Study On Denitrification Performance Of Rare Earth Concentrate Supported Fe₂O₃ For NH₃-SCR

In this paper,rare earth concentrate rich in Ce oxide is used as the carrier of catalytic materials,and a series of mineral catalytic materials are obtained by immersion in ferric nitrate solution,ball milling,high energy ball milling and microwave roasting.XRD,EDS,SEM,TPD,XPS,etc.Means to conduct the relevant characterization analysis of the mineral phase structure,surface morphology,and surface properties of the catalyst,and simultaneously evaluate and compare the denitrification activity of the samples in the microreactor.Preparation process:no ball milling,ordinary ball milling,high energy ball milling,different ferric nitrate concentrations:0mol/L,0.1mol/L,0.5mol/,1.0mol/L,different roasting temperatures:300?,350?,400?,450? as variables,explore the preparation process.In the comparison and detection of various experimental variables in the experiment,the best conditions for preparing the rare earth concentrate-supported Fe₂O₃ catalytic material by the impregnation method are obtainedIn summary,different molar concentrations of ferric nitrate solutions of rare earth concentrates are performed.Structure-activity comparison of Fe₂O₃ supported catalytic materials.The main conclusions are as follows:1.Preparation of rare earth concentrate-supported Fe₂O₃ mineral catalyst material by ball milling at four different temperatures:300?,350?,400?,and 450?.Determine the best roasting temperature of 350?.The denitration performance of each sample was significantly better than the other three roasting temperatures.At a reaction temperature of350?,the denitration rate reached 80.6%.This indicates that there is a synergistic combination of a large amount of Ce element in the rare earth concentrate and Fe element in the iron nitrate solution.The four kinds of microwave roasting catalytic activity are sorted:350? roasted samples>450? roasted samples>400? roasted samples>300? roasted samples.2.Compare the samples without ball milling,ordinary ball milling,and high energy ball milling by dipping method.Make sure that ball milling is positive and effective for sample processing.The high-energy ball milled sample is better than the other two samples.At a reaction temperature of 350?,the denitration rate can reach 92%.This indicates that the sample is subjected to high-energy ball mill vibration,rotation,and the sample is subjected to strong impact,grinding and stirring,and stress and strain occur.Only the energy is generated,the rare earth concentrates are defective,and the activity of the mineral catalytic material is greatly improved.The catalytic activity of the three preparation processes is ordered:high-energy ball milling preparation>ordinary ball milling preparation>no ball milling preparation.3.Microwave roasting can cause a large number of cracks on the surface of mineral particles,increase the specific surface area.Immersion of ferric nitrate solution will increase the surface active sites of mineral particles,rough and porous morphological characteristics,and increase rare earth.The acidic site of the concentrate makes it easier to adsorb alkaline gas NH₃.4.Immersion of ferric nitrate solutions with different molar concentrations+high-energy ball milling+350? microwave roasting;rare earth concentrates accelerate the decomposition of fluorocarbon ceria,and diffraction peaks of Ce₇O₁₂2 and Fe₂O₃ appear.Agglomeration and new characteristic peaks of FeCe₂O₄ appear,indicating that the rare earth concentrate is used as a carrier and Fe₂O₃ is combined and synergistic.Ce₂O₃ Will be converted into Ce₇O₁₂,Ce₇O₁₂2 contains Ce³⁺,so the content of Ce³⁺will increase,and some of the weaker fluorocarbon cerium peaks It has completely disappeared,and most of Fe₂O₃is embedded in the rare earth concentrate in a highly dispersed or amorphous form,forming a small amount of FeCeO composite oxide.5.The XPS results show that the whole process of impregnation and microwave roasting with different concentrations of ferric nitrate increases the ion content of Ce³⁺and Fe²⁺.The active component Ce coexists with Ce³⁺and Ce⁴⁺.Fe coexists in the form of Fe²⁺and Fe³⁺.The conversion of adsorbed oxygen and lattice oxygen increases significantly,so there are more oxygen vacancies for oxygen transfer,and the changes in the valence states of Fe and Ce ions can also be explained,Fe and Ce work together to form a small amount of FeCeO composite oxides.