406 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



[OCTOBEK, 



through the middle of the furnace from front to Lack. A, is the ash pit ; B 

 the fire chamber ; Cthe hearth of (lie puddhng furnace B, into w hich the heated 

 air and flame jiass through the flue space E, and operate upon the material 

 ivithin the furnace in the usual manner; F, is the roof of said furnace; the 

 hearth and roof should be formed of suitable fire stone; G, is a flue above 

 the roof stone, leading to the chimney H : I, represents a front door to the 

 puddling furnace, but the main working door is to be made at the side, as 

 seen at 1', this being its usual place ; J, is the door of the fire chamber for 

 supplying fuel ; K, is a basin at the front of the hearth, and L, a tap hole 

 for the removal of slag, &:c. : as it is desirable to keep the hearth at this part 

 well heated, the fire chamber is sometimes so constructed as to allow it to pro- 

 ject a foot, more, or less, in front of the furnace, by which means this end is 

 effectually accomplished. The lower part of the basin may be strengthened 

 ty giving the hearth stone the form shown by the dotted lines a, a ; M, is 

 the grate, and N, level of the ground. 



When tills furnace is used for the purpose of converting mineral into 

 wrought-ir.n directly from the ore, said ore is to be finely pulverized, and 

 thrown upon the hearth, which must be heated to whiteness; in about half 

 an hour the mineral will be fused, and it is then to be treated in the same 

 manner as when pudling pig-iron ; by this means the sulphur and other 

 volatile matter contained in the ore will be driven off. and the ore will be 

 subjected to the full action of the heated air. Most kinds of ore may be 

 treated in this way without the addition of any flux, or of carbonaceous mat- 

 ter J but where the ore is refractory, and does not fuse readily, fromicontain- 

 ing an excess of oxygen, a small portion of charcoal may be added thereto- 

 When the ore is too fusible, owing to its containing an excess of carbon, I 

 add the scales of iron, or soinc analogous substance, such as the highly oxi- 

 dized ores, as is sometimes done in the puddling of pig-iron. No rule can be 

 given for this, but the judgment of every competent iron master will supply 

 all the information that is necessary. Most commonly, as before remarked, 

 the metal will be brought into nature without any such addition to the iron. 

 When the mineral, or pig metal, has been thus heated until it approaches 

 the melting point, the fire is to be slackened, until it is reduced nearly to a 

 red lieat ; in this state the ore, or the metal, is to be worked with a scraper 

 and paddle until the mineral, or metal, shall have tiecome, as the technical 

 phrase is. sufficiently drif. At this period the heat is to be raised, and, when 

 the welding of the mineral, or metal, commences, it is to be balled into suit- 

 able sizes, cither for the hammer, or the rollers. 



The claim is for the constructing and using of a reverberatory furnace that 

 is heated by means of a fire chamber, situated below its hearth, or floor, and 

 from which the flame and heated air are conducted over its top, so as to heat 

 it as well below as above; the respective parts of the said furnace being com- 

 bined, arranged, and operating, as represented and described. 



Specification for a patent for " mamifaciuring maUeahte iron directly from the 

 ore, in a puililling furnace." Granted to Simeon Broadmeadow, of the city 

 of New York.— May 30, 1844. 



The improvement is the process for manufacturing iron, by means of which 

 malleable iron is obtained directly from the ore, by treating the same in a 

 puddling furnace. 



The form given to the furnace, is somewhat different from that usually 

 given to the pudling furnace, as will be seen by reference to the accompany- 

 ing drawing, which represents it as having one of its side walls removed for 

 the purpose of showing the form of the interior. A A, is the arch, or roof, 

 which, instead of curving down as it approaches the chimney, rises regularly 

 from that part which is above the fire chamber, as it approaches the stock 

 which it may do at an elevation, say of about ten degrees ; it may, however 

 pass horizontally, or even be slightly depressed, without materially interfer- 

 ing with its action; the object of giving to it this form is to prevent its taking 

 the character of a reverberatory, as the reflecting of the flame and heat so as 

 to cause them to reverberate, or impinge, upon the ore, converts the large 

 portion of it into slag, instead of reducing it into malleable iron. The inven- 

 tor elevates the hearth or the furnace at its near end, and prefers to do this 

 to an extent greater than that of the elevation of the roof ; this elevation is 

 shown at D. The object thereof is to contract the throat, or opening, from 

 the furnace into the flue, so as to make it much less than in the ordinary re- 

 verberatory, wliich is usually about two ieet, or two feet six inches, whilst 

 he reduces its height, between the floor and the roof, to about one foot. In 

 the lower part of the chimney, as at a, a, where a sliding register, or damper, 

 is placed, which can be closed at pleasure, so as to retain and regulate the 

 heat ; such regulation being essential to the success of the process, in a fur- 

 nace, 30 constructed, the mineral and the metal obtained therefrom, will be 

 sufficiently heated to produce the intended eflect ; but the form of the fur- 

 nace may, as above indicated, be varied to a considerable extent without ma- 

 terially nterfering with its use; and there have , probably been puddling, or 

 other furnaces constructed, which, under due management, might answer 



the purpose equally well with that described. No claim is made to the par- 

 ticular form of the furnace which is described, but only to indicate the main 

 conditions necessary to the success of the process. 



In this process of reducing the mineral to the metallic state, the inventor 

 does not use any of the earthy, or other fluxes which are employed in the 

 smelting of iron, nor does he, of necessity, mix therewith any carbonaceous 

 matter, as has been uniformly done in the attempts heretofore made to ma- 

 nufacture malleable iron directly from the ore. The most notable of these is 

 the process for which letters patent were obtained in England by W. N.Clay, 

 dated on the 31st of March, 1841. In that patent a claim is made to "the 

 mode of manufacturing wrought, or malleable, iron in reverberatory furnaces 

 from iron ere, by combining therewith twenty-eight per cent., or upwards, 

 of carbonaceous matter." In this present process, on the contrary, the ores 

 of iron are employed alone, by mixing together, in due proportions, such ores 

 as, by their chemical composition, are calculated to react upon each other 

 when duly heated, and to bring the metal contained in each of them into the 

 malleable state, the inventor takes any of the ores which are known as oxides 

 of iron, which he reduces to coarse powder, and with this he mixes a due 

 proportion of the ore known as a carburet of iron, also in powder; this mix- 

 ture he puts into his puddling furnace, and by means of anthracite, or other 

 fuel, subjects it to the proper degree of heat for efi'ecting the reduction. 

 The mass so placed in the furnace, he does not stir, but leaves at rest, until he 

 finds that it is brought into a state in which it is prepared for balling, which 

 condition is produced in consequence of the union of the carbon of the car- 

 buret with the oxygen of the oxide, and the consequent production of parti- 

 cles of iron in the malleable state. 



When charcoal or other carbonaceous matter is mi.xed with the ore which 

 is to be reduced, the carbon will begin to combine with the iron in the oxide 

 which is to be reduced, before the oxygen of said oxide is so far disengaged 

 as to be ready to combine with it, and the metal will become highly charged 

 with carbon, and the whole contents, will, consequently, be converted into a 

 fluid mass, and this may occur notwithstanding the utmost care on the part 

 of the operator ; a very slight deviation in making the mixture, or in the 

 heat to which it is subjected, converting the materials into slag. But when 

 this mixture consists entirely, or nearly so, of the ores to be reduced, as above 

 described, there may be a considerable variation in the temperature without 

 deteriorating the mass, the carbon of the carburet, and the oxygen of the 

 o.'iide, being given out simultaneously, and these, by their affinity, combining 

 with each other, the iron of both the ores will be left in the metallic state, 

 requiring only to be balled up. — It will be manifest to any one acquainted 

 with the nature of ores, that in mixing them no proportionate quantities can 

 be designated, as scarcely any two ores will be found to be identical in com- 

 position ; but the proportionate quantities maybe learnt from analysis, or 

 will readily be ascertained by experiment in the hands of a competent iron 

 master. — Although the addition of carbonaceous matter is not necessary in 

 this process of reduction, the inventor does not interdict its use, as it is mani- 

 fest that a deficient proportion of carburet might find its compensation in 

 such addition, but this would he only a variation of, and not a departure 

 from, the principle upon which he proceeds. ^Vhcn the iron is ready for 

 balling, the slag is to be removed, and the balling is to be efi'ected m the or- 



