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IIIGII-SCIIOOL CIIEMISTRY
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THIS powerful landscape contains all the thrill and dratna of the steel industry. Man's patient efforts, so aptly l)rOportioncd b)' the tiny stealn-shovel, will eventually drag the iron fronl the grirn clutches oCthe earth. Whether this will be fashioned into rails, automobiles, stainless frying-pans, or guns, arlnor, and torpedoes, will be determined by the clouds of war and peace which moyc over thc scene.
Courtesy of U. S. Sleel Photo
GLOWING piles of eoke are pushed from the ovens in which the heat has driven out the volatile matter from cnornl0US charges of soft coal. The escaping "spirits" of the coal are caught and condensed into valuable ulumonia, fuel gas, benzene, coal-tar, whence come forth a lllultitude of things of great use: drugs, lUcdicines, dyes, explosives, and chemicals. The ~oke, lllcantime, has gone to keep an appoin tlnen t wi th the iron orc at the blast furnace.
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94
Courtesy of Office of War Information
FEBRUAllY,
95
1943
HER E before the blast furnaces have corne the ore frorTI the iron mines, Lhe coke frorn the ovens, and linlcstone from the quarries. They will be carefully Ineasured out and nlixed together in the raging heat, each to playa necessary part ill the libera lion of the iron nletal.
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Courtesy of Offia; of War lPt/ormation
AT THE right is the tall, stack-like blast furnace. '"Skips," or dump cars run continuously up and down the inclined track to keep the furnace charged froUl the top with J11casured anlounts of orc, coke, and linlcstone: orc which contains the iron, bound up with tenacious oxygen and .nixed with sandy nlalter froul which it must be freed; coke to burn and keep the furnace hot, and at the sante lime to tear the ox)'gen loose from the iron in the orc; limestone, the "flux" or "f1uid-nluker" to gather up the sandy i.Jl1}>urilics in the orc into a liquid-like InolLcn glass, which trickles down into the bottom of the furnace where it floats on the ])001 of liquid iron. Froln tinle to tinIe, as in the picture, a hole is opened in the side of the furnace and the liquid slag runs off into large fire-brick bowls. I t is then wheeled off and ]Joured ou t to cool, later perhaps to be used on roadways or made into ceOlent or "mineral wool." Less often, a lower hole in the furnace is opened and lhe rDolten iron is tappcd off, sOillctimcs to bc cast into convenient-sized bars or "pigs," sometimes to be carried in enormous ladles directly to the open-hearth furnaces or Bessemer converters, there to be further purified into "steel."
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Courlesy of U. S. Steel Photo
The iron frolu the blast furnace, often known as IJig iron or cast iron, contains such large urnounts of carbon, suUur, silicon, phosphorus, and Inanguncse that it is too brittle for many uses. At the left are the tall "stoves" in which air is heated to high temperatures before it is blown at high pressure into the base of the blast furnace.
96
JOURNAL OF CHE,'1ICAL EDUCATION
HERE THE molLen iron from the blast furnace is being (loured into the open-hearth furnace where hundreds of tons of it lie in a wide, shallow pool, often gently agi Luted by a rocking motion of the whole furnace. Hot blasts of air playing on the surface of the I)OO} will slowly burn out 111.0st of the impurities in the liquid iron. When tests show that this has gone far enough, measured amounts of other ingredjents will be introduced: carbon to gh'c pure iron thc properties characteristic of steel; nickel, luanganese, chromium, tungsten, "'anadjunl, to Inake alloy steels for various purposes. +-
Courtesy of U. S. Sitel Photo
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TREMENDOUS quantities of scrap iron and sleel arc also IncIted up in the open-hearth furnaces. This is not only a .uutter of cconom)' in recirculating the discarded nlulerial, but the furnaces actually operate ,norc efficiently if they arc fed a large proportion of previously purified iron along with Lhe raw nluLerial from the blast furnace. ~
Courtesy
u. s. Stul COTp.
+ THE FI1'lISHED sLeel is here shown heing Lapped
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Courles~
0/ Office 0/ War Information
off fro III a slDaU o(:.en-hearth fu.rnace. Just previous to this, materials arc often introduced to act as "scavengers," substances like aluminuln which will renlOVC the traces of oxygen which the molten Inass may have trapped and whieh Inight leave rusty iInpuriLies when it hardens. In the open-hearth, as in the blast furnace, a liquid "slag" forll1s. This time it is principally the lining of the furnace itself -which is the "fluxing agent," soaking up and cOlnbining with the burned-out impurities of the iron to form a fluid which floats on the molten steel and which is carefully skhnmed off when the la tter is poured ou t, as in the illustration.
FEBRUARY,
97
1943
THIS IS nol the explosion of a trcluendous mortar but the "blowing" of a Besscnlcr converter, another type of furnace in which the impure iron from the blast furnace is refined into steel. In this1case the impurities are burned out by a blast of hot air forced up through the bottom of a bricl
