Changes in electrode paste properties during sintering
At present, the domestic ferroalloy submerged arc furnace usually uses self-baking electrodes. When smelting manganese-silicon alloy, the normal consumption of electrode paste is about 30-40kg/t, which accounts for about 0.7% to 1.5% of the total cost. Although the cost of electrode paste accounts for a very low proportion of the total cost, it plays a key role in the operation of electric furnaces and the economic and technical indicators of smelting. Therefore, people often compare the electrode to the “heart” of the submerged arc furnace, which vividly shows that the electrode is in the submerged arc furnace. The role of the furnace.
Due to the different production conditions of electric furnaces in various factories, some factories feel that standard pastes (standard paste and closed paste) are not very suitable, and often require electrode paste manufacturers to make certain adjustments to the formula, such as appropriately reducing the amount of binder, so gradually A non-standard paste is formed. Especially in recent years, with the improvement of the electric furnace structure in the metallurgical, chemical and other sectors, the open low-power electric furnace has been quickly replaced by the closed high-power electric furnace. The common feature of the closed furnace is that the electrode is sintered by Joule heat and conduction heat, the radiated heat is greatly reduced, and the furnace top temperature is lower, which is very unfavorable for the baking of the electrode. Therefore, it is required to produce an electrode paste with a fast sintering speed to meet the needs of a closed furnace. At present, Zhengzhou Zhongzhou Carbon Factory produces electrode pastes with fast sintering properties according to the requirements of users and the raw material conditions of the factory, which are commonly known as special pastes. The difference between it and the standard paste is that it is blended with appropriate amount of graphitized coke and coal tar, the ash content is low and the strength is high, so that it has high electrical conductivity and thermal conductivity during the sintering process, improves the sintering speed, and meets the needs of medium and large electric furnaces.
Production practice has proved that the change in the properties of the electrode paste during the sintering process is more important than the properties of the electrode paste after firing, because accidents rarely occur once the electrode is fired. The electrode soft cut-off paste accidents that seriously affect production all occur before the electrode is fired, so full attention should be paid to the change in the properties of the electrode paste during the sintering process.