Sludge Formation in Hall Héroult Process: An Existing Problem

This paper provides a concise literature review on the industry and laboratory investigations into sludge formation during the Hall Héroult Process, which is critical for aluminum producers facing the challenges of resistive cathodic deposits. With the rapid increase in aluminum production, particularly from China, understanding and mitigating sludge formation has become imperative for major producers. The review begins by introducing the sludge formation phenomenon and its adverse effects on the Hall Héroult process. It discusses the thermochemistry involved, followed by an in-depth examination of four primary factors contributing to sludge formation: hydrodynamics, operational temperature (superheat level), alumina feeding strategy, and bath chemistry. By shedding light on these pivotal aspects, the paper aims to enhance the understanding of sludge formation mechanisms and support efforts to minimize its impact in aluminum production.