The sintering process of electrode paste is a process in which the coal tar pitch in the electrode paste gradually melts, decomposes, discharges and carbonates with the temperature of the submerged arc furnace gradually rising. The investigation of the sintering process of electrode paste is to investigate the different states of electrode paste in the submerged arc furnace at different temperatures. Fuzhen carbon divides the sintering process of electrode paste into three stages.
1、 Low temperature softening stage. When the temperature rises to 200 ℃ at room temperature, the coal tar pitch inside the electrode paste softens and melts from solid state to plastic state. The moisture and low boiling point components in it begin to volatilize, and the binder produces physical migration. There is no obvious chemical change at this stage.
2、 Drastic change stage. The temperature is between 200-700 degrees. At this stage, the coal tar pitch as the binder is completely decomposed, starts gasification, and a large amount of volatile matter is discharged. The remaining material of coal tar pitch has been semi carbonized or carbonized, and the electrode paste changes from plastic state to solid state.
3、 High temperature sintering stage. When the temperature is above 800 ℃, only a small amount of residual volatile is discharged at this stage, and the carbonization process of coal tar pitch is basically completed. When the sintered electrode is released in the copper tile, the electrode sintering is basically completed.
After the sintering of the electrode paste, the electrode released in the copper tile enters the submerged arc furnace to smelt the product. Because the temperature of the product is generally 2000 ℃, the electrode released in the copper tile is further sintered, resulting in some physical and chemical changes, such as the specific resistance is further reduced, and the thermal shock resistance first rises and then falls with the rise of temperature, etc.
