Research reveals the enrichment mechanism of rare earth elements in the deep sea


The team of professor-level senior engineer He Gaowen of Southern Ocean Science and Engineering Guangdong Provincial Laboratory (Guangzhou) revealed the extraordinary enrichment mechanism of rare earth elements by phosphate components in deep-sea sediments, and confirmed that rare earth enrichment is mainly near the seawater-sediment interface Finish. Related research was recently published in the Journal of Geochemistry and Cosmochemistry.

Rare earth is an indispensable element for high-tech industries and an important strategic resource. With the increasing demand for rare earths in green energy and emerging materials, there is an urgent need for diversified rare earth resources to provide a stable supply. However, the enrichment mechanism of rare earth elements in the deep sea, especially the supernormal enrichment effect of phosphate components on rare earth elements is not clear, the migration of rare earth elements at the seawater-sediment interface, and the enrichment mechanism process are not clear, which restricts the development of rare earth-rich sediments. Establishment of metallogenic model and breakthrough in ore prospecting.

He Gaowen’s team carried out chemical leaching experiments on the sediment columnar samples collected from the deep-sea basin of the western Pacific Ocean, and carried out mineralogy, element and isotope analysis, and found that rare earth elements, phosphorus and calcium content in deep-sea sediments The content of stone particles showed a good correlation, explaining the control effect of phosphate components on rare earth elements. At the same time, it quantitatively reveals the relationship between the rare earth elements and the occurrence phases in the sediments.

Phosphate components in deep-sea sediments have a unique high rare earth content, known as “rare earth-rich phosphate”, which is 1 to 2 orders of magnitude higher than marine phosphorites and terrestrial sedimentary phosphate rocks. The research team found that in the process of rare earth enrichment in deep-sea sediments, the accumulation of phosphorus is the basis, and the formation of rare earth-rich phosphate is the key. The erosion and sorting of sediments by seabed currents lead to the accumulation of rare earth-rich bioapatite particles, which are easy to form rare earth-rich layers. Phosphate components and REE-rich sediments have a unique REE pattern with Ce negative anomalies and Y positive anomalies similar to seawater. However, the content of rare earth elements in seawater is extremely low, and the reversible adsorption of biological particles causes the “top-down” migration of seawater rare earth elements, which are released and enriched near the seawater-sediment interface.

Post time: Feb-20-2023