Graphite electrode, which is mainly made of petroleum coke and needle coke as raw materials and coal asphalt as binder, is made by calcining, batching, mixing, pressing, calcinating, graphitization and machining. It is a conductor that releases electric energy in the form of arc in the arc furnace to heat and melt the charge.
The main raw material of graphite electrode production is petroleum coke. A small amount of asphalt coke can be added to ordinary power graphite electrode, and the sulfur content of petroleum coke and asphalt coke can't exceed 0.5%. High power or ultra-high power graphite electrode also need to add needle coke.
(1) Used in arc furnace
Electric steelmaking is a big user of graphite electrode. The output of electric furnace steel accounts for about 18% of that of crude steel, and the graphite electrode used in steelmaking accounts for 70% ~ 80% of the total amount. Electric steelmaking makes use of the graphite electrode to introduce the current into the furnace and the high temperature heat source generated by electric arc between the electric extremes and the charge to carry out smelting.
(2) Used in ore smelting electric furnace
Ore smelting electric furnace is mainly used in the production of industrial yellow phosphorus and silicon, etc., its characteristic is the lower part of the conductive electrode buried in furnace charge, arc formed within the material layer, and using the furnace charge itself from the resistance of the heat energy to heating furnace charge. It's required that the high current density ore smelting electric furnace utilize graphite electrode, such as silicon 1 t per production to consumption of graphite electrode is about 100 kg, per 1 t yellow phosphorus production to consumption of graphite electrode, about 40 kg.
(3) For resistance furnace
The graphitization furnace for producing graphite products, the melting furnace for melting glass and the electric furnace for producing silicon carbide are all resistance furnaces. The materials in the furnace are both heating resisters and objects to be heated. Generally, the conductive graphite electrode is embedded into the furnace head wall at the end of the resistance furnace for the discontinuous consumption of the graphite electrode here.
(4) Used for preparing heteromorphic graphite products
The blank of graphite electrode is also used for processing various crucibles, molds, dishes and heating bodies and other special-shaped graphite products. For example, in the quartz glass industry, for every 1t of fused tube, 10t of graphite electrode blank is required. For each 1t of quartz brick, 100kg of graphite electrode blank is consumed.