电渗析处理赤泥回水流程研究

STUDY ON THE PROCESS OF TREATINT THE RED-MUD BACKWATER BE ELECTRODIALYSIS

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,在脱盐性能及浓缩性能考察研究的基础上,进行电渗析流程研究,以期得到最佳的技术经济指标。设计了3个不同的电渗析流程进行对比,在淡水产品含碱要求小于0.5 g/L的条件下,比较了各流程淡化段的技术经济指标。试验结果表明,4台逆流淡化流程的能耗最低,并且可得到浓度较高的预浓水,对降低浓缩段的能耗有利。在此基础上,在降低浓水产品浓度的条件下,进行5台全逆流流程试验,结果表明,5台全逆流流程的直流电耗更低,碱直收率,水直收率都较高,但浓水产品浓度较低,会增加后续碱回收工序的能耗。可根据不同工厂的实际情况选用这两个流程。

A process including dealuminium and electrodialysis (ED) was adopted to recover alkali, alumina and water from a sort of waste alkali water which contains a high percentage of alkali and meta-aluminate. The parameters which influence the desalting and concentrating process have been investigated in the previous papers. Three different processes were designed for getting the following results. The concentration of concentrate is more than 70 g/L (Na_2O_T), and the diluate less than 0.5 g/L (Na_2O_T). The results show that the process containing four desalting ED units and one concentrating ED unit is a good choice. Then a process only containing five desalting ED units is investigated. The ED energy consumption of the later process is lower, and the recovery of alkali and water is higher. But the content ration of the concentrate is only 50 g/L (Na_2O_T).