摘要
提出了NH_4HSO_4法焙烧粉煤灰提取Al_2O_3的新方法,考察了焙烧温度、粉煤灰中Al_2O_3与NH_4HSO_4摩尔比对粉煤灰中Al反应率的影响,研究了粉煤灰与NH_4HSO_4焙烧反应动力学.结果表明,粉煤灰与NH_4HSO_4焙烧反应受固体产物层扩散控制,300,350,400℃下的反应速率常数分别为1.25×10^(-3),1.56×10^(-3),1.89×10^(-3)min^(-1),反应活化能为17.19 kJ/mol,反应动力学方程为1-2/3α-(1-α)^(2/3)=0.0422exp[-17190/(RT)]t,最佳工艺条件为:焙烧温度400℃,Al_2O_3与NH_4HSO_4摩尔比1:8,焙烧时间60 min;该条件下Al反应率达90%以上,主要产物为NH_4Al(SO_4)_2和NH_4Fe(SO_4)_2.
A new method was used to prepare A1203 from fly ash by NH4HSO4 roasting process. The effects of roasting temperature and molar ratio of A1203 in fly ash to NH4HSO4 on A1 reaction rate were studied. The results showed that the control step of roasting reaction was solid layer diffusion, the reaction rate constant 1.25x10-3, 1.56x10-3 and 1.89x10-3 rain-1 at 300, 350 and 400℃, and the activation energy calculated as 17.19 kJ/moL The general kinetic equation was expressed as 1-2/3a-（1-a）2/3--O.O422exp[-17190/（RT）]t. The main roasted products were NH4AI（SO4）2 and NH4Fe（SO4）2 ill the reaction process. The AI reaction rate reached more than 90% under the optimized conditions of 400 ℃, molar ratio of A1203 in fly ash to NH4HSO4 1：8 and roasting time 60 min.
出处
《过程工程学报》
CAS
CSCD
北大核心
2013年第4期621-625,共5页
The Chinese Journal of Process Engineering
基金
国家重点基础研究发展计划(973)基金资助项目(编号:2007CB613603)
中国博士后科学基金资助项目(编号:2013M530934)
关键词
粉煤灰
硫酸氢铵
焙烧
动力学
fly ash
ammonium hydrogen sulfate
roasting
kinetics
