Effect of roasting process on the quality of graphite electrodesⅢ

On the one hand, as the temperature gradually increases, the binder asphalt first undergoes physical horizontal infiltration and longitudinal gravity migration. If the binder used is medium-temperature asphalt, the physical migration occurs more than the modified asphalt with high softening point The adhesive is bigger. Therefore, the use of high-temperature modified asphalt instead of medium-temperature asphalt as a binder is an effective measure to improve product quality. As the temperature continues to rise, the binder asphalt begins to decompose and polymerize, the discharge of light volatile gradually increases, and the heavy residues also continue to polymerize. The total volume of raw products is in the radial and longitudinal directions. Expansion occurs as well as contraction. The practice has proved that the longitudinal expansion of raw products is slightly larger than the radial expansion, so the mechanical strength at the upper end of the baked product is lower than the mechanical strength at the lower end, which is directly related to the migration of asphalt. The choice of high temperature modified asphalt binder can improve this situation. Our company also sells steelmaking Graphite Electrode.

On the other hand, the elasticity, air permeability and adsorption of the filler also play a very important role in the firing process. Appropriately reducing the adsorption and air permeability of the filler, or adding refractory bricks above the thermal insulation material, is conducive to increasing the coking value of the binder asphalt. If the type of filler is determined, it depends on the particle size composition of the filler. If the filling material is too fine, the discharge of volatile from large-sized raw products will be blocked too much, which will cause cracks in the product. Therefore, the absorption and air permeability of the filler must be controlled within a suitable range, and the coking value can be maximized when the radial expansion force of the product and the mechanical strength of the surface of the raw product reach a dynamic equilibrium state. Of course, this dynamic balance is closely related to the heating rate. In order to effectively improve the mechanical strength and density of the roasted product, it is necessary to ensure that the particle size composition of the filler material matches the product specifications and heating rate reasonably.

The selection and control of the roasting process are very important because it directly determines the structure and performance of the final product and the length of the production cycle. During the roasting process, along with the chemical reaction and the transfer of mass, heat, and momentum, the three-phase system has undergone a series of continuous unequal phase transitions, which makes the research of the system very complicated.

The above information is provided by the Graphite Electrode Nipple supplier.