Preparation Of NH₃-SCR Denitrification Catalyst Derived From Bayan Obo Rare Earth Ore And Its Performance

In recent years,China has paid more and more attention to environmental issues,and the newly revised laws,regulations and standards on environmental protection have become more and more stringent.Nitrogen oxide（NOx）,as one of the major atmospheric pollutants,can lead to acid rain,photochemical smog and ozone layer destruction.At present,the focus of atmospheric environment governance is coking,iron and steel,and other non-electric industries NOx governance.At present,the most effective SCR denitration technology is mature technology,the traditional denitration catalyst is given priority to with vanadium denitration catalyst,mature technology,has a broad application space in the denitration governance,vanadium titanium system denitration catalyst used are the main active ingredients of vanadium pentoxide,however,is a kind of high toxic substances are the catalyst in recent years,our country each year to replace the toxic denitration catalyst containing vanadium and titanium is 300000～400000 cubic meters,a large number of toxic waste catalyst such as custody or improper handling,extremely easy contaminated soil and groundwater,may cause serious damage to the ecological environment,has been banned by many developed countries.Therefore,the research and development of a new green non-vanadium based medium and low temperature denitrification catalyst is the key to control NOx emission under medium and low temperature conditions.Rare earth Ce O₂because of excellent oxidation reduction performance under a wide range of research and application.This work plan includes the oxalic acid leaching,HCl acid leaching and alkali roasting to modify the rare earth concentrate and fully expose the cerium,iron,lanthanum and other elements.XRD,SEM,BET and XRF were used to observe the structure changes of the rare earth concentrate after treatment.The performance of the catalyst was studied by H₂-TPR,NH3-TPD,NO-TPD and activity tests.The findings:（1）after treatment,the active components of rare earth concentrate are fully exposed to the outside of the active powder,the crystallinity of Ce₇O₁₂ is decreased,and the catalytic performance of Cerium,Lanthanum,iron and other metal oxides is significantly improved;（2）the co-treatment of acid,base and acid-base can improve the oxidation-reduction performance and the adsorption of NH₃and NO.In contrast,alkali-acid co-treatment has better effect on improving the performance of the catalyst;（3）The combined treatment of oxalic acid leaching,HCl acid leaching and Alkali roasting can promote the catalytic activity of rare earth concentrate;（4）When the oxalic acid immersion concentration was 10mol/L,the immersion time was3h,the hydrochloric acid immersion concentration was 0.25mol/L,the immersion time was60min,the baking temperature was 500℃,and the roasting time was 120min,the catalytic reaction capacity of the NH₃-SCR denitrified catalyst reached the maximum 85.1%at 500℃.