Electrode paste is also known as self baking electrode, which relies on the heat in the submerged arc furnace to complete the roasting. Therefore, the matching of the consumption rate of the electrode with the roasting rate is the key to the use of electrode paste. Due to the development of submerged arc furnace technology, it is gradually developing towards large-scale and closed direction. During the roasting process, the more heat transfer and radiant heat reduction of the electrode obtained from the past open furnace type are only heat transfer, Therefore, the heat obtained by the electrode from the furnace is greatly reduced, which requires improving the sintering performance of the electrode paste to make up for this deficiency.
For the manufacturers of electrode paste, the two taboos of * are electrode soft break and hard break, among which soft break is more terrible and easy to cause accidents. Hard fracture is caused by insufficient strength of electrode paste after sintering; Soft fracture refers to the fact that the sintering speed of the electrode is lower than the consumption speed, and the electrode is not fully sintered, which can not bear the tension and lateral impact of the lower part of the electrode, resulting in fracture.
These two problems are directly related to the performance of carbon manufacturer’s electrode paste, and also related to the operation in the process of use. There are only two main links in the production of electrode paste, namely, batching and kneading. Among them, kneading is basically the same at present, as long as the kneading equipment is regular equipment (above 2000L intermittent double shaft kneading pot) and the kneading temperature and time can be well controlled in the process. The key of ingredients is reasonable formula; The selection of raw materials and particle size ratio, especially the softening point of binder asphalt and the amount of binder used. At present, the main problem perplexing manufacturers is that the roasting speed of electrode paste is too slow, so some manufacturers adopt the method of reducing the use of asphalt.
This method is effective to a certain extent, but the low amount of asphalt makes the fluidity of the electrode paste worse, the electrode paste is not easy to be filled in the electrode cylinder, and the poor compactness after sintering is easy to cause hard fracture. Another method is to reduce the softening point of the asphalt and improve the sintering speed of the electrode, but the softening point of the asphalt can not be reduced indefinitely, because the asphalt with low softening point reduces the coking rate of the asphalt, The strength of the electrode should also be reduced, or there should be hard fracture. Therefore, the production of electrode paste should not only properly grasp the above two means, but also improve the sintering speed of the electrode through the adjustment of the formula.
For example, the graphite raw materials with good conductivity and heat transfer performance should be appropriately added to the formula to increase the conduction heat obtained by the electrode from the furnace, so as to speed up the roasting speed. At the same time, try to reduce the consumption of the electrode to reduce the speed of electrode lowering, which can also achieve the matching of electrode consumption and roasting. I began to study the production technology of electrode paste in the 1980s, and tested the production of electrode paste for the electric nickel furnace of Northwest Jinchang company.
I also added certain additives to asphalt, which also had a certain effect. After that, he successively developed products for many large calcium carbide furnaces and ferroalloy furnaces and gained some experience. Therefore, the production of electrode paste can produce good products and obtain the satisfaction of users only by applying drugs to the symptoms, taking multiple measures, considering comprehensively, appropriately and complementing each other’s advantages.