| MATERIALS AND SUSTAINABLE DEVELOPMENT: MATERIALS REMANUFACTURING AND WASTE RECYCLING |
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| Thermal Decoating and Composition Controlled of Aerospace Aluminum Alloys |
| QIAN Guoyu1, WANG Zhi1, SUN Zhi1, LIU Chunwei1, YAN Pengcheng2
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1 Key Laboratory of Green Process and Engineering, National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China
2 Boeing (China) Co. Ltd, Beijing 100027, China |
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Abstract The refractory inorganic salt coating and high zinc content in the mixed waste were the main cause of the retired aircraft of green and efficient recycling difficult. The characteristics of the coating containing inorganic salts and the thermal decomposition mechanism were studied by means of thermogrity, roasting and washing. The volatilization and removal of Zinc (Zn) from aluminum alloy melts under vacuum-electromagne-tic field were investigated by means of calculation and the coupling strengthening of vacuum-electromagnetic. A new method for recovering waste aviation aluminum materials by roasting-washing and vacuum-electromagnetic strengthening was proposed. The study of characteristics and decomposition of coating showed that the thermal decomposition of coating with BaCrO4 and SrCrO4 and other inorganic salt underwent the process of macromolecule organic matter-scorch matter-inorganic film. The inorganic film was closely attached to the cracked aluminum alloy surface, which makes it difficult to remove by washing with clean water. The deep removal of inorganic salt coating was realized by 15% dilute nitrate damage to the cracked surface and erosion to the inorganic salt, and the average content of inorganic components such as Cr, Ba and Sr on the surface of aluminum alloy decreased to less than 0.1%. The study of the vacuum-electromagnetic removing Zn showed that beneficial element magnesium (Mg) can be removed simultaneously during Zn removal. The removal of Zn and Mg was enhanced with the increase of temperature (750—900 ℃), and the degree of Zn volatilization was greater than Mg. When kept at 900 ℃ for 60 min, the content of Zn and Mg decreased to about 0.03% and 0.05% respectively. Further comparative study of 50 Hz and 200 Hz showed that the higher frequency of 200 Hz and higher power (10 kW) were more conducive to the rapid depth removal of Zn, and the removal rate of Zn increased to 0.28%/min within 10 min (0.28%/min at 50 Hz). Taking the mixed waste with the weight ratio of 2024 and 7075 used aviation aluminum as 1∶1 as the object, the new method of roasting-wash, vacuum-electromagnetic strengthening was adopted to prepare the aluminum alloy satisfying the composition requirements of 2024 aluminum alloy.
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Published: 19 January 2021
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| Fund:This work was financially supported by Beijing Natural Science Foundation (2192055). |
About author:: Guoyu Qian received his Ph.D. degree in metallurgical engineering from the University of Science and Techno-logy Beijing (USTB) in Sep. 2010—Jan. 2016. He entered the postdoctoral workstation of the Institute of Process Engineering, Chinese Academy of Sciences (IPE, CAS) upon graduation, and is currently asso-ciate professor of the IPE, CAS. He has presided over a sub-project of National key R & D projects, sub-project of Key projects of NSFC, and completed a Youth Fund Project of NSFC and a Special support project of China Postdoctoral Science Foundation. A number of corporate commissions have been presided. He mainly focuses on the basic research-key technology-industrial application of high value utilization of solid waste energy metals in new energy industry. The main progress and achievements include the study on the structural-activity relationship of new solid waste slag refining, the new method of electroslag remelting and solidification segregation coupling to strengthen impurity remo-val, and the large-scale application of secondary metal resource controlled oxygen smelting refining technology. He has been awarded the first prize of China Nonferrous Metal Industry science and Technology (Fourth place, 2019), and has published more than 20 papers in the core journals of chemical metallurgy such as MMTB, ISIJ. Int, J. Alloy. Compd, Silicon, etc., including 10 SCI papers, and has applied for three invention patents.
Zhi Wang is currently a professor, doctoral supervisor and deputy director of the Green Process Engineering Research Department of Resources and Environment of the Institute of Process Engineering, Chinese Academy of Sciences (IPE, CAS). He is the winner of the National Natural Science Outstanding Youth Foundation (2014) and the project leader of the National key R & D projects. He has won the first prize of China non-ferrous metal industry science and technology award (2019), China industry-university-research cooperation innovation award (2016), Beijing science and technology nova (2008), and China non-ferrous metal metallurgy science and technology paper first prize (2015, 2017), etc. He is member of expert Committee of China Nonferrous Metals Society, Member of Expert Committee of China Silicate Society, member of Beijing Institute of Energy and Environment, member of American TMS Society, member of Japan ISIJ, and so on.
He has carried out in-depth separation, qualitative utilization and pro-duct high-value research on the cycle process of non-ferrous metals strategic resources, and built an integrated green technology system of “multi-scale phase design-interface transfer enhancement-product structure effect regulation-short-range clean process”. He has presided over more than 20 national key research projects, national science and technology support program, National Natural Science Foundation of China, Beijing Natural Science Foundation and enterprise cooperation projects. He published more than 140 SCI papers in core journals of chemical metallurgy such as MMTB, Hydrometallurgy, Crystal Growth & Design, Advanced Energy Materials, etc., and more than 60 authorized invention patents. He has trained more than 30 master and doctoral students, 3 postdocs and 2 visiting scholars of “Western Light”. |
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2021, Vol. 35 
