation modification combined with extrusion molding technology to prepare columnar rare earth tailing catalysts using Bayan Obo rare earth tailings as raw materials, aiming to develop cost-effective NH₃-SCR denitration catalysts with high catalytic activity. The results demonstrated that sulfuric acid-modified rare earth tailings exhibited substantially improved denitration efficiency compared to raw materials, achieving a maximum efficiency of 87.4% at 400°C. The introduction of SO4^2- increased surface acidic sites on the catalyst, thereby enhancing NH3 adsorption capacity and strengthening the Eley-Rideal (E-R) mechanism, which collectively contributed to the improved catalytic performance. Furthermore, the formation of various sulfates (e.g., CaSO₄ and MgSO₄) during sulfuric acid modification significantly enhanced the mechanical strength of the catalysts. This approach not only achieves high-value utilization of mining waste through modified activation but also aligns with the green environmental concept of "using waste to control pollution." The findings provide significant insights for promoting resource-efficient societal development and sustainable environmental management.