What is the role of modified asphalt in the preparation of anode rods?

The role of modified asphalt in the pre-baked anode primarily includes the following aspects:

‌Bonding Action: Modified asphalt, as a binder, can tightly bond solid carbonaceous raw materials such as petroleum coke and asphalt coke together, forming a pre-baked anode blank with certain shape and size. This bonding action not only enhances the overall strength of the pre-baked anode but also improves its electrical conductivity and corrosion resistance._‌

The Carbonization Process: During the baking of pre-baked anodes, the upgrading asphalt undergoes pyrolysis and condensation reactions, gradually transforming into coke, which significantly enhances the mechanical strength and conductivity of the pre-baked anode. The formation of coke strengthens the overall structure of the pre-baked anode, resulting in a notable increase in mechanical strength.

Pore Filling: Modified asphalt can flow and fill the gaps between solid carbonaceous raw material particles during the heating softening and subsequent coking process, making the structure of the pre-baked anode denser. This not only increases the density of the pre-baked anode but also enhances its erosion resistance and reduces the permeation of gases and electrolytes.

Enhancing Conductivity: The carbon structure formed from the coking of upgraded asphalt exhibits excellent electrical conductivity, enabling the construction of a continuous conductive network in pre-baked anodes. This reduces resistance and improves electrolytic efficiency, which is crucial for the even distribution of current and the enhancement of electrolytic efficiency in the aluminum electrolysis process.

Enhanced Mechanical Strength and Wear Resistance: Modified asphalt boasts superior strength and adhesion, effectively improving the mechanical strength and wear resistance of pre-baked anodes. This allows pre-baked anodes to withstand greater pressure and impact forces, thereby extending their service life during the electrolysis process.

Enhanced Corrosion and Chemical Resistance: Modified asphalt boasts excellent chemical stability and corrosion resistance, effectively combating acidic and alkaline corrosion in electrolytes, thereby extending the service life of pre-baked anode blocks. This corrosion resistance ensures that the pre-baked anode maintains good chemical stability in the electrolyte, reducing the likelihood of dissolution or corrosion.

Enhanced Thermal Stability: The upgraded asphalt maintains excellent stability at high temperatures, resisting softening and loss. This ensures the consistent performance of the pre-baked anode during the high-temperature electrolytic process, minimizing deformation or cracking.