NaOH亚熔盐法处理拜尔法赤泥的铝硅行为  

Behavior of Al and Si in Bayer Red Mud Processed by NaOH Sub-molten Salt

作　　者：孙旺[1,2] 郑诗礼[1] 张亦飞[1] 徐红彬[1] 张懿[1] 

机构地区：[1]中国科学院过程工程研究所绿色过程与工程重点实验室,北京100190 [2]中国科学院研究生院,北京100049

出　　处：《过程工程学报》2008年第6期1148-1152,共5页The Chinese Journal of Process Engineering

基　　金：国家重点基础研究发展规划(973)基金资助项目(编号:2007CB613500);国家高技术研究发展计划(863)基金资助项目(编号:2006AA06Z129);国家“十一五”科技支撑基金资助项目(编号:2006BAC02A05)

摘　　要：针对拜尔法赤泥铝/硅比偏高的问题,对NaOH亚熔盐法处理拜耳法赤泥过程中的Al,Si行为进行了研究.考察了溶出温度、碱/泥比、添加CaO等主要因素对终赤泥化学成分和物相结构的影响.结果表明,溶出温度高、碱/泥比大有利于Al2O3的回收,相应的终赤泥的铝/硅比较低.在碱/泥比6、溶出温度230℃、时间2h的条件下,氧化铝回收率可达79.22%,终赤泥的铝/硅比可降到0.39,终赤泥中的硅主要以NaCaHSiO4和Ca3(Fe0.87Al0.13)2(SiO4)1.65(OH)5.4形式存在.在处理CaO/SiO2>1.2的拜尔法赤泥时继续添加CaO并不能继续提高Al2O3的回收率.Based on the problem of higher Al2O3/SiO2 （A/S） of Bayer red mud, the separation of Al and Si in red mud from Bayer process in digestion with NaOH sub-molten salt was investigated. The effects of digestion temperature, mass ratio of alkali to red mud from Bayer process and CaO addition on the behavior of red mud in the salt were experimentally investigated. The results show that high temperature and mass ratio of alkali to red mud lead to more alumina into the aqueous phase and the decrease of A/S in brown mud. The recovery rate of Al2O3 can reach 79.22% and A/S in the brown mud is decreased to 0.39 under the conditions of mass ratio of alkali to red mud at 6, digestion temperature at 230 ℃, and digestion time for 2 h. Further study shows that Si exists in the form of NaCaHSiO4 and Ca3（Al0.13Fe0.87）2（SiOa）l.65（OH）5.4. The recovery rate can not be further raised under the condition of CaO addition in sub-molten salt process when the molar ratio of CaO to SiO2 over 1.2 in the original red mud .

关 键 词：亚熔盐 拜耳法 赤泥 氧化铝 铝 硅 

分 类 号：TQ133.1[化学工程—无机化工]