Search

CN-121992456-A - Cathode protection method for aluminum electrolysis cell

CN121992456ACN 121992456 ACN121992456 ACN 121992456ACN-121992456-A

Abstract

The invention discloses a cathode protection method for an aluminum cell, which solves the problem of serious cathode non-uniformity abrasion caused by physical abrasion and electrochemical corrosion of the aluminum cell, adopts the technical scheme of implementing integral protection on a cathode abrasion zone, and is characterized in that a repair material is arranged in the cathode abrasion zone of the aluminum cell, a cathode protection frame is arranged above the cathode abrasion zone, a filling material is arranged in the cathode protection frame, the flow resistance of the cathode protection frame is utilized to reduce the flow velocity of the aluminum liquid in the cathode abrasion zone, so that a material precipitation accumulation protection layer is formed above the cathode abrasion zone, the cathode is protected from the scouring abrasion of the aluminum liquid, the current density, the temperature and the aluminum carbide generation speed of the cathode abrasion zone are reduced, the cathode abrasion deepening process is delayed, and the purposes of prolonging the safe operation life of the electrolytic tank and reducing the solid waste discharge are achieved.

Inventors

  • OU JIANMING
  • OU YITING

Assignees

  • 欧建明

Dates

Publication Date
20260508
Application Date
20241108

Claims (10)

  1. 1. A cathode protection method for an aluminum electrolysis cell comprises an aluminum electrolysis cell cathode (1) and a cathode abrasion zone (2), and is characterized in that a repair material (3) is arranged in the aluminum electrolysis cell cathode abrasion zone (2), a cathode protection frame (4) is arranged above the aluminum electrolysis cell cathode abrasion zone (2), a filling material (5) is arranged in the cathode protection frame (4), the particle density of the repair material (3) is greater than the aluminum liquid density, the volume density of the cathode protection frame (4) is greater than the aluminum liquid density, and the particle density of the filling material (5) is greater than the aluminum liquid density.
  2. 2. The method for protecting the cathode of the aluminum electrolysis cell according to claim 1, wherein the cathode protection frame (4) is made of aluminum oxide base material, magnesium oxide base material and silicon carbide base material.
  3. 3. The method for protecting the cathode of the aluminum electrolysis cell according to claim 1, wherein the repairing material (3) is made of fused white corundum, magnesia brick, magnesium fluoride, calcium fluoride and crusting block, and the filling material (5) is made of fused white corundum, magnesia brick.
  4. 4. The method for protecting the cathode of the aluminum electrolysis cell according to claim 1, wherein the length of the cathode protection frame (4) is 500-2500 mm, the width is 500-180 mm, and the height is 50-180 mm.
  5. 5. The method for protecting the cathode of the aluminum electrolysis cell according to claim 1, wherein the cathode protection frame (4) is formed by assembling a plurality of frames with dovetail structures, the lengths of the frames are 150-1200 mm, the widths of the frames are 80-200 mm, the heights of the frames are 50-180 mm, the widths of the dovetail structures are 30-70 mm, the depths of the dovetail structures are 20-60 mm, the heights of the dovetail structures are equal to the heights of the frames, and the gap between a tenon and a mortise in each dovetail structure is 1-5 mm.
  6. 6. The method for protecting the cathode of the aluminum electrolysis cell according to claim 1, wherein the height of the repair material (3) filled in the cathode abrasion region (2) is not higher than 50mm above the surface of the cathode (1) of the aluminum electrolysis cell.
  7. 7. The method for protecting the cathode of the aluminum electrolysis cell according to claim 1, wherein the granularity of the repairing material (3) is 1 mm-80 mm.
  8. 8. The cathode protection method of the aluminum electrolysis cell according to claim 1, wherein the filling thickness of the filling material (5) in the cathode protection frame (4) is 20 mm-150 mm.
  9. 9. The method for protecting the cathode of the aluminum electrolysis cell according to claim 1, wherein the granularity of the filler (5) is 3-100 mm.
  10. 10. The method for protecting the cathode of the aluminum electrolysis cell according to claim 1, wherein the granularity of the uppermost layer of the filler (5) is not less than 8mm.

Description

Cathode protection method for aluminum electrolysis cell Technical Field The invention relates to the technical field of cathode protection of aluminum electrolysis cells, in particular to a cathode protection method of an aluminum electrolysis cell. Background The electrolytic aluminum industry is a key management and control industry in a carbon neutralization stage, and in recent years, the country is greatly pushing energy-saving carbon reduction transformation in the electrolytic aluminum industry, pushing the aluminum electrolysis cell to be large-sized, and popularizing and applying graphitized cathode and other technologies. In the aspect of large-scale aluminum electrolysis cells, the large-scale aluminum electrolysis cells of 400KA and 500KA are in a main launder type, the productivity ratio of the large-scale aluminum electrolysis cells of more than 600KA is steadily improved, however, the large-scale aluminum electrolysis cells have the problems of high local cathode current density, high local aluminum liquid flow speed and the like, so that the physical abrasion and electrochemical corrosion speed of the cathode of the large-scale aluminum electrolysis cells are high, wherein the cathode surface is seriously eroded and abraded due to the rapid flow of the aluminum liquid, the electrochemical corrosion process is accelerated due to the high cathode current density, the cathode damage of the large-scale aluminum electrolysis cells is finally caused about 4 years, particularly, in order to further reduce the electrolysis energy consumption, the graphitized cathode is widely applied by an aluminum electrolysis enterprise, and the problem of cathode abrasion is more serious due to the fact that the graphitized cathode has the characteristic of non-abrasion. Through the analysis and research on the cathode abrasion characteristics of the large-sized aluminum electrolysis cell in recent years, the corresponding relation exists between the part with serious cathode abrasion of the large-sized aluminum electrolysis cell and the strong flow rate area of the aluminum electrolysis cell, more than 90% of the cathode serious abrasion part is positioned in the area with higher aluminum liquid flow rate, reny and the like observe the section of the cathode abrasion of the aluminum electrolysis cell, the section outline of the cathode after the abrasion is found to be a W-shaped curve, and the non-uniform abrasion is particularly obvious in the large-sized aluminum electrolysis cell with high current intensity. Gao Bingliang et al, after on-site observation of the damage condition of the 600KA electrolytic cell, found that the damage usually occurred on the feed side, while the damage on the discharge side was less, which clearly was related to the rapid flow rate of the molten aluminum in the local area of the feed side, the small deposit coverage, and the high current density. It is reported that the abrasion rate of graphitized cathodes on average proceeds at a rate of about 2.4cm/a per year. The early operation period of the aluminum electrolysis cell (within 1500 days of cell age) mainly uses physical abrasion of the aluminum liquid to wash the surface of the cathode, the cathode abrasion speed is relatively slow, when the cathode abrasion depth reaches more than 10cm, the current density of a cathode abrasion area is obviously increased, the generation rate of aluminum carbide is accelerated, the cathode abrasion mainly uses electrochemical corrosion, the generation and removal rate of aluminum carbide is accelerated under the combined action of local cathode high temperature, high current density and high aluminum liquid flow rate, the cathode abrasion speed is rapidly increased, and the abrasion depth is developed from 15cm to 25cm so as to melt a cathode steel rod often less than one year. In order to solve the problem of serious cathode abrasion of large-scale aluminum electrolysis cells, the existing lack of effective countermeasures for the aluminum electrolysis enterprises often arranges that workers use iron tools to probe the cathode when the cathode abrasion depth exceeds 15cm, and then repair materials such as magnesia, magnesia bricks, calcium fluoride, crust blocks, corundum and the like are adopted to fill up the cathode abrasion depth, for example, a method for repairing the partial breakage of cathode carbon blocks of the aluminum electrolysis cells, a method for repairing the cathode breakage of the aluminum electrolysis cells, and the like are disclosed by publication No. CN113755896A, and a method for repairing the cathode breakage of the aluminum electrolysis cells are disclosed by publication No. CN111690951A, but because the aluminum liquid flow rate of the cathode abrasion part is high, the flowing aluminum liquid can take away the repair materials, the maintenance time of the repair effect is generally less than 2 months, and once the cathode deep abrasion problem occurs, a plural