膜技术处理氧化铝厂赤泥回水工业试验研究(Ⅱ)──浓缩性能考察

STUDY ON TREATING RED-MUD BACKWATER OF ALUMINA FACTORY WITH MEMBRANE TECHNOLOGY IN PILOT PLANT SCALE (Ⅱ)──Investigation of Concentration Process

采用碳分脱铝-电渗析工艺处理含铝废碱水，从中回收铝、碱及水资源．在脱盐性能考察完成后，研究该体系的浓缩性能．用淡化段所得的浓水作为浓缩段的料液，经循环浓缩后可得到含碱50～70g／L的浓水产品，可考虑并入氧化铝生产流程加以利用，浓缩段得到的含减量（以Na2O计）约10g／L的淡水，可返回淡化段处理．试验研究了操作电流、原水浓度、电渗析器级段数等对浓缩过程电流效率、单位能耗的影响，并考察了循环浓缩工艺中料液浓度对能耗的影响．试验结果表明，采用电渗析浓缩工艺可以得到合格的浓水产品，电渗析过程能耗在可接受的范围．

For recoverying alkali, alumina and water from alkali waste water containing alumina, a process including dealuminium and electrodialysis is adopted. The concentrate from desalting process was used as feed solution of concentrating process. As a final result, the concentrate reached a concentration about 50--70 g/L (Na2O), which can be used directly in the alumina production process. And the diluate of concentrating process contained about 10 g/L Na2O, which can be recycled to the desalting process as feed solution. In this paper, the parameters influencing the concentrating process were investigated. As the operating current increased, the energy consumption and concentrating rate increased, and the current efficiency decreased. The concentration of the feed solution also influenced the energy consumption and current efficiency, which was discussced in detail in the experiment part. And the influence of electrodialysis' number of class and section is also discussed.