US93758A - Charles william siemens - Google Patents

Description

' have nnule :t new and useful process ot', and

blick, o

A in 1, through for'wnrd by its rotuti index'.

Afurnace, or is brought ix CHA uurs infini-,nini srs-MENS *tenis Pawn N 93,158, 'dared August 17, A15569. f

The Schedule referred tn lu' ettorljutsnt a'nd ot' the same.

To all pcrsmr.; -lo uhom these presents may come:

Be it known that I, Cimnmzs WrLLrAn Simr'uxs; ot' \\'est|ninstl r, in' the eounty of Middlesex, England, inrcutiou, hariugrreirf ence to l-`nrnnces, Appzuutus, und Processes for the Production ot'bteel direct from iron-ore; :ind do bere.- bydeclure the saine to be fully described 'in tlic following specification, reference being had to the' aeeompnnying drawings, and to the figures and letters marked thereon; that is to say- M y improvements have reference prineipnlly to the apparatus lbr muking steel, described in the specification to certain Letters VPatent grunted to me, :ind bearing date April 27, 1869. t

Instead of reducing:r the iron-ore in vertical hoppels descending into the metallic hath, as described-in the speciliention to thesaid patent, I effect its reduction in one or more revolving cylinders, drums, or inutiles, .ivhlch are placed horizontally, or nearly so, arbore the melting-Turnnee. A

The rsvolring cylinder, or xnutlie, is lined with tire r other relractory mntcrial, und is heated by means ot'llue's or passages in the substance ot' its'liuwhich flume is mudo to circulate.

The oreto he reduced, whieh is mixed, by preference, witlra certain propntion ot'solid redueingmgents, :and with suitable tluxes, is t'ed iu ut thc one cxtremit-y of the rotating cylinder, und is worked gradually on, while thc fue at the sume time is heated to redness by the heated lining ot' the cyl- Reducing-gsm is made to enter the. cylinder at the chiu'ging, or both ends, through an opening iu or near its urges, und, being brought extensively into Contact with th'e heated and moving oro, effects its entire and uniform reduction into spongy orupulrcrulcnt metuiliciron, which lutter fails, in due course, through a verticnl hopper or elmnnel into tlie'mcltiiigfurnaoe, where it is readily dissolved and incorporated with the hath oill'uid cast-iron previously prepared onv the hedotl the :to contact with au excess f soiid carbon, charged upon the hearth ofthe' furnace, to torm,'\rith the. spongy reduced metal, the imminencement ot'a liquid bath oi' steel or cust-iron. f". The reducing-grises vemployed also escupe 'onit'he further end oi' the rotating cylinder into 'thc beatingfines or passages, arranged, 'as already mentioned, in the substance ol' the lininp; where atmospheric air is admitted to burn them, the' products ot combustion escaping from the said tiues ueur 'the charging-end toward a. ehiinne \','aml the vdraught being regulated by dampeis.

Instead of ell'ectiug the reductlon'ot this ore within the rotating cylinder entirely, or even partiallyxby menus of reiluei11ggases, solid reducing-zigeuts, such :e: unrhmcite, colic, eluu'eoul, sawdusor pear, nlay be .employed with or without the oil, or resinous substances; Y The same reducing-apparatus may also be employed for the production simply of spongy or Ypulverulcnt metallic iron. In this euse the furnace is taken by a sheet-iron casing, in'whioh. the

-reduced iron is cooled down without access ofair.

In the manufacture ot' 'cust-steel, or ofspougy reduced iron'directly fromthe orc' pure oxides oi iron,

magnetic ores, may be charged into the reducing-muf-l -tle,` 'witlioutauy preparatory treatment, but ores con; taining-any volatile constituents, such as carbouicacid or water of hydration, should be calcined before they Ores contamintcd with sulphur, phosphorus, or arsenic, should be enjoined, and washed after calcina tion-,to remove from them these impurities as much as possible. v Another part of myy invention has reference to certain modifications in the method of purifying `or iniproriug the quality of the bath of liquid 'steel in the furnace, by the introduction into it cui reagents, before it is lapped out .and cast' into' ingots, as has been'ahcady described in the spccication of my betbre-narucd patent, bearing. dato April 27,- 1869. A

Haring thus promised, will nowticulnrly to describe my invention.

Figures marked 1 too of thc'accompauying drwings sho'w the arrangement of reducing-meiand steel-mel ting fummo,

direcetly from the ore.

Figure), shows a, longitudinal section of the" melting'- furmtceoud regcnemtors, und a. transverse section, through the dischar ug-end of the revolving inutile or drum, on line A B, fg. 2.

Figure?. shows a transverse section through the melting-furnace, and a longitudinal section through the educing-muie, on line DE F, iig'. 1.v

Figures 3 and 4 show transverse sections thro the reducing-drum, on lines I K and L M, iig. 2.

Figure 5 is a sectional plan through the inciting- 'nmac'e, at G H, fig. 1

Similar letters of refer each of the iignres.

The` mcltiug-fm'nnee 'itself is similar in construction to that described in thc specilication to my previous potent, to which I bare before referred.

Iu the, arrangement ot' furnace which is described in the spcleution ore was eeeted in two vertical chutes or hnppers,

i placed above the bath of liquid metal i'the melting l chamber, into which they ore gradually sank down hy l gravity' it was red'ueed. 1

i According to my present arrangement, the or'e is more pim ugh 'addition of pitch, itur,

place'ot the melting-4 by the above process, such as many hmatites und" of certain che'mi# for the production-of cast-stcei 'ence indicate similar parts in just named, the reduction of the y 'end -hy thenddit 11 E.

" opcni ulators.

reduced in a. rotating cylinder or drum, l115A, which rests (in u horizontal posit-ion, 'or about so, above the 'rnlgiltig-liirnace) ou four rollers, as shown ou figs. 'Lto 4' fl thx-:accompanying drawings.

'The outer cnsingof' thed'runrA A is divided into vfire-bricks B O,.which are so arranged as to leave a double series of small fines or passages in the sub',-

stance of the.lining,exteuding from the one extremity ot the eylinder"to the other, f a's shown in figs. 2, 3,'

lhcopening ofthe cylinder is diminished at erich ion of inner rings of lining-bricks 'lhc ore ls intrmluced :rt-the one extremity of' the yrevolving drinn, through n. cast-iron chute, F, attached. to the fixed sheet-'iron casing' G.

y lhe chute l" is kept always filled with ore, which is fed graduallyibrward into the reducing-munie through the circular opening H, the thickness of' Vthe hed of ore in theuulfiie beingr regulated by the pla'te'l, which closes there; or less the upper part of the chargingopenlng li.

. 'lhe other extremity et' the reducingafylindcr opens intol n. second sheet-ironcasing, K, whiehjis lined with lire-brick, and c-'ournlunratcs'fdircctly, hy` the slnnll ng L, with tlobath 'ol' the inciting-furnace below. v .A l The two casingsI-i und l\', :it the ends of' the rcvolviln,r cylinder-A A,bcur closelyagzrinstigby means o tneenrzrtely-tnrn-ed faces :tt-M' M M, and ure kept in` contactwith ilijby screw-'clips N N, lig. 2, the ensings (l K being'both sol supported ihn-t. they are fri-e to adjust themselves closely/ to the ends o ftlie revolving I y The cylinder carried by two pairs ofA rollers, R It and S S, figs.4 2, il, and 4, and is pdt-.in motion by the drivinU-nrrnn erneut shown in fi fs. 2 and 4.

A'pulley, O', drivenby'a. bund, or in any other convenientlnunner, connhunicates motion through two'- endless serews'l 1, and two worm-wheelsQ Q, to the rollers ll, It, ,ulrcadygnicntioned which support the grenier purl. of the weight of' the cylinder A A, when il: is filled with ore, and which-drive ili by l`riction.

[By the -rslow rotation of' the reducing-cylindcr or inutile, the ore introduced through the chute F, from v at U U, figs. 2, 3,'nnd 4, between the bricks B0,

' 'lhese projecting bricks carry the mass ofore roiuid with theln, preventing any slipping, andforcinghe ore'to'roll over and over, exposing every part equally to the reducing netionof' the gas.

The excessof reducing-gus is duin-x v end'l) 'of the inutile, into the series offsinall llucs Y in thcbriek lining. Y

Air is drown in nl; the saine of' openings,

time through a series W W, fig. 2, provided .with slides or reg- In' traversing the whole lengtlrof' the outer series l of lines X X, the air drnwnviu ut W W becomes more or less heated before it'ineels witlrthe gus at theapcrl turcs Y Y, and'burns with it along the inner-dues Y, beating the luutlic. to bright redness, and escaping aw-ny, at the ,tube Z, fig. 2, which is furnished with asnlve for regulating the draught, into the main chimney-flue.

'lhe mode of working this furnace is as follows:

The reducing-cylinder is, int-he first instance, heated to redness, and the melting-furnace below is raised to a full steel-melting heatrlhe cylinder is then put into-slow rotation round its niais, and the ore, which I suppose to be hzcmatite, 'mixed with from ten to fifteen percent. of' its weight; o f solid reducing-agents, such as anthracite, coke, charcoal, or with a. somewhat larger proportion of saw- .dustfor peat, and about three percent. et' lime, is filled -in vat the oner extremity through the chute F, from the charging-floor above, a. supply oi' reducing-gus being introduced, at the saine Itime, through the tube T, fig: 2.

and the'ore descending in the curved chut-e Ente heated by the waste gases, ou their passage toward the chimney-flue.

gils, consisting principallyY of' earhonie oxide and nitrogriuf-'flt should be washed thoroughly before it is introduced, through the box T', fig. 2, and thel tube 'l, into the reducing-ruufiie, in order te condense and 1`^euiovc,-as completely' as possible,` the water-vapor that it may contain, and to purify it from sulphur-ous n cid and ither'iujurions compounds.

Altlnnigh 1 lnix withi'he ore, ns aircady mentioned, from ten to ilieen 'per cent. of solid cnr'non, in any ,i'ornl or combination which does not contain sulphur, phosphorus, or other deleterious substances, (among which forms wood nud peut deserve specinl nient-ion,) l depend, also, upon the carbonio oxide introduced into tho inutile ior effecting the reduction ofthe. ore.

The gus entering at l is brought, hy the rotation ofthe drum, into extensive contact; with'l'lic heated ore, but inasmuch ns s 'reducing-notion would cesse as soon as n considerable proportion ol :ne eurhenic ojxide fontuined in it had been converted into cnrhonic acid, (as lshown by lie llny und others.) the presence ot' solid and heatedv carbon is neeessny, in order to bring the carbonio acid back again to the stale of carbonio oxide, unless, indeed, n. vastly excessive quantity ofgas were passed through rhc reducing-drum, which would be attended by waste.

If'such solid redlu-ing-agents are employed as wood are eli-urged in with the ore; und inasmuch as redneing-gases will be evolved from them by heat, the admissin of' gas nt l Ina-y he great-ly diminished when they are employed instead of p nre solid carbons; but, on the. other hand, they must be added in an increased proportion, to bring up the solid carbon to f'rom'ten -to fifteen per cent., :recording to the nature and richness off-he ore. Ncveitheiess, the use of' gnses'caunot be wholly dispensed with, except, at a risk of irregular and imperfect reduction ofthe ore.

lhe ternpemtnre within the reducing-cylinder should be maintained during the process at a f'ull red heat, or from 60()D centigrade to 900 centigrnde tcwaxd'the cud where-the discharge takes place, but diminishing toward the charging-emi.

By the slow rotation of' the cylinder, a portion of the-reduced pu'lrerulent rnctal is discharged through the opening L into the bath of liquid cast-iron, (which is maintained in the melting-furnace below) at each ,revolution o fihe drinn, when the notch D', figs. Land L'Vin -the brie-kring 1), at the end of the inutile. comes into the lowestposition, as shownin the drew' The rate at which the redneed metal is fed in the furnace depends, onthe one. "hand, upon the velocit; ot'xotation 'of the mufllefmhieb should be nnslrfr prathct'controh) and on thezofher, opor .":fe ir. nati-.'51

:it length into the casina! (l. and tin-nee through tlnof the upper surface-ot the hed oi ori- This last is lhe reducinggas, as it passes thnnigh the box T ,The reducing-gas employedis ordinary produceror peut, these should he dried completelyr before they.

Aof pigeirou are introduced if the 'metal is'found tobeiron, coutaixiing not more than onel totwo per cent, of

at from one to't-w'o per cent., by an abunda-nt use of "it over occasionally during,r this period, in order to ex such as lool-steel, it will bc fonud convenient to ein? regulated by closing, to a greater or less extent, the upper part of the charging-opening H, fig. 2, by means ofthe. plate-Ll which can he readily changed either for a decina or a shallowerplate. 4 ,A

ily suitably regulatingthcspeed of rotation of thc inutile, the successive charges offrednccd ap'ongy iron are dropped into the-hath of liquid n1etal'-inI-tlie'xnelt: ing-furnace, in.pr'oportion 'as eachprevious charge is dissolved. f rlhe inet-al. in thc hath is stirred' occasionzlly, and small ,samples arcta-ken ont at intervals, in the manner-described in the specitication 'to my previous patlAdditional 'charges cnt, bearing date Aprilr27, 186i).

come dccarburetted too rapidly; and when a. sulicient aiuouut ofliquidniet-al has accumulated Vinthe bath,

and so much reduced spongy iron has ,been added as to bring the metal into the condition of; liquid soil:

carbon, the rotation of the'drnm is stopped, and from live to eight per cent. of forro-manganeso or spiegel eisen la cbargedin, as 'described in my previous gpc'- neat-ion, above referred to; .or the metal is treatedlu any other known manner, and is tapped out'and'cast into ingots or other forms.

The addition of spiegel eisen. at theeud'of the pro- -may 'ce dispensed with if the ore 1s-rich in mau-J e, or a second' reducing-militie. may be' added, :ingcd will: ure rich in manganese', 'and workedat lused temperature as may be 11i-cruising', for the reduction of that nieta! to be. used lastin that operation. f

'ihe'addition of spiegel eisen, or manganese in other forms, may also he dispensed with in the production, ol" stoel lfor castings which are not to be hammered,-- and need not, therefore, bc so thoroughly purified as ibrge-ingots- I f hardness and tensile strength is the principal ob'- ice-r. rather than ductility and elasticity, tbc carbonl may 'be maintained with advantage, in such casting,

the `reducingqagentn. A comparatively low filmweleluperaturc will suilice for `uch metal.

The reducing mufilc romains stationary until the. charge of steel has been tapped out of the meltingfnrnacc and a. fresh bath of liquid pig-iron has been formed; but thereductionof the ore is still continuolsly carried on in' it-, by maintaining'the supply of reducing aud heating-gas. If the ore employed is'ln the state of line powder, it ,may be desirable fo-.turn

pose it more thoroughly to' the act-ion of the gas. L

In this' case, the'xnutilc may still bo rotate alittle at intervals, the reduced metal being kept from fallinginto the meltingiurnacc' below, by pushing it back from the end of the inutile, by a rake, put in through the door K'. '.flllieniuille may be entirely shut olf, if required, from the melting-furnace, hy inserting a slab of lirecla-y into-the.connecting-channel Iqat L. y -l A furnace, as represented in the drai viugs, when properly constructed, is capableof producing threecharges of cast-steel per tweuty-fourhours, of from three to four tous eac-h charge, but the dimensions of these furnaces may -bc varicdconaidembly. Thus, in producing steel of high quality and rich in carbon,

ploy furnaces` of loss capacity, whereas, ln making large castings of sti-cl, such as guns, bells, aud armorplatcs, or ingots` for engine-shafts, fnrnuces of a capacity exceeding tire, six, or eren ten tous, may be employed.

The contents of'sercral furnacesv may hel poured into the salue 1nould, either by running them' in directly phato of iron.

from the tapping-holes, or by running'thc metal first intoladlcs,a11d then into the` in'ould or moulds. l. i

sagas heat these moulds or ladies beforehand, by any suitable means.

The materials to hcemployed in. the process above The pigof steel, the metal being purified, before tapping it out of themeltiug-furna;ce, by the introduction of chemical reagents, in the manner described hereazer. The or'e l should be a pure oxide of iron,'contaiuing but little ganglio o zearthy matter, and as free as may be from compounds of sulphur, -phosphorous, add arsenic'. Magnetic ores, hzematite ores, oririch calcined spathio' Orcs are particularly suitable. The ore may be in the. ibi-m' of powder, sand, or dust, and on this account many ores are suitable for this process, which, uot withstanding their purity, cannot be employed in blastfurnaces, amongst which the magnetic sands of Oauada, Spain, and New Zealand, the niicaceous ores, and the refuseoro produced in treating pyrites for copper and sulphur, may be especially mentioned. If the ore employed is iu the state of-powder, and therefore not pervlous to the reducing-gas, I prefer to mix it with loose and pewiousvreducing-agents, suchas wood in small pieces, sawdust, dried-peat, or charcoal,

'or with pitch, asphalt, or oils, as already described by me in former pcciioations.

The nature and amount of the during-material to be adde'd depend on theforeigu substances contained in the oie. In soule cases, such' a mixture of ores maybe adoptcd'ascontains both silica andiluxin material, such as lime, magnesio, ,or manganese, in suitable proportions, thus avoiding-the necessity of any separate flux. Hiematite or magnetic ores, couiaiuiug silica, may, for example, be mixed, with adyantage, with spathic ores, containing lime, magnesio,

or manganese, or with clay iroustones. `If nearly pure oxides of iron, such as some hmatites or magnetic 1ere-s, or calciued apathie orcs, are treated, I sometignes employ no tluxing-material, except a small percentage of oxideor carbonate of manganese, which forms, with the smallproportiouof earthy matter invariably associated with theore, suicleut slag for the protection of the m'oltcu metal.

The ores, before use, should always be crushed into powder, or into pieces not exceeding the size of peas or beans, in order to facilitate their reduction into pulverulent or spoiigy iron. They should be mixed intimately'with the tlnxing-material that is added. It'

'they contain volatile.coustituents, such' as carbonio acid, water of hydration, arsenic, or sulphur, they should also bc calciued. v

Orcs containing sulphur in the form of sulphide of iron, should be calcined carefully, at a very low heat, and subsequently washed, in order to remove as largo a proportion as possible ofthe sulphur as soluble sul- 'lhe proportion between the cast-iron and the ore' employed in the production of cast-steel, by the abone process, may be varied between very wide limits.

In case rich ores, not containing sulphur or phosphorus ln any notable quantity, can be obtained at a.

moderate price, it is advantageous to reduce the ore to metallic iron as completely as possible, by employing a large reduciug-mufflc, heated iu the interior nezirly to whiteness, and by mixing the oro with an abundant `proportion of reducing-agents.. It is rutti`v cient, then, to culnunence the operation with no more than from ien to fifteen percent. of cast-iron in the bath of the melting-furnace.

The use of .pigiron for `the purpose oi dissolving the reduced spongy metal, may eren hc lispcnsed with altogether by throwing on the bed of thc melting-furas set forth, an apparatusy consisting of a, revolving cylinder or drum, as described, provided with outer channels, arranged subtantially as specified, through* which, when in use, the gases'resnlting from the reduction of the ore within thedrum may-be caused to pass, and be consumed in connection with air intra,4 duced into and heated within certain of such channels, as described.

I also cla-im the combination and arrangement, as

as explained, wit-h a furnace, as described, (or its `equivalent for the production of cassteel direct from the ore, asset forth; the Awhole heilig suhstantiilly es described. 0, X SIEMENS.-.

Witncses: l ,I

EDWD. N. HOBBS, Both of 2Popes Head Alley, RoBT,Ln'RKsoN, Ccruhill, London, Gents;

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