稀土氨氮废水治理及资源化集成技术的研究

Study on Integrated Technology for Treatment and Recycling of Rare Earth Industrial Wastewater Containing Ammonia-nitrogen

以吸附法与化学沉淀法的集成技术组成氨氮废水处理的闭路循环系统,用自制的MgHPO4(MHP)为吸附剂,对NH4+浓度为5175mg/L稀土硫酸铵废水进行了氨氮吸附性能实验,研究发现pH、MHP的投加量和氨氮初始浓度是影响氨氮去除效果的关键因素。在室温下,调节反应体系pH=9.5,MHP用量按摩尔比n(MHP)∶n(NH4+)=2∶1投料,搅拌吸附30min,氨氮去除率可达85.7%,且氨氮初始浓度越高,吸附效果越好。MHP再生与循环使用实验表明,MAP焙烧可使MHP再生,同时可回收高浓度的氨水,MHP循环使用三次,氨氮的去除率均在70%以上。如果采用MHP二级吸附法后,再用MAP沉淀法处理废水,可使出水氨氮浓度降低为87mg/L,累计氨氮去除率可达到98%以上。

A sewage-integrated treatment technology,consisting of MHP adsorption and chemical precipitation was used to conduct the experiment on rare earth ammona nitrogen wastewater treatment in a closed-loop system.The results shows that the crucial factors affecting the removal rate of ammonia nitrogen from the waste water are pH value,addition of MHP and initial comcentration of ammonia nitrogen.Under the conditions of room temperature,pH 9.5,molar ratio of MHP to NH＋4 2∶ 1 and stirring time 30min,the remval rate of ammonia nitrogen can reach 85.7%.MHP can be regenerated by calcinating MAP,three regeneration cycles of MHP all gave more than 70% of removal rate of ammonia nitrogen,and high concentration ammonia water can be recovered.With MHP two-stage adsorption method and MAP precipitation method,content of ammonia nitrogen in the waste water can be decreased to 87mg/L and the accumulative removal rate of ammonia-nitrogen can reach 98% or higher.