The volume density of graphite electrode reflects the dense state of the electrode and is closely related to the manufacturing process. The volume density of graphite electrodes of different specifications and varieties is regulated by the state. The products with low volume density show that the overall structure of the product has higher porosity, the oxidation speed of the product is faster at high temperature, and the consumption of electrodes is easy to increase.
Generally speaking, the volume density of electrodes is better in the specified value when the steel mill chooses the electrodes. However, it doesn’t mean the higher the volume density, the better graphite electrodes. when some volume density is too high, due to the poor thermal shock resistance of electrodes, surface peeling, debris and cracks are prone to occur during steelmaking, which will affect steelmaking on the contrary.
► Graphite electrodes bulk density:
► Graphite electrode volumetric density detection method:
The graphite electrode sample is processed into a square or cylindrical shape, the cylindrical size of the sample is 45mm×40mm(the allowable deviation of size is ±0.1mm), and it is dried for 2h at 110 ° C ±5 ° C, cooled to room temperature, and weighed the quality of the sample. The vernier caliper (precision 0.02mm) was used to measure the axial and radial dimensions of the sample for three times. The mean values of the axial and radial dimensions were taken respectively, and the volume of the sample was calculated according to formula (1).
V = PI hd2/4 (1)
The volume density is calculated according to formula (2) :
The db = m/V (2)
Db -- volume density, g/cm3
M -- weight, g
V -- volume, cm3
D -- diameter, cm
H - high, cm.
The volume density of graphite electrode is the ratio between its weight and its volume. Unit g/cm3, the higher the volume density, the denser the electrode is, which is proportional to the strength and antioxidant performance. Generally, the higher the volume density of the electrode, the lower the resistivity.
Methods to improve the volume density: adjusting the formula, increasing the amount of small particle size and powder, using coke with high true density, using asphalt with high coking value and increasing the impregnation times, etc.