Ambient temperature in potlines is poor if there is no designed natural ventilation system, as may be the case for Søderberg potlines. There is a high ambient temperature in the potrooms, due to the heat emitted from the cells. Alumina is dissolved in the electrolyte and is electrolyzed at the cathode to form molten aluminum. These two melts have different densities, and as such, they do not mix with each other. Underneath the crust, there is a 15- to 20-cm deep layer of electrolyte, and with 10 to 20 cm of molten aluminum beneath. There should preferably be open holes in the crust along the center line between the two rows of anodes, where the alumina is added automatically to the electrolyte. #Magnetic field effect aluminum oxide plus#Large vertical aluminum bars (called anode risers) conduct the current from the negative cathode of the neighbor cell to the positive anode of the present cell.Ī layer of alumina plus solid electrolyte cover the top of the anodes. Aluminum hoods are there to facilitate collection of the anode gases and fluoride vapors from the electrolyte, and these are sent to the fume-treatment plant. The upper part of the cell is called the cell superstructure. They bring the metal to the cast house for further treatment and casting of aluminum products. Large vehicles transport the metal out of the potline building. Cranes are moved back and forth for transportation and changing of anodes and for removal of aluminum from the cells. The process is still far from fully automated. Added together, the aluminum production in the plant can be huge, and the largest aluminum plants in the world now report an annual production close to or even more than 1 million metric tons. Older cells, which can have amperages less than 200 kA, are often placed end to end, but not always.ĭay and night, each of these cells produces this valuable metal in large amounts, maybe 100 kg or more every hour. These cells are placed side by side as shown in Figure 1, to reduce the adverse magnetic effects of the high electrical current and also to reduce the heat loss from the cells. Modern potlines now typically have amperages from about 300 kA and up to about 600 kA, which are the largest cells in operation at present. A modern potline with high-amperage side-by-side prebake cells.
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