Method for determining electrolytic aluminum carbon paste kneading temperature

Abstract

The invention relates to a method for mixing and kneading carbon paste used in electrolytic aluminum, which is characterized in that when kneading ingredients for the carbon paste, asphalt is added with a softening point controlled at between 90 and 120 DEG C, percentage of toluene insoluble is controlled at between 25 percent and 35 percent and quinoline insoluble at between 6 percent and 15 percent; and the optimal range of asphalt viscosity is between 285 and 700-centipoise, and the mixing and kneading temperature range of the paste is at between 150 and 200 DEG C. The method figures out the relation between the rheologic property and the softening point of the coal asphalt and the relation between the rheologic property and the main components of the asphalt including the toluene insoluble, the quinoline insoluble through analysis of the softening point of coal asphalt and rheologic property of main components of the asphalt including the toluene insoluble, the quinoline insoluble and the coal asphalt, and researches, and determines the optimal range of viscosity, so as to determine the optimal mixing and kneading temperature of the paste. As a result, the asphalt achieves good fluidness and can fully penetrate into pore space of aggregate, and the paste achieves sound plasticity, thereby being favorable for mixing, kneading and forming as well as improving the quality of carbon products.

Description

technical field [0001] The invention relates to a method for determining the kneading temperature of carbon paste for electrolytic aluminum. Background technique [0002] Kneading is a process in which solid carbonaceous materials and coal tar pitch binders are stirred and mixed at a certain temperature to form a plastic paste. The purpose of kneading is to mix aggregates of different particle sizes evenly, so that the molten pitch can infiltrate and distribute on the surface of charcoal particles, and penetrate into the coke pores to form a plastic paste, which is conducive to molding. The kneading temperature is the main factor affecting the kneading effect. The optimum kneading temperature of the paste should be determined according to the softening point of the asphalt, the main components in the asphalt toluene insoluble, quinoline insoluble and the rheology of the asphalt, that is, according to the relationship curve between the rheology of the asphalt and the softeni...

AI Technical Summary

Problems solved by technology

[0003] At present, in industrial production, the kneading temperature is determined by the softening point of asphalt. Generally, the optimal kneading temperature range is selected to be 50-80°C higher than the softening point. This method obviously has certain limitations, and there is no scientific basis. Production experience confirmed

The kneading temperature has a great influence on the carbon material, mainly because the kneading temperature is too low, the viscosity of the coal tar pitch is high, the infiltration effect is poor, the kneading is uneven, the carbon material and the pitch cannot be well and uniformly mixed, and the plasticity of the paste is poor, resulting in carbon Cracks appear in the material during firing

The kneading temperature is too high, the viscosity of coal tar pitch is small, and the infiltration effect is good, but the performance of the pitch will change, the light components will decompose and volatilize, and the components of this group will undergo polycondensation reaction, and the pitch distributed on the surface of the aggregate may be oxidized by air. The plasticity of the paste is deteriorated, the molding performance is poor, and the yield is reduced