Control of secondary emissions in pyrometallurgical smelters

CIM Bulletin, Vol. 87, No. 981, 1994

J.A. Davis, DESOM Engineered Systems Limited, King City, Ontario, and J.E. Taylor, Jan H. Reimers & Assoc. Inc., Oakville, Ontario

Existing environmental, heoJth and safety regulations have forced pyrometallurgical facilities worldwide to drastically change some of their traditional methods ofoperation. In extreme cases, a number offacilities have been closed due to their inability to conform to these existing regulations. Tougher future legislation and government policy will lead to more stringent regulations and enforcement policies. The efficient control of smelter secondary emissions will, therefore, become critical to successful smelter operation. Much attention has been paid to the smelter primary process off-gas systems, including the development of new process designs to reduce the number ofuncontrolled transfer operations. However, even the most modem smelter design requires control ofits secondary contaminant sources, which mayor may not be directly related to the process operation. This paper discusses some ofthe potential secondary emissions encountered in many of the present process technologies. A few of the emission sources presented are only periodic in nature, such as those caused by maintenance procedures, but which have the capability offorcing smelter shut-down because of their direct impact on worker health and safety. The paper deals with a variety of topics relating to the effICient control, maintenance and monitoring of secondary emissions in copper, nickel, aluminum, magnesium and lead smelters, as well as in iron foundries and steel making facilities. Examples ofthe typical problems encountered in each of the above process operations are presented, including fume control at furnace tapping and slagging locations, metal transfer stations,tapping launders, and ladle transfer operations. The parameters for the most efficient design offume capture systems, problems encountered with the handling and clean-up of certain collected emissions, and examples ofsuccessful solutions in particular operations are discussed.

Keywords: Health and safety, Smelter emissions, Secondary emissions,Emissions.