SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Wenju Tao,Jiaxin Yang,Liyu Chen,Yifan Zhang,Shaohua Wu,Jiaming Li,Zhaoshun Liu,Jingui He,Zhaowen Wang
Green and efficient recovery of solid waste from aluminum electrolysis is of great significance. In this study, the sediment generated by aluminum electrolysis at the bottom of the waste tank was used as an alternative F resource. A new process of low-temperature acidification roasting with Al 2 O 3 as the catalyst was performed to effectively recover F. The results of the single-factor experiment showed that a long reaction time and high acid-material ratio were conducive to improving the extraction rate of F. Under the conditions of 275 °C and 5 doses of sulfuric acid, the optimum F extraction rate was realized by roasting for 4 h with 1 dose of Al 2 O 3 as the catalyst. The results of the XRD, SEM and chemical analyses showed that NaAl(SO 4 ) 2 was the main component produced in the calcination reaction using Al 2 O 3 as the catalyst, rather than NaHSO 4 (produced in the calcination process without a catalyst). This ensured complete combination of H and F, which greatly improved the extraction rate of F (from 80.76 to 99.76%). The proposed mechanism can provide not only an optimization scheme for the roasting of waste sediment at the furnace bottom, but also a more effective recovery treatment for the acidification roasting of other solid wastes with low Al 2 O 3 content.
研究领域:
环境科学
·
冶金工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of Sustainable Metallurgy
·
2023
·Vol. 9
·期 3
·1201-1214
·
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
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Jiaxin Yang,Wenju Tao,Jiaming Li,Lingyu Kong,Shaohua Wu,Jingui He,Zhaoshun Liu,Yu Sun,Zhaowen Wang
Low energy consumption and environmentally friendly recycling methods can extract high-added value and high-demand elements from retired waste fluorinated aluminum electrolytes (RWE-Al), which is crucial for alleviating resource shortages and environmental hazards. This study aims to develop a method for recovering fluorine and aluminum from RWE-Al through calcium leaching transformation combined with acid leaching. Compared to the traditional high-temperature roasting transformation and high-concentration alkali-metal-salt leaching process, this new process only involves one step of low-temperature leaching, purification of fluorine, carbonization of excess calcium, and evaporation extraction of aluminum, avoiding the generation of high energy consumption and secondary hazardous waste (F-containing liquid/ residue). Fluorine and aluminum are effectively separated and purified with extraction rates exceeding 96%. The effects of leaching temperature, CaO addition coefficient, liquid–solid ratio, and leaching time on the leaching process were systematically studied. The effects of acid concentration, liquid–solid ratio, time, and temperature on the acid-leaching process were also investigated. In summary, the comprehensive utilization of RWE-Al by this new process has proved to be feasible.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Cleaner Production
·
2024
·
IF 9.7
Hongqiang Li,Chenglong Liu,Zhaokai Peng,Qian Chen,Richard M. Kasomo,Yanfeng Jin,Xiaoqing Weng,Nelima M. Ondiaka,Yingxin Chen,Shaoxian Song
Recovering fluorine from wet-process phosphoric acid (WPA) by the evaporation concentration method has been widely used due to its simplicity and cheapness. However, the low fluorine recovery reduces the WPA quality, which in turn has detrimental effects on fertilizer production and leads to a waste of valuable fluorine resources. In this work, a cost-effective organic liquid, methyltrichlorosilane (MTS), was first employed as the gasification reagent in the WPA concentration process to promote fluorine recovery. The effects of several important parameters including MTS dosage, initial mass of absorptive water, addition stages, stirring speed, and concentration temperature, were investigated. The first three factors emerged as pivotal determinants of the fluorine recovery and the results revealed a remarkable 87.94% recovery of fluorine from WPA, signifying a substantial enhancement compared to the recovery achieved in the absence of MTS, which amounted to 40.36%. The defluorination kinetics data was well-fitted with a second-order model, and showed an activation energy of 23.77 kJ/mol, highlighting the strong interaction between MTS and fluorine in WPA. In addition, liquid MTS could recover fluorine selectively and efficiently without compromising the quality of WPA and exhibited superior fluorine recovery when compared to traditional solid mineral reagents such as diatomite and white carbon black. Further analysis revealed the governing mechanism for fluorine recovery that the addition of MTS prevented the conversion of liquid HF and H 2 SiF 6 to solid Na 2 SiF 6 and K 2 SiF 6 , favoring SiF 4 gas production. Overall, this research provides valuable insights for enhancing fluorine recovery during the WPA concentration process and developing environmentally friendly reagents.
研究领域:
化学工程
·
环境科学
✓ 已验证
DOI
高影响因子
ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH
·
2024
·Vol. 31
·期 18
·27388-27402
·
IF 0
Lan Jinghao,Yan Hengwei,Liu Zhanwei,Ma Wenhui
In aluminum electrolysis, the iron-rich cover material is formed on the cover material and the steel rod connecting the carbon anode. Due to the high iron content in the iron-rich cover material, it differs from traditional cover material and thus requires harmless recycling and treatment. A process was proposed and used in this study to recovery F, Al, and Fe elements from the iron-rich cover material. This process involved aluminum sulfate solution leaching for fluorine recovery and alkali-acid synergistic leaching for α-Al 2 O 3 and Fe 2 O 3 recovery were obtained. The optimal leaching rates for F, Na, Ca, Fe, and Si were 93.92, 96.25, 94.53, 4.48, and 28.87%, respectively. The leaching solution and leaching residue were obtained. The leaching solution was neutralized to obtain the aluminum hydroxide fluoride hydrate (AHFH, AlF 1.5 (OH) 1.5 ·(H 2 O) 0.375 ). AHFH was calcined to form a mixture of AlF 3 and Al 2 O 3 with a purity of 96.14%. The overall recovery rate of F in the entire process was 92.36%. Additionally, the leaching residue was sequentially leached with alkali and acid to obtain the acid leach residue α-Al 2 O 3 . The pH of the acid-leached solution was adjusted to produce a black-brown precipitate, which was converted to Fe 2 O 3 under a high-temperature calcination, and the recovery rate of Fe in the whole process was 94.54%. Therefore, this study provides a new method for recovering F, Al, and Fe in iron-rich cover material, enabling the utilization of aluminum hazardous waste sources.
研究领域:
冶金工程
·
环境科学与工程
✓ 已验证
产品关联
DOI
PubMed
SEPARATION AND PURIFICATION TECHNOLOGY
·
2023
·
IF 8.6
Binbin He,Yuanzhi Zhu,Yun Zu,Yunxiang Nie,Yi Mei
Fluorine (F) is a high-value resource that has been overlooked in the production of wet process phosphoric acid (WPA) due to its high susceptibility to complexation with metal cationic impurities, hindering F efficient recovery and subsequent phosphoric acid purification. This paper firstly emphasizes on investigating the competitive complexation behavior between F species and metal cations (M = Al 3+ , Fe 3+ , Ca 2+ and Mg 2+ ) by designing a series of F-containing model solutions (as HF and/or H 2 SiF 6 ) with fixed combinations of metal cations. The results reveal that the complexation ability between metal cations and “free” F - species from HF dissociation and/or SiF 6 2- hydrolysis follows the order: Al 3+ > Fe 3+ > Ca 2+ > Mg 2+ . DFT calculation further confirms that the acid-soluble AlF 4 - and FeF 3 species with lower binding energies are the main obstacle to difficult recovery of F species in the WPA. Given the above facts, an efficient F recovery strategy is proposed by increasing initial F concentration (as HF and H 2 SiF 6 ) in industrial WPA for preferentially removing metal impurities in the forms of M−F precipitates (e.g., AlF 3 and CaF 2 ), according to the variations in distributions of M−F species under different n(F)/n(M) ratios predicted through establishment of mathematical models. The ultimate F recovery rate is greater than 95% by stripping process when initial HF concentration added is about 7.49 mol/L. This novel strategy has been successfully applied in phosphoric acid purification process.
研究领域:
化学工程
·
环境科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Chemical Engineering
·
2025
·
IF 7.2
Long Yao,Guixuan Shan,Abrar Laiba,Yu Zhao,Yujiao Zhang,Ru’an Chi,Bingwen Long,Wei Li,Jinli Zhang
Fluorine (F) is a valuable by-product in wet-process phosphoric acid (WPA) production, yet its recovery ratio remains below 60 % due to challenges in purification and utilization. Traditional stripping methods release toxic and corrosive fluorine vapors, endangering production safety. Herein, a novel strategy of Fluoride Species Conversion-Enhanced Selective Extraction (FSC-SE) was put forward for the efficient and environmentally friendly recovery of fluorine from wet process phosphoric acid (WPA). By converting HF and H 2 SiF 6 into HBF 4 through the addition of boric acid, the extraction efficiency of fluorine is significantly enhanced, reaching up to 99.8 % using trioctylamine (TOA) as the extractant. Theoretical calculations were carried out to provide a predictive framework for the extraction selectivity of TOA for different acidic species. Key operation parameters, including B:F molar ratio, TOA concentration, extraction time, and temperature, etc, are, optimized to further enhance the process performance. Subsequent water washing and back-extraction steps enabled effective P-F separation and extractant regeneration. Applied to industrial WPA, the single-stage fluorine extraction efficiency can reach 82.4 %, and the total fluorine recovery ratio can reach 80.4 %. FSC-SE provides a safe, efficient, and environmentally friendly method with strong industrial application potential, highlighting the value of the green separation process combining chemical conversion and solvent extraction in the phosphoric acid industry.
研究领域:
化学工程
·
湿法冶金
·
绿色化学
·
资源回收
·
分离科学
✓ 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）