关键词: 含钛高炉渣, 酸解, 钛白粉, 载体, 烟气脱硝, 选择催化还原, 催化剂

Abstract: Titanium oxide (TiO₂) with high specific surface area was prepared from blast furnace slag by steps, in succession, extraction using dilute sulfuric acid (#em/em#.e., acidolysis), hydrolysis and high-temperature calcination, and was used as the support in preparing V₂O₅-WO₃/TiO₂ 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, #em/em#.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 furnace 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.