UPDATE ON THE EVALUATION OF HF EMISSION REDUCTIONrnUSING COVERED ANODE TRAYS

摘要

During the production of aluminium via electrolysis in thernconventional Hall-Héroult process, carbon anodes have to bernreplaced on a regular basis. The anode butts are usually placed onrnuncovered trays for transportation and cooling, a practice thatrnsignificantly contributes to overall hydrogen fluoride (HF)rnemission from the smelters.rnIn 2000, special anode tray covers developed by AlcoarnDeschambault (ADQ) were implemented to significantly reducernfluoride emissions. In 2004, the Alcoa-STAS R&D teamrndeveloped a second generation of anode tray covers for the newrnAlcoa Fjardaál plant.rnIn 2009, the Alcoa-STAS R&D Team designed and fabricated anrnexperimental setup which allows the accurate full-scalernmeasurement of temporal HF emissions from cooling anode trays.rnThis paper presents a description of the setup, a summary of thernprocedure, and an update on the results obtained with the use ofrnthe anode tray covers.