Dissolution behavior of overhaul slag from aluminum reduction cell in a cryolite-based molten salt system

The harmless and reclamation disposal of overhaul slag, which is a hazardous waste from aluminum electrolysis, is a great challenge. Herein, a synergistic disposal strategy, i.e., adopting the overhaul slag as a raw material together with aluminum oxide in the aluminum electrolysis process to produc...

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Main Authors: Jianping Yang, Xiangying Lu, Fanyue Meng, Hailong Li
Format: Article
Language:English
Published: Elsevier 2023-08-01
Series:Energy Reports
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S2352484723003979
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author Jianping Yang
Xiangying Lu
Fanyue Meng
Hailong Li
author_facet Jianping Yang
Xiangying Lu
Fanyue Meng
Hailong Li
author_sort Jianping Yang
collection DOAJ
description The harmless and reclamation disposal of overhaul slag, which is a hazardous waste from aluminum electrolysis, is a great challenge. Herein, a synergistic disposal strategy, i.e., adopting the overhaul slag as a raw material together with aluminum oxide in the aluminum electrolysis process to produce Al–Si alloy, was proposed. The dissolution behavior of overhaul slag in a cryolite-based molten salt system was investigated by thermodynamic calculation and dissolution experiments. The liquidus temperature of molten salt was decreased with the addition of SiO2 and Al2O3. This suggests that the synergistic disposal of overhaul slag did not cause an adverse effect on the aluminum electrolysis process. The possible dissolution products were Na3AlF6, Na5Al3F14, SiO2, NaAlSiO4, NaAlSi3O8, Na2SiO3, Na2SiF6, Na2 MgAlF7 and SiF4. The addition of Al2O3 could enhance the solubility and dissolution rate of SiO2 and hence shorten the dissolution time. The dissolution process of overhaul slag satisfied well with the mass transfer model, suggesting that the dissolution rate was controlled by the diffusion process. This work provides a basis for the synergistic disposal of overhaul slag in the aluminum electrolysis process.
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spelling doaj.art-5564490aaa8e40589feac133453f71bc2023-08-20T04:38:09ZengElsevierEnergy Reports2352-48472023-08-019118127Dissolution behavior of overhaul slag from aluminum reduction cell in a cryolite-based molten salt systemJianping Yang0Xiangying Lu1Fanyue Meng2Hailong Li3School of Energy Science and Engineering, Central South University, Changsha, 410083, ChinaSchool of Energy Science and Engineering, Central South University, Changsha, 410083, ChinaSchool of Energy Science and Engineering, Central South University, Changsha, 410083, ChinaCorresponding author.; School of Energy Science and Engineering, Central South University, Changsha, 410083, ChinaThe harmless and reclamation disposal of overhaul slag, which is a hazardous waste from aluminum electrolysis, is a great challenge. Herein, a synergistic disposal strategy, i.e., adopting the overhaul slag as a raw material together with aluminum oxide in the aluminum electrolysis process to produce Al–Si alloy, was proposed. The dissolution behavior of overhaul slag in a cryolite-based molten salt system was investigated by thermodynamic calculation and dissolution experiments. The liquidus temperature of molten salt was decreased with the addition of SiO2 and Al2O3. This suggests that the synergistic disposal of overhaul slag did not cause an adverse effect on the aluminum electrolysis process. The possible dissolution products were Na3AlF6, Na5Al3F14, SiO2, NaAlSiO4, NaAlSi3O8, Na2SiO3, Na2SiF6, Na2 MgAlF7 and SiF4. The addition of Al2O3 could enhance the solubility and dissolution rate of SiO2 and hence shorten the dissolution time. The dissolution process of overhaul slag satisfied well with the mass transfer model, suggesting that the dissolution rate was controlled by the diffusion process. This work provides a basis for the synergistic disposal of overhaul slag in the aluminum electrolysis process.http://www.sciencedirect.com/science/article/pii/S2352484723003979Overhaul slagAluminum electrolysisDissolutionDiffusion
spellingShingle Jianping Yang
Xiangying Lu
Fanyue Meng
Hailong Li
Dissolution behavior of overhaul slag from aluminum reduction cell in a cryolite-based molten salt system
Energy Reports
Overhaul slag
Aluminum electrolysis
Dissolution
Diffusion
title Dissolution behavior of overhaul slag from aluminum reduction cell in a cryolite-based molten salt system
title_full Dissolution behavior of overhaul slag from aluminum reduction cell in a cryolite-based molten salt system
title_fullStr Dissolution behavior of overhaul slag from aluminum reduction cell in a cryolite-based molten salt system
title_full_unstemmed Dissolution behavior of overhaul slag from aluminum reduction cell in a cryolite-based molten salt system
title_short Dissolution behavior of overhaul slag from aluminum reduction cell in a cryolite-based molten salt system
title_sort dissolution behavior of overhaul slag from aluminum reduction cell in a cryolite based molten salt system
topic Overhaul slag
Aluminum electrolysis
Dissolution
Diffusion
url http://www.sciencedirect.com/science/article/pii/S2352484723003979
work_keys_str_mv AT jianpingyang dissolutionbehaviorofoverhaulslagfromaluminumreductioncellinacryolitebasedmoltensaltsystem
AT xiangyinglu dissolutionbehaviorofoverhaulslagfromaluminumreductioncellinacryolitebasedmoltensaltsystem
AT fanyuemeng dissolutionbehaviorofoverhaulslagfromaluminumreductioncellinacryolitebasedmoltensaltsystem
AT hailongli dissolutionbehaviorofoverhaulslagfromaluminumreductioncellinacryolitebasedmoltensaltsystem