Method of defining the degree of impregnation of the dry aggregate with pitch in the process of anode production

Abstract

Anode paste is a mixture of coke and pitch. In a continuous mixer, the kneading provides for a uniform distribution of pitch and coke in paste, efficient wetting and maximum pitch impregnation of coke and ultimately, it defines the properties of the mix. The impregnation degree depends on the properties of coke and pitch, and the interaction between them, as well as the kneader design, mixing energy, kneading temperature and time. This paper describes a method for evaluating the degree of impregnation of the dry aggregate with coal tar pitch. The method is based on comparing the porosity of a particular dry aggregate fraction before kneading to the porosity of said fraction after kneading. The porosity before and after kneading is defined by the ratio between the bulk density and the apparent density. The method has proved useful and it helped reveal some characteristics on the process of kneading.