| It is difficult to dispose the bearing blast furnace slag(TBBFS)because of the complex, stable and valuable compounds in TBBFS.The TBBFS were collected from Panzhihua-Xichang area in China.Based on the utilization of TBBFS to prepare titanium silicon composite catalyst, it was simulated that the thermodynamic transformation of TBBFS during the physicochemistry process and analyzed that the transformation behavior of TBBFS in practical acid or base solution.Moreover, transformation behavior and influencing mechanism of Ti O2-Si O2 catalyst synthesised from TBBFS in different medium and condition. Meanwhile, according to hydrothermal ore-forming process of crystal nucleation and growth theory, this research optimized the ambient medium and complexing agent, evaluated catalytic performance of the composite catalyst and analyzed the conversion and combination of Ti and Si. Key mechanism of speciation and hydrolysis control of titanium in titanium-silicon composite catalyst derived from titanium bearing blast furnace slag was discussed.Conclusions are listed as follows:1. Alkali basalt was formed with TBBFS in Na OH solution at low temperature(below 150 o C) hydrothermal conditions. Hydrofluoric acid can extract 14%~93% silicon from TBBFS and produce fluoride. Metalions leaching by sulfuric acid mainly exist in the liquid phase in the form of ions, and Ca2+ and SO42+ formed Ca SO4.2.Crystallization phase of Ti O2 showed that the influencing factors included the concentration of Cl- ion and the content of silicon. The main phase of the Ti O2 was anatase with 1 mol/L HCl, and rutile with a hydrochloric concentration of more than 2 mol/L. Moreover, amorphous silica to promote the transformation of Ti O2 from anatase to rutile. The addition of HF played a key role in adjustion of Ti-Si ratio and suppression of rutile. EDTA had obviously sustained effect for the precipitation of Mg, Fe, Ti, Si, and would result in titanium dioxide phase transformation to rutile.3.The performance of the material was characterized by degradation of Rhodamine B, UV-dis and SEM-mapping. After decomposition of TBBFS with hydrochloric acid, titanium ion combined with chloride ion to produce Ti Cl4 and fluorinion to produce Ti F4,which could be rapidly hydrolyzed to titanium dioxide. Complexes between EDTA and Ti4+ would slow down the hydrolysis of titanium ion in acid hydrothermal conditions. Synthetic materials had certain adsorption and catalytic performance for Rhodamine B. HF0.6 showd the best photocatalytic performance and materials added EDTA showed the best adsorption performance.This paper offered a method for titanium-silicon composite material from TBBFS with speciation and hydrolysis control. This study would provide a new way to recovery of Ti slag with high added value of product and low energy consume. |
