Graphite electrodes are mainly made of petroleum Coke and needle Coke as raw materials, and coal asphalt is used as a binder. They are made by calcination, ingredients, mixing, pressure type, roasting, graphitization, and machining. It is a conductor that releases electricity in the form of an arc to heat and melt the furnace. According to its quality index, it can be divided into ordinary power, high power and ultra-high power.
Graphite electrodes include:
(1) Ordinary power graphite electrode. Graphite electrodes with a current density of less than 17A/cm2 are allowed to be used, mainly for ordinary power electric furnaces such as steel-making, Silicon refining, and yellow phosphorous refining.
(2) Antioxidant coated graphite electrode. A graphite electrode coated with an antioxidant protective layer(graphite electrode antioxidant). The protective layer that can conduct electricity and resist high temperature oxidation is formed, which reduces the electrode consumption(19 % to 50 %) during steelmaking, extends the useful life of the electrode(22 % to 60 %), and reduces the electrical energy consumption of the electrode. The widespread use of this technology can have such economic and social effects:
The unit consumption of graphite electrode is less, and the production cost is reduced. For example, in a steel plant, according to the annual production of about 35 graphite electrodes per week in the LF refining furnace, the consumption of 165 furnaces is refined and processed. After the use of graphite electrode oxidation technology, 373 electrodes(153 tons) can be saved each year.) Electrodes, 16 per ton of ultra-high power electrodes, Calculated at 900 yuan, it can save 258.57 million yuan.
The graphite electrode consumes less electricity, saves the unit of steelmaking electricity consumption, saves production costs, and saves energy!
3 Because the number of graphite electrodes is changed less, the labor volume and risk coefficient of the workers are reduced, and the production efficiency is improved.
Graphite electrode is a high consumption and high pollution product. It has very important social significance in the days of energy conservation, emission reduction and environmental protection.
This technology is still in the research and development stage in China, and some domestic manufacturers have also begun to produce. It has been widely used in developed countries such as Japan. At present, domestic companies that specialize in importing these antioxidant protective coatings have also emerged.
(3) High power graphite electrode. Graphite electrodes with a current density of 18 to 25 A/cm2 are allowed and are mainly used in high-power arc furnaces for steelmaking.
(4) Ultra-high power graphite electrode. Graphite electrodes with a current density greater than 25A/cm2 are allowed. Mainly used for ultra-high power steelmaking arc furnace.
Points to note for the use of graphite electrodes:
1, wet graphite electrode, dry before use.
2, remove the foam protective cap on the spare graphite electrode hole, check whether the inner thread of the electrode hole is complete.
3, clean up spare graphite electrode surface and hole thread with compressed air without oil and water; Avoid cleaning sand cloth with steel or metal brushes.
4, carefully rotating the connector into the electrode hole at one end of the backup graphite electrode(it is not recommended to load the connector directly into the electrode removed from the furnace), not to collide threads.
5, the electrode hanging equipment(recommended graphite hanging equipment) into the electrode hole at the other end of the backup electrode.
6, when lifting the electrode, loosen the soft material to the bottom of the end of the standby electrode connector to prevent the ground from hitting the connector; Lift the pendant ring with a hook, and the lifting electrode must be stable to prevent the electrode from loosening from the B end or colliding with other fixing devices.
7, hanging the spare electrode to the top of the electrode to be connected, pointing at the electrode hole and slowly falling; Rotate the backup electrode so that the spiral hook rotates with the electrode to drop; When the two electric extremes are 10-20mm apart, the exposed parts of the two ends and joints of the electrode are cleaned again with compressed air; When the electrode is finally completely decentralized, it must not be too violent. Otherwise, due to violent collisions, the electrode holes and joints will be damaged.
Unscrew the backup electrode with a torque wrench until the end surfaces of the two electrodes are in close contact(the correct connection between the electrode and the joint is less than 0.05 mm).