Inspection of Prebaked Carbon Anodes Using Multi-Spectral Acousto-Ultrasonic Excitation.

Autor: Boubaker, Moez Ben, Picard, Donald, Duchesne, Carl, Tessier, Jayson, Alamdari, Houshang, Fafard, Mario
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Zdroj: Metals (2075-4701); Aug2017, Vol. 7 Issue 8, p305, 15p
Abstrakt: Reduction cell operation in primary aluminum production is strongly influenced by the properties of baked anodes. Producing consistent anode quality is more challenging nowadays due to the increasing variability of raw materials. Taking timely corrective actions to attenuate the impact of raw material fluctuations on anode quality is also difficult based on the core sampling and characterization scheme currently used by most anode manufacturers, because it is applied on a very small proportion of the anode production (about 1%), and long-time delays are required for lab characterization. The objective of this work is to develop rapid and non-destructive methods for the inspection of baked anodes. Previous work has established that sequential excitation of smaller parts collected from an industrial sized anode using acousto-ultrasonic signals at different frequencies allowed detecting and discriminating anode defects (pores and cracks). This was validated qualitatively using X-ray computed tomography. This work improves the method by using frequency-modulated excitation and building quantitative relationships between the acousto-ultrasonic signals and defects extracted from tomography images using Wavelet Transforms and Partial Least Squares (PLS) regression. The new excitation approach was found to provide similar or better inspection performance compared with sequential excitation, while requiring a shorter cycle time. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index