PROCESS SAFETY AND ENVIRONMENTAL PROTECTION
·
2024
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IF 6.9
Buju Guo,Yaowu Wang,Yuyao Huang,Jianping Peng,Yuezhong Di,Chang Wang,Ke Wang
The amount of scrap aluminum has increased continuously in recent years such that the widely adopted method of remelting no longer meets the demands of high-quality recycled secondary aluminum. Molten salt electrolysis is a method of upcycling scrap aluminum to pure aluminum. In this study, pure aluminum was recovered from scrap aluminum through the electrolysis of a 56 mol%LiCl-36 mol%KCl-8 mol%NaCl molten salt system. The electrochemical dissolution behavior of scrap aluminum was studied adopting an anodic polarization curve. The results show that Al dissolved preferentially compared with Si and Fe in scrap aluminum. The effects of electrolysis parameters, such as the AlCl 3 concentration, electrolysis temperature, and current density, on the current efficiency and cathode products were studied along with the process of purifying scrap aluminum. The results show that the adoption of a suitable current density, electrolysis temperature and AlCl 3 concentration increases the current efficiency and improves the morphology of the cathode products. Pure aluminum of industrial grade with purity of 99.8 % can be obtained on the cathode at an electrolysis temperature of 550 °C, AlCl 3 concentration of 10 mol%, electrolysis time of 3 h, and current density controlled below 0.15 A/cm 2 .
研究领域:
材料科学
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环境工程
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2025
·
IF 13.2
Jiaxin Yang,Wenju Tao,Jiaming Li,Jingui He,Zhaowen Wang
Low-cost and efficient recycling methods are crucial for recovering strategic elements from lithium-containing waste electrolytes (LiWE), which are essential for energy storage and environmental protection. This study aims to develop a method for recovering lithium from LiWE through one-step calcination of CaCl 2 . Compared with the traditional high-temperature acidification roasting process, this low-temperature calcification only involves one-step roasting and low-temperature pure water leaching, which avoids the introduction of hazardous reagents such as acid/alkali. The thermodynamic analysis results indicate that the transition temperature of LiF during the calcification roasting process is higher than that of Na 3 AlF 6 . 550 ℃, 2.5 (Ca/Li ratio) and 1.0 h have been proven to be the most suitable roasting conditions. Meanwhile, 75 ℃, 7 mL/g (L/S) and 1.0 h are expected to be the most preferred leaching processes. The recovery rate of lithium exceeds 98 % and maintains a high purity (>99.0 %) of Li 2 CO 3 . The economic benefits of this process have been comprehensively evaluated, with a profit of 2.65 $/kg. Finally, the regenerated LCO prepared from recycled Li 2 CO 3 has been proven to have good electrochemical performance compared to commercial LCO with a capacity exceeding 151 mAh g-1 at 1C, demonstrating the feasibility of energy storage applications. In summary, the low-temperature calcification roasting method has been proven feasible for extracting lithium from LiWE.
研究领域:
材料科学
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环境科学
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能源科学
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产品关联
DOI
高影响因子
Journal of Sustainable Metallurgy
·
2023
·Vol. 9
·期 3
·1201-1214
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IF 2.4
Tao Wenju,Yang Jiaxin,Chen Liyu,Zhang Yifan,Wu Shaohua,Li Jiaming,Liu Zhaoshun,He Jingui,Wang Zhaowen
The high-value, green and harmless purification of aluminum electrolysis comprehensive solid waste can not only reduce its harm to the environment and soil but also separate and recover the high-value rare elements. This study aims to develop a process for recovering and treating waste aluminum electrolytes by sulfuric acid roasting. The results of orthogonal experiments and single factor experiments indicate that under the premise of not decomposing sulfuric acid to produce secondary hazardous waste, the high-value element F in WAE can be effectively separated under the condition of calcination at 275 °C for 4 h and an acid to material ratio of 7, with a recovery rate of 87.31%. According to the mechanism obtained from the analysis and characterization results of SEM, XRD, and chemical analysis on the residual water leaching residue after roasting, the process of sulfuric acid roasting WAE is a multi-step separation process of fluorine: from Na 3 AlF 6 and Na 5 Al 3 F 14 to AlF 3 and Al 2 (SO 4 ) 3 . Each phase transformation process is accompanied by the precipitation of fluorine in the form of HF. Graphical Abstract
研究领域:
化学工程
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环境科学
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产品关联
DOI
高影响因子
Journal of Cleaner Production
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2025
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IF 10
Buju Guo,Yaowu Wang,Ruoyu Li,Yifei Li,Boxiong Zhang,Jianping Peng,Yuezhong Di,Ke Wang,Chang Wang
Scrap aluminum (Al) alloy recycling is critical for energy conservation and decreasing carbon emissions. Conventional remelting process does not remove alloying elements, severely limiting the value and applications of recycled Al. To overcome this limitation, this study develops an efficient process for recovering pure Al from scrap Al alloys via soluble anode electrolysis in a designed MgCl 2 -KCl-NaCl (MKN) molten salt system. Real-time monitoring of the electrolysis process, time-dependent characterization of cathodic deposits, and electrochemical analyses reveal a three-stage cathodic deposition mechanism in the MKN molten salt system: initial underpotential deposition of Mg 2+ transitions to co-deposition of Mg 2+ and Al 3+ , and ultimately to exclusive reduction of Al 3+ , which is driven by progressive Al 3+ accumulation. The introduction of AlCl 3 proves pivotal, simultaneously enhancing Al 3+ deposition efficiency while effectively suppressing Mg 2+ co-reduction. Systematic optimization identifies 12.5 wt% AlCl 3 addition, 500 °C, and 0.15 A/cm 2 as the ideal operational parameters, achieving recycled Al with 99.84 wt% purity. The soluble anode electrolysis process in the MKN molten salt system represents an efficient and scalable alternative to conventional remelting. The developed process is capable of producing recycled Al with purity comparable to that of primary Al while addressing critical sustainability challenges in the Al industry.
研究领域:
材料科学
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冶金学
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电化学
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可持续技术
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回收工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）