气溶胶反应器中合成TiO_2超细颗粒

Preparation of Ultrafine TiO_2 Particles by Vapor Phase Hydrolysis of Ti(OC_4H_9)4 at Lower Temperature

将金属醇盐水解反应移至气相反应中,利于Ti(OC_4H_9)_4醇盐经喷雾和惰性气体冷激形成亚微米级的液滴,然后同水汽反应,在较低温度下合成了纯度高且单分散性能好的TiO_2超细粒子。将上述过程分解为混合段与反应段,导出了表征颗粒成核与生长的多段全混反应器串级模型。该模型较好地解释了实验现象和结果,理论预测和实验研究表明,产物颗粒粒径与反应器中流动、混合状况及反应体系的热力学性质有关。

Metal alkoxide hydrolysis was carried out in a vapor phase reactor, a hot nitrogen flow in a mixing chamber carting vapor Ti(OC_4H-9)_4, was mixed with a cold nitrogen flow in a mixing chamber to generate submicrometer droplets, then the droplets were hydrolysed with water vapor at lower temperature to synthesize TiO_2 ultrafine particles of high purity and nerrow size distribution. A mathematical model of perfectly mixed reators (CSTR) in series was developed which was able to predict mean particle size variations as function of operation conditions. Particle size was experimentally and theoretically found to be dependent both on fluidodyamic and thermodynamic conditions.