摘要
预计2030年我国的废铝供应量将达到4400万t,但再生铝的成分复杂、杂质含量波动大,限制了再生铝回收利用。本文构建了再生铝熔体中金属杂质硫化去除的热力学模型,分析再生铝熔体中金属杂质硫化去除趋势,探索硫化除杂的可行性,并开展再生铝熔体中金属杂质硫化去除的实验研究。研究表明,通过渣金分配比L可将再生铝熔体中35种杂质元素分为易去除、难去除、不可去除三类;硫化剂对易去除类型的杂质Ca、Na、Mg有较好的去除效果,去除率分别可达到59.5%、66.6%、51.3%,对于难去除和不可去除杂质并无影响,这些杂质的含量在原材料的初始水平附近波动,这也验证了热力学计算的结果。
China has considerable reserves of waste aluminum,and numerous aluminum products have reached their end-of-life cycle.According to industry forecast data,China's waste aluminum supply will reach 44 million tons by 2030,while the proportion of recycled aluminum in primary aluminum production in China is only about 20%.Compared with primary aluminum production,the energy consumption of recycled aluminum production is merely around 5%of that of primary aluminum.The recycling of waste aluminum is conducive to reducing carbon emissions,thus endowing the recycling and utilization of recycled aluminum with promising development prospects.Nevertheless,the complex composition and large fluctuations in impurity content in recycled aluminum have become the main technical bottleneck restricting the circular utilization of recycled aluminum resources.Therefore,how to efficiently adjust the composition of recycled aluminum and control the content of harmful impurity elements has become a key issue in recycled aluminum recycling.In this study,recycled aluminum ingots were used as raw materials to analyze the types of metallic impurity elements in the aluminum melt.Based on thermodynamic calculations,the chemical reaction pathways for the sulfidation removal of impurities were determined,the activity coefficients of metallic impurities in the aluminum melt were calculated,and a thermodynamic model for the slag-metal distribution ratio of sulfidation removal was established.Through thermodynamic calculations,the slag-metal distribution ratios of metallic impurities in the aluminum melt of recycled aluminum were confirmed.Meanwhile,with recycled aluminum as the raw material and pure FeS as the sulfidizing agent,experimental research on the sulfidation removal of metallic impurities in the recycled aluminum melt was carried out.The thermodynamic study on sulfidation removal showed that the reaction equations for the sulfidation removal of metallic impurities in the recycled aluminum melt were derived.A database of activity coefficients of different metallic impurities in the aluminum melt was established by consulting relevant literature,and then the activity coefficients of metallic impurities in the aluminum melt under different temperature conditions were calculated.Consequently,the slagmetal distribution ratios of sulfidation removal under different temperature conditions were obtained,and the distribution of 35 metallic impurity elements in the recycled aluminum melt was clarified.According to the slag-metal distribution ratio L,the metallic impurities in the recycled aluminum melt can be classified into three categories:easily removable,nonremovable,and hardly removable.Among them,13 impurity elements in the recycled aluminum melt,including La,Ce,Li,Ca,Na,and Mg,are categorized as easily removable;20 elements such as Ti,Fe,Si,Cr,and Cu are non-removable;and Mn and Zn are hardly removable.The thermodynamic experiments on sulfidation removal indicated that FeS exhibited good removal effects on the easily removable impurities Ca,Na,and Mg,with removal rates reaching 59.5%,66.6%,and 51.3%respectively.It had no impact on the hardly removable and non-removable impurities,whose contents fluctuated around the initial levels of the raw materials.This fully verified the accuracy of the thermodynamic calculation model,providing a theoretical basis for the precise regulation of impurities in the recycled aluminum melt.Addressing the problems of abundant waste aluminum resources but a low proportion of recycled aluminum in primary production and impurity-restricted circular utilization in China,this study adopted recycled aluminum ingots as raw materials and combined thermodynamic theoretical calculations with experimental verification to confirm the accuracy of the model.This research provides important theoretical support for the precise regulation of impurities in the recycled aluminum melt and holds significant significance for promoting the high-quality recycling of recycled aluminum and reducing carbon emissions in the non-ferrous metal industry.
作者
杨森
王文豪
金会心
赵建军
YANG Sen;WANG Wenhao;JIN Huixin;ZHAO Jianjun(School of Materials and Metallurgy,Guizhou University,Guiyang 550000,China;Laboratory of Intelligent Optimized Manufacturing in Mining&Metallurgy Process/Beijing Key Laboratory of Process Automation in Mining&Metallurgy,Beijing 102628,China)
基金
贵州省科技厅-贵州大学联合基金(黔科合成果-LH[2024]重大018号)
矿冶过程智能优化制造全国重点实验室开放课题(BGRIMMKZSKL-2023-8)
贵州省科技厅科技支撑计划(黔科合支撑[2024]一般123号)
贵州省教育厅揭榜挂帅项目(黔教技[2024]001号)。
关键词
再生铝
热力学
硫化除杂
渣金分配比
recycled aluminum
thermodynamics
sulfide impurity removal
slag-metal distribution ratio
