Technological Conditions and Mineralogical Changes of Alkaline Treatment on Ti-bearing Blast Furnace Slag

Ti-bearing blast furnace slag is the industrial waste produced by blast furnace ironmaking in Panzhihua steel plant,and the results of XRD,XRF and metallurgical microscopy analysis of the slag suggest that the main mineral phase includes perovskite,diopside and spinel with 20% of titanium content,and the mineral facies are closely combined. This research adopted alkaline calcinations to dispose the Ti-bearing blast furnace slag and then used deionized water to leach the roasted product for the recovery of SiO₂,Al₂O₃ and the enrichment of titanium component,which can realize separation of the three kinds of valuable component.Through researching the effects of the calcination temperature and time,mass ratio of Na₂CO₃ to slag on the extraction efficiency of SiO₂ and Al₂O₃ and the mineralogical changes in the reaction process,the results show that the spinel precedes diopside to react with Na₂CO₃ but perovskite does not react with the additives. Under the following optimum conditions: calcination temperature 900 ℃,mass ratio of Na₂CO₃ to slag 2:1 and reaction time 180 min,47.52% SiO₂ and 82.97% Al₂O₃ can be extracted.