菱镁矿制备轻烧氧化镁及其水化动力学研究

Preparation of light-burned magnesia from magnesite and its hydration kinetics

以菱镁矿为原料,制备轻烧氧化镁,并对轻烧氧化镁的水化动力学进行研究,考察水化温度,氧化镁质量浓度和颗粒度对水化过程的影响。研究结果表明:煅烧温度和保温时间对氧化镁活性影响要比颗粒度的大,最佳煅烧条件是温度为750℃,煅烧时间为1.5 h,颗粒度为1 mm;氧化镁的水化反应过程为内扩散控制类型,表观反应活化能为23.78 kJ/mol,在此基础上,用MATLAB做多元线性归回分析,得到表观反应速率常数关于水化温度、氧化镁浓度和颗粒度的经验表达式。

Light-burned magnesia was prepared from magnesite ore,and the hydration dynamic of light-burned magnesia was investigated.The effects of temperature（θ）,mass concentration of magnesia（ρ0） and particle size（r0） of magnesia on hydration kinetics were studied.The calcination tests show that calcination temperature（θ） and heating time（t） have greater influence than the particle size（r0） on the activity of magnesia.And the best calcination condition is that θ=750 ℃,t=1.5 h,and r0=1 mm.The hydration process of magnesia is controlled by intra-particle diffusion,and the apparent activation energy is 23.78 kJ/mol.Based on the theory model,an experiential formular including three parameters（θ,c0 and r0） is proposed through MATLAB multiple regression analysis.