Abstract: In this work, a series of mineral catalytic materials were obtained by using Bayan Obo rare earth concentrate rich in Ce oxide as the catalyst material, impregnated with ferric nitrate solution and microwave roasted. XRD, SEM, EDS, XPS and other methods were used to characterize the mineral phase structure and surface morphology of the catalyst, and to determine its denitration activity. The results showed that the rare earth concentrate impregnated in 0.5 mol/L ferric nitrate solution (Catalyst 3) had the best structural characteristics, the surface was rough and porous, and obvious and deep cracks appeared, which was conducive to the diffusion of gas on the surface of the material. Most Fe2O3 was embedded in the rare earth concentrate in a highly dispersed or amorphous form. The content of Ce3+ and Fe2+ were increased after immersion in ferric nitrate solution and microwave roasting. Active components Ce coexisted in the form of Ce3+ and Ce4+, Fe coexisted in the form of Fe2+ and Fe3+. The conversion of adsorbed oxygen and lattice oxygen increased significantly, and there were more oxygen vacancies for oxygen transfer. The change in the valence of Fe ions and Ce ions indicated that Fe and Ce had a combined effect to generate a small amount of Fe and Ce composite oxides. With the increase of medium and strong acid sites on the surface of Catalyst 3, the ability of the surface to adsorb NH3 increased, and its denitration effect was the best. When the microwave roasting temperature was 350℃, the denitration rate can reach 80.6%.

Key words: rare earth concentrate, catalytic denitrification, mineral catalysis, carrier

摘要： 以白云鄂博富含Ce氧化物的稀土精矿为催化材料的载体，采用硝酸铁溶液浸渍、微波焙烧获得一系列矿物催化材料。采用XRD, SEM, EDS, XPS等手段对催化剂的矿相结构、表面形貌进行表征，并测定了其脱硝活性。结果表明，在0.5 mol/L硝酸铁溶液中浸渍的稀土精矿(Catalyst 3)结构特征最佳，表面粗糙且多孔，出现了明显且较深的裂纹，大部分Fe2O3以高分散或无定形的形式嵌布在稀土精矿上，有利于气体在材料表面扩散；催化材料中Ce3+, Fe2+含量增加，Fe离子与Ce离子价态变化说明Fe与Ce存在联合作用，形成了少部分Fe和Ce的复合氧化物；Catalyst 3表面中、强酸性位点增加，表面吸附NH3的能力增强，其脱硝效果最佳，当微波焙烧温度为350℃时，脱硝率可达80.6%。

关键词: 稀土精矿, 催化脱硝, 矿物催化, 载体