What is graphite electrode and How does it work?

By:Win Sep 24, 2020
What is graphite electrode and How does it work?
Graphite electrode is a consumable used in steelmaking and a strategic mineral resource. The country does not encourage export.
What is graphite electrode?
Graphite electrodes have only been known in China in recent years. I didn’t know what graphite electrodes are before. Since 17 years, due to the sharp rise of international graphite electrode prices, capital has entered the market with huge profits. However, due to the impact of the epidemic this year, the price of graphite electrodes has fallen all the way, and many graphite electrode factories have been half-closed.
Graphite electrodes are divided into regular power graphite electrodes RP, high-power graphite electrodes HP, and ultra-high-power graphite electrodes UHP according to their power (current passing under a certain voltage). Paired with ordinary power electric arc furnace, high power electric arc furnace and ultra-high power electric arc furnace for steelmaking operations. Therefore, after getting the graphite electrode, it can be used according to its physical and chemical indicators to match the requirements of the electric arc furnace.
Some companies have increased the classification of impregnated graphite electrodes HD/IP (quasi-high power graphite electrodes) and quasi-ultra-high power graphite electrodes SHP due to market demand, which means that their power has increased by two categories among the original three categories . The order of power size is: RP>HD>HP>SHP>UHP.
The structure of the graphite electrode is composed of the electrode body and the electrode nipple:
graphite electrodes structure drawing

How does graphite electrode work?
The working principle of the graphite electrode is very simple. After being inserted into the electric arc furnace, an electric arc is generated, and the electric energy is released in the form of electric arc to heat and melt the steel scrap in the charge. The arc can be generated between the graphite electrode and the scrap steel. Or an arc is generated between the graphite electrode and the graphite electrode. AC electric arc furnace generally requires three graphite electrodes to be energized at the same time. The DC electric arc furnace only needs a graphite electrode, but the diameter is larger.
1) RP graphite electrode is used in general power electric arc furnace, it allows the current density to be lower than 17A/cm2, mainly used for smelting ordinary steel, silicon and yellow phosphorus, etc.
2) HP graphite electrodes are used in high-power electric arc furnaces, and the allowable current density is between 18~25A/cm2, mainly used for steelmaking.
3) UHP graphite electrodes are used in ultra-high power electric arc furnaces, which allow a current density greater than 25A/cm2, and are mainly used for smelting refined steel and special steel.
In addition, graphite electrodes are also used in the field of electrolytic metals. Electrolysis of metal magnesium, aluminum, sodium, the anode in the electrolytic cell also uses graphite electrodes. The furnace head of the resistance furnace for the production of emery also uses graphite electrodes.