Potroom Operations Contributing to Fugitive Roof Dust Emissions from Aluminium Smelters

Recently, “Maximum Achievable Control Technology” (MACT) floor regulations have been implemented in the US for total fugitive particulates from aluminium smelter potlines; similar regulations also now apply in Canada and the EU. These highlight the challenge that smelters face in meeting increasingly stringent air quality limits. For any pollutant, the first step in establishing an effective mitigation strategy is understanding the key sources of emissions. Here we report the results of a time-resolved study that examined the response of fugitive dust emissions to operations in the potroom over an entire work cycle. Identical sets of real-time dust monitors were located at both the potroom roof and floor level between cells. This built upon an earlier study on the composition of potroom dust, involving several prebake point-fed technology smelters. Similar to fugitive HF, it was found that the changing of prebaked anodes was a major contributor to fugitive dust in the potroom. At this potline, other contributors to fugitive roof dust include metal tapping, loading of cover material and mechanical sweeper vehicle movements. As expected, operations related to solids handling/transport were found to release only fugitive dust, with minimal HF emission.