Metals
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2025
·Vol. 15
·期 5
·468
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IF 2.5
Shuo Tian,Jing Song,Hongqian Sun,Congcong Zhao,Zhiyu Zhang,Mingming Han,Tao Qi
Zirconium (Zr) and hafnium (Hf) are very important in nuclear and high-temperature applications, but their similar physical and chemical properties bring great challenges to separation. The current extraction methods have defects, such as low efficiency at high metal concentration. In this article, a zirconium (Zr)/hafnium (Hf) solvent extractive separation from sulfuric acid solutions using trioctylamine (TOA) as the extractant was researched at room temperature. The aqueous solution is prepared using zirconium sulfate (containing Hf), and the concentration of metal ions (Zr4+and Hf4+) was about 1.096 mol·L−1. The effects of the aqueous acidity, the concentration of TOA, the contacting time, and the organic to aqueous O/A ratio on the separation of Zr and Hf were investigated. It is observed that the Zr can be extracted in the organic phase selectively, and the optimal conditions were: TOA concentration of 40 vol%, organic to aqueous O/A ratio of 3, contacting time of 5 min. Under these conditions, the single-stage extraction rate of Zr is 61.23%, while the Hf is almost not extracted. The mechanism of Zr extraction by TOA was studied through the saturation capacity and slope methods. Based on the results, it is believed that the structure of the extracted complex may be [R3NH]2[Zr(SO4)3]. This study provides a new approach for the development of industrialized Zr-Hf separation.
研究领域:
化学工程
·
核工业
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DOI
高影响因子
JOURNAL OF NANOPARTICLE RESEARCH
·
2014
·Vol. 16
·期 8
·1-12
·
IF 2.278
Yang Ping,Chen Hsueh Shin,Zhang Qiang,Shi Ruixia,Wang Junpeng,Che Quande
To investigate the shell deposited kinetics, CdSe quantum dots (QDs) and nanorods (NRs) with a maximum length of 17 nm were fabricated via organic synthesis routes. CdSe with a hexagonal crystal structure (wurtzite) favors epitaxial growth on the {002} surfaces when well-controlled conditions were used. The morphologies and sizes of CdSe samples depended strongly on chemicals and temperature. In the case of 320 °C, CdSe NRs with adjusted length of 7–17 nm were obtained from trioctylphosphine oxide (TOPO) and tetradecylphosphonic acid (TDPA). In contrast, short CdSe NRs (less than 10 nm) were created from octadecylphosphonic acid (ODPA) and trioctylamine (TOA). Spherical CdSe QDs were further fabricated using stearic acid (SA) and TOPO at 300 °C. CdSe cores were coated with Cd 0.5 Zn 0.5 S and CdTe shells. Anisotropic growth occurred during shell deposition because CdS shells grown preferentially on the {001} facet of the CdSe core. In the case of CdSe core prepared from TOPO and TDPA, CdSe/Cd 0.5 Zn 0.5 S core/shell samples prepared from long CdSe NRs (more than 10 nm) revealed a peanut morphology while the core/shell samples created from short ones (less than 10 nm) exhibited a spherical morphology. All of the CdSe/Cd 0.5 Zn 0.5 S core/shell samples revealed a similar length to that of the CdSe cores. This phenomenon was also observed for the core/shell samples fabricated using CdSe NRs prepared by ODPA and TOA. This is ascribed to the well-developed crystal structure of CdSe NRs fabricated using an organic synthesis at high temperature. In contrast, this anisotropic growth did not occur when spherical CdSe QDs prepared from SA and TOPO and the shell (Cd 0.5 Zn 0.5 S) coating carried out using SA and TOA. To indicate the shell depositing process, CdSe NRs fabricated using TDPA and TOPO were coated with a CdTe shell. CdTe monomers were deposited on the middle and tip parts of the CdSe NRs to form a tetrapod-like morphology at 220 °C. This is ascribed to the large difference of structure of CdSe (hexagonal) and CdTe (zinc blende).
研究领域:
材料科学
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纳米技术
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化学合成
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DOI
高影响因子
MINERALS ENGINEERING
·
2025
·
IF 5
Yubo Ge,Hualing Zhao,Guiqing Zhang,Qinggang Li,Shengxi Wu,Zhiyong Gao
In previous work, we developed an H 2 SO 4 -Fe 2 (SO 4 ) 3 roasting and water leaching method to leach rare earth elements (REEs), niobium (Nb), and titanium (Ti) from a low-grade concentrate mixture of the Baerzhe ore deposit in China ( Ge et al., 2024 ). However, conventional chemical precipitation and fluorine-ligand extraction methods for separating REEs/Nb/Ti in the leach solution face challenges, including co-precipitation of REEs and Nb/Ti, low recovery efficiency, and significant environmental concerns. To address these issues, a novel two-step solvent extraction process for efficient separation and recovery of Nb and Ti from leach solution was proposed in this work. The quaternary ammonium salt extractant (N263-CO 3 2- ) was employed to selectively co-extract Nb and Ti from the leach solution for achieving effective separation them from REEs. The resultant Nb(OH) 5 /Ti(OH) 4 precipitates were dissolved in H 2 C 2 O 4 -H 2 SO 4 mixture for selective extraction of [NbO(C 2 O 4 ) 2 - ] using tri-n-octylamine (TOA). The extraction mechanism confirmed that N263 preferentially extracts Nb/Ti via anion exchange, with the primary contribution from N263-CO 3 2- to Nb/Ti extraction, followed by N263-SO 4 2- , while protonated TOA selectively extracts [NbO(C 2 O 4 ) 2 - ] through anion–cation association. Ultimately, the recovery efficiencies of Nb and Ti reached 96.0 % and 69.0 %, respectively, producing Nb 2 O 5 (99.6 %) and TiO 2 (99.2 %), with REEs losses < 0.5 %. This study offers a novel approach for the efficient selective separation and recovery of Nb/Ti from leach solution.
研究领域:
冶金学
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材料科学
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化学工程
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环境科学
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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
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湿法冶金
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绿色化学
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资源回收
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分离科学
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DOI
高影响因子
JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY
·
2019
·Vol. 93
·期 2
·391-401
·
IF 1.986
Yi Huilin,Wan Yanchun,Zhang Yang,Wang Yujun,Fei Weiyang,Luo Guangsheng
This study describes a novel and facile route for fabricating highly uniform γ-alumina microspheres with controllable size, morphology, and pore structure by integrating the sol–gel route for alkoxide with “temperature/pH-induced gelation” in a coaxial microchannel. Taking advantage of the controllability of the microfluidic devices and Al–O–Al chains formed by the sol–gel route of aluminum alkoxide, the uniformity of the microspheres was assured, and the mechanical strength of the microspheres was greatly improved to 18–27 N/mm 2 . The effects of the continuous phase composition and two-phase flow rate on the size, morphology, and pore structure of the obtained microspheres were investigated. When triocylamine (TOA) was added to the continuous phase and the two-phase flow rate ratio was larger than 188, the as-prepared microspheres had a smooth surface and good sphericity; otherwise, the microspheres had poor spheriticy and included many ravines on the surface, which can be explained by the mutual influence of long-lasting movements of molecular chains resulted from low gelation speed and inner circulation of the droplets. Under different continuous phase compositions, the average pore diameter, pore volume, and specific surface area ranged from 7 to 12 nm, 0.89 to 1.58 mL/g, and 293.7 to 387.7 m 2 /g, respectively.
研究领域:
材料科学
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化学工程
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微流控技术
✓ 已验证
产品关联
DOI
高影响因子
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