What is the role and influence of petroleum coke in electrode paste?

Electrode paste is an indispensable material in the process of electrolytic aluminum production, its main components include petroleum coke, graphite, asphalt and so on. Among them, petroleum coke plays a crucial role in the electrode paste. The effect of petroleum coke on electrode paste is discussed in this paper.

1. Definition and properties of petroleum coke

Petroleum coke is a solid carbonaceous product obtained by heat treatment of petroleum asphalt at high temperature, which has the characteristics of high carbon content and low volatile content. The properties of petroleum coke mainly depend on the composition of raw asphalt and heat treatment conditions. According to its shape and structure, petroleum coke can be divided into needle petroleum coke, spherical petroleum coke and spongy petroleum coke.

2. The role of petroleum coke in electrode paste

(1) Provide carbon source

Petroleum coke is the main carbon source in the electrode paste, and its high carbon content is conducive to improving the conductivity of the electrode. In the process of electrolytic aluminum production, the electrode paste needs to be in contact with the aluminum liquid at high temperature, at which time the carbonized part of petroleum coke will gradually transfer to the aluminum liquid, forming aluminum carbide, thereby improving the electrical conductivity of the aluminum liquid.

(2) Enhanced electrode structure

Petroleum coke plays a skeleton role in the electrode paste, and its needle-like structure can form interwoven network to enhance the structural stability of the electrode. In addition, petroleum coke interacts with graphite, asphalt and other components to form a certain strength of the electrode structure, which is conducive to improving the service life of the electrode.

(3) Reduce alumina consumption

Petroleum coke can reduce the consumption of alumina during electrolysis. The research shows that the carbonaceous substances in petroleum coke can form compounds with alumina, thus reducing the consumption of alumina in the electrolytic process and improving the electrolytic efficiency.

3. The influence of petroleum coke on the performance of electrode paste

(1) Affect the adhesion of the electrode paste

The amount of petroleum coke added will affect the adhesion of electrode paste. The proper amount of petroleum coke can improve the adhesion of electrode paste, which is conducive to the forming and sintering of electrode. However, excessive petroleum coke may cause the adhesion of the electrode paste to decrease, affecting the strength and stability of the electrode.

(2) Affect the conductivity of the electrode paste

The electrical conductivity of petroleum coke has an important effect on the electrical conductivity of electrode paste. The results show that the electrical conductivity of petroleum coke is closely related to its microstructure and surface properties. Therefore, when choosing petroleum coke, we should choose petroleum coke with good conductivity to improve the conductivity of electrode paste.

In short, petroleum coke plays a crucial role in the electrode paste. Reasonable selection and use of petroleum coke can improve the performance of electrode paste, and thus improve the efficiency and quality of electrolytic aluminum production. In the actual production process, the appropriate petroleum coke should be selected according to the specific situation, and the ratio of electrode paste and production process should be optimized to achieve efficient and sustainable development of electrolytic aluminum production.