rp 250 graphite electrode
Influencing factors of the mixing and kneading process of rp 250 graphite electrode
1 The main indicators of binder asphalt are softening point, coking value and adhesion. The softening point of the binder pitch used by the American Carbon Factory is about 110°C (the test method is the air stereo method). The softening point of the cemented asphalt produced by vet in Germany is about 109℃, and the coking value of the cemented asphalt is generally about 55%. The ρ content of the Japanese asphalt is about 20%, which is slightly lower than that of the American asphalt.
When using this kind of asphalt, it is necessary to control the ratio of the asphalt during the batching. The high-power rp 250 graphite electrode only needs to be dipped once, so high-quality asphalt with high softening point and high coking value must be used as the binder to produce high-power, The ultra-high power rp 250 graphite electrode realizes short process production (less impregnation and less roasting).
Temperature influence During the kneading process, temperature is an important factor affecting the kneading effect and product quality. During the paste kneading process, pitch with a certain rheology evenly penetrates the surface of the carbon-containing particles, and part of the pitch penetrates into the internal voids (through holes and cavities) of the carbon-containing material, which can further improve the density and cohesiveness of the paste. If the rheological properties of asphalt are adjusted to the best, the greater the permeability, the better the kneading effect. However, if the kneading temperature of the paste is too low, the rheological properties of the asphalt will be poor, and it will be difficult for the asphalt to penetrate into the voids of the carbonaceous material, making it difficult to mix and get out of the pot, and the paste has poor plasticity, which is not conducive to molding; If the kneading temperature is too high, the light components of the asphalt have wettability and cohesiveness, are easy to volatilize, and are also prone to condensation reactions. Part of the asphalt attached to the surface of the carbonaceous material will be oxidized. The adhesion of the asphalt will decrease and the plasticity will be lower. Poor and paste molding.
If the rheological properties of the asphalt are not good, the wetting and bonding effect of the asphalt cannot be guaranteed. Therefore, the optimal kneading temperature of the asphalt mixture should be within the temperature range where the rheological properties of the asphalt are good and the asphalt composition remains unchanged. In this temperature range, the greater the wettability of the asphalt to the solid carbon material, the better the rheological properties of the asphalt, the more uniform the kneading of the asphalt paste, and the better the plasticity. Make the final product reach the ideal density, strength and other physical and chemical indicators, improve the yield, and reduce the increased cost due to the increase in the number of immersion. The viscosity of the binder asphalt decreases sharply with the increase of temperature.
The relationship between the viscosity of warm asphalt and temperatureTemperature/C Eighty one hundred twenty one hundred forty viscosity/Pa.S1718 x 10-389.13 x 10-3 inches 11.35 x 10-3 inches 2.327 x 10-3 inches of asphalt The viscosity also increases as the softening point increases. Therefore, the heating temperature should vary with the softening point of the asphalt. The optimum temperature of the paste depends on the softening point of the adhesive. In general, when the paste temperature is higher than about twice the softening point of the binder, the binder has good wettability to the carbon powder. According to experience, when using medium temperature asphalt as the binder, the paste temperature should be controlled at 140℃~180℃~150℃~160℃; when using hard asphalt with a softening point of 100~120, the paste temperature should be increased to 180℃~240℃ . In this temperature range, the asphalt has good wettability and permeability to the dry material, the kneaded paste has good plasticity and extrusion properties, and the compressed product has a uniform structure and high bulk density. Therefore, the temperature should be well controlled in actual production. When the steam heating pressure is lower than 0.45MPa, the kneading time should be extended. When the steam pressure is lower than 0.4MPa, production should be stopped.
Using a mixture of anthracene oil and coal tar can appropriately lower the kneading temperature. When using modified asphalt or high-temperature asphalt for rp 250 graphite electrode, the kneading temperature should be appropriately increased. In addition, the kneading temperature is also related to the climate. In winter, the temperature is low and heat dissipation is fast, and in summer, the temperature is high and the heat dissipation is slow. Therefore, the kneading t