相山铀矿田超临界流体铀成矿作用的试验初探OA

Xiangshan uranium ore field is a famous ultra large volcanic rock type uranium ore field in China,and its uranium mineralization has always been a focus and hotspot of research.Previous scholars have proposed various mineralization theories and viewpoints,all of which suggest or imply the existence of uranium mineralization under high-temperature and high-pressure.With the deepening of research,more and more evidence shows that the ore field has a high-temperature mineralization stage,namely the supercritical fluid action stage.To further reveal the mechanism of abnormal uranium enrichment in Xiangshan ore field,this paper conducted a research from the perspective of supercritical fluid action.Through dissolution experiments in the rich uranium ore-H2O system,rich uranium ore-NaCl-H2O system,and rich uranium ore-NaHCO3-H2O system,the solubility of uranium during fluid phase transition was testified,and the variation characteristics of uranium solubility during phase transition were summarized.Based on the research results of previous studies on the mineralization characteristics and controlling factors of ore fields,the supercritical fluid uranium mineralization in Xiangshan ore field was preliminarily revealed,providing a basis for improving the theory of hydrothermal uranium mineralization and guiding deep exploration.The research results show that:The uranium solubility in the supercritical region of the rich uranium ore-H2O system,rich uranium ore-NaCl-H2O system,and rich uranium ore-NaHCO3-H2O system is significantly increased;The uranium solubility in the rich uranium ore-NaHCO3-H2O system is significantly higher than that in the rich uranium ore-H2O and rich uranium ore-NaCl-H2O systems,confirming that the addition of CO2 component is beneficial for the extraction and migration of uranium by ore-forming fluids;The gas formed by the phase transition of supercritical fluid is rich in uranium,much higher than the uranium content of conventional solution steam,confirming that the phase transition of supercritical uranium ore-forming fluid can form uranium rich hydrothermal solution and uranium rich gas;The Xiangshan uranium ore field was formed by supercritical fluid uranium mineralization.The process of supercritical fluid uranium mineralization in Xiangshan ore field mainly involves three processes:activation and extraction of minerals from the source area by supercritical fluid,migration of minerals from the source area to the enrichment area,and uranium precipitation and enrichment of minerals by crossing the critical point in the enrichment area.There is phase separation gas uranium mineralization.