Flotation is a complex multifaceted process that is widely used for the separation of finely ground minerals. The theory of froth flotation is complex and is not completely understood. This fact has been brought many ...Flotation is a complex multifaceted process that is widely used for the separation of finely ground minerals. The theory of froth flotation is complex and is not completely understood. This fact has been brought many monitoring challenges in a coal processing plant. To solve those challenges, it is important to understand the effect of different parameters on the fine particle separation, and control flotation performance for a particular system. This study is going to indicate the effect of various parameters （particle Characteristics and hydrodynamic conditions） on coal flotation responses （flotation rate constant and recovery） by different modeling techniques. A comprehensive coal flotation database was prepared for the statistical and soft computing methods. Statistical factors were used for variable selections. Results were in a good agreement with recent theoretical flotation investigations. Computational models accurately can estimate flotation rate constant and coal recovery （correlation coefficient 0.85, and 0.99, respectively）. According to the results, it can be concluded that the soft computing models can overcome the complexity of process and be used as an expert system to control, and optimize parameters of coal flotation process.展开更多
Flotation is considered as an effective and energy efficient method for harvesting microalgae.However,the interaction mechanism between bubble-algae cell and cell-cell interfacial boundaries in microalgae flotation is...Flotation is considered as an effective and energy efficient method for harvesting microalgae.However,the interaction mechanism between bubble-algae cell and cell-cell interfacial boundaries in microalgae flotation is not completely clear.To better understand the effects of surface characteristics on microalgae flotation performance,the hydrophobicity and the zeta potential of two different microalgae species were quantified based on experimental measurements and the extended DLVO(Derjagin–Landau–Verwey–Overbeek)theory.Flotation experiments were then carried out and the effects of surface characteristics on microalgae flotation performance were analyzed.Algae Chlorella vulgaris and Anabaena vasriabilis show naturally hydrophilic and hydrophobic properties,respectively.The addition of a cationic surfactant(C16TAB)can modify hydrophilic microalgae cells into hydrophobic and further Chlorella hydrophobicity is enhanced with increased C16TAB concentrations.The zeta potentials of both algae strains are negative in the tested pH range.Compared with Chlorella vulgaris,the magnitude of zeta potential of Anabaena vasriabilis is found larger at the same pH,resulting in a more dispersed distribution in the suspension.In addition,flotation experiments demonstrated that microalgae hydrophobicity and zeta potential have significant impacts on the harvesting efficiency and concentration factor.The hydrophobic attraction is found to play a more important role in determining the harvesting performance than electrostatic repulsion between the interacting surfaces,especially for hydrophobicity algae in the present study.Finally,the highest flotation efficiency and the highest concentration factor could not be concurrently obtained for both algae strains,suggesting that optimized flotation conditions should be selected as a compromise.展开更多
In this work,the effect of ammonium sulfate on the adsorption characteristics of low-concentration Pb(Ⅱ)ions on the sulfidized hemimorphite surface was comprehensively investigated.The results showed that ammonium su...In this work,the effect of ammonium sulfate on the adsorption characteristics of low-concentration Pb(Ⅱ)ions on the sulfidized hemimorphite surface was comprehensively investigated.The results showed that ammonium sulfate could increase the maximum recovery of hemimorphite from 69.42%to 88.24%under a low concentration of Pb(Ⅱ)ions.On the hemimorphite surface pretreated with ammonium sulfate,the adsorption of Pb(Ⅱ)ions was enhanced and the main species of Pb adsorbed was changed from Pb―O/OH to PbS.This was due to the larger amount of ZnS providing more effective adsorption sites for Pb components to generate Pb S.Meanwhile,the intensity of ZnS decreased with the formation of PbS,demonstrating that ZnS was covered by PbS which formed later on the mineral surface.It was beneficial for the adsorption of butyl xanthate on the hemimorphite surface to form more hydrophobic substances.As a result,ammonium sulfate played a crucial role in realizing the efficient recovery of hemimorphite.展开更多
文摘Flotation is a complex multifaceted process that is widely used for the separation of finely ground minerals. The theory of froth flotation is complex and is not completely understood. This fact has been brought many monitoring challenges in a coal processing plant. To solve those challenges, it is important to understand the effect of different parameters on the fine particle separation, and control flotation performance for a particular system. This study is going to indicate the effect of various parameters （particle Characteristics and hydrodynamic conditions） on coal flotation responses （flotation rate constant and recovery） by different modeling techniques. A comprehensive coal flotation database was prepared for the statistical and soft computing methods. Statistical factors were used for variable selections. Results were in a good agreement with recent theoretical flotation investigations. Computational models accurately can estimate flotation rate constant and coal recovery （correlation coefficient 0.85, and 0.99, respectively）. According to the results, it can be concluded that the soft computing models can overcome the complexity of process and be used as an expert system to control, and optimize parameters of coal flotation process.
基金the National Natural Science Foundation of China(41230314,51208059)the Special Fund for basic Scientific Research of Central Colleges,Chang’an University(310829163406).
文摘Flotation is considered as an effective and energy efficient method for harvesting microalgae.However,the interaction mechanism between bubble-algae cell and cell-cell interfacial boundaries in microalgae flotation is not completely clear.To better understand the effects of surface characteristics on microalgae flotation performance,the hydrophobicity and the zeta potential of two different microalgae species were quantified based on experimental measurements and the extended DLVO(Derjagin–Landau–Verwey–Overbeek)theory.Flotation experiments were then carried out and the effects of surface characteristics on microalgae flotation performance were analyzed.Algae Chlorella vulgaris and Anabaena vasriabilis show naturally hydrophilic and hydrophobic properties,respectively.The addition of a cationic surfactant(C16TAB)can modify hydrophilic microalgae cells into hydrophobic and further Chlorella hydrophobicity is enhanced with increased C16TAB concentrations.The zeta potentials of both algae strains are negative in the tested pH range.Compared with Chlorella vulgaris,the magnitude of zeta potential of Anabaena vasriabilis is found larger at the same pH,resulting in a more dispersed distribution in the suspension.In addition,flotation experiments demonstrated that microalgae hydrophobicity and zeta potential have significant impacts on the harvesting efficiency and concentration factor.The hydrophobic attraction is found to play a more important role in determining the harvesting performance than electrostatic repulsion between the interacting surfaces,especially for hydrophobicity algae in the present study.Finally,the highest flotation efficiency and the highest concentration factor could not be concurrently obtained for both algae strains,suggesting that optimized flotation conditions should be selected as a compromise.
基金the Fundamental Research Funds for the Central Universities(Nos.2022JCCXHH09 and 2022YJSHH01)the Yueqi Outstanding Scholar award of CUMTB+3 种基金the National Key R&D Program of China(No.SQ2022YFC2900065)the Ordos Science&Technology Plan(No.202204)the National Natural Science Foundation of China(No.52274283)the Open Research Fund of State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization(No.CNMRCUKF2107)。
文摘In this work,the effect of ammonium sulfate on the adsorption characteristics of low-concentration Pb(Ⅱ)ions on the sulfidized hemimorphite surface was comprehensively investigated.The results showed that ammonium sulfate could increase the maximum recovery of hemimorphite from 69.42%to 88.24%under a low concentration of Pb(Ⅱ)ions.On the hemimorphite surface pretreated with ammonium sulfate,the adsorption of Pb(Ⅱ)ions was enhanced and the main species of Pb adsorbed was changed from Pb―O/OH to PbS.This was due to the larger amount of ZnS providing more effective adsorption sites for Pb components to generate Pb S.Meanwhile,the intensity of ZnS decreased with the formation of PbS,demonstrating that ZnS was covered by PbS which formed later on the mineral surface.It was beneficial for the adsorption of butyl xanthate on the hemimorphite surface to form more hydrophobic substances.As a result,ammonium sulfate played a crucial role in realizing the efficient recovery of hemimorphite.
