The major reason of Al anode activation is that Ga can plate out on the aluminum surface and form activated points. The Al-Sn, Al - Ga binary alloys can’t be activat6d in alkaline medium. During the dissolution of th...The major reason of Al anode activation is that Ga can plate out on the aluminum surface and form activated points. The Al-Sn, Al - Ga binary alloys can’t be activat6d in alkaline medium. During the dissolution of the Al - Sn - Ga ternary anode, Sn and Ga dissolove solution aions as ions. After Sn ions deposit on the surface of Al anode, Ga ions will underpotentially deposit on Sn. The higher activation of the polycomponent alloy anode is caused by much more new activated points being continually formed. The activation mechanism for the polycomponent Al-alloy anode in alkaline medium is abided by the" di ssolution-deposition".展开更多
In order to study the anodic behavior and microstmctures of A1/Pb-Ag-Co anode during zinc electrowinning, by means of potentiodynamic investigations, scanning electron microscopy （SEM） and X-ray diffraction （XRD） ...In order to study the anodic behavior and microstmctures of A1/Pb-Ag-Co anode during zinc electrowinning, by means of potentiodynamic investigations, scanning electron microscopy （SEM） and X-ray diffraction （XRD） analyses, the mechanism of the anodic processes playing on the surface of A1/Pb-0.8%Ag and A1/Pb-0.75%Ag-0.03%Co anodes prepared by electro-deposition from methyl sulfonic acid bath for zinc electrowinning from model sulphate electrolytes have been measured. On the basis of the cyclic voltammograms obtained, information about the corrosion rate of the composite in PbO2 region has been concluded. The microstructures were also observed by means of SEM and XRD which showed Pb-0.75%Ag-0.03%Co alloy composite coating has uniform and chaotic orientation tetragonal symmetry crystallites of PbSO4, but Pb-0.8%Ag alloy composite coating has well-organized orientation crystallites of PbSO4 concentrated in the certain zones after 24 h of anodic polarization. It is important that Al/Pb-0.75%Ag-0.03%Co anode oxide film consists of non-conductive dense MnO2 and PbSO4 and a, fl-PbO2 penetrated into which, in fact, are the active centers of the oxygen evolution after 24 h of anodic polarization.展开更多
Anodic electrochemical behavior was studied on graphite anode at 1000 ℃ in cryolite-alumina molten salt by means of cyclic voltammetry. The high current peak in a typical cyclic voltammogram was discussed. It is cons...Anodic electrochemical behavior was studied on graphite anode at 1000 ℃ in cryolite-alumina molten salt by means of cyclic voltammetry. The high current peak in a typical cyclic voltammogram was discussed. It is considered that a type of oxyfluoroaliminate complex anions reacts with carbon to form a high-resistance CF film on the anode surface at a high potential. The passivation potential is 3.28 V in 0.5% alumina-containing electrolyte, and the passivation potential increases with alumina content increasing which indicates that the alumina content determines the anodic process in the cryolite-alumina molten salt system.展开更多
文摘The major reason of Al anode activation is that Ga can plate out on the aluminum surface and form activated points. The Al-Sn, Al - Ga binary alloys can’t be activat6d in alkaline medium. During the dissolution of the Al - Sn - Ga ternary anode, Sn and Ga dissolove solution aions as ions. After Sn ions deposit on the surface of Al anode, Ga ions will underpotentially deposit on Sn. The higher activation of the polycomponent alloy anode is caused by much more new activated points being continually formed. The activation mechanism for the polycomponent Al-alloy anode in alkaline medium is abided by the" di ssolution-deposition".
基金Project(51004056)supported by the National Natural Science Foundation of China
文摘In order to study the anodic behavior and microstmctures of A1/Pb-Ag-Co anode during zinc electrowinning, by means of potentiodynamic investigations, scanning electron microscopy （SEM） and X-ray diffraction （XRD） analyses, the mechanism of the anodic processes playing on the surface of A1/Pb-0.8%Ag and A1/Pb-0.75%Ag-0.03%Co anodes prepared by electro-deposition from methyl sulfonic acid bath for zinc electrowinning from model sulphate electrolytes have been measured. On the basis of the cyclic voltammograms obtained, information about the corrosion rate of the composite in PbO2 region has been concluded. The microstructures were also observed by means of SEM and XRD which showed Pb-0.75%Ag-0.03%Co alloy composite coating has uniform and chaotic orientation tetragonal symmetry crystallites of PbSO4, but Pb-0.8%Ag alloy composite coating has well-organized orientation crystallites of PbSO4 concentrated in the certain zones after 24 h of anodic polarization. It is important that Al/Pb-0.75%Ag-0.03%Co anode oxide film consists of non-conductive dense MnO2 and PbSO4 and a, fl-PbO2 penetrated into which, in fact, are the active centers of the oxygen evolution after 24 h of anodic polarization.
基金Projects (50804010, 51074046) supported by the National Natural Science Foundation of China
文摘Anodic electrochemical behavior was studied on graphite anode at 1000 ℃ in cryolite-alumina molten salt by means of cyclic voltammetry. The high current peak in a typical cyclic voltammogram was discussed. It is considered that a type of oxyfluoroaliminate complex anions reacts with carbon to form a high-resistance CF film on the anode surface at a high potential. The passivation potential is 3.28 V in 0.5% alumina-containing electrolyte, and the passivation potential increases with alumina content increasing which indicates that the alumina content determines the anodic process in the cryolite-alumina molten salt system.
