The first step in steel production requires the conversion of iron ore into usable metal. This is performed using a blast furnace, which consists primarily of a column 30 feet or more in diameter, and over 100 feet high. This column contains a mixture of iron ore, coke and limestone, which is surrounded by hot gas. The gas is produced by the combustion of coke in the bottom of the furnace. On interaction with the gas, the iron is released from the ore, and sinks to the bottom of the furnace, where it is tapped off as a liquid.
The process requires extremely high temperatures (up to several thousand degrees Fahrenheit) to produce the chemical reactions necessary for releasing the iron from the ore. In addition, once started, a blast furnace can operate continuously for up to ten (10) years, with only periodic shutdowns for maintenance purposes. In order to keep the furnace operating efficiently, large amounts of cooling water are required. The walls of the column must be cooled, typically through the use of cooling jackets. The bottom of the furnace usually has large diameter cooling pipes which provide cooling water.
The furnace also incorporates a series of nozzles, called tuyeres, through which the hot air for combusting the coke is introduced. The tuyeres are made of copper and must be cooled by a continuous flow of water, as they may be exposed to temperatures up to 4000°F or more.
A tremendous amount of heat is generated within a blast furnace, due to the high temperatures required to produce the chemical reactions. In order to keep the system running smoothly and prevent shutdowns, a large volume of cooling water is required. The water may be from an intake water source, such as a river or lake, or from on-site cooling tower. Whichever the case, this water will contain scale, silt, sand, microbiological growth, etc. which can foul the cooling system and result in inefficient furnace operation. Recalyx Filters provide an excellent solution for the removal of these solids, ensuring proper furnace operation.