Air pollution control systems clean furnace exhaust
When Alcan wanted new air pollution control systems that would remove tar and hydrogen fluoride from the exhaust of its anode-baking furnaces, systems using indirect gas coolers, electrostatic precipitators, and dry scrubbers worked well.
Alcan Smelters and Chemical Ltd. of Jonquiere, Quebec, processes aluminum by using carbon anodes produced in two covered anode-baking furnaces that were installed in 1985. Exhaust from each furnace contains condensable tars, hydrogen fluoride, and miscellaneous solid particulates [such as bits of carbon and coke].