USRE798E - Improvement in refining iron h the hearth of a blast furnace - Google Patents

Description

C-SHUNK. v Refining Iron and Steel.

Reissued Aug. 16, 1859,

UNITED STATES PATENT OFFICE.

CHRISTIAN snnNK, OF o N oN, 011-10.;

IMPROVEM ENT IN REFINING IRON N THE HEARTH 0Fv A BLASTFJRNACE,

Specification forming'part of Letters Patent No. 24,060, dated May 17, 1859; Reissue NoQIQQdatd August 16, 1859. I i i i I To all whom it may concern Be it known that I, CHRISTIAN SHUNK, of Canton, in the county of Stark and State of Ohio, (formerly of Slate Lick, in the county of Armstrong and State of Pennsylvania,) ha'. e invented a new and useful improvement in the process of refining and decarboniz'ing the melted metal in the hearth of the ordinary blastfurnace used in the manufacture of pigmetal; and I do hereby declare the following to be a full,clcar, and exact description thereof, reference being had to the accompanying drawings, making a part of this specification anu illustrative of the same, in which Figure 1 represents a vertical seclionthrough the stack, tamp-arch, and one' of the tuyere arches of an ordinary blast-furnace for the manufacture of pig-iron from the ore and as constructed and arranged for the use of my improved process. Fig; 2 is a horizontal sectiou'through the tuyere-arches and hearth of the blast-furnace. (Shown in Fig. 1.)

similar letters of reference, where they occur in the separate figures, refer to like parts in both of them.

My improvement consists in refining and decarbonizing the melted metal in the hearth of the blast-furnace before it leaves the hearth by passing a blast or blasts of air through the body of the molten metal by means of anauxiliary tuyere pipe or pipes, so arranged as to discharge the blast under the surface of the melted metal and give to it a rapid rotary motion therein, and thus insureafree admixture of the oxygen of the air-thus blown in'with the particles of the iron, causing the union of the carbon in the iron with the oxygen thus supplied, and so refining the metal before itis made into pig-iron.

My invention supersedes entirely the use of the finery or run-out fire, the use of which arose from the necessity of an intermediate process of refining or purification between the blast-furnace where the ore is converted into metallic iron and the puddli'ng-furnace, this necessity being occasioned by the impurities in the iron and the presence of an excess of carbon. My invention thus not only avoids the trouble and delay of this intermediate process, but causes a great saving of iron, which is usually converted into slag and wasted by the finery or the run-out process, as'well as a pig.

saving of the fuel used int-he remelting of the of oneor more additional tuycre-holes for thc" ad mission of the auxiliary tuyere pipe or pipes .v

used for introducing the blast into the iron. The ordinary tuyere pipes used in the blast-furnaces are not dispensed with, nor is their position or mode of application necessarily varied, excepting that when the refining process is being carried on all the blast is caused to pass through the auxiliary tuyere pipe or pipes, and is shut off or stopped y, from passing through the ordinary tuyere-pipes;

To introduce the blast for refining the iron by my process I use a separate'and independent tuyere pipe, which isintrod uced intothe hearth of the furnace under, the tamp-stoneiu front or at one of the sides, as may be preferred. If it be introduced'at one of the sides,itis in serted tlirougha tuyerearchin a manner sunilar to the ordinary tuyere-pipes, excepting that'the nozzle of the auxiliary tuyere-pipe is much longer and enters into the hearth, which the nozzle of the ordinary tu-yere-pipe does not. The nozzle of the auxiliary tuyere-pipe, after entering the cavity forming the hearth, dips downward to within a short distance of the hearthstone d, so that its mouth is covered by the molten metal. It is preferable to set the nozzle of the auxiliary tuyere-pipe at such an angle as that the blast of air entering the iron may strike the wall of the hearth at (as nearly as possible) aline tangential to a circle drawn therein, so as to expend its force more effectually in causing the molten metal to rotate in the'hearth and to become more diifused through it, as every particle of iron thus moved around must come in contact withthe blast of air and a more certain commingling of them produced. The rotary motion thus given to the molten metal in the hearth greatly relieves the pressure against the incoming blast, as the motion of-the metal is 1n the same direction in which the blast enters, and

th e-forcclof the blast is cumulative on the -iron when the latter is onceset in motion. The auxiliary 'tuyere h, as shown in Fig. 2, is represented as being rather a chord or secant of the circledrawnwi-thin thehearth than a tangent, but that is about the right inclination to etl'ect'a. rapid rotationot' the metal inthe hearth. introduced in front of the furnace, it is dune by inserting it through the. small openi E and the "top of the dam-stohe f, in which, case a movabletamp-plate, G, is placed over the damf, covering the aperture between the temp-stone and thedam-sione. The auxiliary pipe is inserted in an opening of convenient size in said plate Gr, so as to penetrate the liquid metal near the bottom of the furnace hearth, and this plate may be swung out of the way when the'refining process over.

It will thus be seen that my improvement,

' though very important iuits results, requires so little alteration in the constiuctiouand arrangement of the ordinary blast-furnace as to be easily and cheaply introduced into practi cal. operation. But I do 'not desire to'confine' myself in the application of my improvement to the precise manner of application herein described so long as the molten: metal is rapidly. moved around in the hearth. Y After the char e of iron has rundown into the hearth of the est-furnace, (the smelting process being carried on in the usual way,)

and when the molten metal is ready, accordng to the ordinary process, to be run out intopigs, my refining processiscornmenoed, The

auxiliary tuyere pipe or pipes are now iutro-. dnced into the molten iron, and the whole blast 0t air used for'the hlastihrnace isnow diverted from the ordinary tuyere-pipes and caused to pass with great force'and pressure through the auxiliary tu-yere pipe or pipes h it used in my process.' Uold ai'ris mueh'preferable as a blast for refining the iron, though either cold or hot may be used. Care must be taken to proportion the size of the auxiliary tuyer-pipes' to. the' quantity of air to be forced through them by the blowingcylinders, which" must he very considerable It the'auxiliary tuyerepipe is to .9 J6. tween the lower front edge of the temp-stone in volume and pressure to cause a rapid motion and ebullition of the molten iron in thefurnaee-hearth, so as to expose all the particles of the iron to'contact with the air, by means of which the. iron is refined of its-impurities and decarbonized by the admixture of the oxy' gen of the airand the carbon in the -iron before itis run intopig-metal,

The process of refining requires but a few minutes for its-accomplishment, andwhen finishedthe-molten metal is drawn. oft through the tapping-hole in the usual manner and molded into pi g-iron.

' The useof a strong blastof cold airand' its intimate admixture with. the molten iron has not the eli'ect ot'chilling the iron in the furnaceheartlnbut rather the-reverse, as the chemical efl'ect'of the unionof the oxygen antlcarbon is to produce an intense heat, which pre serves, and-,if anything,increases, the fluidity of the metal but this cold blast must not he continuedtoo' long, for,'if so, the iron will coinmence to granulate. The propentime is soon learned by the workman by'the appearance of the metal to the eye, whichistheonly reliable way ofdetermining its condition in its various stages of manufacture.

; Having thus fnlly descrihed the nature and object of my invention, I'woi1ld state that It so not broadly claim the introduction of at? 'rnospherio'air into. molten metal re "zdless of 'of the manner of doing it; hut- W hat I do claim as new in the manufacture of pig-iron fromtne ore, and desire to secure by Letters'Patent, is-- The employmentimmediatelybefore the tappin'g of the furnace of an auxiliary tnyere pipe or'pipes within the hearth of the" coup mon blast-furnace when charged with molten iron at such an inclination as" te -cause the blast of air to eommingle with the particles of iron and give to the whole mass in the a spiral 01; rotary motion, substantially as dek scribed. I CERISTIaISI Witnesses Y W. A. Wormnrzsenasna, CHAS. F. Hnsnsnmntn

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