摘要
硫酸铵热分解能为硫酸氢铵溶液浸出粉煤灰提取氧化铝工艺过程提供硫酸氢铵溶液和氨水,研究硫酸铵热分解过程的机理和热分解动力学具有重要意义。通过X射线衍射、质谱和傅里叶变换红外光谱等对硫酸铵热分解过程的产物进行了表征,结果表明硫酸铵的热分解产物为硫酸氢铵、焦硫酸铵、氨气、水、氮气和二氧化硫。采用X射线衍射、质谱和傅里叶变换红外光谱等表征方法并与热重分析技术联用对硫酸铵进行了分析,结果发现硫酸铵的热分解过程分为3个阶段:硫酸铵分解形成硫酸氢铵和氨气;硫酸氢铵脱水形成焦硫酸铵;焦硫酸铵分解。采用Ozawa-Flynn-Wall和Kissinger-Akahira-Sunose无模型方法计算每个阶段的活化能。采用Coats-Redfern方法确定每个阶段最可能的机理函数。结果表明:第一阶段的平均活化能(E)为125.21 kJ/mol,ln A为18.46;第二阶段的平均活化能(E)为110.21 kJ/mol,ln A为13.94;第三阶段的平均活化能(E)为97.70 kJ/mol,ln A为8.44。
Thermal decomposition of ammonium sulfate can provide ammonium bisulfate solution and ammonia water for the process of leaching fly ash with ammonium bisulfate solution to extract alumina.It is of great significance to study the mechanism and thermal decomposition kinetics of its thermal decomposition process.The products of the decomposition process were characterized by X-ray diffraction,mass spectrometry and Fourier transform infrared spectroscopy,proving that the decomposition products of ammonium sulfate were ammonium hydrogen sulfate,ammonium pyrosulfate,ammonia,water,nitrogen and sulfur dioxide.The characterization method combined with thermogravimetric analysis showed that the thermal decomposition process of ammonium sulfate was divided into three stages:the decomposition of ammonium sulfate to form ammonium bisulfate and ammonia gas,the dehydration of ammonium bisulfate to form ammonium pyrosulfate,and the decomposition of ammonium pyrosulfate.The Ozawa-Flynn-Wall and Kissinger-Akahira-Sunose model⁃free methods were used to calculate the activation energy for each stage.The Coats–Redfern method was used to determine the most likely dynamic mechanism function for each stage.The results showed that the average activation energy was E=125.21 kJ/mol in the first stage,and ln A=18.46;the average activation energy of the second stage was E=110.21 kJ/mol and ln A=13.94;the average activation energy of the third stage was E=97.70 kJ/mol and ln A=8.44.
作者
吴迪
李来时
王俊凯
吴玉胜
王昱征
李明春
WU Di;LI Laishi;WANG Junkai;WU Yusheng;WANG Yuzheng;LI Mingchun(School of Materials Science and Engineering,Shenyang University of Technology,Shenyang 110870,China)
出处
《无机盐工业》
CAS
CSCD
北大核心
2023年第10期86-92,共7页
Inorganic Chemicals Industry
关键词
硫酸铵
热分解
分解动力学
热重分析
ammonium sulfate
thermal decomposition
decomposition kinetics
thermogravimetric analysis
