【摘要】 针对高硫铁精矿氧化焙烧释放SO2气体的问题,进行了固硫焙烧实验及其反应动力学研究。通过XRD、SEM和EDS等检测手段考察了高硫铁精矿固硫氧化焙烧过程的矿相变化规律。根据热重曲线,采用Coats-Redfern积分法和Achar-Brindley-SharpWendworth微分法进行动力学计算,确定了不同温度段高硫铁精矿固硫焙烧的反应机制。结果表明,在理论配碱量、保温时间30 min、温度550℃条件下,固硫剂Na₂CO₃的固硫率为93.3%,焙烧产物为Fe₂O₃和水溶性Na₂SO₄。动力学分析表明,在300⁵50℃范围内,高硫铁精矿固硫氧化焙烧分为3个阶段:在前两个阶段,脱硫反应机理均符合Avrami-Erofeev方程,为随机成核和随后生长的化学反应控制,只是反应级数和表观活化能有所不同;在第3阶段,固硫反应属于三维扩散控制的Z-L-T模型,反应表观活化能分别为142.73 k J/mol和150.66 k J/mol。更多还原

【Abstract】 In view of SO₂ gas released during the oxidizing roasting process for high-sulfur iron concentrate,an experiment of roasting process with stabilization of sulfur was conducted and the reaction kinetics was analyzed. The changes of the mineral phase in high-sulfur iron-concentrate during the whole process were analyzed by XRD,SEM and EDS. According to thermogravimetric curves,the reaction mechanism of stabilization of sulfur during the roasting process at different temperature ranges for high-sulfur iron-concentrate was determined by calculating with Coats-Redfern integral and Achar-Brindley-Sharp-Wendworth differential methods. Results show that roasting process with a theoretical alkaline addition,at the temperature of 550 ℃ with the retaining time of 30 min,can bring in the sulfur stabilizing rate reaching93. 3% by the sulfur-stabilizing agent（Na₂CO₃）,and yield a roasted product Fe₂O₃ and water-soluble product of Na₂SO₄. The kinetics analysis indicates that within the temperature range of 300 550 ℃,the whole process could be divided into three stages. In the first two stages,the reactions were all dominated by a chemical reaction of random nucleation and growth,and the sulfur-removal reaction mechanism conforms to Avrami-Erofeev equation with difference only in the reaction order and the apparent activation energy of reaction. In the third stage,the reaction is dominated by three-dimensional diffusion and sulfur-removal reaction mechanism conforms to Z-L-T equation with the apparent activation energy at 142. 73 k J/mol and 150. 66 k J/mol,respectively.更多还原