The end of an era for Søderberg Technology in North and South America

Abstract

In the 1970s twenty three Søderberg smelters located in North and South America had a primary aluminum capacity over 3 million tpy. The largest operating Søderberg smelter, Companhia Brasileira de Aluminio with a plant capacity of 475,000 tpy built the last Søderberg potline in 2007. Today there are only five Søderberg smelters operating with a capacity of less than 1 million tpy. Compared with prebake technology, Søderberg cells have higher production costs, they are more difficult to automate and they have the greatest environmental and health challenges. Health studies from the middle of the 1970s show a clear link between Søderberg tar fume exposure and the incidence of various types of cancer lead companies to propose a program of replacement. Starting in the late 1970s a number of programs and actions were taken to reduce PAH emissions and worker exposure to fumes, but in Canada they were always seen as stop-gap actions until replacement was completed.