稀土尾矿催化剂脱硝性能研究

Denitrification Performance of Rare Earth Tailings Catalysts

白云鄂博矿经选矿后的稀土尾矿富含稀土、铁等催化活性物质。将稀土尾矿研磨后经不同温度焙烧,以制备高性能稀土尾矿基脱硝催化剂。脱硝性能测试表明:在500~900℃反应温度段,400℃焙烧稀土尾矿样品呈现出最优异的催化脱硝性能。X射线衍射(XRD)图谱表明,相对于原矿样品,焙烧之后的稀土尾矿,Fe2O3的衍射峰强度增强,CeCO3F衍射峰强度减弱。扫描电镜(SEM)图表明样品表面出现裂纹与孔洞。氢气程序升温还原(H2-TPR)谱图表明400℃焙烧尾矿的还原温度范围变宽且还原峰增多。X射线光电子能谱(XPS)分析表明,样品中Ce以Ce3+和Ce4+形式共存,Fe以Fe2+,Fe3+形式共存,400℃焙烧稀土尾矿晶格氧含量明显多于稀土尾矿。当稀土尾矿焙烧温度为400°C,NO浓度为500×10-6,CO/NO为4,反应温度为800℃时,催化剂的脱硝效率最佳,可达93. 37%。本研究将为稀土尾矿堆积问题的解决提供参考。

The rare earth tailings of Bayan Obo mine are rich in rare earth,iron and other catalytic active substances. In this paper,rare earth tailings were ground and roasted at different temperatures,to prepare high performance rare earth tailings based denitrification catalyst. Denitration performance test showed that in the reaction temperature range of 500~900 °C,400 ℃ calcination of rare earth tailing samples presented a most excellent catalytic denitration performance. X-ray diffraction(XRD)pattern showed that,compared with raw ore samples,the diffraction peak intensity of Fe2 O3 and CeCO3 F after roasting of rare earth tailings increased,while that of CeCO3 F decreased. Scaning electron microscope(SEM)showed that cracks and holes appeared on the surface of the sample.The H2-temperature programmed reduction(H2-TPR)spectrum showed that the reduction temperature range of the 400 ℃ calcined tailings was broadened and the reduction peak was increased. X-ray photoelectron spectroscopy(XPS)analysis showed that Ce in the form of Ce3+and Ce4+,and Fe coexisted in the form of Fe2+and Fe3+,rare earth tailing lattice oxygen content of 400 ℃ calcination tailings was significantly higher than that of the rare earth tailings. When the rare earth tailings roasting temperature was 400 ℃,NO concentration was 500×10-6,CO/NO was 4,and the reaction temperature was 800 ℃,the denitrification efficiency of catalyst was the best,up to 93.37%. This study would provide a reference for the solution of rare earth tailings accumulation problems.