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The submerged arc mode represents the optimal operating condition for self-baking electrodes (electrode paste), the covering burden layer ensures a stable baking temperature and uniform electrode sintering, thereby reducing the risk of both "soft breaks" and "hard breaks." Following the description of the submerged arc mode, detailed analyses of the remaining two modes are provided below.

Mechanism: Virtually no electric arc is formed, smelting is driven by Joule heat generated through the resistance of the furnace charge, with resistive heat being the dominant factor. Typical product is Ferrotungsten. Process characteristics: Electrodes are deeply submerged to suppress arc formation, low voltage and high current are employed, the charge itself acts as the resistive heating element, and there is minimal agitation of the molten pool.

Mechanism: Energy is primarily released at the surface of the molten pool, the arc is not fully buried deep within the furnace charge but is partially shielded by the charge and slag (representing a state between a fully submerged arc and a completely open arc). Operation involves a hot furnace mouth, the typical product is ferronickel. Process characteristics: Intermediate between submerged arc and open arc, the arc contributes significant heat at the molten pool surface, the furnace mouth is hot with high flue gas generation, corresponding to the reduction stage conditions of an RKEF submerged-arc furnace.

1. Submerged-arc (cold charge surface):

The charge layer provides excellent baking conditions for the electrode, ensuring stable sintering of the electrode paste and a low risk of soft breakage. However, precautions against "paste hanging" are necessary.

2. Submerged-arc (hot furnace opening):

High temperatures at the furnace opening expose the upper part of the electrode to significant heat.

3. Arc Shielding Mode:

Furnace opening heat and arc radiation increase electrode oxidation and burn-off, leading to increased electrode paste consumption.

4. Resistance mode:

Slow electrode slipping rates and long baking cycles place high demands on the high-temperature sintering performance of the electrode paste.