化学法处理核工业高氟氨废水的研究

Chemical treatment for high concentration fluoride and ammonia wastewater in nuclear industry

采用序批式烧杯试验,通过生成CaF2和MgNH4PO4(MAP)强化除氟脱氨的化学方法处理高浓度氟氨废水,研究了除氟脱氨顺序、投加药剂种类、pH、药剂投加量对高氟氨废水去除效果的影响。结果表明,先脱氨后除氟时,Ca2+会争夺MAP中的PO43-生成Ca3(PO4)2,释放NH4+降低脱氨效率;先除氟后脱氨时,控制n(Mg2+)∶n(PO43-)∶n(NH4+)为1.3∶1.1∶1.0,混合液pH为11.0,可达到理想的除氟脱氨效果。沉淀物的XRD分析表明,沉淀物主要成分为MAP,表明MAP颗粒以Ca F2为晶核发生了类似絮凝的自絮凝作用。

The sequential batch beaker experiment was conducted to study the fluoride and ammonia removal in high concentration fluoride and ammonia wastewater by chemically producing CaF2 and MgNH3 PO4(MAP). The effects of factors,such as the orders of fluoride and ammonia removal,the types of additives,the pH value and the dosage of additives,on the removal efficiency were also investigated. The results showed that when ammonia was removed earlier than fluoride,Ca2+competed for PO43-in MAP to convert to Ca3(PO4)2,resulting in the release of ammonia which reduced the efficiency of ammonia removal. When fluoride was removed earlier than ammonia,the optimum effect of fluoride and ammonia removal can be achieved by controlling n(Mg2+)∶n(PO43-)∶n(NH4+) at 1.3∶1.1∶1.0 and the pH value of the mixed solution at 11.0. XRD analysis showed that main component of the sediment was MAP,which indicated that the self-flocculation of MAP particles with CaF2 as crystal nucleus was similar to flocculation.