Graphite electrodes are low in cost and easy to process. The use of electric arc furnace steelmaking is less investment than blast furnace steelmaking, and there is less environmental pollution.
Graphite electrode is a conductive rod used in electric arc furnace steelmaking and an important material for steelmaking. The main raw material for graphite electrode production is petroleum coke. RP graphite electrodes need to add pitch coke (petroleum coke and pitch coke sulfur content <0.5%), HP and UHP graphite electrodes need to add needle coke (1.05 tons of needle coke to produce 1 ton of UHP graphite electrode). The electric arc furnace consumes 2 kg of graphite electrodes for each ton of steel.
Graphite electrode production process: calcination, batching, kneading, pressing, roasting, graphitization, and machining. According to the power usage level, it can be divided into RP ordinary power graphite electrode, HP high power graphite electrode and UHP ultra high power graphite electrode .
Properties of graphite electrodes
Graphite electrode is a good conductor of electricity and heat. It has stable chemical properties, strong electrical conductivity, high mechanical strength and good vibration resistance at high temperatures. Graphite electrode contains less other impurities and is suitable for smelting metals, silicon, yellow phosphorus, etc.
The graphite electrode has a diameter of φ200~700mm and a length of 1800~3000mm. When used, three electrodes are inserted into the electric arc furnace at the same time.
The physical and chemical indicators of the graphite electrode in accordance with the national standard:
The resistivity, flexural strength, elastic modulus, bulk density and linear expansion coefficient of the graphite electrode are used as quality assessment indicators, and ash content is used as a reference indicator.
Advantage of using graphite electrodes
1. The high temperature resistance of graphite electrode can reach 3900°C, boiling point is 4250°C, and the working temperature of electric arc furnace is above 3000°C, so after high temperature arc burning, its loss is very small, graphite will increase with the temperature in the electric arc furnace The mechanical strength is strengthened. When the temperature reaches 2000°C, the strength of the graphite electrode is doubled.
2. The conductivity of the graphite electrode is 100 times higher than that of ordinary non-metallic minerals, because the average particle size of the graphite electrode is small, the discharge condition is stable, the better the surface quality, the greater the current. The graphite electrode has low loss, and the loss ratio with the copper electrode is 1:2. Strong thermal conductivity, graphite will become an insulator at extremely high temperatures.
3. The graphite electrode has stable chemical properties, and can resist acid, alkali and organic solvent corrosion at room temperature.
4. Easy to machine, the processing speed is 2~3 times faster than the copper electrode, and no additional manual processing is required.
5. Compared with copper electrode, light weight and low cost. The graphite electrode is directly sublimated and consumed during the steelmaking process, and no impurities will fall into the electric arc furnace. Graphite electrodes are more cost-effective.