How to better reduce the consumption of soderberg paste in electric furnaces and improve the quality of soderberg paste?
The research status of soderberg paste consumption reduction at home and abroad In recent years, with the vigorous development of my country’s electric furnace steel industry, energy saving and consumption reduction and production cost reduction, especially the requirements of soderberg paste consumption reduction in electric arc furnace steelmaking, related fields at home and abroad Experts, scholars and front-line staff have conducted a lot of research, exploration and practice on this, and formed several more effective processes, which are summarized as follows: The surface modification research of 1soderberg paste melting system is through the development of melting system material surface alloying Process, the surface alloying process of soderberg paste and the oxidation kinetics of soderberg paste were systematically studied, and the kinetic model of oxidation of soderberg paste was established. Through comparative experiments, it was proved that the oxidation of soderberg paste can be reduced after surface alloying treatment by melting method. loss. 2.2 Optimizing power supply system parameters Power supply parameters are a key factor affecting the consumption of soderberg paste. When the secondary side voltage is 410V and the current is 23kA, the front-end consumption of the soderberg paste can be minimized. Stable electric arc furnace equipment and perfect operation technology can effectively reduce the mechanical loss of soderberg paste.
The results of practice have proved that by optimizing the power supply parameter system and reducing the mechanical loss of soderberg paste, the consumption of soderberg paste in the No. 1 steelmaking plant of Lianyuan Iron and Steel has been reduced from the original 5.0kg/t to 3.81kg/t. Choosing the best power supply parameters, stabilizing the electric furnace equipment, and improving the process can effectively reduce the unit consumption of soderberg paste.
2.3 Water-cooled composite soderberg paste Water-cooled composite soderberg paste is a new type of soderberg paste developed abroad in recent years. The use of water-cooled composite soderberg paste for steelmaking can generally reduce the consumption of soderberg paste by 20%-40%. The water-cooled composite soderberg paste is composed of an upper water-cooled steel pipe section and a lower graphite working section. The water-cooled section occupies about 1/3 of the length of the entire soderberg paste. Since the water-cooled steel pipe section has no high-temperature oxidation (graphite oxidation), soderberg paste oxidation is reduced, while maintaining good contact between the water-cooled steel pipe section and the holder. Since the threads of the water-cooled section and the graphite section are water-cooled, the shape is stable and no damage. It can withstand greater torque, which improves the strength of the soderberg paste interface, thereby significantly reducing the consumption of soderberg paste. 2.4 Water spray soderberg paste anti-oxidation mechanism Aiming at the consumption of soderberg paste in the smelting process, the focus of reducing soderberg paste consumption should be focused on reducing end consumption, which greatly reduces the unit consumption of soderberg paste per ton of steel. In the consumption of soderberg paste, the consumption of side oxidation accounts for about 50%, up to 70%. For a long time, a lot of research work has been done to prevent the side oxidation consumption of soderberg paste at home and abroad, and a variety of technical measures have been taken, and results have been achieved, so that the consumption of electric furnace steel soderberg paste has been gradually reduced.
Using the existing results for reference, the technical measures of spraying the anti-oxidation solution on the soderberg paste are adopted. Through experimental research, this technology has a significant effect on preventing the side oxidation of the soderberg paste and increases the anti-oxidation ability of the soderberg paste by 6-7 times. And the technical measures are practical. The water spray soderberg paste protection method is a new soderberg paste protection technology developed first in Japan. The technology uses a circular water spray device below the soderberg paste holder to spray water on the surface of the soderberg paste so that the water flows down the surface of the soderberg paste. Above the soderberg paste hole L of the furnace cover, a circular tube is used to blow compressed air to the current surface to make Water atomization. After adopting this method, the consumption of soderberg paste per ton of steel has dropped to 1.9-2.2kg. At the same time, due to the effect of atomized steam, the life of the refractory furnace cover is doubled. This new technology was first applied to ultra-high-power electric furnaces. The soderberg paste method is simple in equipment, convenient and safe to operate. Large cooling effect can be achieved with a small amount of water. However, the main problems in actual industrial production are as follows: 1) Soderberg paste breaks a lot.
Among them, it may be caused by improper operation. It may also be caused by the partial chilling of the dry soderberg paste by water, and the uneven temperature causes internal stress, which is easy to break when the operation is improper. 2) The small holes on the spray ring are often blocked by cold slag and molten steel. Its cooling effect is mainly in the part from the upper part of the furnace cover to the spray ring of the soderberg paste. It does not increase power consumption and hydrogen content in steel. The high temperature oxidation of the surface of the soderberg paste is an important factor causing the loss of the soderberg paste. Water cooling of soderberg paste is an effective way to reduce the consumption of soderberg paste. Different water cooling methods have different effects on the heating conditions and surface temperature distribution of soderberg paste, and they have their own characteristics and disadvantages. At present, Canada, Germany, the United States, etc. have conducted research on composite water-cooled soderberg paste, and Japan has conducted water-drenching soderberg paste experiments. These are methods of indirect or direct water cooling of soderberg paste to reduce the surface oxidation of soderberg paste, thereby reducing the consumption of soderberg paste . 2.5 Hollow soderberg paste Soderberg paste is also one of the main raw materials consumed in ferroalloy smelting. In recent years, Western Europe and Sweden have begun to use hollow soderberg paste in the production of ferroalloy submerged arc furnaces. Hollow soderberg pastes are generally self-contained soderberg pastes. The soderberg paste is cylindrical, and the inner shell is properly sealed with inert gas. The hollow soderberg paste improves the baking conditions of the soderberg paste and increases the strength of the soderberg paste due to its hollowness. Generally, hollow soderberg paste can save 30%-40% of soderberg paste, preferably up to 50%. The use of hollow soderberg paste not only improves the use conditions of soderberg paste, but also brings a series of benefits to ferroalloy smelting, such as direct use of fine ore smelting, and blowing of reducing powder from the hollow soderberg paste.
DC electric arc furnace DC electric arc furnace is a new type of smelting electric arc furnace newly developed in the world in recent years. According to foreign publications, the DC electric arc furnace is the most effective technology to reduce the consumption of soderberg paste. Generally, it can reduce the consumption of soderberg paste by about 40%-60%. In the DC electric arc furnace, the negative electrode of the rectifier is connected to graphite. The positive electrode is connected to the bottom of the furnace soderberg paste (usually composed of a water-cooled metal plate and refractory material). The soderberg paste, the metal bath, the furnace bottom soderberg paste, and the rectifier form a current loop, and an arc is started between the soderberg paste and the metal bath. . In April 1984, the Narco Steel Plant in the United States built the first 20-ton three-phase soderberg paste DC electric arc furnace. The DC electric arc furnace produced 60,000 tons of steel from January to November 1986. The soderberg paste consumption of the electric furnace was 4.77kg. /t steel is reduced to 1.9kg/t steel, which is a reduction of more than 60%, and power consumption is reduced by about 33.3%. In particular, a DC electric furnace with only one large diameter soderberg paste is compared with an AC electric furnace with the same power using three soderberg pastes. Because the oxidation area of soderberg paste is reduced by about half, the unit consumption of soderberg paste is reduced by 40% compared to an AC electric furnace with the same capacity. about. At present, DC electric arc furnaces have begun to be promoted and applied in developed countries around the world. According to reports, the soderberg paste consumption of large-scale DC ultra-high power electric furnaces has been reduced to 1.6kg/t.
Permanent soderberg paste In recent years, developed countries are using the comprehensive advantages of their technology to develop permanent soderberg paste. The so-called permanent soderberg paste is a water-cooled ceramic soderberg paste made by special processing using conductive cermet materials. Its oxidation, sublimation, and fracture losses are extremely low. The permanent soderberg paste developed in Sweden was tried on a 1.5 ton electric arc furnace. A ceramic soderberg paste (segment length 500mm) has a service life of more than 1 year.
Improve the quality of soderberg paste and reduce natural loss. Soderberg paste has to conduct a high current, and at the same time work under high temperature, it is also affected by mechanical vibration and very bad working conditions. Therefore, strict requirements are put forward on the quality of soderberg paste. must:
① Good conductivity, that is, the resistivity is small;
②It can withstand high temperature and has high mechanical strength;
③Good oxidation resistance, the temperature at which it starts to oxidize strongly in the air is high;
④Requirements for regular geometric shapes.
Soderberg paste surface coating technology Soderberg paste coating technology is a simple and effective technology to reduce the consumption of soderberg paste. Generally, it can reduce the consumption of soderberg paste by about 20%. Commonly used soderberg paste coating materials are aluminum and various ceramic materials, which have strong oxidation resistance at high temperatures and can effectively reduce the oxidation consumption of the side surface of the soderberg paste.
The Ceracon coating developed by Japan, tried in some manufacturers, can not only reduce the consumption of soderberg paste, but also reduce the energy consumption of steel-making electricity by 20-30kW·h/t steel. The soderberg paste coating method mainly uses spraying and grinding, and its process is simple and easy to implement. It is the most commonly used method to protect the soderberg paste. 2.10 Dipping soderberg paste dipping soderberg paste is generally immersing the soderberg paste in a chemical agent to make the surface of the soderberg paste chemically react with the agent to improve the high temperature oxidation resistance of the soderberg paste. The use of dipping soderberg paste can reduce the consumption of soderberg paste compared to the general soderberg paste About 10% to 15%. If you are interested, please go to the official website for consultation. Official website URL: www.zhenxingtansu.com