A Heuristic View About Resource Recovery Of Titania-Bearing Blast Furnace Slags

The application of photocatalytic technology to functional materials and environmental protection has attracted great attention of researchers. In the present work, a new method to apply titania-bearing blast furnace slag (TBBFS), high-titania slag (HTS) and concentrated titania ore (CTO) as the raw materials for making photocatalytic materials was proposed, aiming at an integrated utilization of resources and low-cost fabrication of semiconducting photocatalytic materials. Through photocatalytic degradation of methylene blue (MB) solution, photocatalytic activities of the three materials after treatment and the influencing factors were investigated. Pure minerals that exist in the TBBFS were prepared to investigate the effect of impurity ions on photocatalytic activities. The degradation of reactive brillian red (X-3B) and orth-nitrophenol by the TBBFS, HTS and CTO and their antibacterial effect were studied.Photocatalytic materials were made using three kinds of slag from Panzhihua Iron and Steel Corporation, Chengde Iron and Steel Corporation, and Maanshan Iron and Steel Corporation, respectively, and their photocatalytic activities were evaluated by the degradation ratio of MB solution. The effect of TiO₂ content, particle size of the powder, heat treatment temperature, rare earth oxide content, and melting-crystallization on photocatalytic activities was investigated. All the tree slag materials show photocatalytic activities, but they vary greatly with TiO₂ content. Photocatalytic activity increases with the decrease of particle size of the materials. Heat treatment temperature also influences photocatalytic activity of the materials, and the highest photocatalytic activity was achieved by heat-treating at 800℃. Photocatalytic activity can be improved by CeO₂ doping and a melting-crystallization treatment. In order to investigate photocatalytic mechanism of the titania-bearing blast furnace slag, pure minerals of perovskite, diopside and spinel were selected and their photocatalytic activity was investigated. The perovskite was doped by Fe₂O₃, CeO₂ and V₂O₅. The results show that perovskite has good photocatalytic activity, and diopside and spinel have no photocatalytic activity. Doping influences photocatalytic activity of the perovskite. Photocatalytic activity improves significantly by doping small amount of CeO₂ or Fe₂O₃, but deceases with the doping of V₂O₅. Doping with both CeO₂ and Fe₂O₃ can further improve the photocatalytic activity.Photocatalytic activity of the HTS and CTO was evaluated by the degradation of...