摘要
煤基固废作为煤炭开采和利用过程中产生的大宗废弃物,富含Ti、Li、Y、Ga和Ge等稀有元素,具有重要的资源回收价值。氯化焙烧技术因高效性和适应性,成为回收此类元素的关键手段。本文系统模拟了煤基固废氯化焙烧过程的热力学行为,重点分析氯化剂(NaCl)用量、温度、C/O_(2)摩尔比对稀有元素氯化路径及挥发顺序的影响。结果表明:NaCl在C-O_(2)体系中通过直接氯化和分解生成Cl_(2)间接氯化双重路径参与反应;O_(2)显著促进稀有元素直接氯化但抑制其间接氯化,而C可协同促进两条路径氯化并缓解O_(2)的抑制作用;基于氯化物蒸气压差异,稀有金属挥发顺序为GeCl_(4)>TiCl_(4)>GaCl_(3)>YCl_(3)>LiCl,且温度和C/O_(2)摩尔比是调控反应选择性的关键参数。本研究阐明了煤基固废中稀有元素的氯化回收机制,为固废资源化和稀有金属高效提取提供了热力学理论支撑。
Coal-based solid waste,a bulk byproduct from coal mining and utilization,contains strategically valuable rare metal elements Ti,Li,Y,Ga and Ge with significant resource recovery potential.Chlorination roasting has emerged as a key technology for recovering these elements due to its high efficiency and adaptability.This study systematically investigated the thermodynamic behavior during chlorination roasting of coal-based solid wastes,with focused analysis on how NaCl dosage,temperature,and C/O_(2) mole ratio affect chlorination reaction pathways and volatility sequence of rare metal elements.The results indicate that,in the C-O_(2) system,NaCl participates in reactions via two pathways:direct chlorination and Cl_(2) generation through decomposition for indirect chlorination.O_(2) significantly promotes direct chlorination of rare elements but suppresses indirect chlorination,while C synergistically facilitates both pathways and mitigates the inhibitory effect of O_(2).Based on the differences in vapor pressures of chlorides,the volatility sequence of rare metals is GeCl_(4)>TiCl_(4)>GaCl_(3)>YCl_(3)>LiCl.The temperature and C/O_(2) molar ratio are the key parameters governing reaction selectivity.This study elucidates the mechanism of chlorination recovery of rare elements in coal-based solid waste,offering a thermodynamic theoretical foundation for the solid waste resource utilization and efficient rare metal extraction.
作者
吴浩
张子东
段思宇
马骏
郭少青
WU Hao;ZHANG Zidong;DUAN Siyu;MA Jun;GUO Shaoqing(School of Environment and Resources,Taiyuan University of Science and Technology,Taiyuan 030024,China;School of Chemical and Environmental Engineering,China University of Mining and Technology Beijing,Beijing 100083,China;Guangxi Huaxi Group Co.,Ltd.,Liuzhou 545000,China)
出处
《中国有色金属学报》
北大核心
2025年第12期4387-4405,共19页
The Chinese Journal of Nonferrous Metals
基金
国家自然科学基金资助项目(22408256)
中国博士后科学基金资助项目(2024M750604)
中央引导地方科技发展基金资助项目(YDZJSX2025D052)。
关键词
煤基固废
稀有元素
氯化焙烧
热力学分析
选择性回收
coal-based solid waste
rare elements
chlorination roasting
thermodynamic analysis
selective recovery
