微波加热高碳铬铁粉固相脱碳动力学

Solid-state decarburization kinetics of high-carbon ferrochrome powders by microwave heating

采用微波加热对高碳铬铁粉固相脱碳进行了动力学研究.以碳酸钙粉为固体脱碳剂,按高碳铬铁粉中碳与碳酸钙粉完全分解后产生的CO2的摩尔比为1︰1和1︰1.4混合,在微波场中对内配碳酸钙高碳铬铁粉加热到不同温度并保温脱碳一定时间,测定其碳含量并计算固相脱碳反应的表观活化能.实验表明:提高内配碳酸钙的比例,物料的脱碳率会相应提高,但混合物料的微波加热升温速率会变小;对于脱碳摩尔比相同的物料,随着脱碳温度的提高和保温时间的延长,物料的脱碳率随之提高.当1200℃保温脱碳60 min时,两种脱碳摩尔比下物料脱碳效果最好,脱碳率分别为65.56%和82.96%.微波场能促进高碳铬铁粉中碳的活化扩散和CO2的吸附扩散.微波加热内配碳酸钙高碳铬铁粉固相脱碳反应近似为一级反应,脱碳反应的表观活化能为68.43 kJ·mol 1.

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.