The main production process of graphite electrode
(1) Calcining. Both petroleum coke and pitch coke need to be calcined, and the calcining temperature should reach 1350°C to fully remove the volatiles contained in the carbonaceous raw materials and improve the true density, mechanical strength and conductivity of the coke.
(2) Crushing, screening and ingredients. The calcined carbonaceous raw materials are crushed and sieved into aggregate particles of a specified size, and part of the coke is ground into fine powder, which is weighed according to the formula and aggregated to form a dry mixture of various particles.
(3) Kneading. In the heating state, the dry mixture of various particles with a quantitative decrease and a quantitative binder is stirred and mixed, and kneaded into a plastic paste.
(4) Forming. Under external pressure (extrusion molding) or high-frequency vibration (vibration molding), the paste is pressed into a green electrode with a certain shape and higher density.
(5) Roasting. Put the green electrode in a special baking furnace, use metallurgical coke powder to fill and cover the green electrode, and carbonize the binder at a high temperature of about 1250°C to generate coke, thereby preparing an unfired carbon electrode.
(6) Impregnation. In order to improve the density and mechanical strength of the electrode product, the roasted electrode is installed in the high-voltage equipment, the liquid impregnant pitch is pressed into the pores of the electrode, and the second roasting should be carried out after the impregnation. According to the product performance requirements, sometimes impregnation and second roasting It needs to be repeated 2-3 times.
(7) Graphitization. The calcined electrode is put into the graphitization furnace, covered with the insulating material, and the carbon electrode is converted into a graphite electrode with a graphite crystalline structure at a high temperature of 2200-3000 DEG C by directly energizing the heating method to generate a high temperature.
(8) Mechanical processing. According to the requirements of use, the graphite electrode blank is processed for surface turning, flat end faces and screw holes for connection, and the joints for connection are processed.
(9) After passing the inspection, the graphite electrode shall be appropriately packaged and sent to the user.