离子型稀土原地浸矿残留氨氮“源--汇”一体化控制技术模式研究

Technical model of “Source-Flow-Sink” integration for pollution control of residual ammonia nitrogen after in-situ leaching of ion-type rare earth ore

  • 摘要: 针对离子型稀土原地浸矿场地残留氨氮的污染特征,提出源头减量、过程拦截、末端治理的“源-流-汇”一体化技术模式。研究表明:以木质素磺酸钙为主淋洗剂的源头淋洗技术消减了原地浸矿场地残留氨氮的90%以上,同时提升了土壤稳固性;拦沙坝-地表可渗透性反应墙运行初期氨氮最高消减率为87.65%,pH最高提升1.24,运行6个月后仍可拦截泥沙90.38%,有效发挥了调蓄水量、拦截泥沙、消减氨氮和提升pH的作用;渗滤耦合生物处理系统连续9个月稳定运行,出水氨氮浓度低于1 mg/L,达到地表水Ⅲ类水质标准限值要求。源头减量、过程拦截、末端治理的“源-流-汇”一体化技术模式,为离子型稀土矿区环境治理提供了技术支持,同时也为实现离子型稀土资源绿色可持续发展提供了重要支撑。

     

    Abstract: Based on the characteristics of site point source pollution and watershed non-point source pollution of residual leaching agents in ion-type rare earth mining areas, this study proposed an integrated technology model of source reduction, process interception and terminal treatment of “Source-Flow-Sink”. The results show that the source leaching technology with lignosulfonate as the main leaching agent can reduce the residual ammonia nitrogen by more than 90% and improve soil stability. The high concentration of ammonia nitrogen in the leaching solution is absorbed and used for ecological restoration. At the initial stage of the sand barrier - Surface Permeable reaction wall, the highest reduction ratio of ammonia nitrogen and the highest increase of pH are 87.65% and 1.24, respectively. After 6 months of operation, the wall can still intercept silt by 90.38%, effectively playing the role of regulating water storage, intercepting suspended matter and sediment, reducing ammonia nitrogen and increasing pH. The filtration coupled biological treatment system runs continuously and stably for 9 months, and the effluent ammonia nitrogen concentration is less than 1 mg/L, which meets the requirements of Class Ⅲ water quality standards of surface water. The integrated technology model of “Source-Flow-Sink” proposed in this study not only provides technical support for the environmental treatment of ion-type rare earth mining areas but also provides important support for the green and sustainable development of ion-type rare earth resources.

     

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