Determination of optimum vibro-compaction time using sound analysis

Abstract

The quality of carbon anodes plays an essential role in the production of primary aluminum. The vibro-compaction is one of the most important steps of the anode fabrication process, which affects the anode quality. Over and under-compacting results in anodes with high electrical resistivity, poor mechanical and physical properties. Therefore, the compaction conditions should be chosen carefully. A method and a sound analysis software were developed to determine the optimum vibration time using the sound generated by the vibro-compactor during anode compaction. This method was tested with a bench-scale system both in the laboratory and in the plant. It is simple, fast and inexpensive. The effect of anode raw materials (types of coke and pitch) and top-former bellow pressure of the vibro-compactor on the optimum compaction time as well as the effect of compaction time on anode properties were investigated. The results showed that there are three stages of anode formation during vibro-compaction, good quality anodes can be produced by using compaction time around the optimal value, and the utilization of sound analysis reduces the compaction time. • Raw materials as well as the mixing and compaction parameters affect the anode quality. • Anodes go through three stages during vibro-compaction. • Utilization of optimum compaction-time will improve the anode properties. • The sound of the vibro-compactor can be used to determine the optimum compaction-time. • The method developed can assure that each anode is compacted using its specific compaction-time.