Solid-state decarburization kinetics of high-carbon ferrochrome powders by microwave heating
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摘要: 采用微波加熱對高碳鉻鐵粉固相脫碳進行了動力學研究.以碳酸鈣粉為固體脫碳劑,按高碳鉻鐵粉中碳與碳酸鈣粉完全分解后產生的CO2的摩爾比為1︰1和1︰1.4混合,在微波場中對內配碳酸鈣高碳鉻鐵粉加熱到不同溫度并保溫脫碳一定時間,測定其碳含量并計算固相脫碳反應的表觀活化能.實驗表明:提高內配碳酸鈣的比例,物料的脫碳率會相應提高,但混合物料的微波加熱升溫速率會變小;對于脫碳摩爾比相同的物料,隨著脫碳溫度的提高和保溫時間的延長,物料的脫碳率隨之提高.當1200℃保溫脫碳60 min時,兩種脫碳摩爾比下物料脫碳效果最好,脫碳率分別為65.56%和82.96%.微波場能促進高碳鉻鐵粉中碳的活化擴散和CO2的吸附擴散.微波加熱內配碳酸鈣高碳鉻鐵粉固相脫碳反應近似為一級反應,脫碳反應的表觀活化能為68.43 kJ·mol-1.Abstract: Solid-state decarburization kinetics of high-carbon ferrochrome powders was investigated by microwave heating. Calcium carbonate powders were used as a solid decarburizer. The high-carbon ferrochrome powders and calcium carbonate powders were mixed at the mole ratio between carbon in the high-carbon ferrochrome powders and CO2 decomposed from the calcium carbonate powders of 1:1 and 1:1.4. Then the mixtures were heated at different temperatures and decarburized in a microwave heating field. The carbon content of decarburized materials was measured and the apparent activation energy of decarburization reaction was calculated. Experimental results show that as the proportion of calcium carbonate in the mixtures enlarges, the decarburization rate increases, but the heating rate of the mixtures decreases. The decarbonization rate is higher at a higher temperature and for a longer holding time at the same mole ratio. The highest decarbonization rates are 65.56% and 82.96% for both the mixtures decarburized at 1200℃ for 60 min, respectively. Carbon activation diffusion and CO2 adsorption diffusion in the high-carbon ferrochrome powders are enhanced in a microwave heating field. Solid-phase decarburization approximates the first-order reaction and the apparent activation energy of decarburization reaction is 68.43 kJ·mol-1.
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Key words:
- ferrochrome /
- calcium carbonate /
- microwave heating /
- decarburization /
- reaction kinetics
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