The growing characteristics of metallic iron particles during reductive roasting of boron-bearing magnetite concentrate under different conditions were investigated.The size of the metallic iron particles was quantita...The growing characteristics of metallic iron particles during reductive roasting of boron-bearing magnetite concentrate under different conditions were investigated.The size of the metallic iron particles was quantitatively measured via optical image analysis with consideration of size calibration and weighted ratio of image numbers in the core,middle and periphery zones of cross-section of pellets.In order to guarantee the measurement accuracy,54 images were captured in total for each specimen,with a weighted ratio of 1:7:19 with respect to the core,middle and periphery section of the cross-section of pellets.Increasing reduction temperature and time is favorable to the growth of metallic iron particles.Based on the modification of particle size measurement,in terms of time(t)and temperature(T)a predicting model of metallic iron particle size(D),was established as:D=125−0.112t−0.2352T−5.355×10^−4t^2+2.032×10^−4t∙T+1.134×10^−4T^2.展开更多
A new transition metal-antimony oxo-cluster based compound has been synthesized in water under room temperature.Its formula is Na_(6)[Cu_(6)MnSb_(6)(μ_(3)-OH)_(2)(OH)(μ_(4)-O)_(6)(tartrate)_(6)]-_(2)0H_(2)O(1),where...A new transition metal-antimony oxo-cluster based compound has been synthesized in water under room temperature.Its formula is Na_(6)[Cu_(6)MnSb_(6)(μ_(3)-OH)_(2)(OH)(μ_(4)-O)_(6)(tartrate)_(6)]-_(2)0H_(2)O(1),where tartrate represents rac-tartaric acid.It was characterized by elemental analysis,infrared spectrum and X-ray single-crystal diffraction.The compound crystallizes in the monoclinic system,space group P2_(1/n).Structural analyses revealed that two Sb_(3)(μ_(3)-0)(tartrate)_(3)scaffolds sandwich a Cu^(Ⅱ)_(_(6))Mn^(Ⅲ)middle layer to form the cluster.In the middle layer,all the seven metal ions lie in an almost regular hexagon,with Mn^(Ⅲ)ion in the center and six Cu^(Ⅱ)ions along the edges of the hexagon.As a 4-connected node,each cluster is interlinked to its nearest four{Cu_(6)Mn}neighbors through Na^(+),generating a 3D supramolecular framework.The temperature-dependent magnetic susceptibilities indicated dominating antiferromagnetic interactions in 1 with J_(Cu-Cu)=176.34 and J(Cu-Mn)=-14.44 cm^(-1).展开更多
基金Project(51804346)supported by the National Natural Science Foundation of ChinaProject(2019JJ50767)supported by the Natural Science Foundation of Hunan Province,ChinaProject(KY[2017]125)supported by Youth Foundation of Guizhou Education Department,China。
文摘The growing characteristics of metallic iron particles during reductive roasting of boron-bearing magnetite concentrate under different conditions were investigated.The size of the metallic iron particles was quantitatively measured via optical image analysis with consideration of size calibration and weighted ratio of image numbers in the core,middle and periphery zones of cross-section of pellets.In order to guarantee the measurement accuracy,54 images were captured in total for each specimen,with a weighted ratio of 1:7:19 with respect to the core,middle and periphery section of the cross-section of pellets.Increasing reduction temperature and time is favorable to the growth of metallic iron particles.Based on the modification of particle size measurement,in terms of time(t)and temperature(T)a predicting model of metallic iron particle size(D),was established as:D=125−0.112t−0.2352T−5.355×10^−4t^2+2.032×10^−4t∙T+1.134×10^−4T^2.
基金Supported by the National Natural Science Foundation of China(No.22001064)the Natural Science Foundation of Hunan Province(No.2020JJ4155)+1 种基金the Hunan Province College Students Innovation Entrepreneurship Training Program(2020 No.3373,2021 No.3340)the Scientific Research Project of Hunan Province Department of Education(No.20B105)。
文摘A new transition metal-antimony oxo-cluster based compound has been synthesized in water under room temperature.Its formula is Na_(6)[Cu_(6)MnSb_(6)(μ_(3)-OH)_(2)(OH)(μ_(4)-O)_(6)(tartrate)_(6)]-_(2)0H_(2)O(1),where tartrate represents rac-tartaric acid.It was characterized by elemental analysis,infrared spectrum and X-ray single-crystal diffraction.The compound crystallizes in the monoclinic system,space group P2_(1/n).Structural analyses revealed that two Sb_(3)(μ_(3)-0)(tartrate)_(3)scaffolds sandwich a Cu^(Ⅱ)_(_(6))Mn^(Ⅲ)middle layer to form the cluster.In the middle layer,all the seven metal ions lie in an almost regular hexagon,with Mn^(Ⅲ)ion in the center and six Cu^(Ⅱ)ions along the edges of the hexagon.As a 4-connected node,each cluster is interlinked to its nearest four{Cu_(6)Mn}neighbors through Na^(+),generating a 3D supramolecular framework.The temperature-dependent magnetic susceptibilities indicated dominating antiferromagnetic interactions in 1 with J_(Cu-Cu)=176.34 and J(Cu-Mn)=-14.44 cm^(-1).
