CaO--TiO2--Fe2O3三元系中Ca3TiFe2O8的生成机理

钒钛磁铁矿是烧结矿重要的原料之一,Ca3TiFe2O8作为钒钛烧结矿中矿物被发现之后,其生成机理尚不明确.本文采用X射线衍射分析、元素能谱分析和TG--DSC分析相结合的方法,研究了Ca3TiFe2O8的生成机理以及不同温度、CaO与TiO2含量下Ca3TiFe2O8的生成规律.实验结果表明,Ca3TiFe2O8由Ca2Fe2O5和CaTiO3反应生成,即CaO和Fe2O3反应生成Ca2Fe2O5;其后,与CaTiO3反应生成Ca3TiFe2O8.反应时间越长,Ca3TiFe2O8的生成量越大,但反应温度对Ca3TiFe2O8生成的影响并不明显.另外,还发现 CaO含量越高,Ca3TiFe2O8越易于生成,而且等摩尔 Fe2O3和 CaO下只要存在 TiO2,就会有Ca3TiFe2O8生成.

Formation mechanism of Ca3TiFe2O8in a CaO--TiO2--Fe2O3system

Vanadium-titanium magnetite is one of the important raw materials for iron making in a blast furnace. Ca3TiFe2O8, which is a mineral of vanadium-titanium sinter, was discovered to form during the process; however, its formation mechanism is not clear. In this work,an X-ray diffraction analysis,an elemental spectroscopy,and a TG--DSC were employed to investigate the forma-tion mechanism of Ca3TiFe2O8and the formation law at different temperatures and at CaO and TiO2contents in the CaO--TiO2--Fe2O3 system. The formation mechanism of Ca3TiFe2O8is clarified: CaO reacts with Fe2O3to form Ca2Fe2O5, and then continues to react with the CaTiO3to form Ca3TiFe2O8. The longer the reaction time, the greater is the amount of Ca3TiFe2O8formed. However, the effect of temperature on the formation of Ca3TiFe2O8is not obvious. It is found that high CaO content contributes to the formation of Ca3TiFe2O8. Further,so long as TiO2is present,Ca3TiFe2O8is formed under the condition of equal molar concentration Fe2O3and CaO.