Solvent extraction is the main method used to separate and purify rare earth elements.In the process of rare earths extraction,emulsification often generated due to the instability of the aqueous and organic phases or...Solvent extraction is the main method used to separate and purify rare earth elements.In the process of rare earths extraction,emulsification often generated due to the instability of the aqueous and organic phases or improper operating conditions.Once emulsification occurs,it would not only lead to low rare earths recovery efficiency,small product quantities,high production costs and the losing of extractant and rare earth resources,but also result in serious environmental pollution.Therefore,it is very important to study the micro-mechanisms of emulsification and establish new methods to prevent emulsification at the source.In this paper,possible factors resulting in emulsification,such as the compositions and properties of the organic and aqueous phases,the operating conditions of the rare earths extraction are reviewed.The micro-mechanisms of emulsification are summarized basing on the microscopic structures in the bulk phase,aggregations of the extractants at the organic-aqueous interface,spectral characterizations and computational simulations.On this basis,new formation mechanisms are proposed for emulsification.Preliminary explorations are employed to verify the correctness of these new viewpoints.Finally,future directions for studies of the emulsification micro-mechanism are proposed.This study provides a theoretical basis for further understanding the micro-mechanisms of interfacial instability resulting in emulsification in the process of rare earths extraction.展开更多
The high-acidity vanadium-containing solution contains high concentrations of iron and aluminum with pH around 0.5,the ketoxime extractant with the active ingredient of 2-hydroxy-5-nonylacetophenone oxime(HNAO,HL) was...The high-acidity vanadium-containing solution contains high concentrations of iron and aluminum with pH around 0.5,the ketoxime extractant with the active ingredient of 2-hydroxy-5-nonylacetophenone oxime(HNAO,HL) was proposed to extract vanadium from the solution.Under the phase ratio(O/A)of 1:2,HNAO concentration of 0.542 mol·L^(-1) at 25℃ for 10 min,99.06% of vanadium was extracted after a three-stage countercurrent extraction,while the extraction of impurities was less than 1%,with the separation coefficients of vanadium from iron and aluminum were 137050 and 43197,respectively.The antioxidant properties of the extractant were studied.At 25℃,the extractant basically did not undergo oxidative degradation.Besides,about 91.2% of the loaded vanadium was effectively stripped using 2.5 mol·L^(-1)Na_(2)CO_(3) solution.The extraction mechanism of vanadium was investigated through the slope analysis method,the spectral characterizations and density functional theory calculations.It has been observed that VO_(2)^(+) substitutes the H atom on the phenolic hydroxyl and coordinates with the N atom on the oxime and the O atom on the phenolic hydroxyl to form of a six-membered ring,and the extraction complexes were determined to be VO_(2)(H_(2)O)L and VO_(2)L.展开更多
Enlarging the steric hindrance to the molecular structures of extractants is a common way to improve their selectivity.To improve the separation factor of thorium(Ⅳ)and cerium(Ⅳ),cyclic groups having large steric hi...Enlarging the steric hindrance to the molecular structures of extractants is a common way to improve their selectivity.To improve the separation factor of thorium(Ⅳ)and cerium(Ⅳ),cyclic groups having large steric hindrance such as phenyl,cyclohexyl,and benzyl were introduced into theα-aminophosphonate extractant molecules.Bis(2-ethylhexyl)((phenylamino)methyl)phosphonate(PAMP),bis(2-ethylhexyl)((cyclohexylamino)methyl)phosphonate(CAMP),and bis(2-ethylhexyl)((benzylamine)methyl)phosphate(BAMP)were synthesized and applied in the separation and recovery of thorium(Ⅳ)and cerium(Ⅳ)from sulfuric acid solution.The separation ability between cerium(Ⅳ)and thorium(Ⅳ)descends in the order of CAMP>BAMP≈Cextrant230>DEHAMP>>PAMP,which is consistent with the decreasing order of steric hindrance.Nearly non-extraction of both cerium(Ⅳ)and thorium(Ⅳ)and the lowest separation ability for PAMP will be due to the conjugation of the lone pair of the amino N atom and benzene ring in PAMP.Furthermore,the extraction of REs(Ⅲ)by CAMP is lower than that of thorium(Ⅳ).Thermodynamic parameters(ΔG^(0),ΔH^(0),ΔS^(0))and extraction equilibrium constants were determined.An extraction process was developed to separate and retrieve thorium(Ⅳ)and cerium(Ⅳ)from a bastnaesite leaching solution.The final product purity of CeO2and ThO2is 99%and 98.4%,respectively,and the yields are 90.2%and 97.6%,respectively.展开更多
The extraction kinetics of Ce（Ⅳ） and Ce（Ⅳ）-F^- mixture systems from sulfuric solutions to n-heptane solution containing Bif-ILE[A336][P204]（[trialkylmethylammonium][di-2-ethylhewanxylphosphinate]） with a const...The extraction kinetics of Ce（Ⅳ） and Ce（Ⅳ）-F^- mixture systems from sulfuric solutions to n-heptane solution containing Bif-ILE[A336][P204]（[trialkylmethylammonium][di-2-ethylhewanxylphosphinate]） with a constant interfacial area cell with laminar flow were studied,just to elucidate the extraction mechanism and the mass transfer models.The data were analyzed in terms of pseudo-first-order constants.The effects of stirring speed,specific interfacial area and temperature on the extraction rate in both systems were discussed,suggesting that the extractions were mixed bulk phases-interfacial control process.Supported by the experimental data,the corresponding rate equations for Ce（Ⅳ） extraction system and Ce（Ⅳ）-F^- mixture extraction system were obtained.The experimental results indicated the rate-controlling step.The kinetics model was deduced from the rate-controlling step and consistent with the rate equation.展开更多
针对玉米杂草识别过程中因光照变化导致识别精确度低及漏检问题,该研究以幼苗期玉米及其伴生杂草为研究对象,设计一种基于WEED-YOLOv10的玉米杂草检测方法。首先,通过无人机快速采集田间高分辨率图像构建了玉米杂草数据集;其次,以YOLOv...针对玉米杂草识别过程中因光照变化导致识别精确度低及漏检问题,该研究以幼苗期玉米及其伴生杂草为研究对象,设计一种基于WEED-YOLOv10的玉米杂草检测方法。首先,通过无人机快速采集田间高分辨率图像构建了玉米杂草数据集;其次,以YOLOv10n为基线网络,将骨干网络替换为ConvNeXtV2以增强特征提取能力;继而,为避免因模块拼接可能带来的信息冗余或丢失问题提升对光照干扰的鲁棒性,嵌入CBAM注意力机制;然后,引入SlimNeck结构优化网络计算效率,有效平衡了模型计算资源消耗与特征表征能力;最后,使用Focaler-EIoU损失函数进一步提高模型定位精度。试验结果表明,WEED-YOLOv10在精确率、召回率、mAP@50、mAP@50:95和F1分数上分别达到85.4%、88.1%、90.9%、48.5%和86.7%,较基准模型分别提升了2.4、2.9、3.5、7.0、2.6个百分点,各项精度指标均优于其他对比模型,部署在NVIDIA Jetson orin NX上的图片推理速度达到28.7帧/s,实现了检测速度与精度的平衡。进一步地,基于WEED-YOLOv10开发对靶喷药系统,该系统实时捕捉并解析来自模型的识别信号,实现对除草喷施装置的精准调控。田间试验结果显示,对靶喷药系统施药准确率为93.7%,喷洒覆盖率为90.5%,对靶偏差为1.45cm,杂草实时检测速度为20.1帧/s,实现了自动化的玉米田间除草作业。该研究为复杂光照场景下农田杂草治理提供了可靠的技术方案,对推动农业智能化作业具有重要意义。展开更多
基金Project supported by the National Natural Science Foundation of China(52074031)the Key Research and Development Program of Shandong Province(ZR2021MB051,ZR2020ME256)the Open Project of Key Laboratory of Green Chemical Engineering Process of Ministry of Education(GCP202117)。
文摘Solvent extraction is the main method used to separate and purify rare earth elements.In the process of rare earths extraction,emulsification often generated due to the instability of the aqueous and organic phases or improper operating conditions.Once emulsification occurs,it would not only lead to low rare earths recovery efficiency,small product quantities,high production costs and the losing of extractant and rare earth resources,but also result in serious environmental pollution.Therefore,it is very important to study the micro-mechanisms of emulsification and establish new methods to prevent emulsification at the source.In this paper,possible factors resulting in emulsification,such as the compositions and properties of the organic and aqueous phases,the operating conditions of the rare earths extraction are reviewed.The micro-mechanisms of emulsification are summarized basing on the microscopic structures in the bulk phase,aggregations of the extractants at the organic-aqueous interface,spectral characterizations and computational simulations.On this basis,new formation mechanisms are proposed for emulsification.Preliminary explorations are employed to verify the correctness of these new viewpoints.Finally,future directions for studies of the emulsification micro-mechanism are proposed.This study provides a theoretical basis for further understanding the micro-mechanisms of interfacial instability resulting in emulsification in the process of rare earths extraction.
基金the financial support from Deep Earth Probe and Mineral Resources Exploration—National Science and Technology Major Project,China (2024ZD1003408)Strategic Priority Research Program of the Chinese Academy of Sciences,China (XDA0430103)。
文摘The high-acidity vanadium-containing solution contains high concentrations of iron and aluminum with pH around 0.5,the ketoxime extractant with the active ingredient of 2-hydroxy-5-nonylacetophenone oxime(HNAO,HL) was proposed to extract vanadium from the solution.Under the phase ratio(O/A)of 1:2,HNAO concentration of 0.542 mol·L^(-1) at 25℃ for 10 min,99.06% of vanadium was extracted after a three-stage countercurrent extraction,while the extraction of impurities was less than 1%,with the separation coefficients of vanadium from iron and aluminum were 137050 and 43197,respectively.The antioxidant properties of the extractant were studied.At 25℃,the extractant basically did not undergo oxidative degradation.Besides,about 91.2% of the loaded vanadium was effectively stripped using 2.5 mol·L^(-1)Na_(2)CO_(3) solution.The extraction mechanism of vanadium was investigated through the slope analysis method,the spectral characterizations and density functional theory calculations.It has been observed that VO_(2)^(+) substitutes the H atom on the phenolic hydroxyl and coordinates with the N atom on the oxime and the O atom on the phenolic hydroxyl to form of a six-membered ring,and the extraction complexes were determined to be VO_(2)(H_(2)O)L and VO_(2)L.
基金Project supported by the National Natural Science Foundation of China(92262301)。
文摘Enlarging the steric hindrance to the molecular structures of extractants is a common way to improve their selectivity.To improve the separation factor of thorium(Ⅳ)and cerium(Ⅳ),cyclic groups having large steric hindrance such as phenyl,cyclohexyl,and benzyl were introduced into theα-aminophosphonate extractant molecules.Bis(2-ethylhexyl)((phenylamino)methyl)phosphonate(PAMP),bis(2-ethylhexyl)((cyclohexylamino)methyl)phosphonate(CAMP),and bis(2-ethylhexyl)((benzylamine)methyl)phosphate(BAMP)were synthesized and applied in the separation and recovery of thorium(Ⅳ)and cerium(Ⅳ)from sulfuric acid solution.The separation ability between cerium(Ⅳ)and thorium(Ⅳ)descends in the order of CAMP>BAMP≈Cextrant230>DEHAMP>>PAMP,which is consistent with the decreasing order of steric hindrance.Nearly non-extraction of both cerium(Ⅳ)and thorium(Ⅳ)and the lowest separation ability for PAMP will be due to the conjugation of the lone pair of the amino N atom and benzene ring in PAMP.Furthermore,the extraction of REs(Ⅲ)by CAMP is lower than that of thorium(Ⅳ).Thermodynamic parameters(ΔG^(0),ΔH^(0),ΔS^(0))and extraction equilibrium constants were determined.An extraction process was developed to separate and retrieve thorium(Ⅳ)and cerium(Ⅳ)from a bastnaesite leaching solution.The final product purity of CeO2and ThO2is 99%and 98.4%,respectively,and the yields are 90.2%and 97.6%,respectively.
基金Project (2012CBA01202) supported by the National Basic Research Program of ChinaProject (51174184) supported by the National Natural Science Foundation of China+2 种基金Project (KGZD-EW-201-1) supported by the Key Research Program of the Chinese Academy of SciencesProject (BK2013030) supported by Science and Technology Plan of Nantong City,ChinaProject (RERU2014016) supported by Open Subject of Changchun Institute of Applied Chemistry,Chinese Academy of Sciences,China
文摘The extraction kinetics of Ce（Ⅳ） and Ce（Ⅳ）-F^- mixture systems from sulfuric solutions to n-heptane solution containing Bif-ILE[A336][P204]（[trialkylmethylammonium][di-2-ethylhewanxylphosphinate]） with a constant interfacial area cell with laminar flow were studied,just to elucidate the extraction mechanism and the mass transfer models.The data were analyzed in terms of pseudo-first-order constants.The effects of stirring speed,specific interfacial area and temperature on the extraction rate in both systems were discussed,suggesting that the extractions were mixed bulk phases-interfacial control process.Supported by the experimental data,the corresponding rate equations for Ce（Ⅳ） extraction system and Ce（Ⅳ）-F^- mixture extraction system were obtained.The experimental results indicated the rate-controlling step.The kinetics model was deduced from the rate-controlling step and consistent with the rate equation.
文摘针对玉米杂草识别过程中因光照变化导致识别精确度低及漏检问题,该研究以幼苗期玉米及其伴生杂草为研究对象,设计一种基于WEED-YOLOv10的玉米杂草检测方法。首先,通过无人机快速采集田间高分辨率图像构建了玉米杂草数据集;其次,以YOLOv10n为基线网络,将骨干网络替换为ConvNeXtV2以增强特征提取能力;继而,为避免因模块拼接可能带来的信息冗余或丢失问题提升对光照干扰的鲁棒性,嵌入CBAM注意力机制;然后,引入SlimNeck结构优化网络计算效率,有效平衡了模型计算资源消耗与特征表征能力;最后,使用Focaler-EIoU损失函数进一步提高模型定位精度。试验结果表明,WEED-YOLOv10在精确率、召回率、mAP@50、mAP@50:95和F1分数上分别达到85.4%、88.1%、90.9%、48.5%和86.7%,较基准模型分别提升了2.4、2.9、3.5、7.0、2.6个百分点,各项精度指标均优于其他对比模型,部署在NVIDIA Jetson orin NX上的图片推理速度达到28.7帧/s,实现了检测速度与精度的平衡。进一步地,基于WEED-YOLOv10开发对靶喷药系统,该系统实时捕捉并解析来自模型的识别信号,实现对除草喷施装置的精准调控。田间试验结果显示,对靶喷药系统施药准确率为93.7%,喷洒覆盖率为90.5%,对靶偏差为1.45cm,杂草实时检测速度为20.1帧/s,实现了自动化的玉米田间除草作业。该研究为复杂光照场景下农田杂草治理提供了可靠的技术方案,对推动农业智能化作业具有重要意义。
