论文部分内容阅读
纳岭沟铀矿床位于鄂尔多斯盆地北东部,是我国近年发现的一个特大型砂岩铀矿床,铀矿体赋存于中侏罗统直罗组下段河流相砂体中,受古层间氧化带控制,呈板状。铀矿物主要为铀石、沥青铀矿和钛铀矿,其中铀石是最主要的铀矿物。沥青铀矿中w(CaO)较高;铀石中w(UO_2)偏低、w(SiO_2)偏高,w(UO_2)/w(SiO_2)达到1:1.29,远低于正常值;钛铀矿则呈现U低Ti高的特点。根据各铀矿物的形成、富集机理,认为纳岭沟铀矿床在古层间氧化发育阶段赋矿砂体属于酸性环境,SiO_2活度较低,形成铀矿物主要为沥青铀矿。始新世晚期及以后,氧化作用不发育,赋矿砂体被二次还原,岩石地球化学环境由酸性转变为弱碱性,SiO_2活度增大,使早期阶段形成的沥青铀矿转变为铀石。钛铀矿主要是在氧化—还原作用下由含铀溶液中的铀(UO_2~(2+))交代重矿物—钛铁矿中的Fe2+而形成。
The Nalainggou uranium deposit is located in the northeast Ordos Basin and is a very large sandstone-type uranium deposit discovered in recent years in China. Uranium ore bodies occur in the fluvial sand body of the Lower Jurassic Zhiluo Formation and are controlled by the paleo-oxidation zone , Was plate. Uranium minerals are mainly uranium, pitch uranium and titanium uranium, of which uranium is the most important uranium mineral. (UO 2) in uranium is low and w (SiO 2) is relatively high. The content of w (UO 2) / w (SiO 2) reaches 1: 1.29, much lower than the normal value. U ore is low Ti Ti high characteristics. According to the formation and enrichment mechanism of each uranium mineral, it is considered that the ore-bearing sand body of the Nailinggou uranium deposit belongs to an acidic environment during the paleo-interlayer oxidation development stage, and the activity of SiO_2 is relatively low. The formation of uranium minerals is mainly uraninite. Late Oxiocene and later, the oxidation is not developed, the ore-bearing bodies are secondary reduction, the rock geochemical environment from acidic to weakly alkaline, SiO 2 activity increases, the early stage of the formation of uraninite into uranium . Titanium uranium ore is formed mainly from the replacement of heavy minerals - Fe2 + in ilmenite with uranium (UO_2 ~ (2+)) in uranium solution under oxidation-reduction.