Study On Co-precipitation Of Ti-Al-Si Liquor Ternary System

Ti-bearing blast-furnace slag which generally consists of CaO, MgO, SiO2,Al2O3and TiO2components,can be used as raw materials and modifiers to prepare therefractory materials-Al2TiO5.This paper aims at providing theoretical supports forextract the valuable components from Ti-bearing blast furnace slag by leaching,theco-precipitate of valuable components,and preparation of high value-addedmaterial-Al2TiO5.The object of this study is titanium silicate systems of acidhydrolysis titanium-bearing blast furnace slag by H2SO4solution, Under thecircumstance of alkaline coprecipitation of the titanium silicate system, combinedcontrol law of the target component precipitation was systematically studied.Moreover, co-precipitates for materialization were simply researched.The chemical reagents are used to simulate the main composition of Ti-bearingblast furnace slag, namely Ti-Al-Si ternary system. The system was precipitated byalkali titration, and then the progress of co-precipitation and the co-precipitates werestudied. The progress of co-precipitation reaction was analyzed by the change trendsof pH values and conductivity of system.The type of precipitating agent, pH value atthe end of titration, reaction temperature, the mole ratio of Al/Ti on the effects ofco-precipitate composition, structure and property were investigated emphatically.The precipitation was formed with the alkali added to the ternary system, theprogress of total precipitation reaction was analyzed by the change trends of pHvalues and conductivity of ternary system, the sudden change points of the pH valuesand conductivity changing curves and experimental phenomenon showed the exactlytime of the precipitation started to emerge, the co-precipitates form in large amountsand precipitation reactions towards the end.The co-precipitates are prepared by chemical precipitation,using NH3·H2O andNaOH as precipitating agent respectively.The effect of the precipitating agent type,pH value at the end of titration, reaction temperature, the mole ratio of Al/Ti onco-precipitation was analyzed. focus on the effect of these reaction conditions on theprecipitation rates of Ti, Al and Si in precipitates, the average size ofco-precipitates,the morphology of co-precipitates, the chemical bond ofco-precipitates and thermal properties of the co-precipitates. The type of alkali has small impact on the precipitation rates of components, the chemical bond ofco-precipitates and thermal properties of the co-precipitates. The average size ofco-precipitates was smaller when NH3·H2O as a precipitant agent than with NaOH asa precipitant. The effects of titration pH value, reaction temperature, the mole ratio ofinitial Al/Ti on co-precipitates structure and properties are slight.F-TIR spectrashowed that the change of reaction conditions can impact the form of Ti-O-Al,theraman spectra proved the accuracy of the results of the precipitation rates of Ti, Aland Si.The last section of this paper is to research the materials produced byco-precipitates under different reaction conditions, and preliminary study on Al2TiO5materials made by co-precipitates calcination generates, then test its performances.The results show that the co-precipitation of products contain rutile TiO2when thesample system mole ratio of Al/Ti is on1.5:1under the calcination temperature of1450°C and thermal180min conditions; the co-precipitation of products is Al2TiO5under other reaction conditions.