30+ YEARS OF EXPERIENCE IN CARBON INDUSTRY

The full name for a "mineral heat furnace" is the Submerged Arc Furnace (SAF), its core mechanism is carbothermic reduction driven by electrical energy. These furnaces are classified based on five dimensions—arc operating status, operational regime, power supply system, furnace sealing method, and slag system process. Corresponding to various products such as ferrosilicon, industrial silicon, silicomanganese, high-carbon ferrochrome, titanium slag, ferronickel, and calcium carbide. Classification by arc operating state represents the most fundamental operational distinction, specifically comprising the submerged arc mode (subdivided into two types), resistance mode, and shielded arc mode. This constitutes the classic tripartite classification used in the ferroalloy industry.

Mechanism: The electrodes are inserted into the slag layer, where electrical energy is primarily released as heat. The temperature at the top of the furnace is high, and the molten slag serves as the main heat-generating medium. Typical ferroalloy products include high-carbon ferrochrome and silicomanganese, this involves a slag-based smelting process.

Process characteristics: A thick molten slag layer exists within the furnace, the working ends of the electrodes are submerged in the slag, the furnace top temperature is high, requiring periodic slag tapping, and self-baking electrodes operate relatively stably.

Mechanism: The electrodes are deeply embedded within the solid charge, and the arc is completely enveloped by a thick layer of cold material. The energy is concentrated in the reduction reaction zone, resulting in a low temperature at the charge surface (hence the term "cold charge surface"). Ferrosilicon production is a typical example of this process, which utilizes a slag-free smelting method.

Process characteristics: Operation involves a thick charge layer with no high-temperature emissions at the surface, reduction reactions occur within the charge itself, and there is virtually no significant slag formation.

While both fall under the category of submerged-arc processes, they differ completely in terms of heat source location, charge surface conditions, and slag systems.