Study on Uranium Occurrence State of Sandstone-Type Uranium Deposits in HJQ Region, Ordos Basin

Because of its important economic value, sandstone-type uranium deposit have been highly concerned by geology exploration department around the world. The paper mainly studied the occurence state of Uranium in sandstone-type Uranium deposits in the Ordos Basin, using methods of electron probe, sequential extraction procedure and α-track etching. The results show that the Uranium ore is rich in coffinite,and contains very small amounts of uranothorite and brannerite, which mainly exist as adsorbed particles (1-5 μm). Part of the Uranium particles, presenting as larger microparticle assemblages, mainly exist in pyrite, chlorite, calcite and the cracks of organic matter, and a few of them appear in the cracks of quartz, limonite, mica and other minerals. α-track etching further confirms that the percentage of Uranium ore in the deposit is up to 50%, in which the dispersive adsorbed Uranium accounts for about 50%. What's more, the dispersive absorbed uranium is basically found in pyrite and organic matter, adsorption to other minerals is just about 5%.