粉煤灰提铝渣制备δ-层状硅酸钠及其性能研究  

Synthesis,characterization and performance of δ-layered sodium silicate from alumina-extracted slag of coal fly ash

作　　者：张丽宏 柳向阳 方莉 程芳琴 Zhang Lihong;Liu Xiangyang;Fang Li;Cheng Fangqin(State Environmental Protection Key Laboratory of Efficient Utilization Technology of Coal Waste Resources,Shanxi Collaborative Innovation Center of High Value added Utilization of Coal related Wastes,Institute of Resources and Environmental Engineering,Shanxi University,Taiyuan030006,China)

机构地区：[1]山西大学资源与环境工程研究所,山西低附加值煤基固废高值化利用协同创新中心,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,山西太原030006

出　　处：《无机盐工业》2018年第12期54-59,共6页Inorganic Chemicals Industry

基　　金：国家重点研发计划项目(2017YFB0603100,2017YFB0603101);山西省高等学校科技创新项目资助(2017109);“三晋学者”支持计划项目.

摘　　要：以粉煤灰预脱硅-碳酸钠活化-酸浸提铝过程副产的提铝渣(含预脱硅液和酸浸渣)为原料,将酸浸渣溶于预脱硅液中进行硅钠比[n(SiO2)/n(Na2O)]调控,然后蒸发浓缩、高温煅烧,制备了高性能、高δ型含量的层状硅酸钠。通过X射线衍射、固体核磁共振、拉曼光谱、扫描电镜和透射电镜等对产物的结构和形貌进行了表征,通过Rietveld方法对产品的物相组成进行了定量分析。考察了硅钠比、煅烧温度、煅烧时间对产物晶型和钙镁离子交换能力的影响。结果表明:在硅钠比为2.02、煅烧温度为720℃、煅烧时间为120 min条件下,可以制备出晶相中δ型含量高达92%(质量分数)的层状硅酸钠,其钙镁离子交换能力分别为358、430 mg/g,优于GB/T 19421—2008《层状结晶二硅酸钠试验方法》的规定值。该研究实现了粉煤灰提铝工艺中废液和废渣的协同利用,提高了粉煤灰的综合利用率。Using alumina extracted slag(containing desilication solution and acid leaching slag)generated from predesi lication-Na2CO3activation acid leaching process for aluminum extraction from coal fly ash as the feedstock,δ-layered sodium silicate(δ-Na2Si2O5)was prepared by dissolving acid leaching slag into the desilication solution followed with evaporation and concerntration and calcination.The structure and morphology of the obtainedδ-Na2Si2O5were characterized by XRD,NMR,Raman spectroscopy,SEM and TEM in detail,and the phase analysis was carried out by Quantitative Rietveld analysis.The effects of n(SiO2)∶n(Na2O),calcination temperature and calcination time on crystal shape and Ca2+and Mg2+exchange capacity were investigated in detail.The optimum conditions were determined as follows:n(SiO2)∶n(Na2O)=2.02,and the calcination tempera ture and time at720℃and120min.Thus the amount ofδ-Na2Si2O5reached92%(mass fraction)in the obtained crystal phases,and its exchange capacities of Ca2+and Mg2+were up to358mg/g and430mg/g respectively,higher than the standard values required in GB/T19421-2008,Test Methods of Crystalline Layered Sodium Disilicate.The synergistic utilization of waste liquid and slag in the process of extracting aluminum from coal fly ash could be realized and the comprehensive utilization rate of fly ash was improved.

关 键 词：粉煤灰 预脱硅液 酸浸渣 δ型层状硅酸钠 钙镁离子交换能力 

分 类 号：X752[环境科学与工程—环境工程]