Study On Transformation Migration And Catalytic Performance Of Titanium Components In Blast Furnace Titanium Slag Under The Action Of Roasting And Microwave

The titanium in the titanium-bearing blast furnace slag accounts for half of the world’s titanium resource reserves,but its utilization ratio is less than 3%,which is a problem that the industry has failed to overcome.Based on the analysis of the difference in the physical and chemical properties of different components,the new technology of"melt pretreatment-microwave selective heating"was first proposed to realize the efficient extraction of titanium from blast furnace slag,taking the titanium-bearing blast furnace slag as the research object.The extracted titanium-bearing components have excellent catalytic properties.The effects of roasting and microwave treatment on the transformation and migration of titanium components found that the low-valent titanium-bearing components(Ti²⁺,Ti³⁺)in blast furnace slag could be all directionally enriched to form CaTiO₃:When the temperature exceeds 1250℃,roasting can convert all Ti³⁺（Fassaite）and part of Ti²⁺（Augite titanium）into Ti⁴⁺（Perovskite）;Microwave selective heating converts all Ti²⁺（Augite titanium）into Ti⁴⁺（Perovskite）.Microwave processing can separate titanium and silicon at the atomic level to achieve the mineralogical reconstruction of CaTiO₃,that is,CaTiO₃ is gradually transformed from amorphous in the interlocked state to free-state crystal branches.At the same time,microwave processing can realize the directional migration of CaTiO₃,so that the free-state crystal branches migrate to form a dense network structure.Because there are obvious differences in the density and melting point of CaTiO₃ and silicate,the"selective heating"and"spot heating"of microwaves will cause silicate melting,forming the stratification of CaTiO₃ and silicate.After microwave heating for 20 min,the stratification slag was separated by gravity to extract CaTiO₃ products,the recovery rate of titanium was 84.15%,and the grade of CaTiO₃ was 82%.The extracted titanium-bearing component（MM-CaTiO₃）is a CaTiO₃ branch with a special aspect ratio,and its main lattice orientation is CaTiO₃（110）and CaTiO₃（112）,so its band gap is low and the visible light response is good.DFT theoretical calculations show that CaTiO₃（110）crystal faces are more likely to form oxygen vacancies,which is conducive to photocatalytic reactions.Photocatalytic experiments of MB degradation showed that the photocatalytic capacity of MM-CaTiO₃ was 3.2 times that of CaTiO₃and 2.2 times that of Ti O₂.The degradation mechanism study showed that MM-CaTiO₃could directly react with acridine in MB to achieve damage to hydroxyl radicals in a short time.This study pioneers an effective path and provides important guidance for the component extraction of titanium-bearing slag.In addition,it also creates a feasible way for the preparation of excellent photocatalysts from solid waste and contributes to sustainable development.