30+ YEARS OF EXPERIENCE IN CARBON INDUSTRY

In the manufacturing of electrode paste, coal tar serves as a binder, a role it shares with coal pitch. Coal pitch is a product derived from the deep processing of coal tar, while they share the same origin, they are distinct materials. Coal pitch acts as the primary binding material, whereas coal tar functions as a modifying additive within the formulation. As an optional component, it can be included or omitted based on specific customer requirements. For instance, our facility once produced 2,000 tons of electrode paste for a prominent client that did not contain any coal tar.

1. When liquid coal tar is blended with coal pitch, it reduces the overall viscosity of the binder. During the kneading stage, this facilitates more thorough wetting of the carbon aggregate particle surfaces, resulting in a more uniform mixture and improved plasticity of the green (unbaked) paste, which in turn eases the forming process.

2. Furthermore, it enhances the wetting and spreading of the pitch over anthracite and coke powder particles, reducing interfacial voids between the aggregate and the binder, and thereby improving the density of the green paste.

3. Additionally, as coal tar consists of highly volatile components, it vaporizes early during the heating process within the electrode shell, this allows for fine-tuning of the electrode's self-baking rate.

Therefore, standard electrode paste requires the addition of coal tar. While electrode paste without coal tar does exist, its use depends on the specific type of furnace the customer operates. A binder combination of coal tar and coal pitch allows the electrode paste to melt perfectly and subsequently sinter within a submerged arc furnace, the absence of coal tar would negatively affect the softening process of the paste.

The oval, trapezoidal and cylindrical shapes electrode paste produced by our factory, are formulated with coal tar. In the case of high-grade, dense electrode paste intended for ferronickel production, the formulation requirements are even more stringent.