Rare Earth Elements Occurrence and Economical Recovery Strategy from Shale Gas Wastewater in the Sichuan Basin, China
Lun Tian, Haiqing Chang, Peng Tang, Tong Li, Xiao-Fei Zhang, Shi Liu, Qiping He, Ting Wang, Jiaqi Yang, Yuhua Bai, Radisav D. Vidić, John C. Crittenden, Baicang Liu
Abstract
Global demand for rare earth elements (REEs), which are central to many modern high-tech industries, is increasing rapidly. For the first time, we discovered and determined the REEs concentrations in Sichuan Basin shale gas flowback and produced water (FPW). The total REEs in shale gas FPW investigated in this work ranged from 4.5 to 118.3 μg/L. Europium (Eu) was found in all samples (0.92–79.62 μg/L). Our study suggests that there was approximately 4.2 tons of Eu2O3 in FPW worldwide in 2016, and that this value could increase to 16.8–111.7 tons in 2030. We discussed potential methods for Eu recovery from FPW and further research needs to facilitate recovery of REE. The results suggest that wastewater from oil and gas extraction constitutes a promising resource for REEs, especially for Eu.