Ways to reduce electrode consumption in arc furnace smelting

How to reduce the consumption of three circumference electrodes in smelting is not only the technology of carbon manufacturers, but also the important work of smelting manufacturers to cooperate in the use and optimize the operation of electric furnaces. 

As far as the consumption of graphite electrode in smelting is concerned, the first thing to be solved is the fracture of the joint, and the second thing to be considered is the oxidation resistance and thermal shock resistance. This requires us to first understand the development of smelting industry, smelting process, furnace and operation technicality, and then conduct targeted technical research, scientifically organize production, and implement effective technical services. Only in this way can we achieve the purpose of matching production and use.

1. Consumption reduction of new electric furnace technology

The establishment of large UHP and LF electric furnaces has laid a solid foundation for the scale development of the steel industry. Large production capacity and low energy consumption are the characteristics of new smelting technology. Large flow of chemical energy (accounting for 60%~70% of the total energy consumption) is scientifically used for large arc. The use of furnace low burner, automatic oxygen lance and preheating shaft effectively increases the power consumption and electrode consumption by more than 60%; The application of water cooling system has greatly increased the furnace life and reduced the material consumption, especially the unit consumption of graphite electrode reduced by at least 1/3 due to spray water cooling; The utilization of chemical energy has shortened the smelting cycle by at least half, and greatly increased the output, so the unit consumption of electrode is decreasing.

2. Consumption reduction of hot charging smelting process

While developing large-scale electric furnaces, the iron and steel industry has also extended to large-scale converters and blast furnaces in recent years. Most of the newly built blast furnaces are 2000m long ³ Above (the maximum in China is 4050m ³); The hot metal converter smelting with LF and electric furnace hot charging (generally 40%~60%) has become a popular smelting technology; Hot charging of molten iron effectively shortens the smelting cycle, reduces the consumption of electric energy, chemical energy and various materials, especially the unit consumption and demand of graphite electrode.

The new electric furnace has perfect supporting facilities. The selection of graphite electrode by introducing technology prevents the problem of "big horse pulling small cart", which is a challenge for domestic electrode. Impedance furnace operation and furnace automatic monitoring system have played a great role in electrode control, effective use and loss reduction. The electrode breaking rate of large electric furnace is less than 2%.

The transformation of the old electric furnace is also equipped with necessary facilities, and the selection of power supply equipment is mostly limited, so quasi UHP and quasi HP electric furnaces have emerged, which has virtually improved the quality requirements of the same grade of graphite electrodes, such as the use of 30t AC high impedance electric furnace φ The consumption of 450MM HP and FG electrode is about 1kg, and the electrode breaking rate is less than 3%, which has been praised by users and is also a major progress in carbon technology.

3. Strictly control consumption reduction in power transmission system

Strict control of power transmission system is the premise to ensure normal smelting. Different steel grades and smelting processes have corresponding arcing voltage and current gears to prevent excessive current fluctuation and strictly control the peak current working time. Thus, electrode reddening, reactive oxidation consumption and furnace fracture are effectively prevented.

4. Consumption reduction in standardized use

Carbon manufacturers must strictly require or guide users on site to store, transport, and connect electrodes. Especially for the connection technology of electrodes, in principle, the connection under the furnace must be required for large-sized electrodes; During connection, avoid collision to produce thread fragments and keep the upper electrode always vertical; When it is evenly screwed to 8~10 mm, inertial locking shall be used, and then the long arm wrench shall be used to apply the pre tightening torque until it cannot be screwed, and the slotted electrode shall not be put into the furnace; If the phase sequence is wrong and the connection is good, it is better not to install a fixed pin. The purpose of these basic requirements is to avoid breaking and falling loss.

In addition, special attention shall be paid to the following matters: when the flame is high, the top section shall be connected with high electrode in time to prevent the screw thread from being damaged; When sliding the electrode, there must be a soft connection to avoid hard collision; The holder must be perpendicular to the electrode to prevent it from scratching the electrode with the small furnace cover; Avoid the oxygen lance directly facing the lower electrode in the furnace. This is a technical requirement for the use of electrodes, and the purpose is to avoid and reduce the direct loss of electrodes.