离子型稀土矿中残留氨氮的淋洗去除及动力学研究

Removal and kinetics of residual ammonia nitrogen in ionic rare earth tailings by leaching

  • 摘要: 采用木质素磺酸钙、鼠李糖脂、硫酸镁、硫酸镁钾对离子型稀土尾矿中残留氨氮进行杯浸和柱淋洗实验。杯浸实验考察了浸出剂浓度(0~20 g/L)、温度(5~50 ℃)、固液比(1∶2.5~1∶15,单位g/mL)和浸出时间(0~24 h)对氨氮去除效率的影响;通过柱淋洗实验对比了不同种类淋洗剂的淋洗效果并对其进行动力学拟合。实验结果表明:木质素磺酸钙通过柱淋洗实验去除氨氮85.88%,相对于清水淋洗,氨氮去除率提升了4.02倍;硫酸镁和硫酸镁钾淋洗氨氮的过程较符合准一级动力学方程,而木质素磺酸钙淋洗氨氮的过程对双常数方程拟合度更高。结合土壤淋洗后理化性质的分析,木质素磺酸钙作为淋洗剂,既可以有效去除氨氮,又可以调节土壤pH,具有良好的工程应用潜质。

     

    Abstract: Calcium lignosulfonate, rhamnose-lipids, magnesium sulfate and potassium magnesium sulfate were used for cup leaching and column leaching of residual ammonia nitrogen in ionic rare earth tailings. The effects of concentration (0~20 g/L), temperature (5~50 ℃), solid-liquid ratio (1∶2.5~1∶15) and time (0~24 h) on the removal efficiency of ammonia nitrogen were investigated. Column leaching experiments were conducted to compare the leaching effects of different agents and to carry out kinetic fitting. The results show that the removal ratio of ammonia nitrogen by column leaching of calcium lignosulfonate is 85.88%, which is 4.02 times higher than that by water leaching. The leaching process of magnesium sulfate and potassium magnesium sulfate conforms to the quasi-first-order kinetic equation, while the leaching process of calcium lignosulphonate fits the double constant equation better. Combined with the physical and chemical properties analysis of soil after leaching, calcium lignosulfonate as a leaching agent can not only effectively remove ammonia nitrogen, but also adjust soil pH, which has good engineering application potential.

     

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