EFFECT OF Si ANTIOXIDANT ON THE RATE OF OXIDATION OF CARBON IN MgO- C REFRACTORY
محل انتشار: ماهنامه بین المللی مهندسی، دوره: 24، شماره: 4
سال انتشار: 1390
نوع سند: مقاله ژورنالی
زبان: انگلیسی
مشاهده: 180
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شناسه ملی سند علمی:
JR_IJE-24-4_006
تاریخ نمایه سازی: 17 بهمن 1400
چکیده مقاله:
Progressive conversion/shrinking core (PC-SC) models of constant-size cylinders were exploited to interpret the decarburization reactions of MgO-C-Si bricks heated up under blown air. Chemical adsorption/solid (or pore) diffusion mechanisms governed the reaction rate. With ۵% silicon, chemical adsorption vanished at ۱۰۰۰ and ۱۱۰۰°C. The oxidation rate lowered then with temperature. This was due apparently to the blocking of the pore-end gorges by the voluminous compounds (like Forstrite). Arrhenius plots of the specific rates yielded the activation energies of the prevailing steps. Without Si antioxidant, three steps were appreciated having activation energies of ۵۱.۶۵ (for chemical adsorption), ۱۲۵.۷۵ (for solid-phase diffusion) and ۹.۰۸ KJ/mol (for pore diffusion). With ۵ wt% silicon addition, two steps existed with activation energies of ۵۱.۶۵ (for chemical adsorption) and ۱۳۴.۵۹ KJ/mol (for solid-phase diffusion). These values were slightly lower than the corresponding activation energies reported earlier for MgO-C and MgO-C-Al systems. Small differences could apparently attribute to the tortuosity differences of the samples.
کلیدواژه ها:
نویسندگان
S. Mahshid
MS&E, SUT
N. Bagheri
Ceramics, MERC
S.K. Sadrnezhaad
Materials Science and Engineering, Sharif University of Technology