焙烧温度对稀土基复合氧化物催化剂活性的影响

Effect of Calcination Temperature on Activity of Rare Earth-Based Composite Oxides

以白云鄂博稀土精矿为催化剂的原材料,采用水热方法,将稀土精矿经15 mol·L-1 HNO3处理,过滤后取出滤液,进行干燥,焙烧制得稀土基催化剂,用在脱硝领域,研究焙烧温度对其脱硝活性的影响。通过XRF, TG-DSC, XRD, BET, SEM, TPD, TPR等手段对催化剂理化特性、 NH3/NO吸附能力及氧化还原性进行表征分析。结果表明:随焙烧温度的增加,催化剂的催化活性呈先上升后降低的趋势。在焙烧温度为600℃,反应温度为350℃的条件下,催化剂的脱硝率能达到60%以上,并且此条件下制得的催化剂具有较好NH3, NO吸附特性及较强的氧化还原性。随着焙烧温度的增加,催化剂的主晶相峰变得更加尖锐,结晶度增强。

With Bayan Obo rare earth ore concentrate as the raw material of catalyst,rare earth ore concentrate was processed with nitric acid of 15 mol·L-1 by using the hydrothermal method,then we filtered it and took the filtrate out,dried the filtrate,and calcinated it to obtain rare earth-based catalyst,which was used in the denitration process or studying the effect of calcination temperature on its denitration activity.The XRF,TG-DSC,XRD,BET,SEM,TPD and TPR characterizations of the catalysts were performed to reveal the physical and chemical properties,including NH3/NO adsorption capability and redox ability.The results showed that with the increase of calcination temperature,the catalytic activity first increased and then decreased.When the calcination temperature reached 600℃,the reaction temperature was 350℃,the denitrification rate of catalyst could reach over 60%.What′s more,the catalyst obtained under such conditions had better NH3/NO adsorption property and strong redox property.As the calcination temperature,the major phase peak of catalyst became sharper,and the crystallinity was enhanced.