流化床反应器处理高浓度含氟废水的效率和稳定性

采用小试规模的流化床反应器处理氟质量浓度为500~1 400 mg/L的模拟高浓度含氟废水。以氟化钙颗粒为晶种,以氯化钙溶液为沉淀剂（流量25 L/h）,考察了流化床连续运行过程中沉淀除氟的效率和稳定性。实验结果表明：氟化钙的沉淀反应在30.7 s内即可完成;在废水流量为11~23 L/h、反应pH为7.0~9.0、上升流速为0.005 9~0.013 0 m/s、钙与氟的摩尔比为0.85~1.00的条件下,出水清液中氟质量浓度低于10 mg/L,达到《污水综合排放标准》（GB 8978—1996）要求。连续运行过程中,流化床沉淀除氟高效稳定,操作条件范围较宽。流化床出水中细颗粒沉淀物的存在会导致氟浓度显著升高,应采取有效措施减少其产生或溢出,以保证沉淀除氟效率。

Treatment of high concentration fluorine-containing wastewater by fluidized bed reactor：removal efficiency and operational stability

The high concentration fluorine-containing simulated wastewater,with the fluorine mass concentration 500-1 400 mg/L,was treated by the laboratory-scale fluidized bed reactor. The efficiency and stability of fluorine removal by precipitation during the continuous operation were investigated,with calcium fluoride particles as seeds and calcium chloride solution as precipitant （at the flow of 25 L/h）. The experimental results showed that the precipitation of calcium fluoride took place within 30.7 s and that under the conditions of influent flow 11-23 L/h,reaction pH 7.0-9.0,upflow velocity 0.005 9-0.013 0 m/s and molar ratio of Ca to F 0.85-1.00,the fluorine mass concentration of centrifugal effluent was less than 10 mg/L,which met the national discharge standard （GB 8978-1996）. The fluoride removal efficiency of the fluidized bed was high and stable with wide operational conditions during the continuous operation. The existence of the fine particles led to the obvious increase of the effluent fluorine concentration. Effective methods should be taken to reduce the formation and overflow of the fine particles,so that the removal efficiency of fluorine retained stable.