Graphite electrode according to the bearing current density, bending strength, compressive strength, density, resistivity, thermal shock resistance, thermal expansion coefficient and other indicators and uses, divided into ordinary power graphite electrode (RP), impregnated graphite electrode (including antioxidant coated graphite electrode and pitch impregnated electrode), high power graphite electrode (HP) and ultra-high power graphite electrode (UHP) four categories. In principle, various graphite electrodes are configured with ultra-high power graphite electrode nipples of different qualities according to quality indicators.
1.Ordinary power graphite electrode(RP)
The ordinary power graphite electrode is made from ordinary calcined petroleum coke or pitch coke as aggregate,mixed with binder pitch,then under the process of cooled,pressed,baked,graphitized and machined.Compared with high-power and ultra-high-power graphite electrodes,the strength and bulk density of ordinary power graphite electrodes are relatively low,and the current density can be carried is relatively small,which is suitable for calcium carbide,industrial silicon and small current arc furnace.
2.Impregnated graphite electrode(antioxidant coated graphite electrode)
Anti-oxidation coating is a measure used to protect the electrode to reduce oxidation,there are generally two coating processes,one is the"Impregnation"coating,the other is the external coating.Graphite electrode antioxidants are nano-ceramic materials dispersed in aqueous solution,is translucent blue liquid.After the graphite electrode is treated with anti-oxidant YHG-03 negative pressure or pressure impregnation,a layer of high-temperature ceramic protective film is formed on its surface and inside the micropores of the body to effectively isolate the air.It can delay the oxidation rate of electrode and reduce the unit consumption of electrode.It is an effective anti-oxidation impregnating agent for electrode.By introducing graphite electrode anti-oxidation treatment technology,the amount of graphite electrode can be directly saved by about 15%,and it does not bring any negative impact to the production site.
The impregnated graphite electrode is mainly used in the smelting of electric arc furnace steelmaking,yellow phosphorus,etc.
3.High power graphite electrode(HP)
Compared with ordinary graphite electrodes,high-power graphite electrodes in the production process except to adding a part of needle coke to improve the electrode current density,strength,product density,will add one time impregnating and re-baking process,other processes are similar to ordinary graphite electrodes.
High power graphite electrode is mainly used in electric arc furnace steelmaking and chemical industry.
4.Ultra-high Power Graphite Electrode(UHP)
Compared with the high-power graphite electrode,the ultra-high power graphite electrode in the production process will all use needle coke,add a impregnation and re-baking process,the electrode can carry the current density,strength,product density will be greatly improved,other processes are similar to ordinary graphite electrodes.Compared with ordinary and high-power graphite electrodes,because all the use of needle coke,the bending strength of ultra-high power graphite electrodes will be greatly improved,so that it can adapt to large current impact and high performance requirements against thermal shock resistance.
Graphite electrode production process description:
Raw petroleum coke or pitch coke,after calcination at 1250/1450℃,with calcined petroleum coke or pitch coke as the aggregate,after crushing and screening,grinding,batching,adding to the kneading pan for preheating till meet the technical required temperature(corresponding to the nature of coal pitch),adding heating and melting dehydrated liquid coal pitch for kneading,and then through cooling material,pressing to make green electrodes.Green electrodes are baked under the protection of insulation material(shaped and prevent oxidation),in order to improve the strength and density of the product,if necessary,the baked product can be impregnated and burned two or three times,and then through graphitization,and finally machined into the specified size of the finished graphite electrode(Nipple).
Type of furnace used: Calciner, Ring pit furnace, Re-baking tunnel kiln, Graphitization furnace
