多相条件下亚硫酸镁非催化氧化反应动力学及机理

副产物的氧化回收利用是影响镁法脱硫工艺发展的关键.本文通过真空旋转蒸发的方式制备了高纯度的亚硫酸镁样品,并利用鼓泡式反应装置,研究了亚硫酸镁非催化氧化的反应动力学,考察了pH、氧分压、亚硫酸镁浓度、气体流量、温度等因素对亚硫酸镁氧化反应速率的影响,得到了各反应物的分级数及表观活化能.结合三相反应过程的数学模型推断出亚硫酸镁氧化的本征反应在慢反应区进行,且氧的传质扩散是总反应的速率控制步骤.研究结果为氧化回收镁法脱硫副产物提供了理论依据.

Mechanism and kinetics of uncatalyzed oxidation of magnesium sulfite under heterogeneous conditions

The oxidation of residual product for recycling is a key problem to develop the magnesia desulfurization process. Samples of high purity magnesium sulfite were prepared by rotary evaporation in vacuum. The uncatalyzed oxidation kinetics of magnesium sulfite was studied by a bubbling apparatus. Effects of pH,oxygen partial pressure,concentration of magnesium sulfite,gas feed flux and temperature on the reaction rate were investigated and the orders of reagents and the apparent activation energy were achieved. Integrated with the mathematical models involving the reaction process among three phases,it is deduced that the intrinsic oxidation of magnesium sulfite proceeds in the slow reaction region and the mass transfer of oxygen is the controlling step of the whole reaction. The results show benefit to oxidizing and recycling the residual product in magnesia desulfurization.