Study on Uranium Occurrence State of Daying Sandstone-Type Uranium Deposits in Ordos Basin

The Daying uranium deposit is a newly discovered deposit in Ordos basin recently, the detailed research on the uranium occurrence state has a great significance for mineral smelting and mining. Through using electron probe, sequential chemical extraction and α-trackmethods, the uranium occurrence state of Daying sandstone-type uranium deposits in Ordos Basin has been studied. The results show that the uranium ore is rich in coffinite, containing very small amounts of water silicon coffinite and titanium uranium. These uranium mineral occur as adsemblages, mainly exist in pyrite, calcite and the cracks of organic mattert.The sequential chemical extractionfurther confirms that the percentages of uranium ore in the Daying deposit area significantly different.The average amounts of sulfide-organic matter speciation, carbonates speciation, residual speciation, exchangeable speciation, and Fe-Mn speciation decreased in order as 40.88%, 28.33%, 24.89%, 3.2% and 2.64%.The uranium minerals take up 53.22% of total uranium, while the scattered adsorption uranium occupies 46.72%. And the scattered adsorption uranium is dominated by organic matter and pyrite. To sum up, the Daying uranium deposit mainly occurs as uranium minerals and scattered adsorption uranium, and both of them have same proportion. The uranium minerals are composed of coffinite, while the scattered adsorption uranium is developed within pyrite and organic matter.