基于地球化学模型对低温热液中Au、As赋存状态的研究

发布时间：2018-05-25 00:42

  本文选题：低温热液 + Geochemist’s　； 参考：《中国地质大学(北京)》2017年硕士论文

【摘要】：成矿流体中化学元素的赋存状态一直都是地球科学领域非常关注的问题,近年来,随着地质行业的不断发展,已经逐步建立起了相对比较丰富的关于成矿流体的热力学和动力学数据库,这些数据库为科研人员通过数据建模的方式模拟地质过程提供了有力的支撑。随着计算机技术的不断发展,通过计算机来建立相应的地球化学模型,进而模拟地球化学相关反应的方法已经逐步建立起来,并在地球化学领域得到了广泛的运用。本文主要基于地球化学模型中的连续滴定模型和部分平衡模型,建立相应的地球化学模型,运用Geochemist’s Workbench软件,研究了Au、As在低温热液中的赋存形式,并通过调整变量,探究了温度、离子浓度、氧逸度、硫逸度、pH、Eh对Au、As在低温热液中的赋存形式的影响。模拟结果表明:0~300℃范围内,Au主要以固态金(纳米级的自然金)、AuCl2-和AuCl4-三种形式存在,富氧状态下,有利于AuCl2-和AuCl4-的生成;温度越高,越有利于AuCl2-的生成,AuCl4-逐渐向AuCl2-转化;低pH状态下,氯离子浓度的升高,有利于AuCl4-的生成,抑制了AuCl2-的生成;固态金形态主要受氯离子浓度的影响,氯离子浓度越高,越容易转变为AuCl2-和AuCl4-。当lg aCl--3.6时,固态金开始转化为AuCl2-和AuCl4-。As主要以H3AsO4、H2AsO4-、HAsO42-、AsO43-、As(OH)4-、AsO2OH2-、As(OH)3、雌黄矿物和雄黄矿物的形式存在。温度升高,H3AsO4和As2S2消失,生成白砷石矿物,As主要以H2AsO4-、HAsO42-、AsO43-、As(OH)4-、AsO2OH2-、As(OH)3、雌黄矿物和白砷石矿物的形式存在。酸性条件下,有利于H3AsO4、H2AsO4-的生成。碱性条件下,有利于HAsO42-、AsO43-的生成。
[Abstract]:The occurrence of chemical elements in ore-forming fluids has always been a matter of great concern in the field of earth science. In recent years, with the development of geological industry, A relatively rich database of thermodynamics and dynamics of ore-forming fluids has been gradually established, which provides a powerful support for scientific researchers to simulate geological processes by means of data modeling. With the development of computer technology, the method of modeling geochemical reaction by computer has been established step by step, and has been widely used in the field of geochemistry. In this paper, based on the continuous titration model and partial equilibrium model of geochemical model, the corresponding geochemical model is established. The occurrence form of Autias in cryogenic hydrothermal solution is studied by using Geochemist's Workbench software, and the variables are adjusted. The effects of temperature, ion concentration, oxygen fugacity and sulfur fugacity (pH = Eh) on the occurrence of Autas in low temperature hydrothermal solution were investigated. The simulation results show that au is mainly in the form of solid gold in the range of 300 鈩，

本文编号：1931331