摘要
随B2O3过量系数γ的增加,Mg热还原B2O3反应3Mg(l)+B2O3(l)=3MgO(s)+2B(s)的绝热温度(Tad)降低.当B2O3的过剩系数γ小于1 102时,反应才能以正常的自蔓延方式进行,此时该反应的绝热温度Tad等于1800K.由DTA曲线分析可知,该反应起始反应温度在750～810℃之间,属于液 液反应机制。通过计算可知:反应3Mg(l)+B2O3(l)=3MgO(s)+2B(s)的表观活化能E=18 8kJ·mol-1,反应级数为n=0.7.
The adiabatic temperature (T_(ad)) of reaction 3Mg(l)+B_2O_3(l)=3MgO(s)+2B(s) will decrease with the increase of the excess coefficient of B_2O_3 in the thermal reduction of B_2O_3 with magnesium. This reaction can proceed in the way of self-propagating only if the excess coefficient (γ) of B_2O_3 is less than 1.102. Under this condition, the adiabatic temperature (T_(ad)) is 1 800 K. It is known through DTA curve that the beginning temperature of reaction is 750℃, and this reaction belongs to the mechanism of liquid-liquid reaction. It is also known by calculation of reaction 3Mg(l)+B_2O_3(l)=3MgO(s)+2B(s) that the apparent activation energy (E) is 18.8 kJ·mol^(-1), and the reaction order (n) is 0.7.
出处
《材料与冶金学报》
CAS
2004年第1期46-50,共5页
Journal of Materials and Metallurgy
关键词
镁热还原
过量系数
绝热温度
自蔓延
表观活化能
反应级数
thermal reduction with magnesium
excess coefficient
adiabatic temperature
self-propagating
apparent activation energy
reaction order
