沉渣溶液淋洗离子型稀土尾矿残留浸矿剂的研究

Study on Removal of Residual Leaching Agent from Ion-absorbed Type Rare Earth Tailings Using Sediment Solution

以硫酸铵为浸矿剂的离子型稀土尾矿残留大量水溶态和可交换态的铵离子,严重威胁周边流域的水资源安全。本文以稀土开采产生的沉渣作为淋洗剂淋洗尾矿,建立了沉渣阳离子解吸铵离子的数学模型,探讨了淋洗效率随沉渣溶液用量的变化关系,分析了石灰水的护尾效果。结果表明,可以采用Langmuir方程量化沉渣阳离子解吸铵离子的过程,在此基础上,确定PN和XW尾矿的合理淋洗剂浓度分别为8.27 mmol/L和12.64 mmol/L;淋洗效率随着沉渣溶液用量的增加而增加,当沉渣溶液用量大于2.5倍孔隙体积时,水溶态和可交换态铵离子的总淋洗效率大于95.0%;淋洗结束后,采用石灰水护尾,PN和XW尾矿柱内吸附态无机羟基铝分别占80.6%和85.1%,绝大部分铝离子被石灰水固定。由此可见,沉渣溶液能高效去除离子型稀土矿残留的浸矿剂,且避免产生二次污染,该方案也能用于硫酸镁等其他残留浸矿剂的淋洗,为离子型稀土绿色矿山的建设提供技术支持。

The ion-adsorption type rare earth tailings using ammonium sulfate as leaching agent has a large amount of water-soluble and exchangeable ammonium ions,which seriously threatens the water resources security of surrounding watersheds.In this paper,the sediment produced by rare earth mining was used as the eluent to elute the tailings,the mathematical model of the desorption of ammonium ions by the sediment cations was established,the relationship between the leaching efficiency and the amount of the sediment solution was discussed,and the tailings protection effect of lime water was analyzed.The results showed that the Langmuir equation can be used to quantify the process of sediment cation desorption of ammonium ions,on this basis,the reasonable eluent concentrations of PN and XW tailings were determined to be 8.27 mmol/L and 12.64 mmol/L,respectively;The leaching efficiency increases with the amount of sediment solution,when the amount of sediment solution was greater than 2.5 times the pore volume,the total leaching efficiency of water-soluble and exchangeable ammonium ions was greater than 95.0%;After rinsing,lime water was used to protect the tailings,the adsorbed inorganic hydroxyaluminum in the PN and XW tailings columns accounted for 80.6%and 85.1%,respectively,and most of the aluminum ions were fixed by the lime water.It can be seen that the sediment solution can efficiently remove the leaching agent remaining in the ion-adsorption type rare earth and avoid second pollution,the scheme can also be used for the leaching of other residual leaching agents such as magnesium sulfate,providing technical support for the construction of ion-adsorption type rare earth green mines.