Electric Arc Furnace
Ferroalloys and silicon metal are produced in electric arc furnaces that are specially designed for smelting purposes. These furnaces are referred to as Submerged Arc Furnaces (SAF's). In the SAF electric power heats the raw materials and provides the energy needed to smelt the ore to a metallic state. These furnaces are termed submerged arc since the electrodes are buried deep in the furnace burden and the reduction takes place near the tip of the electrode. These processes produce copious amounts of heat and fume that must be captured before escaping to the atmosphere.
The environmental regulatory agencies in most countries strictly regulate emissions from these operations.
Dust To be handled: Pig-iron/Slurry ash
Nature of dust: Fine, free-flowing, mildly abrasive
Cleaning Mode: Offline or Online
Design Gas temperature:120-220 Degree Celsius
Design Surge Temperature: 150-240 Degree Celsius
The furnace hood design and process conditions are critical to the air pollution control equipment sizing. Closed furnaces are often used to produce alloys with a low gas generation rate. The furnace off-gas may have a high percentage of CO that can be captured and used somewhere in the process. High carbon ferromanganese (FeMn) and ferrosilicon 50% or less in silicon content may be produced in closed furnaces. Ferrosilicon with more than 50% silicon content and silicon metal are produced in open or semi-open furnaces due to the high gas generation rate from these processes. The focus of this paper is on open and semi-open furnaces that are operated open to the atmosphere.