Impact of Preferential Flow in Ionic Rare Earth Macropores on Water and Salt Transport by Soil Sensors

To investigate the impact of preferential flow in ionic rare-earth macropores on water and salt transport, dynamic leaching experiments were conducted on ionic rare-earth ores, with ammonium sulfate as the leaching agent.Indoor column leaching tests were employed to study the transport of the leaching agent in the macropore and matrix zones of soil samples.With the monitoring of the distribution of water potential and solute concentration by soil sensors, the mechanisms of and factors affecting macropore preferential flow were analyzed.Additionally, the relationship between rare earth leaching efficiency and factors such as moisture content, temperature, and solution concentration (electrical conductivity) was examined.To gain a clearer and more intuitive understanding of the water and salt transport process, and to obtain richer data such as the flow velocity distribution for a comprehensive evaluation of various factors affecting macropore preferential flow or solute transport, numerical simulation studies were conducted with Comsol Multiphysics software based on the physical model from indoor experiments.The combined analysis of indoor experiment and numerical simulation results aims to provide technical reference for rare earth leaching in mining operations.