The quality, physical and chemical indexes of the electrode paste are listed in the above table, among which the elongation is a reference index. Electrode paste can be divided into closed paste No. 1 and No. 2; Standard Lake No. 1, No. 2, and No. 3; Chemical electrode paste. It is recommended to use electric forging anthracite as the raw material for No. 1 airtight paste. Chemical electrode paste is mainly used in semi-closed calcium carbide submerged arc furnace.