黄铁矿与辉铜矿、铜蓝选择性生物浸出机理研究

发布时间：2018-03-21 22:34

本文选题：黄铁矿　切入点：辉铜矿　出处：《北京有色金属研究总院》2017年博士论文　论文类型：学位论文

【摘要】：随着矿产资源的不断开发,有价金属品位不断降低,共伴生程度日益复杂,浸出过程中有价有害元素同步溶解,后续溶液分离难度大,实现有价金属选择性浸出是湿法冶金未来发展的趋势。紫金山铜矿是我国大型斑岩型次生硫化铜矿,铜品位低,黄铁矿含量高,生物浸出中出现酸过剩、铁累积现象,对环境影响大,并导致生产成本升高,是制约铜金属高效回收的瓶颈技术难题。本论文以福建紫金山铜矿为研究对象,针对主要矿物黄铁矿、辉铜矿和铜蓝,采用MLA矿物组成分析法、模拟计算和高通量测序法等现代研究手段,通过电子结构特性、电化学、动力学、微生物学等研究探讨了选择性浸出机理,揭示不同硫化矿物溶解差异性,并确立合理的调控手段,为低品位硫化铜矿选择性浸出提供了新的研究思路和理论指导。通过采用基于密度泛函理论的第一性原理方法,从分子和原子水平研究了黄铁矿、辉铜矿和铜蓝三种硫化物电子结构及性质,在微观本质上揭示了三种硫化矿物溶解差异性。研究表明,从黄铁矿、铜蓝到辉铜矿,能带宽度依次变窄,稳定性逐渐减弱,溶解反应难度依次降低,黄铁矿的氧化性最强,更易得到电子,而辉铜矿的还原性最强,更易失去电子。三种硫化矿物晶体结构不同,决定了溶解性存在较大差异,为实现选择性浸出奠定了理论基础。基于缩核模型,得到细菌接种浓度、Fe3+浓度、pH值、温度等因素与硫化溶解速率之间的关联指数,建立了硫化矿溶解半经验动力学模型。升高温度是促进黄铁矿、辉铜矿和铜蓝溶解的关键因素,其中铜蓝活化能(84.97kJ/mol)最高,对温度最敏感,而细菌接种浓度、Fe3+浓度、pH值与溶解速率关联指数较低,对浸出过程影响较小。氧化还原电位对辉铜矿和铜蓝浸出影响较小,在低电位下,浸出速率也较快。而黄铁矿的浸出与电位呈强相关性,当电位低于760mV时,黄铁矿浸出速率很慢,浸出20天,铁浸出率不足20%。低温、低电位下,黄铁矿与辉铜矿和铜蓝溶解差异性显著。揭示了矿物种类、电位与优势菌群组成之间的关联规律,建立以硫氧化菌为优势菌的浸出体系,是实现选择性浸出的必要条件。不同类型硫化矿,对细菌组成有一定影响,黄铁矿与辉铜矿和铜蓝性质存在差异,对细菌的影响不同。黄铁矿浸出过程中优势菌主要以铁氧化菌Leptospirillum为主,随着浸出过程的进行,Acidithiobacillus和Sulfobacillus菌数量和占比大幅降低。而铜蓝和辉铜矿浸出过程中,优势菌主要为Acidithiobacillus和Sulfobacills,其中Sulfobacilus菌属占比较高。当氧化还原电位较高时,浸出体系优势菌主要以Leptospirillum为主,随着氧化还原电位的降低,占比逐渐降低,当电位低于700mV以下时,Leptospirillum菌占比基本降为零,而氧化还原电位对Acidithiobacillus菌的影响较小,不同电位下都可成为优势菌。低温(≤45℃)、低电位(≤760mV)和硫氧化菌占绝对优势的浸出体系下,黄铁矿与辉铜矿和铜蓝硫化矿物溶解差异性最大,能确保实现辉铜矿和铜蓝的高效浸出,并可有效抑制黄铁矿的浸出。
[Abstract]:With the continuous development of mineral resources, valuable metal grade decreased and the associated degree is more complicated, the leaching process of valuable harmful elements simultaneously dissolved, subsequent solution separation is difficult to achieve selective leaching of valuable metals is the future development trend of hydrometallurgy. Zijinshan Copper Mine is a large porphyry type secondary copper sulfide, copper low grade, high pyrite content, acid excess bioleaching, the accumulation of iron, a large impact on the environment, and lead to increased production costs, is a bottleneck problem efficient recovery of copper metal. This paper takes Fujian Zijinshan Copper Mine as the research object, the main mineral pyrite, chalcocite and covellite, using MLA mineral composition analysis, simulation and research methods of modern high-throughput sequencing method, the electronic structure characteristics, electrochemical kinetics, microbiology research on selective leaching machine Daniel, reveal the different sulfide mineral dissolution differences, and establish reasonable regulation and control means, to provide new research ideas and theoretical guidance for the selective leaching of low grade copper sulfide. By using the first principle method based on density functional theory, from the molecular and atomic level of pyrite, chalcocite and covellite three sulfide electronic structure in the micro essence and nature, reveals three differences in dissolved sulfide minerals. The results show that from pyrite, covelline to chalcocite, band width are narrow, stability gradually weakened, difficult dissolution reaction reduces in turn, the strongest oxidizing pyrite, more electronic, and the reduction of the strongest chalcocite, more easily lose electrons. Three sulfide mineral crystal structure, determines the difference of solubility, provides a theoretical basis for the realization of selective leaching. The shrinking core model based on the obtained bacteria Inoculum concentration, Fe3+ concentration, pH value, temperature and other factors and the correlation index between sulfide dissolution rate, a semi empirical kinetic model of dissolved sulfide. Temperature is the key factor to promote the pyrite, chalcocite and covellite dissolved, the activation energy of ceruloplasmin (84.97kJ/mol) the highest, most sensitive to temperature, and the bacterial concentration. Fe3+ concentration, pH value and the dissolution rate of correlation index is low and has little effect on the leaching process. The redox potential has little effect on the leaching of chalcocite and covellite, at low potential, the leaching rate is higher. And the leaching and potential of pyrite showed strong correlation, when the potential is lower than 760mV, the leaching rate of pyrite leaching is very slow, 20 day, iron leaching rate of less than 20%. at low temperature, low potential, pyrite and chalcocite and covellite dissolution reveals significant differences. Mineral species, association rules and potential advantages of flora between the establishment of The leaching system of sulfur oxidizing bacteria were the dominant bacteria, is a necessary condition to achieve the selective leaching of sulfide minerals. Different types of bacteria, which have a certain influence, there are differences of pyrite and chalcocite and covellite properties, effects on bacterial leaching process. The advantages of different pyrite bacteria are mainly iron oxidizing bacteria Leptospirillum, with the leaching process Acidithiobacillus and Sulfobacillus, the number of bacteria and accounted for a substantial decrease. And the leaching process and chalcocite covellite, dominant bacteria were Acidithiobacillus and Sulfobacills, of which Sulfobacilus bacteria accounted for the higher. When the redox potential is higher, the leaching system of dominant bacteria is dominated by Leptospirillum, with the redox potential decreased and the proportion gradually decreased when the potential is less than 700mV, Leptospirillum bacteria accounted for basic zero, and the redox potential of Acidithiobacillus bacteria The effect under different potentials can become dominant. Low temperature (less than or equal to 45 DEG C), low potential (760mV) leaching system and sulfur oxidizing bacteria dominated by pyrite and sulfide chalcocite and covellite mineral dissolution of greatest difference, to ensure the efficient implementation of leaching of chalcocite and covellite, leaching and effectively the suppression of pyrite.

【学位授予单位】：北京有色金属研究总院
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TF811

【参考文献】