To improve the separation efficiency of a conventional Teetered Bed Separator(TBS) in beneficiation of fine coal with a wide size range,an Aeration TBS(A-TBS) was proposed in this investigation.The bubbles were introd...To improve the separation efficiency of a conventional Teetered Bed Separator(TBS) in beneficiation of fine coal with a wide size range,an Aeration TBS(A-TBS) was proposed in this investigation.The bubbles were introduced to A-TBS by a self-priming micro-bubble generator.This study theoretically analyzed the effect of bubbles on the difference in hindered settling terminal velocity between different density particles,investigated the impact of superficial water velocity(V_(SW)) and superficial gas velocity(V_(Sg)) on bed fluidization,and compared the performance of the TBS and A-TBS in treating 1-0.25 mm size fraction particles.The results show that the expansion degree of fluidized bed which was formed by different size particles or has different initial height,is increased by the introduction of bubbles.Compared with the TBS,at the same level of clean coal ash content,the A-TBS shows an increase in the combustible recovery of clean coal,ash content of tailings,and practical separation density by 5.26%,6.56%,and 0.088 g/cm3 respectively,while it shows a decrease in the probable error(E_p) and V_(SW) by 0.031 and 3.51 mm/s,respectively.The addition of bubbles at a proper amount not only improves the separation performance of TBS,but also reduces the upward water velocity.展开更多
Two new pentanary sulfides Ba_(3)La_(4)Ga_(2)Sb_(2)S_(15)(1)and BaLa_(3)GaSb_(2)S_(10)(2)have been discovered by high temperature solid state reactions.Ba_(3)La_(4)Ga_(2)Sb_(2)S_(15)features a new zero-dimensional str...Two new pentanary sulfides Ba_(3)La_(4)Ga_(2)Sb_(2)S_(15)(1)and BaLa_(3)GaSb_(2)S_(10)(2)have been discovered by high temperature solid state reactions.Ba_(3)La_(4)Ga_(2)Sb_(2)S_(15)features a new zero-dimensional structure type,which consists of unique isolated Sb_(2)S_(7)dimers and GaS_(4)tetrahedra.In contrast,with less GaS_(4)tetrahedra in the formula,BaLa_(3)GaSb_(2)S_(10)forms a one-dimensional structure which is constructed by teeter-totter(SbS_(4))n chains and isolated GaS_(4)tetrahedra.On the basis of UV/Vis spectroscopy,their band gaps are determined to be 2.42 and 2.15 eV,respectively,which are much wider than that of analogue La_(4)FeSb_(2)S_(10)(1.0 eV).In addition,theoretical studies illustrate the important role of Ga in expanding the band gaps with respect to Fe atoms.The calculated crystal orbital Hamilton population and electron localization function confirm that the long Sb-S bonds in Ba_(3)La_(4)Ga_(2)Sb_(2)S_(15)(2.932(2)A)and BaLa_(3)GaSb_(2)S_(10)(3.216(5)and 3.219(5)A)have weak but nonnegligible bonding interactions.展开更多
基金supported by the National Natural Science Foundation of China(No.51474213)the National Natural Science Foundation of China(No.51374205)+1 种基金the Fundamental Research Funds for the Central Universities(No.2014XT05)A Priority Academic Program Development of Jiangsu Higher Education Institutions
文摘To improve the separation efficiency of a conventional Teetered Bed Separator(TBS) in beneficiation of fine coal with a wide size range,an Aeration TBS(A-TBS) was proposed in this investigation.The bubbles were introduced to A-TBS by a self-priming micro-bubble generator.This study theoretically analyzed the effect of bubbles on the difference in hindered settling terminal velocity between different density particles,investigated the impact of superficial water velocity(V_(SW)) and superficial gas velocity(V_(Sg)) on bed fluidization,and compared the performance of the TBS and A-TBS in treating 1-0.25 mm size fraction particles.The results show that the expansion degree of fluidized bed which was formed by different size particles or has different initial height,is increased by the introduction of bubbles.Compared with the TBS,at the same level of clean coal ash content,the A-TBS shows an increase in the combustible recovery of clean coal,ash content of tailings,and practical separation density by 5.26%,6.56%,and 0.088 g/cm3 respectively,while it shows a decrease in the probable error(E_p) and V_(SW) by 0.031 and 3.51 mm/s,respectively.The addition of bubbles at a proper amount not only improves the separation performance of TBS,but also reduces the upward water velocity.
基金supported by the NSF of China(No.21225104,21233009,91422303,21571020,21301175,21171168 and 21671023)。
文摘Two new pentanary sulfides Ba_(3)La_(4)Ga_(2)Sb_(2)S_(15)(1)and BaLa_(3)GaSb_(2)S_(10)(2)have been discovered by high temperature solid state reactions.Ba_(3)La_(4)Ga_(2)Sb_(2)S_(15)features a new zero-dimensional structure type,which consists of unique isolated Sb_(2)S_(7)dimers and GaS_(4)tetrahedra.In contrast,with less GaS_(4)tetrahedra in the formula,BaLa_(3)GaSb_(2)S_(10)forms a one-dimensional structure which is constructed by teeter-totter(SbS_(4))n chains and isolated GaS_(4)tetrahedra.On the basis of UV/Vis spectroscopy,their band gaps are determined to be 2.42 and 2.15 eV,respectively,which are much wider than that of analogue La_(4)FeSb_(2)S_(10)(1.0 eV).In addition,theoretical studies illustrate the important role of Ga in expanding the band gaps with respect to Fe atoms.The calculated crystal orbital Hamilton population and electron localization function confirm that the long Sb-S bonds in Ba_(3)La_(4)Ga_(2)Sb_(2)S_(15)(2.932(2)A)and BaLa_(3)GaSb_(2)S_(10)(3.216(5)and 3.219(5)A)have weak but nonnegligible bonding interactions.
