Busbar arrangement for aluminum electrolysers with a longitudinal position

Abstract

The invention relates to a busbar arrangement for heavy-duty aluminum electrolyzers when said electrolyzers have a longitudinal position. The busbar arrangement comprises anode busbars, risers and cathode rods, which are divided into groups, each of which is connected to separate cathode busbars, wherein the cathode busbars for the groups of rods closest to the input end of the preceding electrolyzer are connected to the risers positioned at the input end of the following electrolyzer, and the remaining groups of cathode rods are connected to the risers at the output end of the following electrolyzer. The cathode busbars for the groups of rods closest to the input end of the preceding electrolyzer are positioned beneath the base of the preceding electrolyzer, and the cathode busbars of the remaining groups of rods are positioned beneath the base of the preceding and the following electrolyzers or of the preceeding and following electrolyzers and along the cathode sheath on the front face side of the following electrolyzer. The risers at the input end of the following electrolyzer are mounted with an offset towards the center of the electrolyzer relative to the risers at the output end of the following electrolyzer. A high degree of compensation of electromagnetic forces in the melt is achieved by virtue of optimization of the configuration of the magnetic field in the electrolyzer bath and a reduction in the vertical magnetic field.

Claims

1. A busbar system for aluminum reduction cells, the system comprising: a preceding reduction cell, the preceding cell being longitudinally arranged in a housing adjacent to a following reduction cell, the preceding cell and following cell each comprising an input end and an output end and each having a front side; a plurality of anode buses, a first group and a second group of risers, and a first and a second group of collector bars, the first group of collector bars being connected to a first group of cathode buses, and the second group of collector bars being connected to a second group of cathode buses; wherein the first group of collector bars is closer to the input end of the preceding cell than the second group of collector bars; wherein the first group of risers is located at the input end of the following cell and the second group of risers is located at the output end of the following cell; wherein the first group of cathode buses is located underneath the preceding cell and is connected to the first group of risers; wherein the second group of cathode buses is located underneath the preceding cell and following cell and is connected to the second group of risers; and wherein the first group of risers are installed with an offset to the center of the cell relative to the second group of risers.

2. The busbar system as per claim 1, wherein the following cell further comprises a cathode shell, wherein one of the second group of cathode buses is situated along the cathode shell on the front side of the following cell and the one of the second group of cathode buses provides for distributing 70-100% of the amperage from the total amperage supplied to the risers located at the output end of the following cell.

3. The busbar system as per claim 1, further comprising a cathode shell situated on the front side of the following cell, wherein one of second group of cathode buses is located along the cathode shell.

Description

(1) The essence of the invention is clarified with the following figures:

(2) FIG. 1 shows a diagram of the busbar with cathode buses located underneath the preceding and following cells.

(3) FIG. 2 shows a diagram of the busbar as per the prior art.

(4) FIG. 3 shows a vertical component of the induction of the magnetic field (in gauss) for a 150 kA cell as per the prior art.

(5) FIG. 4 shows a vertical component of the induction of the magnetic field (in gauss) for a cell as per the claimed busbar.

(6) FIG. 5 shows a diagram of the busbar with cathode buses located underneath the preceding and following cells and along the cathode shell on the front side of the following cell.

(7) The design of the cell busbar includes two risers 1 and 2 located at the input end of the cathode shell of the following cell symmetrically with respect to its middle and two risers 3 and 4 symmetrically located at the output end of the cathode shell of the following cell. For the prior art (see FIG. 2), part of the collector bars located on the side of the input end is connected with the help of cathode buses 5 and 6 to risers 1 and 2. Cathode buses 7 and 8 transmit the current from the collector bars of the cell on the side of the output end of the cathode shell to risers 3 and 4. The claimed busbar (FIG. 1, 5) is characterized by cathode current collection underneath the cell. Part of the collector bars located on the side of the input end is connected with the help of cathode buses 5 and 6 to risers 1 and 2 and located underneath the cell. Cathode buses 7 and 8 are located underneath two cells and transmit the current from the collector bars of the cell on the side of the output end of the cathode shell to risers 3 and 4. It is possible to have the cathode bus on the front side of the cell, not underneath the following cell but along the side of the cathode shell of the following cell, on the front side. Transmission of a higher current to the cathode bus on the front side of the following cell, rather than to the cathode bus on the back side of the cell, compensates for the magnetic field of the neighboring row of cells (FIG. 5). In the limiting case, when 100% of the current is transmitted through said bus, we have a 3-riser busbar: two risers at the input end of the cell and one riser is at the output end.

(8) High MHD stability is related to the minimization of the vertical magnetic field in the cell bath. An increase in the process parameters of the cell is achieved due to stable cell operation at lower ACDs.

(9) The effect of the proposed technical solution is displayed in FIG. 4, which shows the lines of the vertical magnetic field in the layer of molten metal. Comparison with FIG. 3 (the magnetic field as per the prior art) shows that, when the current is supplied according to said busbar diagram, including running the current underneath the cell, it results in a significant decrease in the value of the vertical magnetic field. As detailed numerical calculations regarding MHD stability show, the new busbar provides significantly higher MHD stability of the cell.