Acoustic Emissions of Cathode Carbon Block from Aluminum Electrolytic Cell Under Deformation

Abstract

In order to understand the propagation mechanism of microcrack developing into destructive penetrating cracks and the evolution process of that in cathode carbon block, the acoustic emission (AE) characteristics of cathode carbon block in the process of failure were studied under uniaxial compression loads. The experiment results show that the failure process of cathode carbon block can be divided into four stages. Based on the characteristic parameters of AE signal and its macroscopic fracture state, the causes and corresponding fracture modes of AE signals in each stage are analyzed. In addition, AE signals in the failure process of cathode carbon block can be divided into four types according to k-means clustering analysis. According to the parameter characteristics, waveform characteristics, and time distribution of all types of signals, it can be concluded that class A signals correspond to tensile failure caused by the interaction of macro crack and the friction between aggregate particles in post-peaking stage. Class B signals are considered as the noise generated by the friction between the testing machine and the end face of the cathode carbon block. It is considered that class C signals correspond to the shear slip cracking before the macro cracking as well as the crack propagation and penetrating large-scale shear failure at the peak stress that affects the overall stability of the cathode carbon block. Class D signals are generated by the fracture of the connection between aggregate particles and the compaction of pores between aggregate particles during the early stage of loading. The results provide basic data and experimental basis for the detection of electrolytic cell damage in electrolytic aluminum industry.