中南大学学报（自然科学版）2025，Vol.56Issue(7)：2635-2646,12.DOI:10.11817/j.issn.1672-7207.2025.07.002
铜渣尾矿微波还原提铁过程行为与分离特性研究
Separation characteristics and reduction behavior of iron extraction process from copper slag tailings by microwave reduction roasting
摘要
Abstract
The sustainable development and efficient utilization of mineral resources are critical goals for achieving global sustainability.Copper slag tailings from Hubei Province,which contain a total iron content(TFe)of 36.89%,Pb mass fraction of 0.15%,and Zn mass fraction of 4.12%,were examined in this study.The extraction of iron and the separation of Pb and Zn from copper slag tailings were successfully achieved through a process combining pelletizing,microwave reduction roasting,and magnetic separation.A range of analytical techniques,including chemical analysis,XRD,TGA,SEM,and EPMA-EDS was employed to investigate the chemical composition,mineral phase transformations,reduction and aggregation behavior of the iron phase,and the volatilization and release characteristics of lead and zinc during the microwave reduction and iron extraction processes.The results show that copper slag tailing pellets with carbon-to-oxygen mole ratio of 1.3,when heated in a microwave oven at 1 200℃for 15 min,undergo efficient reduction and decomposition of their primary mineral phases-fayalite and magnetite-into metallic iron.Subsequent weak magnetic separation produces an iron concentrate with a total iron(TFe)grade of 83.77%～85.00%and a recovery rate of 85.69%～91.30%.Simultaneously,Pb and Zn mass fraction are reduced from 0.15%and 4.12%to 0.000 74%and 0.060%,respectively,demonstrating exceptional separation performance.Transformation of iron-bearing compounds in the slag pellets into metallic iron occurs quickly in the microwave reduction environment.During this process,Pb and Zn volatilize as flue gases,ensuring their recovery with volatilization rates of 99.83%for Pb and 99.46%for Zn.Fayalite in the slag pellets is effectively decomposed and reduced into metallic iron and silica(SiO2).The metallic iron predominantly forms spherical particles of varying sizes,while discrete silica bodies and inclusions are also observed.Furthermore,increasing the roasting temperature and extending the holding time enhance the reduction process and promote particle aggregation.These results present a highly efficient approach for recovering iron and separating lead and zinc from copper slag tailings,contributing to sustainable resources utilization and environmental stewardship.Microwave reduction roasting can selectively and preferentially heat iron oxides such as magnetite and olivine,forming multiple localized high-temperature reduction micro zones inside and outside different layers of the copper smelting-slag'particles,achieving rapid reduction and energy saving and consumption reduction.This study is anticipated to present a promising and efficient solution for recovering iron and separating lead and zinc from copper slag tailings,fostering sustainable resources utilization and advancing environmental management efforts.关键词
铜渣尾矿/球团/微波还原焙烧/金属铁/还原机理Key words
copper smelting-slag tailing/pellets/microwave reduction roasting/reduced iron/reduction mechanism分类
矿业与冶金引用本文复制引用
罗立群,田国庆,张倩倩..铜渣尾矿微波还原提铁过程行为与分离特性研究[J].中南大学学报（自然科学版）,2025,56(7):2635-2646,12.基金项目
地球深部探测与矿产资源勘查国家科技重大专项(2024ZD1004005) （2024ZD1004005）
国家自然科学基金资助项目(51874219)(Project(2024ZD1004005)supported by the National Major Science and Technology Project for Deep Earth Exploration and Mineral Rescurces Survey （51874219）
Project(51874219)supported by the National Natural Science Foundation of China) （51874219）
