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为了揭示硼铁精矿的碳热还原机理,以高纯石墨为还原剂,进行硼铁精矿含碳球团等温还原实验,并采用积分法进行动力学分析.还原温度分别设定为1000、1050、1100、1150、1200、1250和1300℃,配碳量即C/O摩尔比=1.0.当还原度为0.1<α<0.8时,温度对活化能和速率控制环节有重要影响:还原温度≤1100℃时,平均活化能为202.6 k J·mol-1,还原反应的速率控制环节为碳的气化反应;还原温度>1100℃时,平均活化能为116.7 k J·mol-1,为碳气化反应和Fe O还原反应共同控制.当还原度α≥0.8时(还原温度>1100℃),可能的速率控制环节为碳原子在金属铁中的扩散.碳气化反应是含碳球团还原过程中主要速率控制环节,原因在于硼铁精矿中硼元素对碳气化反应具有较强烈的化学抑制作用.
In order to reveal the mechanism of carbothermal reduction of boron iron concentrate, high temperature pure graphite was used as reductant to carry out the isothermal reduction experiment of carbon-containing pellets of boron-iron concentrate, and the kinetic analysis was carried out by integration method.The reduction temperature was set to 1000, 1050, 1100, 1150, 1200, 1250 and 1300 ° C with C / O molar ratio = 1.0. When the reduction is 0.1 <α <0.8, the temperature has an important effect on the activation energy and the rate control: the reduction temperature The average activation energy was 202.6 kJ · mol-1 when the temperature was less than 1100 ℃. The rate control of the reduction reaction was carbon gasification reaction. The average activation energy was 116.7 kJ · mol-1 when the reduction temperature was 1100 ℃ Carbon gasification reaction and Fe O reduction reaction jointly controlled when the reduction degree α ≥ 0.8 (reduction temperature> 1100 ℃), the possible rate of control is the carbon atoms in the diffusion of carbon in the carbon gasification reaction is a carbon-containing ball The main reason for the rate control in the process of group reduction is that the boron element in the boron-iron concentrate has a stronger chemical inhibition effect on the carbon gasification reaction.