Critical metals in coal and coal-bearing sequences: A comparison between China and the United States

Critical metal resources are of paramount importance to economic development and national security. The entire process, i.e., from exploration, mining, separation, purification, to application of critical metals, has attracted significant global attention and has become a core issue in geopolitical competition among major powers around the world. Critical metals hosted in coal and coal-bearing sequences have emerged as a cutting-edge research topic in coal geology, mineralogy, metallurgy, and mineral processing. China and the United States are the two most influential members in this field. This paper firstly summarizes the current research status of both countries in the areas of mineralization theory, exploration, extraction, and separation of coal-based critical metals, and further analyzes their strengths and weaknesses. In the past decade, the United States has made a significant progress in the discovery and separation of critical metals in coal and coal-bearing sequences, due to the unified deployment and substantial funding from the U.S. Department of Energy. China, on the other hand, has made significant advancements in the establishment of mineralization theories, evaluation indices and standards of critical metals in coal, thanks to the complex coal-forming geological conditions that led to the coexistence of critical metals in the same basin, as well as diverse combinations and spatial occurrences of these metals. The intensely geopolitical competition has heightened the struggle for control over critical mineral resources. Therefore, a realistic and accurate understanding of the status of critical metals hosted in coal and coal-bearing sequences in China and the United States, as well as their research progress, strengths, and weaknesses, is crucial for further leveraging China's advantages in critical mineral resources in the context of great power geopolitical competition, addressing the severe challenge of ensuring a stable supply of China’s scarce critical metals, and reducing the dependence on external supply chains.