含钛高炉渣制备SCR烟气脱硝催化剂

SCR denitration catalyst prepared from titanium-bearing blast furnace slag

以含钛高炉渣为原料，稀硫酸为溶剂提取钛液，钛液经水解、高温焙烧后制得高比表面积的TiO2，并以其为载体采用分步浸渍法制备了V2O5-WO3／TiO2催化剂。优化了含钛高炉渣的酸解条件，对所得TiO2进行了XRD、XRF、BET表征，用自制催化剂评价系统考察了所制备催化剂的脱硝性能及抗硫抗水性能。结果表明：H2SO4浓度40％、酸渣比1．5、酸解温度80℃、酸解时间3h条件下，Ti02浸出率可达90％，水解产物主要为锐钛型Ti02，纯度达到74％，含有21．2％无定形SiO2及少量其他杂质。SiO2的存在提高了产物的比表面积、孔径，有利于活性组分的负载。以含钛高炉渣基TiO2为原料制备的V2O5-WO3／TiO2脱硝催化剂相比于以商业TiO2和TiOSO4制备的催化剂，在250-450℃具有更高的催化活性，且在300℃具有较好的抗硫抗水性能。

Titanium oxide （TiO2） with high specific surface area was prepared from blast fumace slag by steps, in succession, extraction using dilute sulfuric acid （i.e., acidolysis）, hydrolysis and high-temperature calcination, and was used as the support in preparing VEO5-WO3/ZiO2 catalyst for flue gas denitration by selective catalytic reduction （SCR）. The prepared TiO2 support was characterized with XRD, XRF and BET, and the catalyst was evaluated in a laboratory fixed bed reactor for SCR of NO by NH3 including both activity and stability in simulated flue gas containing SO2 and H2O. The leaching rate of TiO2 could reach 90% under the optimized acidolysis conditions, i.e. sulfuric acid 40%（mass）, acid/slag ratio 1.5, leaching time 3 h and reaction temperature 80℃. The hydrolysate was mainly composed of 74%（mass） anatase TiO2, 21.1% （mass） amorphous SiO2 and some other impurities. The presence of SiO2 significantly increased the specific surface area and pore volume of the TiO2 support, which was beneficial to disperse the loaded active catalytic components. The prepared V2O5-WO3/TiO2 catalyst with the TiO2 support from titanium-bearing blast fumace slag exhibited higher catalytic activity than the ones prepared from commercial TiO2 and TiOSO4 at temperatures of 250--450℃, while it presented also good resistance even at 300℃ to the negative effects of sulfur dioxide and water in flue gas.