赤泥中水溶性氟化物的电渗析去除

Electrodialysis removal of water-soluble fluoride from red mud

为减少赤泥中的氟化物含量,采用自制电渗析装置,通过单因素实验对赤泥中的氟化物进行了电渗析去除研究,考查了电压梯度和液固比对电流以及悬浮液pH和电导率的影响,分析了电渗析技术去除赤泥中氟化物的效果。结果表明:电渗析初期,电流从最大值迅速减小;在同一电压梯度下,电流随着液固比的增大而减小;在电渗析过程中,悬浮液pH和电导率随时间的延长而减小;电渗析技术可有效去除赤泥中的水溶性氟,其去除量随着电压梯度的升高而增大,最高去除率可达77.22%;液固比增大减小了水溶性氟的去除量,在1.0和2.0 V·cm-1电压梯度下,较大的液固比有助于水溶性氟的去除。利用电渗析技术去除赤泥中氟化物时,应综合考虑电压梯度和液固比对去除量及去除率的不同影响,在保证去除效果的同时尽可能降低能耗。研究结果可为赤泥的进一步综合利用提供参考。

In order to reduce the fluoride content in the red mud, self-made electrodialysis equipment was used to conduct a single-factor experiments studying the electrodialysis removal of fluoride in the red mud. The influences of voltage gradient and liquid-solid ratio on the current, as well as on the pH and conductivity of the suspension were investigated. The removal efficiency of fluoride in red mud by electrodialysis technique was analyzed. The results showed that the current decreased rapidly from the maximum value at the initial stage of electrodialysis. Under the same voltage gradient, the current decreased with the increase of liquid-solid ratio.During electrodialysis process, the pH and conductivity of the suspension decreased with the extension of time.The electrodialysis technique could effectively remove water-soluble fluorine in the red mud. The removal amount increased with the rise of the voltage gradient and its highest removal rate was 77.22%. The increase of the liquid-solid ratio reduced the removal amount of water-soluble fluorine. At 1.0 V·cm-1 or 2.0 V·cm-1 voltage gradient, higher liquid-solid ratio helps to remove water-soluble fluorine. When the electrodialysis technique was used to remove fluoride in the red mud, the different influence of voltage gradient and liquid-solid ratio on the removal amount and removal rate should be fully considered, so as to reduce the energy consumption as much as possible while ensuring the removal effect. The study can provide reference for the further comprehensive utilization of red mud.