Method of impregnating and pressurizing electrode paste
During the impregnation process of electrode paste, there are three ways of pressurizing the coal asphalt in the impregnated tank:
(1) Compressed air pressure. The outlet air pressure of the air compressor is only 0.8MPa, and the actual impregnation pressure is only 0.5MPa. Using compressed air for low pressure impregnation, the impregnation effect is poor, it is difficult to penetrate large size carbon billets, and it will cause oxidation of impregnating agent asphalt of electrode paste, and reduce the quality of impregnating agent asphalt.
(2) High-pressure nitrogen pressure. The nitrogen filling pressure of the nitrogen cylinder can reach 12MPa, and the general impregnation pressure is below 2MPa, so it can be adjusted in a large range. In the actual impregnation operation, in order to save nitrogen consumption, pre-pressurize with 0.6MPa compressed air, so that some of the impregnating asphalt of the electrode paste enters some of the open pores of the carbon billet, and then continue to pressurize with nitrogen to 1.0~1.2MPa, and maintain the specified time in this pressure range. The impregnation pressure consumes nitrogen, so the cost of impregnation production increases, and the pressure value and pressure holding effect are greatly affected by human factors, which is often difficult to guarantee.
(3) asphalt pump liquid pressure. Using the coal pitch itself as the pressurizing medium, the coal pitch of the electrode paste is directly pressurized by the asphalt pump into the impregnating tank. By using this method, the cooling effect of compressed air or nitrogen on the impregnation tank can be prevented, the time of vacuum exhaust and asphalt injection can be reduced, and the productivity of the electrode paste impregnation equipment can be improved, and the use of liquid pressure equipment is safer. Asphalt pump generally adopts two-stage cock pump, its working pressure can reach 1.5MPa, flow rate is 60 ~ 1250L/min.
