Study On The Distribution Of Microorganism Involving In The Process Of Geochemistry Circulation Of S,Fe And Its Effect On Uranium Deposit In Shihongtan Uranium Deposit

Sandstone uranium mine is not only one kind of deposit relatively cheaper to exploit but also the main resource of uranium products. The research finds out that this kind of uranium deposit coexists with pyrite, therefore, the process of the geochemical circulation of the element of S,Fe in the deposit is closely related to the formation of uranium deposit.Objectives: From the pilot study of microorganism involving in the process of the geochemical circulation of the element of S,Fe and by discussing its relation in the element circulation with its effect of uranium mineralization in the Shihongtan uranium deposit in Xinjiang province, this thesis is aimed to provide a biological approach for the mineralization and exploration of uranium.Approaches: By using biological approach, the bacterium of S,Fe in the subtropical rocks involving in the process of geochemical circulation in the Shihongtan uranium deposit in Xinjiang province were seperated and identified, their geochemical distribution was analysed; its effect to uranium mineralization and ore leaching was tested; a experiment system of ore water- bacterial mineralization and water-rock-bacterial ore bleaching were designed in order to understand the process of element circulation of bacterial and its effect to uranium mineralization.Results: Mircoorganisms involving in the circulation of the element of S,Fe separated from the Shihongtan uranium deposit in Xinjiang province includes SRB, iron bacteria, Thiobacillus. Their distribution of microorganisms in different subtropical rock zones was determined bythe factors of the content of organic carbon, Fe²⁺ , Fe³⁺ dissolved oxygen and uranium, presenting an obvious characterstics of geochemical distribution. From the oxidation zone, the incomplete oxidation zone, the redox transitional zone to the reduction zone, the quantities and species of bacteria were gradually decreased. The result of biomineralization showed that SRB could generate H₂S in itself, providing a strong deoxidizing environment for the uranium. On the other hand, Thiobacillus and ferric oxide bacteria, could change the environment by metabolizability in itself, which was be propitious to U(IV) bleaching. Their inter-effects of these microorganisms promoted the bleaching-transference-deposition of uranium in uranium deposit.Conclusions: The category and quantity of the bacteria group involving in the circulation of the element of S, Fe in the Shihongtan uranium deposit showed itself an obvious characterstics of geochemical distribution. Their process of biological metabolizability, with the aggradation and transference of mineralized element, was of great significance to the formation of uranium deposit.