不同溶浸作用对离子型稀土持水特性的影响研究

The Effect of Different Leaching on the Water Retention Characteristics of Ion-absorption Type Rare Earth

土-水特征曲线是研究离子型稀土持水特性的重要工具。通过室内模拟浸矿试验与Geo-Experts压力板仪测试系统,得到不同溶浸作用下稀土矿体基质吸力与含水率关系。分别利用Van Genuchten模型、Fredlund&Xing三参数模型和Fredlund&Xing四参数模型,研究不同溶浸作用下离子型稀土的土-水特征曲线,分析了不同模型参数的变化规律,得到了不同溶浸方式对土体持水特性的影响规律。对于不同种类溶浸液,持水能力由强到弱依次是纯水、3%硫酸镁溶液、3%硫酸铵溶液;随着溶浸液浓度增大,稀土矿体持水能力逐渐降低,且浓度从0到2%之间下降最明显。土-水特征曲线“滞回效应”显著程度从高到低依次为纯水、3%硫酸镁溶液、3%硫酸铵溶液,随溶浸液浓度增大,“滞回效应”呈现减弱趋势。

Soil-water characteristic curve is an important tool to study the water-holding characteristics of ion-absorption type rare earth.Through an indoor simulated leaching test and Geo-Experts pressure plate apparatus,the relationship between matric suction and water content under different leaching actions was obtained.By using the Van Genuchten model,the Fredlund&Xing three-parameter model,and the Fredlund&Xing four-parameter model,respectively,the soil-water characteristic curves of different ion-absorption types of rare earth were studied,and the changing trend of each parameter of the three models was analyzed.The results show that the Fredlund&Xing four-parameter model has the best effect for fitting the soil-water characteristic curve of ion-absorption type rare earth.According to the analysis of the water-holding characteristics of ion-absorption type rare earth after the leaching action of different types of leaching solutions,the water holding capacity of the soil was most improved by pure water,followed by 3% magnesium sulfate solution and 3% ammonium sulfate solution.As the concentration of the leaching solutions increased,the water holding capacity of the sample gradually decreased,and the concentration decreased most significantly from 0 to 2%,Moreover,the significance levels of actors affecting the"hysteresis effect"of the soil-water characteristic curve were decreased from pure water,3% magnesium sulfate solution,to 3% ammonium sulfate solution.With an increase in the concentration of the leach solution,the same trend appeared.