Geochemical characteristics of rare earth elements in Late Permian coals in Western Henan and indicative meaning

With the wide application of rare earth metals in high-tech fields such as medical treatment and new materials, its strategic position has been increasing. As a major country in rare earth, China supplies rare earth products of different varieties and grades to all countries in the world, making great contributions to the development of emerging industries in the world .In order to explore the enrichment degree, occurrence state and sedimentary environment of rare earth elements in late Permian coal in western Henan, 20 stratified coal samples from No.2₁ coal in Huixiang mining area in western Henan were taken as the main research object. The rare earth elements and major elements in stratified coal samples were measured by ICP-MS and XRF, and the content characteristics and enrichment degree of rare earth elements in coal samples were discussed. The occurrence state and sedimentary environment of rare earth elements in samples were discussed by correlation analysis and characteristic parameters .The results show that the mass concentration of REY is 35.29-133.61 μg/g, and the average concentration is 79.14 μg/g, which is slightly higher than the average concentration of REY in the world coal, but obviously lower than the average concentration of REY in China coal. The REY content is low, and LREY is mainly enriched. There is a significant positive correlation between REY and ash content (Ad), SiO₂, Al₂O₃ and other major oxides in the No.2₁ coal of Huixiang mining area, indicating that REY mainly occurs in clay minerals .The negative anomalies of Ce and Eu elements and slight positive anomalies of (Gd/Gd)_N^* in the samples in the study area indicate that the study area is mainly affected by terrigenous sources and the coal forming environment is a weakly acidic reducing environment.