室内模拟地表PRB处理离子型稀土矿区尾水

Indoor simulation of surface PRB treating tailwater in ionic rare earth mining area

采用室内模拟PRB装置,以粒径2~4、0.6~1 mm沸石为填料,研究了地表PRB主要构造因子对渗流量的影响,并考察了地表PRB对稀土矿区尾水氨氮削减和泥沙拦截的效果。结果表明,细粒沸石级配为10%~15%时,渗流量变化平缓,有利于PRB系统稳定运行;渗流量与PRB厚度成线性负相关,与水位差成线性正相关;当进水口位置为1/3 PRB高度时,在较宽的水位差范围内水流均以渗流方式经过PRB,因而提高了PRB填料的利用率。优化设计PRB装置对稀土尾水的氨氮平均去除率为14.2%,泥沙平均去除率为58.2%,出水pH在运行前期有明显提高,其处理容量放大60倍后相当于尾水日处理能力354 t·d^(−1),可满足矿区一般小流域支流的实际需要。以上研究结果可对南方离子型稀土矿区治理提供参考。

An indoor simulated permeable reactive barrier(PRB)unit filled with zeolite particles of 2~4 and 0.6~1 mm was used to study the influence of the main construction parameters of surface PRB on the seepage flow,and ammonia nitrogen reduction and sediment interception from the tail water in rare earth mining area.The results showed that at the fine zeolite grading of 10%~15%,the variation of the seepage flow was relatively smooth,which was conducive to the stable operation of PRB system.Seepage flow was linearly negatively correlated with PRB thickness while was positively correlated with water level difference between inlet and outlet of the PRB.At water inlet position set at 1/3 PRB height,the water seepage was able to flow through the PRB across a wide range of water head,which could improve the utilization rate of PRB packing.The optimal simulated PRB could achieve an average ammonia nitrogen removal rate of 14.2%and an average sediment removal rate of 58.2%.The leachate pH increased significantly at the early stage of PRB treatment.Its treatment capacity with magnification of 60 times can be equivalent to 354 t·d^(−1) of tail water,which can generally meet the actual need of small tributaries in mining area.The above research results can provide a reference for the treatment of ion-type rare earth mining areas in south China.