氧化钙添加剂对碳酸钠活化粉煤灰的影响及机理  

Effect and Mechanism Analysis of Calcium Oxide Additive on the Sodium Carbonate Activation of Fly Ash

作　　者：燕可洲 郭彦霞 李宁静 程芳琴 YAN Ke-zhou;GUO Yan-xia;LI Ning-jing;CHENG Fang-qin(State Environmental Protection Key Laboratory on Efficient Resource-utilization Techniques of Coal Waste,Institute of Resources and Environmental Engineering,Shanxi University,Taiyuan 030006,China)

机构地区：[1]山西大学资源与环境工程研究所,国家环境保护煤炭废弃物资源化高效利用技术重点实验室,太原030006

出　　处：《硅酸盐通报》2018年第3期1003-1009,共7页Bulletin of the Chinese Ceramic Society

基　　金：国家重点研发计划(2017YFB0603101);山西省煤基低碳科技重大专项(MC201645);三晋学者支持计划专项

摘　　要：碳酸钠焙烧粉煤灰是一种反应温度低、氧化铝溶出率高,且可同步实现铝、硅高效分离的活化方式,然而该活化过程中所需助剂耗量较大,成为其大规模产业化应用的瓶颈。借鉴高温(1200~1300℃)碱石灰烧结活化粉煤灰工艺,在中温(600~1000℃)条件下,采用正交实验和单因素实验方法,分别研究了氧化钙添加对碳酸钠焙烧活化粉煤灰后氧化铝溶出率的影响。结果表明,在中温条件下可通过添加一定比例的氧化钙来部分替代碳酸钠,当m(CFA∶Na_2CO_3∶CaO)=1∶0.6∶0.2时,即可使粉煤灰中的氧化铝溶出率达90%以上。通过傅里叶变换红外光谱(FT-IR)、X射线衍射分析(XRD)进一步研究发现,氧化钙之所以可以部分替代碳酸钠,主要是由于低聚合度的硅酸钙形成所导致的。Coal fly ash calcined with sodium carbonate is an effective method to activate the reactivity of aluminum and silicon in it;however,the large consumption of sodium carbonate hinders its industrial application.In this paper,the effect of calcium oxide additive on the sodium carbonate activation of coal fly ash for aluminum extraction was studied by orthogonal experiment and single factor experiment at the medium temperature(600-1000℃).The results show that the sodium carbonate can be partially replaced by adding a certain percentage of calcium oxide in the reaction system at the medium temperature.When the mass ratio of coal fly ash,sodium carbonate,and calcium oxide equaled to 1:0.6:0.2,the dissolution percentage of aluminum from coal fly ash can be more than 90%.Through FT-IR and XRD analysis,it is found that the partial substitution of sodium carbonate by calcium oxide is mainly due to the formation of calcium silicate with the low polymerization degree.

关 键 词：粉煤灰 碳酸钠 氧化钙 焙烧活化 氧化铝 

分 类 号：TU551[建筑科学—建筑技术科学]