SEPARATION AND PURIFICATION TECHNOLOGY
·
2018
·
IF 3.927
Junlian Wang,Xinyu Liu,Jiashuai Fu,Meiying Xie,Guoyong Huang,Huajun Wang
Scientists have always been seeking more efficient extractants for rare earths extraction and separation, especially for heavy rare earths. In this paper, a novel extractant (2,4-dimethylheptyl)(2,4,4′-trimethylpentyl)phosphinic acid (USTB-2) was synthesized. The structures of the intermediate and USTB-2 were characterized by 31 P NMR, 1 H NMR, FT-IR and ESI-MS. Its p K a was 5.62. Its extraction ability was between Cyanex 272 and P507. Its extraction mechanism was cation exchange. Its extraction capacity was larger than that of Cyanex 272 and lower than that of P507. Its solubility in 3 mol/L HCl and deionized water was 11.2 mg/L and 19.0 mg/L, respectively. The Lu(III) loaded in USTB-2 solution can be easily stripped by HCl, HNO 3 and H 2 SO 4 . It has good separation performance for heavy rare earths. Its average separation factor ( β ¯ ) for adjacent heavy REs from Gd to Lu was 2.18. For some heavy RE couples like Er/Ho, Yb/Tm and Lu/Yb (especially for Lu/Yb), USTB-2 possesses even better separation performance than Cyanex 272. Its extraction efficiency for nonferrous metal ions was in the order Al > Gd > Zn > Nd > La > Co > Cu. The separation factors of Al/Gd, Gd/Zn, Zn/Nd, La/Co by USTB-2 were 2.67, 5.39, 3.35 and 26.67, respectively.
研究领域:
化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF RARE EARTHS
·
2025
·
IF 7.2
Yuhe Ran,Ru’an Chi,Zhenyue Zhang,Yuting Shi,Wendou Chen,Fei Long,Hanjun Wu
Weathered rare earth ores are an important strategic mineral resource in China, and they are the primary source of medium and heavy rare earths (MHRE). The efficient recovery of MHRE is of great significance from an industrial standpoint. In this study, fulvic acid (FA) is employed as a precipitant to investigate the precipitation of rare earth (RE). The results indicate that the precipitation rates ( w ) of RE range from 89.69 wt% to 99.86 wt% with the pH of 9, the molar ratio of 2, and the temperature of 40 °C, except for Lu 3+ , the w reaches 97.33 wt% with the pH of 9, the molar ratio of 3, and the temperature of 25 °C. The w of RE in the ammonium acetate rare earth leaching solution ranges from 95.99 wt% to 98.54 wt%, with the MH/L of the rare earth distribution after precipitation increasing from 0.77 to 0.80. The use of FA as a precipitant is demonstrated to yield effective precipitation of RE, particularly those of MHRE. FA complexes with RE 3+ , where deprotonation of COO – increases the surface electron density of oxygen atoms, creating additional active sites for electron-deficient RE 3+ . The mechanism provides a theoretical basis for using carboxylic acid compounds as new precipitants. Further, a novel technology for FA complexation precipitation of RE from lignite extract is proposed.
研究领域:
化学工程
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矿物加工
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环境科学
✓ 已验证
DOI
高影响因子
Nanoscale Research Letters
·
2015
·Vol. 10
·期 1
·1-6
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IF 2.779
Li Chengyin,Liu Hui,Yang Jun
Nanosized rare earth (RE) hydroxides including La(OH) 3 , Nd(OH) 3 , Pr(OH) 3 , Sm(OH) 3 , Gd(OH) 3 , and Er(OH) 3 with rod-like morphology are fabricated via a convenient hydrothermal approach. This strategy calls for the first preparation of metal complexes between RE precursors and dodecylamine (DDA) in water/ethanol mixture at room temperature and subsequent thermal decomposition at elevated temperature. The influence of reaction time and water/ethanol volume ratios on the morphology and size of as-prepared RE hydroxides are investigated. CeO 2 nanoparticles with spherical shape could be directly obtained by hydrothermal treatment of complexes formed between Ce precursors and DDA. In addition, by further calcinating the RE hydroxides at high temperature in air, RE oxide nanorods could be readily produced.
研究领域:
材料科学
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化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MINERALS ENGINEERING
·
2022
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IF 5.479
Xianping Luo,Xianqiang Yuan,Kunzhong He,Yongbing Zhang,Caigui Luo,Zishuai Liu,Hepeng Zhou
Impurity metal ions in ionic rare earth ores are similar to rare earth ions in terms of occurrences and similarities in properties. During the leaching operation, a large number of impurity ions enter the rare earth leaching solution, which makes the crystal form of the rare earth unstable or forms an amorphous flocculent precipitate. The commonly used ammonium bicarbonate (NH 4 HCO 3 ) precipitation crystallization process has low rare earth precipitation rate, long precipitation crystallization period, and high ammonia nitrogen content in precipitation wastewater. In this paper, the leaching solution obtained by ionic rare earth ore magnesium salt leaching-combined impurity removal process was taken as the research object, and the effects of precipitants, such as NH 4 HCO 3 , calcium oxide, sodium carbonate, and oxalic acid, on the preparation of crystalline rare earth precipitation were investigated through comparison. On the premise of determining the best rare earth precipitant, the effects of dosage, stirring speed, stirring time, and aging time on the preparation of crystalline rare earth precipitate were investigated further. The precipitation effects of different precipitation processes were studied systematically combined with SEM-EDS, laser particle size analysis, and other means to characterize the morphology of crystalline products. Results showed that when calcium oxide was used as a precipitant, the molar ratio was 2.5. After stirring at a constant speed of 200 r/min for 4 h and aging for 4 h, precipitates with good crystal appearance, smooth crystal surface and easy filtration were obtained. This process promoted crystal growth of rare earth precipitates, and the crystal grain size, which was beneficial to the improvement of the quality of rare earth products, increases significantly.
研究领域:
化学工程
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MEMBRANE SCIENCE
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2022
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IF 10.53
Weiguo Pan,Li Chen,Yitan Wang,Yongsheng Yan
How to efficiently utilize the low-concentration rare earth wastewater has become an urgent demand for the sustainable mining and resource utilization of ion-type rare earth minerals in China. Herein, we developed Y ion-imprinted electrospun membranes (Y-IIEMs) for the selectively separation of neighboring heavy rare earth ion Y(III) from Ho(III) and Er(III) by applying high efficient ligand-inducing and aqueous phase ion-imprinting. Cyanex272 was applied as carrier in membrane matrix and also as high-efficient ionic ligand in imprinted layer. Thermal stability of Cyanex272 was greatly improved after pDA bionic adhesion and sol-gel aqueous phase imprinting. Water contact angle of Y-IIEMs was only 23.2° which was probably a combination result from all the polar groups P O and P–OH from Cyanex 272 ligand, the imino groups from pDA layer and the silicon hydroxyls from sol-gel imprinting. And the calculated static adsorption imprinting factor of Y(III) was more than 7 indicating that valid recognition sites were successfully formed. The separation factors β (Y/Ho) and β (Y/Er) in dynamic permeation process increased significantly from 1.24 and 0.85 for non-imprinting to 2.01 and 1.77 for imprinting membranes. After 8 cycles of dynamic permeation, Y-IIEMs’ flux decreased only 13.8%, which implied good stability and reuse performance.
研究领域:
材料科学
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环境科学
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化学工程
✓ 已验证
产品关联
DOI
高影响因子
PLANT AND SOIL
·
2025
·
IF 4.1
Luo Jie,Zhang Qin,Chen Xiulong,Zhou Kai,Zhou Jiahui,Zhao Xiaomin
Background and Aims The heap leaching technique causes considerable damage to environment during the mining of ionic rare earth ore in southern China. Restoration of abandoned mining sites into arable land requires determination of the contents of rare earth elements (REEs) and non-rare earth toxic elements in soil and crops. Methods In the present study, five treatments, including rare earth tailings without any amendment or navel orange cultivation (RET), biochar and fly ash combined with three organic fertilizers (cow manure organic fertilizer [CF], pig manure organic fertilizer [PF], sugarcane bagasse organic fertilizer [SF]), and a treatment without any amendments (CK) were arranged to explore the effects of different treatments on rare earth and non-rare earth toxic elements contents in soil and crops. Results Total EDTA-extractable concentrations of REEs in CF, PF, and SF soils were 42.8%, 26.7%, and 30.5% lower than that those in CK, respectively. Total EDTA-extractable concentrations of non-REEs in the CF, PF, and SF, soils were significantly higher than those in the CK, with the highest in PF, at 337.5%. Compared with CK, all treatments reduced total REEs in navel orange leaves, peel, and pulp. Besides, total rare earth and non-rare earth toxic elements contents in the pulp of the all-treatments navel oranges were all lower than the pollutant limit values for food. Conclusions Use of biochar, fly ash, and SF is the optimal strategy for improving ionic rare earth tailings soil, and navel orange cultivation, is a potential strategy for remediating such abandoned mining sites.
研究领域:
环境科学
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土壤科学
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农业科学
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地球化学
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植物科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2024
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IF 13.3
Lulu Liu,Yuxuan Liu,Jianquan Luo,Yinhua Wan,Weijie Song
Taking advantage of the environmentally-friendly properties of a magnesium salt leaching agent, magnesium oxide (MgO) was used as a precipitant to enrich rare earth (RE) from leaching liquor in the magnesium salt system. This approach not only tackles the issue of ammonia–nitrogen pollution but also enables efficient magnesium recycling. However, due to the high concentration of magnesium ions and the low concentration of RE ions in the leaching solution, the precipitation kinetics of RE concentrates are sluggish, leading to low RE purity in the resulting precipitated product. In this work, we proposed a novel strategy that combines complexation-ultrafiltration (UF) pre-concentration with subsequent MgO precipitation to enhance the hydrolysis of MgO, promoting the precipitation of RE. We further improved the RE enrichment efficiency by optimizing membrane type, complexing agent selection, concentration levels, precipitation temperature, and MgO dosage. Under the conditions of concentrating the leaching solution using optimal UF membrane and employing glyphosate as the complexing agent, the RE ions concentration increased from 101 to 3940 mg/L, and we successfully separated magnesium ions with a separation factor of 36.4. A comparison between direct MgO precipitation and the pre-concentration approach revealed an 80 % reduction in precipitation time and an 80 % decrease in MgO usage with pre-concentration. Furthermore, this combined process led to an 8 % increase in RE recovery and a 2.8-fold enhancement in RE purity, and similar results were obtained when using actual mine leaching solutions. Additionally, the glyphosate present in the UF permeate and the precipitated mother liquor can be efficiently reclaimed through resin adsorption. This proposed process holds significant potential for engineering applications aimed at enriching RE.
研究领域:
环境工程
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化学工程
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材料科学
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矿物加工
✓ 已验证
产品关联
DOI
高影响因子
SEPARATION AND PURIFICATION TECHNOLOGY
·
2024
·
IF 8.1
Yucheng Liu,Qian Xu,Fuping Li,Fan Yu,Zijian Yu,Kaibo Hu,Hao Chen,Xuewei Li,Chonggang Wang,Dong Han Seo,Ming Xie,Sotto Arcadio,Jiuyang Lin,Youming Yang,Yinhua Wan
Rare earth elements (REEs) are commonly categorized into light (LREEs), medium (MREEs), and heavy (HREEs) groups. Separation between LREEs and MREEs or MREEs is relatively straightforward. However, isolating LREEs themselves is particularly challenging because of their similar ionic radii and identical charges. Traditional separation processes are hindered by drawbacks including low recovery rates for dilute REEs, poor selectivity, complex protocols, and environmental pollution. Consequently, developing a cleaner and more efficient method for LREEs separation is imperative. In this study, we employed a single-module hollow fiber supported liquid membrane (HFSLM) system with 2-ethylhexyl phosphoric acid mono-2-ethylhexyl ester (P507) as an extractant to concurrently extract and strip La 3+ and Nd 3+ from the mixed LREEs containing solutions. We also investigated the impact of flow rate, stripping solution acidity, feed solution pH, P507 concentration, Nd 3+ concentration of feed solution, and the volume ratio between the feed and stripping solutions influence the extraction and stripping of LREEs, as well as the molar fractions of La 3+ and Nd 3+ in the solutions. Under optimal condition, the molar fraction of La 3+ was 99.0% in the feed solution, whereas the molar fraction of Nd 3+ reached 91.6% in the stripping solution. Furthermore, the experimental results demonstrated a consistent preference of P507-HFSLM system for extracting Nd 3+ over La 3+ , and the underlying mechanism was thoroughly investigated. In summary, this study offers comprehensive insights and technical approaches for selective separation and purification of LREEs.
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 SCIENCE AND TECHNOLOGY
·
2021
·
IF 2.475
Xuekai Zhang,Kanggen Zhou,Qingyuan Lei,Yan Xing,Changhong Peng,Wei Chen
A new approach was developed using NaH2PO4 as the stripping agent for Fe stripping from Fe-loaded Aliquat 336 during rare-earth elements recovery from red mud leachate. Owing to the strong coordination between Fe3+ and H2PO4‒, Fe mainly exists as FeH2PO42+ at [H2PO4‒] higher than 0.5 M, which can be readily stripped. The results showed a maximum Fe stripping efficiency of 95.5% under optimal condition. Moreover, the extraction capacity of the extractant after stripping was comparable to that of fresh extractant, and decreased only by 2% after 6 cycles, indicating the robustness of this approach for Fe stripping and extractant regeneration.
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
·
2021
·
IF 7.312
Yaxing Han,Ji Chen,Yuefeng Deng,Tianchi Liu,Hailian Li,Deqian Li
The current separation technique of ion-adsorption high yttrium (Y) rare earth ore (high-yttrium ore) using 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (P507) and naphthenic acid (NA) has been confronted with low separation efficiency and high acid consumption. This is a consequence of the low selectivity and the difficulty of complete stripping of heavy rare earths (HREEs). Therefore, an innovative separation technique of high-yttrium ore was proposed. The leachate of high-yttrium ore was firstly divided into Erbium (Er) / Thulium (Tm) groups with P507-isooctanol followed by separating Y (III) from the high Y-enrichment of Er (III) group with sec -octylphenoxy acetic acid (CA12)-tri- n -butyl phosphate (TBP). The basic thermodynamics experiments and cascade extraction simulations were conducted to verify the feasibility of this technology. The results show that P507-15vol% isooctanol is superior to P507 in both stripping ability and separation selectivity of HREEs. The first cascade extraction for Er (III) / Tm (III) grouping with P507-15vol% isooctanol was simulated successfully, reducing acid consumption but obtaining high purity products. In theory, the second cascade extraction simulation designed for separating Y (III) with CA12-TBP could not only improve the separation ability between Y (III) and light rare earths (LREEs) but also shorten the extraction stages and reduce the production costs. All these results revealed that this two-step separation process probably provided a promising application prospect for separating high-yttrium ore.
研究领域:
冶金工程
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稀土化学
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分离科学与技术
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资源加工工程
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湿法冶金
·
萃取分离
✓ 已验证
DOI
高影响因子
MINERALS ENGINEERING
·
2020
·
IF 3.795
Shuainan Ni,Qianwen Chen,Yun Gao,Xiangguang Guo,Xiaoqi Sun
Unlike the classic separation technologies, an extraction-precipitation strategy has been developed for the recovery of rare earth (RE) and from industrial wastewater using a novel phenoxycarboxylic acid of 2-(4-butoxyphenoxy) acetic acid (BPAA). Compared with 4-(4-butoxyphenoxy) butanoic acid (BPBA) and 2-(4-(benzyloxy) phenoxy) acetic acid (BZAA), BPAA enabled minimal reagent/equipment/energy uses in each step of the sustainable process. It was successfully used to enrich REEs with the concentration of 159 mg/L, and the enrichment factor of 189 times was reached. The formed precipitate sizes were bigger than the REEs precipitates from industrial precipitants, i.e., oxalic acid , ammonium hydrogencarbonate, CaO and MgO, which could be settled quickly within 1 min. Compared with COD value of 432 mg/L and 725 mg/L in traditional liquid-liquid extraction using P507 and NA, the COD value of 45 mg/L from BPAA using extraction-precipitation strategy were much lower. It is worthwhile mentioning that BPAA has revealed some advantages in the extraction-precipitation process, i.e., higher efficiency, larger processing capacity, lower energy consumption and simple process. The extraction-precipitation strategy may be suitable for large-scale applications.
研究领域:
环境科学
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化学工程
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资源回收
✓ 已验证
DOI
高影响因子
Minerals
·
2021
·Vol. 11
·期 1
·61
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IF 2.644
Wenjie Zhang,Xian Xie,Xiong Tong,Yunpeng Du,Qiang Song,Dongxia Feng
Solvent extraction is the most widely used method for separation and purification of rare earth elements, and organic extractants such as di(2-ethylhexyl) phosphoric acid (P204) and di(1-methyl-heptyl) methyl phosphonate (P350) are most commonly used for industrial applications. However, the presence of impurity ions in the feed liquid during extraction can easily emulsify the extractant and affect the quality of rare earth products. Aluminum ion is the most common impurity ion in the feed liquid, and it is an important cause of emulsification of the extractant. In this study, the influence of aluminum ion was investigated on the extraction of light rare earth elements by the P204-P350 system in hydrochloric acid medium. The results show that Al3+competes with light rare earths in the extraction process, reducing the overall extraction rate. In addition, the Al3+stripping rate is low and there is continuous accumulation of Al3+in the organic phase during the stripping process, affecting the extraction efficiency and even causing emulsification. The slope method and infrared detection were utilized to explore the formation of an extraction compound of Al3+and the extractant P204-P350 that entered the organic phase as AlCl[(HA)2]2P350(o).Keywords:Al3+;light rare earths;P204;P350;impurity
研究领域:
化学工程
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材料科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）