Effect of the in situ leaching solution of ion-absorbed rare earth on the mechanical behavior of basement rock

A clear understanding of the evolution characteristics of leaching solution's damage to the basement rock of ion-adsorbed rare earth deposits is essential in the in situ leaching mining. In this study, some laboratory tests were carried out to investigate the deterioration behavior and failure mechanism of rock under the erosion of leaching solution. For this purpose, granite specimens were soaked in the leaching solution for different periods and then some physical and mechanical parameters were measured. The experimental results show that the strength of the rock without any soaking is the maximum. After 60 d, the rock strength, mass (dry) and P-wave velocity (dry) decrease to the minimum, while the porosity of the specimens reaches the maximum. Moreover, the failure pattern of the specimens in the uniaxial compression tests is affected as the soaking time increases. The scanning electron microscopy (SEM) image results indicate that the erosion of quartz crystals inside the rock specimens gets more intense with the increase of soaking time. Also, the internal crystal failure mode gradually changes from the trans-granular to the inter-granular. The insights gained from this study are helpful for better understanding the evolution characteristics of leaching solution's damage to the basement rock of ion-adsorbed rare earth deposits.