The non-destructive 3-D characterization of pre-baked carbon anodes using X-ray computerized tomography

Carbon anodes represent about 25% of the production cost of aluminum, therefore quality control is of important to the smelting operation. Typical quality control methods involve testing cores from production and scrap anodes. The parameter of particular interest is density. The aim of this research is to determine the density profile of carbon anodes through a non-destructive analysis. X-ray computerized tomography (CT) is a technique that can determine the density of materials and represent the information visually at high resolution. A bench-scale green anode was scanned using X-ray CT, over the length of the anode. The anode was baked in an industrial laboratory and re-scanned at the same registration. The density data were converted into a series of images. The density difference between the green and baked sample is apparent. The presence of additional features such as localized areas of inadequate amounts of binder were also observed.