| Abstract |
The results of a survey of 12 United States and 2 Japanese primary aluminum (7429905) facilities (SIC-3334) were examined. The U.S. facilities include seven centerwork and two sidework prebake units, and two horizontal and one vertical Soderberg facility. The Japanese sites included one vertical stud Soderberg and one centerwork prebake facility. The control technology currently used for prebake and Soderberg primary aluminum smelting facilities were described, focusing on effective control technologies found in ore handling and storage, green carbon unit, carbon bake unit, anode rodding, and potlines. Specific chemical agents included fluorides in the potrooms, hydrocarbon vapors in the green carbon facility, sulfur-dioxide (7446095), and hydrocarbons in the carbon bake unit, airborne particulates in ore handling, and metal dust and fumes in the rodding room. All sites provided formal health and safety programs, and personal protective equipment. Personal and area air samples revealed that total fluoride (16984488) concentrations were controlled below 2.5 milligrams per cubic meter (mg/cu m), but concentrations of coal-tar (8007452) pitch volatiles commonly exceeded 0.20 mg/cu m. The authors conclude that the use of solid pitch may reduce exposure to pitch volatiles. The cleaning of conveyor belts for hot pitch anode mix should reduce hydrocarbon fume generation. |
