Generally, the diameter of the molybdenum electrode is between 35 and 75mm, and the selection of the size of the molybdenum electrode is mainly determined by the current density. Usually, electrodes with a diameter of φ50mm are used for melting borosilicate glass, and the advancement of electrodes during operation is determined according to the actual current density. For vertical electrodes, when the density value reaches 0.8A/cm2, it is necessary to consider the problem of continuous electrode advancement. For the electric melting furnace with a long furnace age (more than 4 years), the current density increases with the consumption of the electrode. If the electrode is not ready for continuous advancement, the current density needs to be controlled at a lower value, and the current density of the molybdenum electrode runs at 0.6 When A/cm2 or less, the electrode is hardly consumed. The current density of the electrode for melting borosilicate glass electro-melting is between 0.42 and 0.49A/cm2, and the electrode is almost not consumed in two years and does not need to be continued.
Soda-lime glass and other low-resistance glass, the resistivity is lower than 15Ω·cm, the electrode is difficult to control the current density below 0.6A/cm2, due to its low viscosity and low resistivity, often use φ75mm electrodes. In addition, the electrode will also have different degrees of loss during operation, so the electrode must be made into a continuous type. From the point of view of the operating cost of the electrode, the plate electrode consumes less and is more suitable for electro-melting of soda-lime glass.
The conductive distance of the electrode has a direct impact on the operating life of the electrode. The electrode distance is too close, and the operation is in a state of low voltage and high current. This local high power will not only reduce the life of the refractory material but also increase the electrode loss and bring defects to the product. In addition, if the current density value is too large, the destructive effect on the electrode is even greater. Within the allowable voltage range that the electric melting furnace can withstand, the operation scheme of high voltage and low current can improve the efficiency, but it must meet the requirements of the melting process and operation safety. When the correct process design establishes the operating state of low voltage and high current, increasing the conductive area of the electrode can improve the life of the electrode, that is, choose a rod electrode with a larger diameter, or use multiple electrodes in combination, or increase the number of electrodes. , or use plate electrodes when the process permits.
