The electrode paste, which has been broken into pieces in advance, is regularly added from the top of the cylinder welded by the steel plate. The electrode paste in the bucket begins to soften and melt under the action of heat, and then the binder coal pitch is thermally decomposed to escape the volatile matter, until it is baked into a Carbon electrodes with better conductivity and greater mechanical strength rely on the roasted electrodes to direct current into the submerged electric furnace. Due to the high-temperature oxidation and the chemical reaction involved in the charge, the lower end of the electrode is constantly consumed, so the entire electrode barrel should be lowered regularly, and the upper part of the electrode barrel adapts to connect a new barrel and replenish the electrode paste.
The self-baking process of electrode paste in the submerged electric furnace can be divided into 3 stages:
(1) Soften and melt. The temperature of the electrode paste body rose to 150. C is in a state of plastic flow, and its position is about 500mm above the conductive holder.
(2) Coal tar pitch is pyrolyzed and volatiles are removed. The fully softened and semi-flowing electrode paste flows along the cross section of the cylinder and fills the gaps between the blocks. As the temperature continues to rise, the binder coal pitch in the electrode paste decomposes and escapes volatile components. After pyrolysis and polycondensation reaction, coal pitch is gradually transformed into coke coke.
(3) Sintering stage. The coal pitch contained in the electrode paste is completely coked, the resistivity continues to decrease, and the mechanical strength continues to increase. Basically, the roasted part is in the middle and lower part of the conductive holder. At this time, the electrode paste is self-baked and transformed into a carbon electrode.