A Review of Challenges and Solutions in Ledge Control and Measurement in Aluminium Electrolysis Cell

In aluminium electrolysis cell, thermal balance represents a very sensitive aspect of process control and its optimization. This balance is strongly influenced by the side ledge behaviour, making it crucial for cell performance. Despite the existence of numerous studies on ledge, its precise behaviour remains difficult to assess in a timely manner due to the aggressive environment and the limited access to the ledge. The literature reports only limited methodologies to quantify the formation of ledge in the electrolysis cell, and these are generally only representative of a short period. In this article, the challenges associated to ledge measurement and controls are discussed along with the relevant parameters and thermal events. Solutions proposed to manage these limitations are discussed including numerical and physical methods.