天然气及有机质与铀作用地球化学实验模拟

发布时间：2018-04-19 16:06

本文选题：地球化学实验 + 铀成矿模拟　；参考：《西北大学》2017年硕士论文

【摘要】：铀在自然界成矿过程中伴随有机能源矿产(如煤、石油、煤层气等)共存的现象十分普遍。说明有机-无机矿产在形成过程中有着较为明显的相互作用,有机质参与金属矿物的吸附吸收、迁移沉淀、富集还原等一系列的地球化学过程,而铀元素在化石能源演化形成的过程中也起到了催化活化的作用。有机质既作为路易斯碱与铀元素配位,又作为电子给体充当还原剂。有机质中的腐殖酸吸附铀酰离子,通过形成配合物阻滞铀酰离子的迁移,形成铀矿的初始地质沉积背景;天然气和石油作为还原剂,将活泼且迁移能力强的六价铀还原成难以迁移的四价铀,最终形成铀矿(藏)。为研究天然气的还原成矿机理和有机质配位成键规律,我们通过模拟铀元素地球化学的实验来反映其与有机质作用的化学变化。从理论的角度出发,为铀与多种能源矿产共存提供化学解释,从而揭示无机-有机矿产之间的相互联系。本文将氮杂芳香多羧酸与铀酰离子反应,通过对其晶体结构的解析,推测腐殖酸中含氧官能团与铀酰离子的配位模式和化学结合能力。根据亮晶方解石捕获的原生流体包裹体温度推测成矿温度,模拟地质条件下盆地较深部铀源在天然气存在下与铀酰离子还原反应,研究天然气携铀能力。1.将含有杂原子的芳香有机多羧酸与铀酰离子作用,在水热条件下合成配位聚合物,从而反映腐殖酸中含氧官能团在铀成矿过程中的化学配位能力。总共培养得到7种铀酰配合物的单晶,通过X-射线单晶衍射确定其化学结构,对其进行元素分析、光谱分析和热重-差热分析测试。2.在自行设计的高温高压反应釜中,将天然气通入到低氧、含铀的水溶液中进行地球化学实验模拟,模拟铀在地质条件下与天然气的还原过程。将得到的固态产物进行分离,通过X-射线粉末衍射验证,得到的反应产物的主要成分为UO3的水合物。3.有机质的存在有利于天然气的溶解,将天然气通入到低氧、含铀的水-乙醇体系中进行模拟反应,将粗产物进行酸解处理后,对产物进行X-射线粉末衍射测试,得到处于混合价态的铀氧化物(U308)。
[Abstract]:The coexistence of organic energy minerals (such as coal, petroleum, coalbed methane) is very common in the process of uranium mineralization in nature.The results show that there is obvious interaction between organic-inorganic minerals during their formation. Organic matter is involved in a series of geochemical processes, such as absorption, migration and precipitation of metal minerals, enrichment and reduction, etc.Uranium also plays a catalytic role in the evolution of fossil energy.Organic matter can coordinate with uranium as Lewis base and as electron donor as reducing agent.The humic acid in organic matter adsorbs uranyl ions and forms complexes to block the migration of uranyl ions to form the initial geological and sedimentary background of uranium deposits; natural gas and petroleum are used as reductants.The active and highly mobile hexavalent uranium is reduced to tetravalent uranium which is difficult to migrate, and the uranium deposit is formed.In order to study the mechanism of reduction and mineralization of natural gas and the law of coordination bond formation of organic matter, the chemical change of the interaction between uranium element and organic matter is reflected by simulating the geochemistry of uranium element.From the theoretical point of view, this paper provides a chemical explanation for the coexistence of uranium and many kinds of energy minerals, thus revealing the interrelation between inorganic and organic minerals.In this paper, the coordination mode and chemical binding ability of oxygen-containing functional groups with uranyl ions in humic acid were deduced by analyzing the crystal structure of aromatic polycarboxylic acids and uranyl ions.According to the temperature of primary fluid inclusions captured by bright calcite, the ore-forming temperature is predicted, and the uranium source in the deeper part of the basin reacts with uranyl ion in the presence of natural gas under simulated geological conditions, and the uranium carrying capacity of natural gas is studied.The coordination polymers were synthesized by the interaction of aromatic organic polycarboxylic acids containing hetero-atoms with uranyl ions under hydrothermal conditions, thus reflecting the chemical coordination ability of oxygen-containing functional groups in humic acids during uranium mineralization.A total of 7 uranyl complexes were grown and their chemical structures were determined by X-ray single crystal diffraction. The chemical structures were characterized by elemental analysis, spectroscopic analysis and thermogravimetric differential thermal analysis (TG-DTA).In the autoclave of high temperature and high pressure designed by ourselves, the natural gas was transported into the aqueous solution of low oxygen and uranium, and the geochemical experiment was carried out to simulate the reduction process of uranium with natural gas under geological conditions.The solid product was separated and verified by X-ray powder diffraction. The main component of the reaction product was hydrate of UO3.The existence of organic matter is beneficial to the dissolution of natural gas. The natural gas is transported into the water-ethanol system with low oxygen and uranium for the simulated reaction. After the crude product is treated by acid hydrolysis, the product is tested by X-ray powder diffraction.The mixed valence uranium oxide (U308) has been obtained.
【学位授予单位】：西北大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P618.1;P619.14

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