Colorimetric Methods for Determining Fe,V, and Ni Contents in Coke and Anodes

Prebaked carbon anodes are used in the electrolytic production of aluminum. They are made of petroleum coke, butts, recycled anodes, and coal tar pitch. The anode quality, which depends on the raw material quality and the production conditions, has an important impact on the cell performance. Metallic impurities (V, Ni, and Fe) found in cokes and anodes increase the carbon consumption by catalyzing the air and CO₂ reactivities. In turn, this increases the production cost, energy consumption, and the emission of greenhouse gases. The current methods for detecting the metallic impurities in carbon are time consuming and require intensive sample preparation, skilled personnel, and costly reagents. In this work, simple, rapid, and effective tools were developed using colorimetric methods.