Oxidation mechanism of MgO-C in air at various temperatures

被引:39
作者
Ghosh, NK [1 ]
Ghosh, DN
Jagannathan, KP
机构
[1] Steel Author India Ltd, Res & Dev Ctr Iron & Steel, Ranchi 834002, Bihar, India
[2] Indian Inst Technol, Kharagpur 72130, W Bengal, India
来源
BRITISH CERAMIC TRANSACTIONS | 2000年 / 99卷 / 03期
关键词
Decarburization - Diffusion - Graphite - Magnesia - Oxidation - Porosity - Reaction kinetics - Thermal effects - Vapors;
D O I
10.1179/096797800680839
中图分类号
TQ174 [陶瓷工业]; TB3 [工程材料学];
学科分类号
0805 ; 080502 ;
摘要
Oxidation of MgO-C refractories containing 20 wt-% graphite was conducted by measuring the weight loss at regular intervals at various temperatures fi om 800 to 1600 degrees C in ail. The rate of decarburisation increased with rise in temperature from 800 to 1400 degrees C and then remained more ol less constant from 1400 to 1600 degrees C. The oxidation kinetics were analysed in detail and reaction rate models derived for the temperature range 800-1400 degrees C. The reaction rate was found to be controlled by diffusion of oxygen through the decarburised layer. At higher temperatures (>1400 degrees C), oxidation of graphite also takes place indirectly by the reaction MgO(s)+C(s)-->Mg(g)+CO(g). The magnesium vapour thus produced is reoxidised at the outer surface and redeposited as MgO. This leads to a reduction in porosity in the decarburised outer shell and, consequently, a reduction in the rate of oxidation. (C) 2000 IoM Communications Ltd.
引用
收藏
页码:124 / 128
页数:5
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