The effects of carbonate minerals（dolomite and siderite） on the flotation of hematite using sodium oleate as a collector were investigated through flotation tests, supplemented by dissolution measurements, solution ...The effects of carbonate minerals（dolomite and siderite） on the flotation of hematite using sodium oleate as a collector were investigated through flotation tests, supplemented by dissolution measurements, solution chemistry calculations, zeta-potential measurements, Fourier transform infrared（FTIR） spectroscopic studies, and X-ray photoelectron spectroscopy（XPS） analyses. The results of flotation tests show that the presence of siderite or dolomite reduced the recovery of hematite and that the inhibiting effects of dolomite were stronger. Dissolution measurements, solution chemistry calculations, and flotation tests confirmed that both the cations（Ca^（2＋） and Mg^（2＋）） and CO_3^（2＋）ions dissolved from dolomite depressed hematite flotation, whereas only the 23CO-ions dissolved from siderite were responsible for hematite depression. The zeta-potential, FTIR spectroscopic, and XPS analyses indicated that Ca^（2＋）, Mg^（2＋）, and CO_3^（2-）（HCO_3^-） could adsorb onto the hematite surface, thereby hindering the adsorption of sodium oleate, which was the main reason for the inhibiting effects of carbonate minerals on hematite flotation.展开更多
Solution chemical equilibria involving flotation agents(hereafter llotagents),minerals and solution play a crucial role in determining the behavior of complex flotation systems.Salt-type minerals such as calcite,apati...Solution chemical equilibria involving flotation agents(hereafter llotagents),minerals and solution play a crucial role in determining the behavior of complex flotation systems.Salt-type minerals such as calcite,apatite etc are sparingly soluble in aqueous solution and form dissolved mineral species in bulk solution.It has been found that such dissolved species interact with the minerals,and often lead to surface conversion of the minerals.In addition,they can interact with various llotagents and lead to surface or bulk precipitation and loss of selectivity in the flotation.Relevant solution equilibria of these salt-type minerals and their interactions with conventional and structurally modified reagents are discussed.Better selectivity in their flotation can be achieved by controlling such interactions and manipulating the solution chemical equilibria.展开更多
This paper deals with the flotation separation of wollas-tonite from quartz by using Na-oleate as a collector and metallic ion as an activator. The reasons why wollastonite is difficult to separate from quartz using N...This paper deals with the flotation separation of wollas-tonite from quartz by using Na-oleate as a collector and metallic ion as an activator. The reasons why wollastonite is difficult to separate from quartz using Na-oleate as a collector have been studied. It is found that quartz does not float well in a mixture of wollastonite and quartz because of the solution chemistry effect in a wollastonite suspension. The compositions of the wollastonite suspensions have been studied, and the?potential of the two minerals have been determined to explain the solution chemistry effects on the flotation of the respective minerals.展开更多
The mechanisms of interaction between tannic acid and calcium ions either added externally to or inherently present in the (?)olution ( dissociated from mineral surface ) , are studied by the use of Inductively Couple...The mechanisms of interaction between tannic acid and calcium ions either added externally to or inherently present in the (?)olution ( dissociated from mineral surface ) , are studied by the use of Inductively Coupled Plasma Atomic Emission Spectroscopy ( ICP-AES ) , Ultraviolet Spectroscopy (UV). It is found that wollastonite has a high solubility in the concentration of calcium ions, calcium ions are able to interact with tannic acid.展开更多
The effects of siderite on reverse flotation of hematite were investigated using micro flotation, adsorption tests, and Fourier transform infrared spectroscopy. The flotation results show that interactions between sid...The effects of siderite on reverse flotation of hematite were investigated using micro flotation, adsorption tests, and Fourier transform infrared spectroscopy. The flotation results show that interactions between siderite and quartz are the main reasons that siderite significantly influences the floatability. The interactions are attributed to dissolved siderite species and fine siderite particles. The interaction due to the dissolved species is, however, dominant. Derjaguin-Landau-Verwey-Overbeek（DLVO） theoretical calculations reveal that adhesion on quartz increases when the siderite particle size decreases and that fine particles partly influence quartz floatability. Chemical solution calculations indicate that the dissolved species of siderite might convert the surface of active quartz to CaCO_3 precipitates that can be depressed by starch. The theoretical calculations are in good agreement with the results of adsorption tests and FTIR spectroscopy and explain the reasons why siderite significantly influences reverse flotation of hematite.展开更多
Porous SnO_2 nanostructures with controlled shapes were synthesized by a facile morphologically conserved transformation from Sn C_2O_4 precursor approach. Well-defined Sn C_2O_4 nanostructures can be obtained through...Porous SnO_2 nanostructures with controlled shapes were synthesized by a facile morphologically conserved transformation from Sn C_2O_4 precursor approach. Well-defined Sn C_2O_4 nanostructures can be obtained through a solution-based precipitation process at ambient conditions without any surfactant. The formation mechanism of such microstructures was tentatively proposed on the basis of intrinsic crystal structure and the reaction conditions. We found that the morphologies of precursor were well maintained while numerous pores were formed during the annealing process. The combined techniques of X-ray diffraction, nitrogen absorption–desorption, field emission scanning electron microscopy, and(high-resolution) transmission electron microscopy were used to characterize the as-prepared SnO_2 products. Moreover, cyclic voltammetry(CV) study shows that the shape of CV presents a current response like roughly rectangular mirror images with respect to the zero-current line without obvious redox peaks, which indicating an ideal capacitive behavior of the SnO_2 electrodes. The photoluminescence(PL) spectrum study suggests that the as-obtained porous SnO_2 nanostructures might have a large number of defects, vacancies of oxygen, and local lattice disorder at the interface, interior and exterior surfaces.展开更多
Nucleation from solution is fundamental to many natural and industrial processes.The understanding of molecular mechanism of nucleation from solution is conducive to predict crystal structure,control polymorph and des...Nucleation from solution is fundamental to many natural and industrial processes.The understanding of molecular mechanism of nucleation from solution is conducive to predict crystal structure,control polymorph and design desired crystal materials.In this review,the nucleation theories,including classical nucleation theory(CNT),nonclassical nucleation theory,as well as other new proposed theories,were reprised,and the molecular mechanism of these theories was compared.Then,the molecular process of nucleation,including the current study techniques,the effect of molecular self-assembly in solutions,desolvation process,as well as the properties of solvent and crystal structure on nucleation from solution were summarized.Furthermore,the relationship of molecular conformation in solution and in crystal,and the effect of solute molecular flexibility on nucleation were discussed.Finally,the current challenges and future scopes of crystal nucleation from solution were discussed.展开更多
Cold sintering has recently emerged as a promising approach for preparing dense ceramic materials and composites at low temperatures.It relies on utilizing transient,typically externally introduced,liquid phases to ac...Cold sintering has recently emerged as a promising approach for preparing dense ceramic materials and composites at low temperatures.It relies on utilizing transient,typically externally introduced,liquid phases to accelerate material diffusion and densification under applied pressure.Cold-sintered bioceramics,especially those prepared at temperatures below 100°C,may open up numerous possibilities,not only in producing dense ceramics with refined microstructural properties and reduced time/energy costs,but also in developing multifunctional platforms containing bioactive compounds,therapeutics,growth factors,and signaling molecules for enhanced and targeted biological responses.Cold sintering in the presence of liquids inherently involves dissolution and nucleation,which become particularly intricate under applied pressures and elevated temperatures.Pseudo bio-mineralization,an auspicious approach for tailoring synthetic bone grafts toward targeted mechanics,may serve as a viable route for enhancing the densification mechanisms inherent to cold sintering.We have carefully analyzed the current state of the art in cold-sintered bioceramics and the results achieved,with a focus on the chemistry of the employed liquids and the corresponding changes upon sintering,the selection of transient phases,and mineral nucleation,while also addressing the potential for developing new biomaterials.Despite the widely accepted classical dissolution-precipitation strategy,no clear roadmap can yet be defined regarding the type and amount of liquid phase that should be applied,at least in the case of hydroxyapatite(HAp)densification-the most important representative of calcium phosphates.We strongly advocate the use of water as the transient liquid of choice in the cold sintering of HAp-based bioceramics,instead of strong acids/bases,and emphasize the importance of understanding the various processes and parameters that govern and connect solution chemistry to mineral nucleation.This understanding will enable the advancement of cold sintering protocols in a target-oriented manner,and we provide perspectives on future developments,including practical advice.展开更多
Hydrophilic chelators are crucial for coordinating and separating radioactive f-block elements in nuclear fuel recycling,hazardous waste treatment,environmental remediation,radiopharmaceuticals,and related fields.Howe...Hydrophilic chelators are crucial for coordinating and separating radioactive f-block elements in nuclear fuel recycling,hazardous waste treatment,environmental remediation,radiopharmaceuticals,and related fields.However,their development and understanding lag behind their lipophilic counterparts.This review summarizes the development of hy-drophilic ligands across four categories based on their structural similarities and chronological order.For each category,representative examples are discussed,highlighting their advantages and disadvantages.The review also benchmarks ligands from different groups,outlines current design challenges,and emphasizes the importance of establishing structure-function relationships to guide future ligand design.Additionally,we propose four novel f-block chelating ligands,some of which have shown efficiency in solid-liquid or membrane-based radionuclide separation,aiming to inspire the search for more robust systems for f-block element utilization and recycling.This review aims to provide a comprehensive overview of hydrophilic f-block element chelators and suggest promising approaches for future ligand development.展开更多
Rapid synthesis of metal–organic frameworks(MOFs),especially high-valence MOFs at roomtemperature without external energy,is a challenging topic.In this work,a stable radical solution has been discovered.Various MOFs...Rapid synthesis of metal–organic frameworks(MOFs),especially high-valence MOFs at roomtemperature without external energy,is a challenging topic.In this work,a stable radical solution has been discovered.Various MOFs with versatile metal nodes and ligands were rapidly synthesized at room temperature in the absence of external energy.Especially,MOFs with conjugated ligands achieved instantaneous architecture(in less than 1 s)and quantitative yield.Radicals in the solution play a crucial role in the accelerated kinetics,and the new radical route paves a cyclic pathway for the MOF synthesis.The mechanism has been thoroughly investigated by electron paramagnetic resonance,in situ proton nuclear magnetic resonance,X-ray absorption spectra,in situ small-angle X-ray scattering-wide-angle X-ray scattering,and density functional theory calculations.展开更多
基金financially supported by the National Natural Science Foundation of China (Nos. 51374079 and 51504053)the Hundred, Thousand and Ten Thousand Talent Project of Liaoning Province, China (No. 2014921014)+1 种基金the Postdoctoral Science Foundation of China (No. 2015M571324)China Scholarship Council for the financial support for his visiting study to the University of Alberta, Canada
文摘The effects of carbonate minerals（dolomite and siderite） on the flotation of hematite using sodium oleate as a collector were investigated through flotation tests, supplemented by dissolution measurements, solution chemistry calculations, zeta-potential measurements, Fourier transform infrared（FTIR） spectroscopic studies, and X-ray photoelectron spectroscopy（XPS） analyses. The results of flotation tests show that the presence of siderite or dolomite reduced the recovery of hematite and that the inhibiting effects of dolomite were stronger. Dissolution measurements, solution chemistry calculations, and flotation tests confirmed that both the cations（Ca^（2＋） and Mg^（2＋）） and CO_3^（2＋）ions dissolved from dolomite depressed hematite flotation, whereas only the 23CO-ions dissolved from siderite were responsible for hematite depression. The zeta-potential, FTIR spectroscopic, and XPS analyses indicated that Ca^（2＋）, Mg^（2＋）, and CO_3^（2-）（HCO_3^-） could adsorb onto the hematite surface, thereby hindering the adsorption of sodium oleate, which was the main reason for the inhibiting effects of carbonate minerals on hematite flotation.
基金supported by the Florida Institute of Phosphate Reseac。
文摘Solution chemical equilibria involving flotation agents(hereafter llotagents),minerals and solution play a crucial role in determining the behavior of complex flotation systems.Salt-type minerals such as calcite,apatite etc are sparingly soluble in aqueous solution and form dissolved mineral species in bulk solution.It has been found that such dissolved species interact with the minerals,and often lead to surface conversion of the minerals.In addition,they can interact with various llotagents and lead to surface or bulk precipitation and loss of selectivity in the flotation.Relevant solution equilibria of these salt-type minerals and their interactions with conventional and structurally modified reagents are discussed.Better selectivity in their flotation can be achieved by controlling such interactions and manipulating the solution chemical equilibria.
文摘This paper deals with the flotation separation of wollas-tonite from quartz by using Na-oleate as a collector and metallic ion as an activator. The reasons why wollastonite is difficult to separate from quartz using Na-oleate as a collector have been studied. It is found that quartz does not float well in a mixture of wollastonite and quartz because of the solution chemistry effect in a wollastonite suspension. The compositions of the wollastonite suspensions have been studied, and the?potential of the two minerals have been determined to explain the solution chemistry effects on the flotation of the respective minerals.
文摘The mechanisms of interaction between tannic acid and calcium ions either added externally to or inherently present in the (?)olution ( dissociated from mineral surface ) , are studied by the use of Inductively Coupled Plasma Atomic Emission Spectroscopy ( ICP-AES ) , Ultraviolet Spectroscopy (UV). It is found that wollastonite has a high solubility in the concentration of calcium ions, calcium ions are able to interact with tannic acid.
基金financially supported by the National Natural Science Foundation of China (No. 51374079)the Hundred, Thousand and Ten Thousand Talent Project of Liaoning Province (No. 2014921014)the Postdoctoral Science Foundation of China (No. 2015M571324)
文摘The effects of siderite on reverse flotation of hematite were investigated using micro flotation, adsorption tests, and Fourier transform infrared spectroscopy. The flotation results show that interactions between siderite and quartz are the main reasons that siderite significantly influences the floatability. The interactions are attributed to dissolved siderite species and fine siderite particles. The interaction due to the dissolved species is, however, dominant. Derjaguin-Landau-Verwey-Overbeek（DLVO） theoretical calculations reveal that adhesion on quartz increases when the siderite particle size decreases and that fine particles partly influence quartz floatability. Chemical solution calculations indicate that the dissolved species of siderite might convert the surface of active quartz to CaCO_3 precipitates that can be depressed by starch. The theoretical calculations are in good agreement with the results of adsorption tests and FTIR spectroscopy and explain the reasons why siderite significantly influences reverse flotation of hematite.
基金the financial support of the National Science Foundation for Distinguished Young Scholars of China(Grant No.51025517)the Innovative Group Foundation of NSFC(Grant No.50721062)the financial support of the National 973 project of China(2007CB607606)
文摘Porous SnO_2 nanostructures with controlled shapes were synthesized by a facile morphologically conserved transformation from Sn C_2O_4 precursor approach. Well-defined Sn C_2O_4 nanostructures can be obtained through a solution-based precipitation process at ambient conditions without any surfactant. The formation mechanism of such microstructures was tentatively proposed on the basis of intrinsic crystal structure and the reaction conditions. We found that the morphologies of precursor were well maintained while numerous pores were formed during the annealing process. The combined techniques of X-ray diffraction, nitrogen absorption–desorption, field emission scanning electron microscopy, and(high-resolution) transmission electron microscopy were used to characterize the as-prepared SnO_2 products. Moreover, cyclic voltammetry(CV) study shows that the shape of CV presents a current response like roughly rectangular mirror images with respect to the zero-current line without obvious redox peaks, which indicating an ideal capacitive behavior of the SnO_2 electrodes. The photoluminescence(PL) spectrum study suggests that the as-obtained porous SnO_2 nanostructures might have a large number of defects, vacancies of oxygen, and local lattice disorder at the interface, interior and exterior surfaces.
基金supported by the National Natural Science Foundation of China(21978201)。
文摘Nucleation from solution is fundamental to many natural and industrial processes.The understanding of molecular mechanism of nucleation from solution is conducive to predict crystal structure,control polymorph and design desired crystal materials.In this review,the nucleation theories,including classical nucleation theory(CNT),nonclassical nucleation theory,as well as other new proposed theories,were reprised,and the molecular mechanism of these theories was compared.Then,the molecular process of nucleation,including the current study techniques,the effect of molecular self-assembly in solutions,desolvation process,as well as the properties of solvent and crystal structure on nucleation from solution were summarized.Furthermore,the relationship of molecular conformation in solution and in crystal,and the effect of solute molecular flexibility on nucleation were discussed.Finally,the current challenges and future scopes of crystal nucleation from solution were discussed.
基金supported by the Ministry of Science,Technological Development,and Innovation of the Republic of Serbia(Contract No:451-03-136/2025-03/200017)the National Natural Science Foundation of China(Grant No:32271421).
文摘Cold sintering has recently emerged as a promising approach for preparing dense ceramic materials and composites at low temperatures.It relies on utilizing transient,typically externally introduced,liquid phases to accelerate material diffusion and densification under applied pressure.Cold-sintered bioceramics,especially those prepared at temperatures below 100°C,may open up numerous possibilities,not only in producing dense ceramics with refined microstructural properties and reduced time/energy costs,but also in developing multifunctional platforms containing bioactive compounds,therapeutics,growth factors,and signaling molecules for enhanced and targeted biological responses.Cold sintering in the presence of liquids inherently involves dissolution and nucleation,which become particularly intricate under applied pressures and elevated temperatures.Pseudo bio-mineralization,an auspicious approach for tailoring synthetic bone grafts toward targeted mechanics,may serve as a viable route for enhancing the densification mechanisms inherent to cold sintering.We have carefully analyzed the current state of the art in cold-sintered bioceramics and the results achieved,with a focus on the chemistry of the employed liquids and the corresponding changes upon sintering,the selection of transient phases,and mineral nucleation,while also addressing the potential for developing new biomaterials.Despite the widely accepted classical dissolution-precipitation strategy,no clear roadmap can yet be defined regarding the type and amount of liquid phase that should be applied,at least in the case of hydroxyapatite(HAp)densification-the most important representative of calcium phosphates.We strongly advocate the use of water as the transient liquid of choice in the cold sintering of HAp-based bioceramics,instead of strong acids/bases,and emphasize the importance of understanding the various processes and parameters that govern and connect solution chemistry to mineral nucleation.This understanding will enable the advancement of cold sintering protocols in a target-oriented manner,and we provide perspectives on future developments,including practical advice.
基金the National Natural Science Foundation of China (U2067213, 22325603)the National Natural Science Foundation of China (22105205)the Beijing Natural Science Foundation (2232002)
文摘Hydrophilic chelators are crucial for coordinating and separating radioactive f-block elements in nuclear fuel recycling,hazardous waste treatment,environmental remediation,radiopharmaceuticals,and related fields.However,their development and understanding lag behind their lipophilic counterparts.This review summarizes the development of hy-drophilic ligands across four categories based on their structural similarities and chronological order.For each category,representative examples are discussed,highlighting their advantages and disadvantages.The review also benchmarks ligands from different groups,outlines current design challenges,and emphasizes the importance of establishing structure-function relationships to guide future ligand design.Additionally,we propose four novel f-block chelating ligands,some of which have shown efficiency in solid-liquid or membrane-based radionuclide separation,aiming to inspire the search for more robust systems for f-block element utilization and recycling.This review aims to provide a comprehensive overview of hydrophilic f-block element chelators and suggest promising approaches for future ligand development.
基金The authors thank the National Natural Science Foundation of China(grant no.22073104)the Beijing Natural Science Foundation(grant no.2222043)+3 种基金the National Key Research and Development Program of China(grant nos.2017YFA0403101,2017YFA0403003,and 2017YFA0403102)the National Natural Science Foundation of China(grant nos.21890761,21733011,and 21533011)the Beijing Municipal Science&Technology Commission(grant no.Z191100007219009)the Chinese Academy of Sciences(grant no.QYZDY-SSWSLH013).The XAS(1W1B)and SAXS(1W2A)measurements were performed at the Beijing Synchrotron Radiation Facility,China.
文摘Rapid synthesis of metal–organic frameworks(MOFs),especially high-valence MOFs at roomtemperature without external energy,is a challenging topic.In this work,a stable radical solution has been discovered.Various MOFs with versatile metal nodes and ligands were rapidly synthesized at room temperature in the absence of external energy.Especially,MOFs with conjugated ligands achieved instantaneous architecture(in less than 1 s)and quantitative yield.Radicals in the solution play a crucial role in the accelerated kinetics,and the new radical route paves a cyclic pathway for the MOF synthesis.The mechanism has been thoroughly investigated by electron paramagnetic resonance,in situ proton nuclear magnetic resonance,X-ray absorption spectra,in situ small-angle X-ray scattering-wide-angle X-ray scattering,and density functional theory calculations.
