1. Heat source for electrode baking
Resistance heat, conduction heat, radiant heat
2. Resistance heating
It is the main heat source for electrode baking Q=0.24PRt
When the electrode paste is stable, the size of the single-phase current determines the amount of calcining heat (it depends on both the total power consumption and the single-phase power consumption) and the amount of lower electrodes. At the same time, it depends on the time based on the single-phase current.
3. Conduction heat
Conductive heat conducted from the end of the electrode. The short electrode conduction heat is relatively large, and vice versa. Not the main source of calories.
4. Radiant heat
The heat around the electrode radiates heat upward to the part of the electrode to be fired. The magnitude of radiant heat is related to variety, controller type, and furnace type.
5. Self-baking electrode temperature zone
It is divided into five areas: the first area is the part of the electrode shell where the electrode paste is not installed; the second area is the section where the bulk electrode paste is located. When approaching the copper watt, the bulk electrode paste begins to melt and form a liquid electrode paste column, which flows into the third zone. The boundary between the second zone and the third zone is 65-75°C isotherm. During this interval, the binder (pitch) melts, and the electrode paste turns into a relatively liquid state. The height of the fourth zone is usually the smallest, but very important, located in the relatively narrow temperature range of 350-550°C. In this area, the pitch forms a coke-like lattice, and at the same time emits a large amount of volatile matter and coking the electrode. The carbon electrode block is divided into the fifth zone from 550°C to the electrode end surface. The electrodes in this zone consist of a solid mixture of coke cemented with a binder. At the same time, it is divided into several sections according to the properties of the carbon blocks roasted at different temperatures: 550℃-850℃, 850℃-1450℃, 1450℃-2500℃, 2500℃ (arc temperature).
The 350°C-550°C area on the electrode should be located at the height of the center of the copper tile, and the electrode temperature from the copper tile outlet should not exceed 900°C-1100°C. The electrode should be in a “plastic” state when it comes into contact with the copper tile, and the temperature of the electrode paste should be 150°C-250°C, which can ensure the necessary contact of the copper tile. The height of each zone is determined by the structure of the contact parts, the electrode blowing system, the alloy type, and the electrical parameters.