Final report on DSA methods for monitoring alumina in aluminum reduction cells with cermet anodes

Abstract

The Sensors Development Program was conducted at the Pacific Northwest Laboratory (PNL) for the US Department of Energy, Office of Industrial Processes. The work was performed in conjunction with the Inert Electrodes Program at PNL. The objective of the Sensors Development Program in FY 1990 through FY 1992 was to determine whether methods based on digital signal analysis (DSA) could be used to measure alumina concentration in aluminum reduction cells. Specifically, this work was performed to determine whether useful correlations exist between alumina concentration and various DSA-derived quantification parameters, calculated for current and voltage signals from laboratory and field aluminum reduction cells. If appropriate correlations could be found, then the quantification parameters might be used to monitor and, consequently, help control the alumina concentration in commercial reduction cells. The control of alumina concentration is especially important for cermet anodes, which have exhibited instability and excessive wear at alumina concentrations removed from saturation.