This study focuses on using a green reagent scheme of methanesulfonic acid (MSA) and citric acid (CA) to extract valuable metals from the cathodes, aiming to minimize environmental impact during the recycling process....This study focuses on using a green reagent scheme of methanesulfonic acid (MSA) and citric acid (CA) to extract valuable metals from the cathodes, aiming to minimize environmental impact during the recycling process. Leaching studies on LiCoO_(2) identified optimal conditions as follows: 2.4 mol/L MSA, 1.6 mol/L CA, S/L ratio of 80 g/L, leaching temperature of 90oC and leaching time of 6 h. The maximum Co and Li extraction achieved was 92% and 85%, respectively. LiCoO_(2) dissolution in MSA-CA leaching solution is highly impacted by temperature;Avrami equation showed a good fitting for the leaching data. The experimental activation energy of Co and Li was 50.98 kJ/mol and 50.55 kJ/mol, respectively, indicating that it is a chemical reaction-controlled process. Furthermore, cobalt was efficiently recovered from the leachate using oxalic acid, achieving a precipitation efficiency of 99.91% and a high-purity cobalt oxalate product (99.85 wt.%). In the MSA-CA leaching solution, MSA served as a lixiviant, while CA played a key role in reducing Co in LiCoO_(2). The overall organic acid leaching methodology presents an attractive option due to its reduced environmental impact.展开更多
The inadvertent dissolution of gangue minerals is frequently detrimental to the flotation of valuable minerals.We investigated the effect of conditioning time on the separation of brucite and serpentine by flotation.B...The inadvertent dissolution of gangue minerals is frequently detrimental to the flotation of valuable minerals.We investigated the effect of conditioning time on the separation of brucite and serpentine by flotation.By analyzing the Mg2+concentration,relative element content,and pulp viscosity,we studied the effect of mineral dissolution on brucite flotation.The results of artificially mixed mineral flotation tests(with-10μm serpentine)showed that by extending the conditioning time from 60 to 360 s,a large amount of Mg2+on the mineral surface gradually dissolved into the pulp,resulting in a decreased brucite recovery(from 83.83%to 76.79%)and an increased recovery of serpentine from 52.12%to 64.03%.To analyze the agglomeration behavior of brucite and serpentine,we used scanning electron microscopy,which clearly showed the different adhesion behaviors of different conditioning times.Lastly,the total interaction energy,as determined based on the extended DLVO(Derjaguin-Landau-Verwey-Overbeek)theory,also supports the conclusion that the gravitational force between brucite and serpentine increases significantly with increased conditioning time.展开更多
Approaches for the fabrication of a low power-operable formaldehyde(HCHO)gas sensor with high sensitivity and selectivity were performed by the utilization of an effective micro-structured platform with a micro-heater...Approaches for the fabrication of a low power-operable formaldehyde(HCHO)gas sensor with high sensitivity and selectivity were performed by the utilization of an effective micro-structured platform with a micro-heater to reach high temperature with low heating power as well as by the integration of indium oxide(In2O3)nanofibers decorated with well-dispersed Au nanoparticles as a sensing material.Homogeneous In2O3 nanofibers with the large specific surface area were prepared by the electrospinning following by calcination process.Au nanoparticles with the well-controlled size as a catalyst were synthesized on the surface of In2O3 nanofibers.The Au-decorated In2O3 nanofibers were reliably integrated as sensing materials on the bridge-type micro-platform including micro-heaters and micro-electrodes.The micro-platform designed to maintain high temperature with low power consumption was fabricated by a microelectromechanical system(MEMS)technique.The micro-platform gas sensor consisting with Au-In2O3 nanofibers were fabricated effectively to detect HCHO gases with high sensitivity and selectivity.The HCHO gas sensing behaviors were schematically studied as a function of the gas concentration,the size of the adsorbed Au nanoparticles,the applied power to raise the temperature of a sensing part and the kind of target gases.展开更多
This study addresses the liquid-liquid extraction behavior of phosphorus from a sulfuric acid solution using benzyl dimethyl amine(BDMA)in kerosene.The extraction equilibria investigated with varied BDMA concentration...This study addresses the liquid-liquid extraction behavior of phosphorus from a sulfuric acid solution using benzyl dimethyl amine(BDMA)in kerosene.The extraction equilibria investigated with varied BDMA concentrations could reveal the formation of 3[BDMA]·[H_(3)PO_(4)]^(-)complex in the organic phase.The thermodynamic properties determined at various temperatures indicated that the process was exothermic with a calculated enthalpy(△H^(Θ))of−24.0 kJ·mol^(−1).The organic-to-aqueous phase(O/A)volume ratio was varied to elucidate the quantitative extraction of phosphorus.The McCabe-Thiele diagram plotted for the extraction isotherm was validated for the requirement of three counter-current stages in the extraction at an O/A volume ratio of 2.0/3.5.The back-extraction of phosphorus from the loaded organic phase was quantitatively achieved by contacting 4.0 mol·L−1 H2SO4 solution in three stages of counter-current contact at an O/A volume ratio of 3/2.This study can be applied to remove phosphorus from the sulfuric acid leach solutions of monazite processing,and many other solutions.展开更多
Previous studies reported that specially designed ventilation systems provide good air quality and safe environment by removing airborne droplets that contain viruses expelled by infected people.These water droplets c...Previous studies reported that specially designed ventilation systems provide good air quality and safe environment by removing airborne droplets that contain viruses expelled by infected people.These water droplets can be stable in the environment and remain suspended in air for prolonged periods.Encounters between droplets may occur and droplet interactions should be considered.However,the previous studies focused on other physical phenomena(air flow,drag force,evaporation)for droplet transport and neglected droplet interactions.In this work,we used computational fluid dynamics(CFD)to simulate the transport and fate of airborne droplets expelled by an asymptomatic person and considered droplet interactions.Droplet drag with turbulence for prediction of transport and fate of droplets indicated that the turbulence increased the transport of 1μm droplets,whereas it decreased the transport of 50μm droplets.In contrast to only considering drag and turbulence,consideration of droplet interactions tended to increase both the transport and fate.Although the length scale of the office is much larger than the droplet sizes,the droplet interactions,which occurred at the initial stages of release when droplet separation distances were shorter,had a significant effect in droplet fate by considerably manipulating the final locations on surfaces where droplets adhered.Therefore,it is proposed that when an exact prediction of transport and fate is required,especially for high droplet concentrations,the effects of droplet interactions should not be ignored.展开更多
文摘This study focuses on using a green reagent scheme of methanesulfonic acid (MSA) and citric acid (CA) to extract valuable metals from the cathodes, aiming to minimize environmental impact during the recycling process. Leaching studies on LiCoO_(2) identified optimal conditions as follows: 2.4 mol/L MSA, 1.6 mol/L CA, S/L ratio of 80 g/L, leaching temperature of 90oC and leaching time of 6 h. The maximum Co and Li extraction achieved was 92% and 85%, respectively. LiCoO_(2) dissolution in MSA-CA leaching solution is highly impacted by temperature;Avrami equation showed a good fitting for the leaching data. The experimental activation energy of Co and Li was 50.98 kJ/mol and 50.55 kJ/mol, respectively, indicating that it is a chemical reaction-controlled process. Furthermore, cobalt was efficiently recovered from the leachate using oxalic acid, achieving a precipitation efficiency of 99.91% and a high-purity cobalt oxalate product (99.85 wt.%). In the MSA-CA leaching solution, MSA served as a lixiviant, while CA played a key role in reducing Co in LiCoO_(2). The overall organic acid leaching methodology presents an attractive option due to its reduced environmental impact.
基金financial support from the Project funded by the China Postdoctoral Science Foundation(No.2020M670709)the National Natural Science Foundation of China(No.51974064)+2 种基金the Fundamental Research Funds for the Central Universities,China(No.N2101025)the Open Foundation of State Key Laboratory of Mineral Processing(No.BGRIMM-KJSKL-2017-02)。
文摘The inadvertent dissolution of gangue minerals is frequently detrimental to the flotation of valuable minerals.We investigated the effect of conditioning time on the separation of brucite and serpentine by flotation.By analyzing the Mg2+concentration,relative element content,and pulp viscosity,we studied the effect of mineral dissolution on brucite flotation.The results of artificially mixed mineral flotation tests(with-10μm serpentine)showed that by extending the conditioning time from 60 to 360 s,a large amount of Mg2+on the mineral surface gradually dissolved into the pulp,resulting in a decreased brucite recovery(from 83.83%to 76.79%)and an increased recovery of serpentine from 52.12%to 64.03%.To analyze the agglomeration behavior of brucite and serpentine,we used scanning electron microscopy,which clearly showed the different adhesion behaviors of different conditioning times.Lastly,the total interaction energy,as determined based on the extended DLVO(Derjaguin-Landau-Verwey-Overbeek)theory,also supports the conclusion that the gravitational force between brucite and serpentine increases significantly with increased conditioning time.
基金supported financially by the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(No.2017R1D1A1B03030796).
文摘Approaches for the fabrication of a low power-operable formaldehyde(HCHO)gas sensor with high sensitivity and selectivity were performed by the utilization of an effective micro-structured platform with a micro-heater to reach high temperature with low heating power as well as by the integration of indium oxide(In2O3)nanofibers decorated with well-dispersed Au nanoparticles as a sensing material.Homogeneous In2O3 nanofibers with the large specific surface area were prepared by the electrospinning following by calcination process.Au nanoparticles with the well-controlled size as a catalyst were synthesized on the surface of In2O3 nanofibers.The Au-decorated In2O3 nanofibers were reliably integrated as sensing materials on the bridge-type micro-platform including micro-heaters and micro-electrodes.The micro-platform designed to maintain high temperature with low power consumption was fabricated by a microelectromechanical system(MEMS)technique.The micro-platform gas sensor consisting with Au-In2O3 nanofibers were fabricated effectively to detect HCHO gases with high sensitivity and selectivity.The HCHO gas sensing behaviors were schematically studied as a function of the gas concentration,the size of the adsorbed Au nanoparticles,the applied power to raise the temperature of a sensing part and the kind of target gases.
基金the Brain Pool Programthrough the National Research Foundation of Korea (NRF)funded by the Ministry of Science and ICT (Grant No.2019H1D3A2A02101993).The author Sadia Ilyas is gratefulto NRF for presenting the Brain Pool Scientists award.
文摘This study addresses the liquid-liquid extraction behavior of phosphorus from a sulfuric acid solution using benzyl dimethyl amine(BDMA)in kerosene.The extraction equilibria investigated with varied BDMA concentrations could reveal the formation of 3[BDMA]·[H_(3)PO_(4)]^(-)complex in the organic phase.The thermodynamic properties determined at various temperatures indicated that the process was exothermic with a calculated enthalpy(△H^(Θ))of−24.0 kJ·mol^(−1).The organic-to-aqueous phase(O/A)volume ratio was varied to elucidate the quantitative extraction of phosphorus.The McCabe-Thiele diagram plotted for the extraction isotherm was validated for the requirement of three counter-current stages in the extraction at an O/A volume ratio of 2.0/3.5.The back-extraction of phosphorus from the loaded organic phase was quantitatively achieved by contacting 4.0 mol·L−1 H2SO4 solution in three stages of counter-current contact at an O/A volume ratio of 3/2.This study can be applied to remove phosphorus from the sulfuric acid leach solutions of monazite processing,and many other solutions.
基金supported by the Brain Pool Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science and ICT,Republic of Korea(No.2019H1D3A 2A02101993).
文摘Previous studies reported that specially designed ventilation systems provide good air quality and safe environment by removing airborne droplets that contain viruses expelled by infected people.These water droplets can be stable in the environment and remain suspended in air for prolonged periods.Encounters between droplets may occur and droplet interactions should be considered.However,the previous studies focused on other physical phenomena(air flow,drag force,evaporation)for droplet transport and neglected droplet interactions.In this work,we used computational fluid dynamics(CFD)to simulate the transport and fate of airborne droplets expelled by an asymptomatic person and considered droplet interactions.Droplet drag with turbulence for prediction of transport and fate of droplets indicated that the turbulence increased the transport of 1μm droplets,whereas it decreased the transport of 50μm droplets.In contrast to only considering drag and turbulence,consideration of droplet interactions tended to increase both the transport and fate.Although the length scale of the office is much larger than the droplet sizes,the droplet interactions,which occurred at the initial stages of release when droplet separation distances were shorter,had a significant effect in droplet fate by considerably manipulating the final locations on surfaces where droplets adhered.Therefore,it is proposed that when an exact prediction of transport and fate is required,especially for high droplet concentrations,the effects of droplet interactions should not be ignored.
