基于分子动力学的升温条件下煤中锂吸附扩散特性研究  

Lithium adsorption and diffusion in coals with temperature increasing based on molecular dynamics calculations

作　　者：张俊爽 张彬 孙蓓蕾[1,3] 刘超[1,3] ZHANG Junshuang;ZHANG Bin;SUN Beilei;LIU Chao(College of Mining Engineering,Taiyuan University of Technology,Taiyuan,Shanxi 030024,China;Key Laboratory of In-situ Property-improving Mining of Ministry of Education,Taiyuan University of Technology,Taiyuan,Shanxi 030024,China;Key Laboratory of Coal Science and Technology,Ministry of Education,Taiyuan University of Technology,Taiyuan,Shanxi 030024,China)

机构地区：[1]太原理工大学矿业工程学院,山西太原030024 [2]太原理工大学原位改性采矿教育部重点实验室,山西太原030024 [3]太原理工大学煤科学与技术教育部重点实验室,山西太原030024

出　　处：《地质学报》2024年第8期2499-2508,共10页Acta Geologica Sinica

基　　金：国家自然科学基金项目(编号42372203,42172193,42302202);国家重点研发计划项目(编号2021YFC2902002);山西省科技创新人才团队专项项目(编号202304051001028)联合资助的成果。

摘　　要：煤是特殊的沉积有机岩石,在其形成过程中可以富集战略性金属,并在煤系中形成大型或超大型金属矿床,成为矿产资源勘探的重要领域。温度是影响煤化作用及其过程中锂等关键金属赋存方式变化的重要因素。为了研究升温过程对煤中锂吸附特征的影响,本文以内蒙古准格尔煤田典型高锂煤为研究对象,构建锂-煤可视化模型,通过分子动力学方法计算了不同温度点锂在煤结构中的径向分布函数、扩散系数,分析了锂与有机大分子结构和高岭石相互作用能的变化,探讨了煤结构对锂的吸附特征。结果表明:锂在吸附过程中与氮原子、有机结构中的氧原子和硅原子存在较强的相互作用,与其他原子相互作用较弱或者不存在相互作用。锂与氮原子和有机结构中的氧原子主要是通过氢键作用吸附,而与硅原子则存在静电力和范德华力作用。从20℃升温到300℃的过程中,锂扩散系数受到温度和煤结构变化的影响,呈现出先升高后降低的趋势;煤结构对锂的吸附作用能以静电能为主。Coal,an important organic sedimentary rock,can become enriched with strategic metals during its formation process.The discovery of coal-related metal deposits has highlighted the increasing importance of strategic metals in coal for mineral resource exploration.Temperature plays a key role in the behavior of metals during coalification.To understand the adsorption characteristics of lithium in coal as temperature increases,a visualization macromolecular model of a typical high-lithium coal from the Jungar coalfield was constructed.Molecular dynamics modeling was then employed to investigate the adsorption characteristics of lithium in coal across a range of temperatures.We calculated the radial distribution function and diffusion coefficient,and analyzed the energy variations associated with lithium interactions with the macromolecule and kaolinite in the coal structure at different temperatures.Our results show that lithium exhibits strong interactions with nitrogen,oxygen,and silicon atoms in the macromolecule structure,while showing weak or no interactions with other atoms.Hydrogen bonding is responsible for the strong interaction between Li and nitrogen and oxygen atoms,whereas the interaction between Li and Si could be a result of van der Waals forces.The diffusion coefficient of Li initially increases then decreases as temperature rises from 20℃to 300℃.The adsorption of Li onto the coal macromolecular is predominantly controlled by electrostatic energy.

关 键 词：准格尔煤田 锂 分子动力学 升温 吸附特征 

分 类 号：P618.11[天文地球—矿床学] P618.71[天文地球—地质学]