J. Li
,
Z.G. Wang
,
Y.Q. Lai
,
Y.Y. Wu
,
S.L. Ye
,
null
,
null
,
null
,
null
,
null
,
null
金属学报(英文版)
Inert anode has been a hot issue in the aluminum industry for many decades. In this article, with the help of FEA (finite element analysis) software Ansys, a model was developed to simulate the thermal stress distribution working condition of an inert anode. To reduce its thermal stress, the effect of some parameters on the thermal stress distribution was investigated, including the anode height, the anode radius, the hole depth, the hole radius, the radius of inner chamfer, and outer chamfer. The results showed that in the actual working condition of an inert anode, there existed a large axial tensile stress near the tangent interface between the anode and bath, which was the major cause of anode breaking. Increasing the anode height and reducing the hole depth properly seemed to be beneficial for the stress distribution. With the increase of anode radius, the stress distribution became better first and then deteriorated, the reasonable value was between 0.045 to 0.06m. The hole radius had a significant effect on the stress and a smaller radius would reduce the thermal stress. The effect of the radius of the inner chamfer and the outer chamfer was less than other parameters.
关键词:
inert anode
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null
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null
Z.L. Tian
,
Y.Q. Lai
,
J. Li
,
null
,
null
,
null
,
null
,
null
金属学报(英文版)
(Cu-Ni)/(10NiO-90NiFe2O4) cermet inert anodes containing metal Cu-Ni 0, 5, 10, 15 and 20 wt% were prepared and their corrosion behavior in Na3AlF6-Al2O3 melts was investigated. The results indicate that the content of metal Cu-Ni has little effect on the steady-state concentration of Ni in electrolyte, the steady-state concentration of Fe decreases from 304ppm to 168ppm and that of Cu increases from 21ppm to 71ppm with the content of metal Cu-Ni increasing from 0 to 20 wt%. Post-examination shows that metallic phase Cu-Ni is corroded preferentially during electrolysis and many pores are left at the anode surface. Considering the corrosion resistance and electrical conductivity, the cermet containing metal Cu-Ni 5 wt% behaves best among NiO-NiFe2O4 based cermet anodes examined, and should be further studied.
关键词:
aluminum electrolysis
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null
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null
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null
J. Li
,
W. Liu
,
Y.Q. Lai
,
null
,
null
金属学报(英文版)
Two full 3D steady mathematical models are developed by finite element method (FEM) to calculate coupled physics fields: the electro-magnetic model is built and solved first and so is the fluid motion model with the acquired electromagnetic force as source body forces in Navier-Stokes equations. Effects caused by the ferromagnetic shell, busbar system around, and open boundary problem as well as inside induced current were considered in terms of the magnetic field. Furthermore, a new modeling method is found to set up solid models and then mesh them entirely with so-called structuralized grids, namely hex-mesh. Examples of 75kA prebaked cell with two kinds of busbar arrangements are presented. Results agree with those disclosed in the literature and confirm that the coupled simulation is valid. It is also concluded that the usage of these models facilitates the consistent analysis of the electric field to magnetic field and then flow motion to the greater extent, local distributions of current density and magnetic flux density are very much dependent on the cell structure, the steel shell is a shield to reduce the magnetic field and flow pattern is two dimensional in the main body of the metal pad.
关键词:
coupled simulation
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null
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null
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null
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null
X.P. Li
,
J. Li
,
Y.Q. Lai
,
H.Q. Zhao
,
Y.X. Liu
金属学报(英文版)
A 2D full cell thermo-electric model of 160kA drained cell was set up using finite
element code to calculate its freeze profile, then the drained cell model was modified
according to the freeze profile computed and its heat balance was calculated. Compared
with that of a 160kA conventional Hall-Heroult cell (H-H cell), though the melts volume of the drained cell reduced greatly, the whole heat loss from it didn't drop down
apparently, and an analysis was presented in the paper. On the other hand, the anode-
cathode distance (ACD) of a drained cell was much less than that of a H-H cell, so
the voltage drop on it and heat produced decreased too, steps should be taken to keep
a workable heat balance on a drained cell.
关键词:
drained cell
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null
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null
J. Li
,
Q.S. Zhang
,
Y.Q. Lai
,
S.L. Ye
,
Y.X. Liu
金属学报(英文版)
The thermal stresses relaxation of Ni/NiFe2O4 system functionally graded cermet inert anode for aluminum electrolysis was optimally designed. The transient thermal stresses of the inert anode under complex boundary condition during high-temp (955℃) electrolysis were calculated using the finite-element software ANSYS, the influence of different parameters on the distribution of the thermal stresses were analyzed. The results showed that, during the process of thermal shock, the thermal hoop tensile stress on the surface of the anode is very large, which is possibly the major cause of anode crack; when the radius of the anode is between 0.05-0.15m, a range that can be realized by recent manufacturing technology, the optimum composition distribution exponent p is 0.25; The hoop tensile stresses reduce with the decrease of anode scale and also decrease with the decrease of the convection coefficient between the electrolyte and the anode.
关键词:
functionally graded material (FGM)
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null
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null
