Siberian Federal University

It is well known that the perfluorocarbon (PFC) gases CF4 and C2F6 are being emitted during anode effects in aluminium cells. These PFC compounds are very strong greenhouse gases, and the aluminium industry has made great efforts to reduce these emissions. From 1990 to 2008 a 90% reduction in PFC emissions has been achieved. However, during the last few years we have received new alarming information, mainly from the Chinese aluminium industry, that there is an almost continuous emission of PFC gases from aluminium potlines even in the absence of anode effects, and it accounts for 10 to 90% of the total PFC emissions, the median being 70%. They named it “Non-anode effect PFC emissions”. This information has later been confirmed from several sources, so it seems to be a universal problem. To our knowledge it was first detected by the late Warren Haupin of Alcoa in 1995, but apparently it was not taken seriously at that time. Now we know better. A recent report from Alcoa indicates that whereas low voltage PFC emissions were observed in all prebake plants being investigated, it was not detected in two Soderberg potlines. Possible reasons for that will be discussed