Ironmaking blast furnace

The most important indusuial reaction of this kind occurs in die ironmaking blast furnace in which iron oxide ore is reduced by carbon in the form of coke. The mixture is heated by the combustion of part of the coke input in air to produce temperatures as high as 2000 K. The reduction reaction is caiTied out via the gas phase by the reaction... 

The reduction of iron ores is carried out on the large industrial scale in the ironmaking blast furnace, where CO is the reducing gas and the product is liquid... 

A model for studying the formation of burden layers in the ironmaking blast furnace has been developed on the basis of a single-point measurement of the stock level by radar. The model, which, furthermore, makes use of geometrical conditions of the problem at hand, has been kept conceptually simple so it can be applied to track the burden distribution in operating blast furnace. The model has been tuned to data from a... 

Ironmaking in the United States did not expand rapidly until after the Revolutionary War. Then, as the colonists moved westward, the need for iron prompted the estabUshment of ironworks near the new settiements. A blast furnace built by Jacob Anschut2 in 1796 was the beginning of the iron and steel center in Pittsburgh, Pennsylvania. 

Ironmaking refers to those processes which reduce iron oxides to iron. By the nature of the processes, the iron produced usually contains carbon and/or other impurities which are removed in downstream processing. There are three principal categories of ironmaking processes, in order of commercial importance blast furnace, direct reduction, and direct smelting. 

Blast Furnace. The blast furnace is the predominant method for making iron. Estabhshed for centuries as the premier ironmaking process, blast furnace ironmaking both enabled and profited from the Industrial Revolution. Although the fundamental principles of operation are unchanged, the blast furnace has evolved into a highly efficient and productive process. 

The lead blast furnace operates at a lower temperature than the iron blast furnace, die temperature at the tuyeres being around 1600K as opposed to 1900K in the ironmaking furnace (see p. 333) and this produces a gas in which die incoming air is not completely reduced to CO and N2, as much as one per cent oxygen being found in the hearth gas. 

The blast furnace (Fig. A, opposite) remains the basis of ironmaking though the scale, if not the principle, has changed considerably since the eighteenth century the largest modem blast furnaces have hearths 14 m in diameter and produce up to 10000 tonnes of iron daily. 

HyL [Hojalata y Lamina] A direct reduction ironmaking process in which pellets or lumps of ore are reduced in a batch reactor using a mixture of hydrogen and carbon monoxide. Used in countries which have natural gas and cannot afford to invest in blast furnaces. Developed in the 1950s in Mexico by the Hojalata y Lamina Steel Company (now Hylsa) and the MW Kellogg Company, and now operated in nine other countries too. See DR. 

ITmk3 [mark 3 indicates that this is a third generation ironmaking process, marks one and two being the blast furnace and direct reduction] A modification of the Fastmet process, for making molten iron. Pelleted iron ore fines are reduced with a solid reductant. The iron in the reduced pellets separates as molten metal, uncontaminated by gangue. Developed in 1996 by Midrex Corporation and Kobe Steel. Commercialization is expected in 2003. 

Blast furnace hearth design, 72 762-765 Blast furnace ironmaking, 74 498-509 Blast-furnace lead smelting, 14 734-736 Blast furnace material balance, 14 504 Blast furnace plant, 14 506 Blast furnace refractory, carbon as, 72 761-765... 

Ironmaking processes, 14 498-521 blast furnace, 14 498-509 direct reduction, 14 509-520 direct smelting, 14 520-521 Iron-manganese-silicon steels, 22 712 Iron melting channel melting furnaces, 12 316... 

These factors have prompted two principal thrusts in ironmaking development. First, progress continues to be made in increasing blast furnace productivity and in decreasing coke rates. Coal (qv) injection to replace coke units has assumed a prominent role. Coal replaces coke on a nearly 1 1 mass basis, and coal injection rates of up to 250 kg/t of hot metal (thm) have been achieved. Injection of oxygen and other reductants besides coal are expected to be used more extensively. Increased additions of scrap, DRI, and HBI are expected to play a significant role in efforts to boost productivity and decrease coke rates. 

J. J. Poveromo, "AISI Survey of Blast Furnace Pellet Properties," in Proceedings, 52nd Ironmaking Conference, AIME-ISS, Dallas, Tex., 1993. 

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