Submerged arc furnaces are categorized by electrode arrangement into two types: those with electrodes arranged in a triangle (including circular and triangular furnaces) and those with electrodes arranged in a straight line (including rectangular and elliptical furnaces). Typical examples include circular furnaces (such as ferroalloy furnaces) and rectangular furnaces (such as matte smelting furnaces).
Compared to rectangular furnaces, circular furnaces feature the following characteristics:
1) The three electrodes are arranged in an equilateral triangle, resulting in relatively balanced three-phase loads (working resistance) and power distribution;
2) The high-temperature zone is relatively concentrated, allowing the furnace core area (between the three electrodes) to reach higher temperatures;
3) The furnace wall heat-dissipation surface area per unit cross-section of the molten pool is smaller; this not only reduces heat loss but also allows for longer power-off periods;
4) The furnace body can be mechanically rotated to ensure the smooth flow and movement of materials within the furnace.
Compared to circular furnaces, rectangular furnaces feature the following characteristics:
1) The furnace structure is relatively simple, and the layout of auxiliary electromechanical equipment (transformers, charging and discharging machinery) is more convenient;
2) They can accommodate six electrodes, thereby expanding the smelting zone;
3) Electrodes impose fewer restrictions on material movement, making it easier to vent gases generated during smelting;
4) Temperature differences across the molten pool are smaller, making localized overheating less likely.
Rectangular furnaces are used for processes such as matte smelting, calcium carbide production, and ferromanganese production. Most ferroalloy furnaces are circular; circular furnaces are also used in the non-ferrous smelting industry, for example, in the smelting of nickel oxide ore and cobalt slag.
The submerged arc furnace is a type of smelting furnace; the most critical dimensions of the furnace body are those of the molten pool-specifically its length, width (or diameter), and depth. Since these furnaces rely primarily on electricity for heating, the molten pool theoretically serves as the effective zone for the conversion of electrical energy into heat; consequently, the dimensions of the molten pool are typically multiples of the electrode diameter.
Rectangular furnaces are usually equipped with a furnace roof and operate as enclosed units; their primary dimensions include the length, width, and depth of the molten pool, as well as the center-to-center spacing of the electrodes and the height of the furnace chamber.