含钛高炉渣中钙钛矿转化为假板钛矿的研究

Study on Transformation of Perovskite into Pseudobrookite in Ti-bearing Blast Furnace Slag

对钙钛矿(CaTiO_3)硫酸化分解,使钛组分转化为假板钛矿(Fe_2TiO_5)的反应体系进行分析,结果表明,采用在CaTiO_3/Fe SO4体系中通入SO_2+O_2混合气体的方法可以将钛组分一步转化为假板钛矿。基于此,考察了反应温度、配料比、气相中SO_2浓度以及反应时间等因素对硫酸化转化的影响。研究表明,在反应温度1 473 K、SO_2浓度为25%(体积分数)、反应时间120 min、CaTiO_3/Fe SO_4摩尔比1∶2.1条件下,钙钛矿中92%的钛组分可以转化成为假板钛矿;钙钛矿硫酸化分解机理随温度而变化,在温度为973~1 373 K时,钙钛矿是按照CaTiO_3+SO_2+1/2O_2=Ca SO4+TiO_2进行分解,而在1 473 K时,钙钛矿是按照CaTiO_3+SO_2+1/2O_2+Fe_2O_3=Ca SO4+Fe_2TiO_5进行分解。

The reaction system in which the titanium component transforms into pseudobrookite （ Fe2TiO5 ） by sulfating decomposition of perovskite （ CaTiO3 ） was analyzed. The results show that the transformation can be completed through one step by introducing SO2 ＋O2 mixed gas into the CaTiO3/FeSO4 reaction system. Based on the analysis, an experimental investigation was conducted with focus on the influences of reaction temperature, reactants molar ratio, SO2 concentration and reaction time on the sulfating reaction. It is indicated that 92% titanium component in perovskite transforms into pseudobrookite with reaction at 1 473 K for 120 min,25% （v/v） of SO2 concentration and 1 ： 2.1 of molar ratio for CaTiO3/FeSO4. The sulfating reaction mechanism changes with temperature. Perovskite is decomposed through the reaction CaTiO3＋SO2＋1/2O2 = CaSO4＋TiO2 at 973-1 373 K and CaTiO3＋SO2＋1/2O2＋Fe2O3 =CaSO4＋ Fe2TiO5 at 1473 K.