A series of high quality Dy_(2)O_(3) and Tm_(2)O_(3)co-doped yttria stabilized zirconia(YSZ) single crystals was synthesized.These crystals have a single cubic structure,and exhibit the characteristic of Dy^(3+)(blue ...A series of high quality Dy_(2)O_(3) and Tm_(2)O_(3)co-doped yttria stabilized zirconia(YSZ) single crystals was synthesized.These crystals have a single cubic structure,and exhibit the characteristic of Dy^(3+)(blue and yellow emissions) and Tm^(3+)(blue emission) under excitation with NUV light.Impo rtantly,the hue can be varied between blue and white by modifying the Tm^(3+)/Dy^(3+)ratio.The photoluminescence and decay curves are consistent with the existence of resonance-type energy transfer from Tm^(3+)to Dy^(3+)ions via an electric multipole interaction mechanism.Maximum luminescence intensity is observed in YSZ doped with 0.50 mol% Tm_(2)O_(3) and 0.75 mol% Dy_(2)O_(3),and this sample has CIE coordinates(x = 0.33,y = 0.33) in accordance with those for white chromaticity.Thus,the outstanding luminescence properties of these single crystals suggest potential applications in white light emission devices.展开更多
Bastnaesite is an important rare earth mineral and is usually beneficiated by flotation.Sodium silicate is commonly used to depress calcium-bearing gangue minerals,however it can also depress bastnaesite when Ca^(2+) ...Bastnaesite is an important rare earth mineral and is usually beneficiated by flotation.Sodium silicate is commonly used to depress calcium-bearing gangue minerals,however it can also depress bastnaesite when Ca^(2+) ions exist in the pulp.In this study,the effect of Ca^(2+) ions and sodium silicate individually or in combination on bastnaesite flotation was studied through micro-flotation,zeta potential,fluorescence spectroscopy and X-ray photoelectron spectroscopy(XPS) measurements.Micro-flotation results show that the combination of Ca^(2+) ions and sodium silicate depresses bastnaesite more severely due to their synergistic effect.Zeta potential results show that the combination renders the surface potential of bastnaesite negatively shifted more significantly.Fluorescence spectroscopy shows that the combination decreases the surface hydrophobicity of bastnaesite more severely.XPS shows that the combination increases the adsorption of sodium silicate on bastnaesite by forming hydrophilic Ca-SiO_(3) precipitate,which causes more serious depression on bastnaesite flotation.展开更多
基金Project supported by the National Natural Science Foundations of China (11975004,12175047)the Key Research and Development Plan Project of Guangxi,China (Guike AB18281007)。
文摘A series of high quality Dy_(2)O_(3) and Tm_(2)O_(3)co-doped yttria stabilized zirconia(YSZ) single crystals was synthesized.These crystals have a single cubic structure,and exhibit the characteristic of Dy^(3+)(blue and yellow emissions) and Tm^(3+)(blue emission) under excitation with NUV light.Impo rtantly,the hue can be varied between blue and white by modifying the Tm^(3+)/Dy^(3+)ratio.The photoluminescence and decay curves are consistent with the existence of resonance-type energy transfer from Tm^(3+)to Dy^(3+)ions via an electric multipole interaction mechanism.Maximum luminescence intensity is observed in YSZ doped with 0.50 mol% Tm_(2)O_(3) and 0.75 mol% Dy_(2)O_(3),and this sample has CIE coordinates(x = 0.33,y = 0.33) in accordance with those for white chromaticity.Thus,the outstanding luminescence properties of these single crystals suggest potential applications in white light emission devices.
基金Project supported by the National Natural Science Foundation of China(51764045)the Open Project of State Key Laboratory of Mineral Processing(BGRIMM-KJSKL-2020-23)+2 种基金the Excellent Youth Foundation of IMUST(2017YQL05)the Inner Mongolia Natural Science Foundation(2020LH05027,2019MS05039)the Inner Mongolia Major Basic Research Open Project(0406091701)。
文摘Bastnaesite is an important rare earth mineral and is usually beneficiated by flotation.Sodium silicate is commonly used to depress calcium-bearing gangue minerals,however it can also depress bastnaesite when Ca^(2+) ions exist in the pulp.In this study,the effect of Ca^(2+) ions and sodium silicate individually or in combination on bastnaesite flotation was studied through micro-flotation,zeta potential,fluorescence spectroscopy and X-ray photoelectron spectroscopy(XPS) measurements.Micro-flotation results show that the combination of Ca^(2+) ions and sodium silicate depresses bastnaesite more severely due to their synergistic effect.Zeta potential results show that the combination renders the surface potential of bastnaesite negatively shifted more significantly.Fluorescence spectroscopy shows that the combination decreases the surface hydrophobicity of bastnaesite more severely.XPS shows that the combination increases the adsorption of sodium silicate on bastnaesite by forming hydrophilic Ca-SiO_(3) precipitate,which causes more serious depression on bastnaesite flotation.