Rare earth elements (REEs) are economically important to modern society and the rapid growth of technologies dependent on REEs has placed considerable economic pressure on their sourcing. This study addresses whether REEs could be released as a byproduct of natural gas extraction from a series of experiments that were designed to simulate hydraulic fracturing of black shale under various pressure (25 and 27.5 MPa) and temperature (50, 90, 130 °C) conditions. The dissolved REEs in the reacted fluids displayed no propensity for the REEs to be released from black shale under high pressure and temperature conditions, a result that is consistent across the different types of fluids investigated. Overall, there was a net loss of REEs from the fluid. These changes in dissolved REEs were greatest at the moment the fluids first contacted the shale and before the high temperature and high pressure conditions were imposed, although the magnitude of these changes (10⁻⁴ μg/g) were small compared to the magnitude of the total REE content present in the solid shale samples (10² μg/g). These results highlight the variability and complexity of hydraulic fracturing systems and indicate that REE may not serve as robust tracers for fracturing fluid-shale reactions. Additionally, the results suggest that significant quantities of REEs may not be byproducts of hydraulically fractured shales.

稀土元素（REEs）对现代社会具有重要的经济意义，而依赖REE的技术的迅速发展给其采购带来了巨大的经济压力。这项研究探讨了REE能否通过一系列实验模拟天然气页岩在不同压力（25和27.5 MPa）和温度（50、90、130°C）下的水力压裂而作为天然气提取的副产物释放出来。条件。在高压和高温条件下，反应液中溶解的稀土元素不显示从黑色页岩中释放出来的稀土元素的倾向，这一结果在所研究的不同类型的流体中是一致的。总体而言，流体中的稀土元素净损失。^-4 相比REE内容本总的固体页岩样品中（大小10微克/克）太小² 微克/克）。这些结果突出了水力压裂系统的可变性和复杂性，并表明REE可能不能用作压裂流体页岩反应的可靠示踪剂。另外，结果表明大量的稀土元素可能不是水力压裂页岩的副产品。