METHOD FOR UNIFORMING DISTRIBUTION OF CURRENT IN ALUMINUM LIQUID IN AN ALUMINUM ELECTROLYTIC TANK

PROCEDE D'UNIFORMISATION DE LA DISTRIBUTION DE COURANT DANS UNE CELLULE D'ELECTROLYSE D'ALUMINIUM

English Abstract

Disclosed is a method for uniforming the distribution of current in an aluminum electrolysis cell. At least one cathode steel bar is fixedly tied or casted at the lower part of a cathode carbon block,and the cathode steel bar is cutted into several sections located at different places along the length direction by a separating seam.The said sections upon the separating seams of the cathode steel bar except those between the separating seams are totally connected with the cathode carbon block by conductive bodies,and the sections between and below the separating seams of the cathode carbon steel bar are insulated from the cathode carbon block by insulators. Insulating materials for separating seam are filled in the separating seam, so that the sections upon and below the separating seams of the cathode steel bar are insulated from each other,and one end of the cathode steel bar penetrates out of the electrolytic cell from its sidepiece. The cathode current of the aluminum electrolysis cell is distributed more uniformly, and the horizontal current in the aluminum liquid is reduced, then the stability of the electrolytic cell is improved, and the aluminum electrolysis cell can be efficiently circulated with a low polar distance, thus the energy consumption for per ton of aluminum is reduced effectively, and the energy-saving effect is achieved, meanwhile the service life of the cathode is also prolonged.

French Abstract

L'invention concerne un procédé d'uniformisation de la distribution du courant dans une cellule d'électrolyse d'aluminium. Au moins une barre d'acier cathodique est attachée de façon fixe ou coulée au niveau de la partie inférieure d'un bloc cathodique au carbone, et la barre d'acier cathodique est coupée en plusieurs sections situées à différents endroits dans le sens de la longueur par un joint de séparation. Lesdites sections sur les joints de séparation de la barre d'acier cathodique, excepté celles entre les joints de séparation, sont totalement raccordées avec le bloc cathodique au carbone par des corps conducteurs, et les sections entre et sous les joints de séparation de la barre d'acier cathodique au carbone sont isolées du bloc cathodique au carbone par des isolants. Les matériaux isolants destinés au joint de séparation remplissent le joint de séparation, de sorte que les sections sur et sous les joints de séparation de la barre d'acier cathodique sont isolées les unes des autres, et une extrémité de la barre d'acier cathodique traverse la cellule électrolytique en sortant de son montant. Le courant de cathode de la cellule d'électrolyse d'aluminium est distribué de manière plus uniforme, et le courant horizontal dans le liquide d'aluminium est réduit. Ainsi, la stabilité de la cellule électrolytique est améliorée, et la cellule d'électrolyse d'aluminium peut circuler efficacement avec une faible distance polaire, ce qui permet de réduire efficacement la consommation d'énergie par tonne d'aluminium, et d'atteindre l'effet d'économie d'énergie, alors que la durée de vie de la cathode est également prolongée.

Claims

CLAIMS:
1. A method for uniforming the distribution of current in an aluminum
liquid
in an aluminum electrolytic tank, comprising: fixedly bundling or casting at
least one
cathode steel bar at the lower part of a cathode carbon block, wherein the
cathode
steel bar is divided into several sections at different positions along the
length
direction by one or more separating seams, any section of the cathode steel
bar
between the one or more separating seams is connected with the cathode carbon
block by an insulator and any section of the cathode steel bar below a lowest
separating seam is connected with the cathode carbon block by the insulator,
and
any remaining section is totally connected with the cathode carbon block by
conductive bodies; the one or more separating seams are filled with an
insulating
material for the one or more separating seams, so that the sections of the
cathode
steel bar above and below the one or more separating seams are insulated from
each other, and one end of the cathode steel bar penetrates out of the
electrolytic
tank from the side of the electrolytic tank.
2. The method for uniforming the distribution of current in the aluminum
liquid in the aluminum electrolytic tank according to claim 1, wherein the
conductive
body is carbon paste or ferrophosphorus.
3. The method for uniforming the distribution of current in the aluminum
liquid in the aluminum electrolytic tank according to claim 1, wherein the
cathode
steel bar is partially fixedly bundled or casted in the cathode carbon block.
4. The method for uniforming the distribution of current in the aluminum
liquid in the aluminum electrolytic tank according to claim 1 or 3, wherein
the number
of the one or more separating seams in each cathode steel bar is 1 to 20.
5. The method for uniforming the distribution of current in the aluminum
liquid in the aluminum electrolytic tank according to claim 1, wherein the
cross section
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of the cathode steel bar is in the shape of a square, a circle, a semi-circle,
a trapezoid
or a triangle.
6. The method for uniforming the distribution of current in the
aluminum
liquid in the aluminum electrolytic tank according to claim 1, wherein below
the
cathode carbon block is mounted 1 to 50 cathode steel bars.
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Description

CA 02834290 2013-10-25
FPME12140009P
METHOD FOR UNIFORMING DISTRIBUTION OF CURRENT IN
ALUMINUM LIQUID IN AN ALUMINUM ELECTROLYTIC TANK
TECHNICAL FIELD
The present invention relates to an aluminum electrolytic tank for
producing primary aluminum by Hall-Heroult electrolysis, more specially, to a
method for uniforming distribution of current in aluminum liquid in an
aluminum
electrolytic tank.
BACKGROUND ART
The metal aluminum is produced by molten salt electrolysis in the industry,
i.e., aluminium oxide dissolved in an electrolyte with molten cryolite as the
main component is electrolyzed. Currently, the mainly method is Hall-Heroult
electrolysis.
The direct apparatus for producing electrolytic aluminum is an electrolytic
tank, which mainly consists of two major portions, one is an anode generally
made of a carbon material, and the other is a cathode formed by laying of
carbon blocks and an inner liner material.
The aluminum electrolytic tank is connected in series in the entire
electrolytic system, wherein the current enters the electrolytic tank from the

anode, and enters the cathode carbon block through the molten electrolyte and
the aluminum liquid in liquid form, wherein the current is collected by
cathode
steel bar(s) assembled in the cathode carbon block, and is guided into the
next
electrolytic tank by a cathode busbar.
The cathode structure of the existing aluminum electrolytic tank is: the
bottom of the cathode carbon block is provided with cathode steel bar(s), the
cathode steel bar and the carbon block are entirely connected by means of
paste bundling or casting ferrophosphorus, each cathode carbon block is
provided with one or two cathode steel bars, the cathode steel bar and the
cathode carbon block are placed horizontally in the same direction, and one

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end of the cathode steel bar extends out from the side wall of the
electrolytic
tank and is connected with the cathode busbar. In the electrolytic tank with
such a structure, the cathode conductive structure has a rather great
disadvantage: since the cathode steel bar and the cathode carbon block are
placed horizontally in the same direction, a rather substantial horizontal
current
is produced in the aluminum liquid, the horizontal current co-working with the

vertical magnetic field in the aluminum liquid to produce an electromagnetic
force, which drives the aluminum liquid in liquid form to flow and fluctuate
in the
electrolytic tank; if the horizontal current in the electrolytic tank is too
large and
is not in uniform distribution, the interface between the aluminum liquid and
the
electrolyte will fluctuate greatly, such that the electrolytic tank generates
severe instability during production and the efficiency of the current is
decreased. In addition, the horizontal current in the aluminum liquid is not
in
uniform distribution along the length direction of the cathode carbon block,
such that the current at the end of the cathode carbon block has the maximum
density, resulting in that corrosion at this part of the cathode carbon block
is
significantly expedited and the service life is the electrolytic tank is
decreased.
In order to increase stability of the electrolytic tank, the common manner is
to control strictly, in the design of the electrolytic tank, the distribution
of the
vertical magnetic field in the aluminum liquid, which not only increases
difficulty
in the design of a cathode busbar, but also results in that the configuration
of
the cathode becomes complicated, more busbars are used, and the cost is
increased.
SUMMARY OF THE INVENTION
For solving the aforesaid technical problems, i.e., to uniform the
distribution of the current in the aluminum liquid and to increase stability
of the
electrolytic tank, the present invention provides a method for uniforming the
distribution of current in the aluminum liquid in an aluminum electrolytic
tank,
which aims to reduce the horizontal current in the aluminum liquid, to make
the
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current in the aluminum liquid distributed more uniformly, to greatly improve
the
stability of the electrolytic tank, to enable the electrolytic tank to operate
efficiently
and stably under a very low polar distance, to reduce the energy consumption
for per
ton of aluminum effectively, and meanwhile to make the density of the cathode
current more uniform, to reduce the rate of cathode abrasion, and to prolong
the
service life of the cathode.
An aspect of the invention relates to a method for uniforming the
distribution of current in the aluminum liquid in an aluminum electrolytic
tank, in which
at least one cathode steel bar is fixedly bundled or casted at the lower part
of a
cathode carbon block, and the cathode steel bar is divided into several
sections at
different positions along the length direction by separating seams, the
sections of the
cathode steel bar on each separating seam are totally connected with the
cathode
carbon block by conductive bodies, except those sections between the
separating
seams, and the remaining sections of the cathode steel bar are all insulated
from the
cathode carbon block by insulators; the separating seams are filled with an
insulating
material for the separating seams, so that the both sections of the cathode
steel bar
above and below the separating seam are insulated from each other, and one end
of
The cathode steel bar penetrates out of the electrolytic tank from the side of
the
electrolytic tank.
In another aspect, the conductive body is carbon paste or
ferrophosphorus.
In another aspect, the cathode steel bar is partially fixedly bundled or
casted in the cathode carbon block.
In another aspect, the number of the separating seams in each cathode
steel bar is 1 to 20.
In another aspect, the cross section of the cathode steel bar is in the
shape of a square, a circle, a semi-circle, a trapezoid or a triangle.
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In another aspect, below each set of the cathode carbon blocks are
mounted 1 to 50 cathode steel bars.
The invention may further relate to a method for uniforming the
distribution of current in an aluminum liquid in an aluminum electrolytic
tank,
comprising: fixedly bundling or casting at least one cathode steel bar at the
lower part
of a cathode carbon block, wherein the cathode steel bar is divided into
several
sections at different positions along the length direction by one or more
separating
seams, any section of the cathode steel bar between the one or more separating

seams is connected with the cathode carbon block by an insulator and any
section of
the cathode steel bar below a lowest separating seam is connected with the
cathode
carbon block by the insulator, and any remaining section is totally connected
with the
cathode carbon block by conductive bodies; the one or more separating seams
are
filled with an insulating material for the one or more separating seams, so
that the
sections of the cathode steel bar above and below the one or more separating
seams
are insulated from each other, and one end of the cathode steel bar penetrates
out of
the electrolytic tank from the side of the electrolytic tank.
The present invention may have great practicability, i.e., when the
electricity output manner of the cathode remains unchanged (electricity is
output from
the side), the horizontal current in the aluminum liquid may be greatly
reduced, the
current in the aluminum liquid is distributed more uniformly, the stability of
the
electrolytic tank may be greatly improved, the service life of the cathode may
be also
prolonged, the electrolytic tank may operate efficiently and stably under a
very low
polar distance, the energy consumption for per ton of aluminum may be reduced
effectively, and a remarkable energy-saving effect may be achieved.
BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a schematic structure view of the cathode structure of the
present invention.
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Fig. 2 is a schematic view of the combined structure of the cathode
carbon block and the cathode steel bar of the present invention.
Fig. 3 is a top plan structure view of the combined structure of the
cathode carbon block and the cathode steel bar of Fig. 2.
Fig. 4 is a schematic view of A-A sectional structure in Fig. 3.
Fig. 5 is a schematic structure view of the cathode steel bar partially
fixedly bundled or casted in the cathode carbon block.
In the figures, reference number 1 refers to the cathode carbon block;
reference number 2 refers to the cathode steel bar; reference number 3 refers
to the
separating seam; reference number 4 refers to the insulating material for the
separating seam; reference number 5 refers to the insulator; and reference
number 6
refers to the conductive body.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Next, the present invention will be illustrated in details in conjunction
with the drawings, whereas the scope of protection of the present invention is
not
limited by the embodiments.
As shown in the drawings, the present invention provides a method for
uniforming the distribution of current in the aluminum liquid in an aluminum
electrolytic tank, in which at least one cathode steel bar 2 is fixedly
bundled or casted
at the lower part of a cathode carbon block 1, and the cathode steel bar 2 is
divided
into three upper, middle and lower sections along the length direction by two
separating seams 3, the section of the cathode steel bar 2 between the two
separating seams 3 is connected with the carbon block 1 by an insulator 5, the

section of the cathode steel bar 2 below the lower separating seam 3 is
connected
with the cathode carbon block 1 by an insulator 5, and the remaining sections
of the
cathode steel bar 2 are totally connected with the cathode carbon block 1 by
conductive bodies 6; the separating seam 3 is filled with an insulating
material 4 for
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the separating seam, so that the sections of the cathode steel bar 2 above and
below
the separating seam 3 are insulated from each other, and one end of the
cathode
steel bar 2 penetrates out of the electrolytic tank from the side of the
electrolytic tank;
the conductive body 6 is carbon paste or ferrophosphorus, the cathode steel
bar is
wholly or partially fixedly bundled or casted in the cathode carbon block 1,
the cross
section of the cathode steel bar 2 is in the shape of a square, a circle, a
semi-circle, a
trapezoid or a triangle, and below each set of the cathode carbon blocks 1 may
be
mounted 1 to 50 cathode steel bars.
The number of the separating seams 3 in each above-mentioned
cathode steel bar 2 is Ito 20.
In the present invention, when the electricity output manner of the
cathode remains unchanged, by changing the structure of the cathode steel bar,
the
manner for connecting the cathode steel bar with the cathode carbon block,
etc., the
combined resistance of the cathode carbon block and the cathode steel bar may
be
regulated, thereby the current in the aluminum liquid is distributed more
uniformly, the
horizontal current in the aluminum liquid may be greatly reduced, the
stability of the
electrolytic tank may be greatly improved, the electrolytic tank may operate
efficiently
and stably under a very low polar distance, the energy consumption for per ton
of
aluminum may be reduced effectively, and the remarkable energy-saving effect
may
be achieved. The purposes of uniforming the distribution of current in the
aluminum
liquid, reducing the horizontal current and improving the stability of the
electrolytic
tank may be achieved.
The embodiments herein only list a method for uniforming the
distribution of current in the aluminum liquid in an aluminum electrolytic
tank by using
two separating seams, and the detailed embodiments in the present patent
describe
the measures for implementing the method only directing to the drawings,
whereas
the scope of protection of the present patent is not limited by the
embodiments in the
present patent.
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Representative Drawing