Graphite Electrode Manufacturing Flow
By:Yvonne Jul 23, 2020
Simple talk about graphite electrode manufacturing process flow.
The graphite electrode manufacturing process includes the following main processes.
● Screening and mixing of raw materials (green or raw petroleum coke) and blending with coal tar pitch to form a dense paste.
● Formation or extrusion of the electrode.
The paste was passed through a proprietary extruder mixer to form elongated rods of uniform diameter.
● Calcining or Baking of the electrode to decompose and devolatilize (purify) the petroleum needle coke by removing organic materials, moisture and volatile combustible matter, thereby increasing the fixed carbon content, electrical conductivity and real/true density in the resultant calcined petroleum coke (“CPC”).
● First Pitch Impregnation (“1PI”) which consists of impregnating/soaking the electrode with tar pitch binder to reduce porosity or void fractions within the graphite rod to improve strength.
Following calcination, the graphite rods were soaked in a solution of tar pitch for 1 hour.
● Re-Calcining or Re-Baking — this step is to ensure that all voids within the rods are filled with pitch coke binder.
● Second Pitch Impregnation (“2PI”) — to ensure that all gaps within the rods are filled with pitch coke binder.
● Graphitization — removes additional impurities and improves the electrodes’ key qualities: thermal and electrical conductivity, thermal shock resistance performance, lubricity, and abrasion resistance.
● Machining to create the exact sizes and smooth surface.
Complete graphite electrode manufacturing process flow chart: