The main raw materials for manufacturing carbon electrode are preheated anthracite or anthracite, in which part of recycled materials (broken electrode, etc.) or casting coke is added, bituminous coal pitch or pitch containing anthracene oil is used as binder, and a small amount of natural graphite is added for extrusion molding and roasting.
The performance of carbon electrode is regulated by the Ministry of metallurgical industry standard heavy color 1922-55 as follows:
1. The quantity of joint and paste is one joint for each electrode and 5kg paste per ton of electrode.
2. After the electrode is connected with a joint, the end gap should not exceed 0.5mm.
3. When the electrodes are connected together, the deviation between the center line of one electrode and that of the other electrode shall not exceed 3mm.
4. The bending of any diameter electrode shall not exceed 0.5% of its length. It is allowed to supply shorter electrodes, but not less than one meter, and the quantity shall not exceed 10% of the total weight in each batch.
5. The depth of block falling on the edge of electrode end shall not be greater than 10 mm, and the total length shall not be greater than 40 mm. The length of the joint hole and the thread on the joint shall not be more than 15mm, not more than two places, and no transverse crack is allowed on the electrode and the joint.