不同条件对钢渣碳酸化反应的影响及动力学分析

Effects of Different Conditions on Carbonation Reaction of Steel Slag and Kinetic Analysis

钢渣碳酸化捕集固定CO2既可实现CO2的减排,又能改善钢渣的安定性,具有很好的发展前景。以转炉钢渣为原料,系统研究了不同气氛、温度、升温速率下钢渣的碳酸化反应。通过热重实验,分析了不同升温速率下钢渣碳酸化反应的速率和温度区间,计算了CO2和水蒸气气氛下钢渣碳酸化反应的活化能;利用XRD分析了不同条件下钢渣碳酸化试样中碳酸钙和游离氧化钙含量的变化规律。结果表明,不同气氛下钢渣碳酸化反应受温度的影响不同。单一CO2气氛下,钢渣碳酸化反应速率随着温度的升高而加快,在600~700℃范围内,碳酸化率达到最高;CO2和水蒸气同时通入时,钢渣碳酸化反应更易进行,在400℃已有明显碳酸化反应,随温度升高在600℃左右碳酸化率达到最大温度升高到700℃后,碳酸钙的分解反应明显加快,游离氧化钙增多。同时通入CO2和水蒸气的气氛下,在400~500℃时,钢渣碳酸化反应的活化能为2.35 kJ•mol^-1。

Carbon dioxide capture and fixation by carbonation of steel slag can not only reduce CO2 emission,but also improve the stability of steel,so it has a good development prospect.The carbonation of converter slag under different atmospheres,temperatures and heating rates was systematically investigated.The rate and temperature range of carbonation reaction of steel slag under different heating rates were analyzed by thermogravimetric analysis(TGA).The activation energy of carbonation reaction of steel slag under CO2 and water vapor atmosphere was calculated.The change law of the content of calcium carbonate and free CaO in carbonation samples of steel slag under different conditions was analyzed by XRD.The results show that the effect of temperature on carbonation of steel slag is different in different atmospheres.The carbonation rate of steel slag accelerates with the increase of temperature in a single CO2 atmosphere,and reaches the highest in the temperature range between 600℃and 700℃.When CO2 and water vapor are introduced at the same time,the carbonation reaction of steel slag becomes easier.The obvious carbonation reaction has been found at 400℃,and the carbonation rate reaches the maximum at about 600℃with the increase of temperature.When the temperature increases to 700℃,the decomposition reaction of calcium carbonate accelerates,and the amount of free CaO increases.The activation energy of carbonation of steel slag at temperatare between 400℃and 500℃is 2.35 kJ•mol^-1 when CO2 and water vapor are introduced simultaneously.