摘要
为研究粒径对磷石膏脱水反应动力学的影响,测定了流动N2气氛中,不同粒径磷石膏脱水反应的TG-DSC同步热分析数据。运用Flynn-wall-Ozawa法、Kissinger法和Satava-Sestak法相结合计算动力学参数,得出不同粒径(105~125μm、125~150μm、150~200μm和200~300μm)磷石膏脱水动力学模型,利用动力学方程对不同粒径磷石膏在相同条件下等温热分解进行预测,得出不同粒径、不同温度下磷石膏脱水率与时间的关系。结果表明:当磷石膏粒径由200~300μm减小到105~125μm时,磷石膏第一步脱水活化能从114.62kJ/mol减小到82.55kJ/mol,第二步脱水活化能由96.30kJ/mol减小到78.5kJ/mol。磷石膏脱水活化能随粒径的减小而减小,机理函数均符合Avrami-Erofeev方程。在相同的煅烧温度下,粒径小的磷石膏完全脱水所需时间缩短。
To study the effect of particle sizes on the kinetics of the thermal dehydration of phosphogypsum,the TG-DSC simultaneous thermal analysis data of different sizes of phosphogypsum dehydration in the flowing N2 atmosphere were measured.The Flynn-wall-Ozawa method,Kissinger method,and Satava-Sestak method were used to calculate the kinetic parameters of phosphogypsum dehydration kinetics model with different particle sizes（105—125μm,125—150μm,150—200μm and 200~300μm）.The isothermal decomposition of phosphogypsum with different particle sizes under the same experimental conditions was predicted by the kinetic equation developed.The results showed that,while the phosphogypsum particle sizes decreased from 200—300μm to 105—125μm,the phosphogypsum dehydration activation energy in the first step fell from 114.62 kJ/mol to 82.55 kJ/mol,and then the second step declined from 96.30 kJ/mol to 78.5 kJ/mol.The phosphogypsum dehydration activation energy decreased with the reduction of its particle size and the mechanism function accords with the Avrami-Erofeev equation.At the same calcination temperature,the small particle sizes of phosphogypsum took less time to fully be dehydrated.
出处
《化工进展》
EI
CAS
CSCD
北大核心
2018年第1期53-59,共7页
Chemical Industry and Engineering Progress
基金
教育部"春晖计划"(Z2006-1-52004)
贵州省科技厅联合基金(黔科合LH字[2014]7618)项目
关键词
磷石膏
粒径
脱水反应
动力学
phosphogypsum
particle size
dehydration
kinetics
