In different molten glass should use different type molybdenum electrodes. The following tables are the four different molten glass containing different glass fiber components, respectively, S1#, S2#, alkali-free (E-glass) and middle-alkali (C-glass). By analyzing the application effect of sintered molybdenum electrode, forged and smelted molybdenum electrode as electrode material in molten glass, which can better use the correct molybdenum electrodes, producing high-quality glass.
Sintered Molybdenum Electrode
Sintered molybdenum electrodes purity is 99.94% and impurity content is about 0.06%. Besides, the oxygen content is between 40 ~ 60PPM. It is a raw martial and semi-finished product for forged molybdenum electrode and smelted molybdenum electrode. And it is characterized by loose density, low strength, easy to break. Due to molten glass has high temperature (1570 ~ 1600 ℃), when sintered molybdenum electrodes used in the glass furnace with S1#, S2# molten glass, there are large erosion on the electrodes. Besides, it will harm furnace service life. Sintered molybdenum electrode is used in alkali-free, meddle-alkali molten glass and the molten glass temperature is between 1320 ~ 1400 ℃, causing localized erosion on electrodes, so that the electrode mild ptosis and can not secondary using.
Foraged Molybdenum Electrode and Smelted Molybdenum Electrode
Forged or smelted molybdenum electrode is compact and purity is about 99.9%. Besides it is uniform and impurity content is 0.05%. Oxygen content is between 10 to 355PPM. Forged or smelted molybdenum electrode has good mechanical strength and oxidation resistance, so used in S1#, S2# molten glass is not easily deformed and sagging. The electrodes worked 100 days at a temperature of 1570 ~ 1600 ℃, there has erosion on the bottom of the electrodes and electrode weight loss is about 8%. These molybdenum electrodes used in platinum drawing furnace with S1#, S2 #, middle-alkali and alkali-free molten glass, if protective cover is reasonable, the electrodes can be used for second times.
In S1#, S2#, middle-alkali and alkali-free molten glass, molybdenum electrode is used as a heating element. But it will oxidize at high temperature, to prevent oxidation of the electrode should prevent the electrode surface temperature is too high. Beside, the strict requirements of the electrode surface current density should control at 1A/cm2. What’s more should protect the bottom of electrode to prevent large areas corrosion, resulting electrode current carrying capacity decreased, so that local overheating, resulting electrode blown.
Molten Glass Ingredient