US65830A - Improved process of refining iron, steel, and other metals - Google Patents

Description

' g m a niteh tates gamut 1 first.

'JACOBQ REESE, 0 F rlr'rsnnnc. PENNSYLVA NIA.

Letters lntcntNa. 05,530, (intuit June 18, 1867.

IMPROVED PROCESS OF REFINING IRON, STEEL, AND OTHER METALS.

din fitlgebnb tcfemh tr in tlgcse itntns can mm uniting m at tlge same.

TO ALL WHOM IT MAY CONCERN:

Be it known that JACOB REESE, of the city of Pittsburg, in the'connty of Allegheny, and State of Pennsylvania, have invented a new and useful improvement in the Process of Refining Iron, Steel, and other Metals; and I do hereby declare the following to be a full, clear, and exact description thereof.

My invention consists in certain improvements inthe process of refining iron or steel, and may be applied to the ordinary refinery fire or other furnaces or refining-chambers, and does not necessarily involve the use of any apparatus of novel construction, or any material alteration in the furnaces heretofore employed for the refinery process.

These improvements, which constitute my invention are, first, the use of a bath or layer of melted oxide 7 of iron in the chamber of the refinery fire, between the fuel which floats on the surface and the melted metal which lies below it, for he purpose, chiefly, of preventing the carbon of the fuel uniting with the metal to be refined; second, the use, in the process of refining iron-or steel, of hydrogen in a gaseous state, or combined with carbon as a fluid hydrocarbon, for the purpose of dccarbonizing the metal and removing the sulphur and phosphorus which may be combined with it. i

The first-mentioned improvement is designed to he used where coke or other fuel is employ pd in the process of refining, and may be employed in combination with the use of hydrogen as a decarbonizing, andpurifying agent, or when oxygen-or atmospheric blast is resorted to for that purpose. The second improvement is applicable to the process of refining either with or without separate fuel, and may be advantageously employed, in combination with the use of atmospheric air, for decavbonizing and purifying the metal.

The old refinery or run-out fires are made with brick or stone bottoms, the chamber being formed of cast iron, water bashes fm'm'rn-g-threc sides, and enclosed-entire further side'by a dam-plate. Two or three in'yeres are placed on each side, projecting downwards ever the tops of the boshes, communicating with blast pipes to force atmospheric air into the melted metal. The chamber being first heated with a fire of coke or coal placed therein, the melted metal is run into the refinery from the blast-furnace, and the heat being kept up by the fuel, (coke,) the metal is exposed to a blast of atmospheric air for about two hours,'after which .it is run out into moulds and cooled with water. This process causes a great waste of iron, owing to the long-continued action of the oxygen on the metal,-rendered necessary by the constant accession of carbon to the iron, from the fuel with which it is in immediate contact. Although, by this process, the iron is nltimately deprived of nearly all of its carbon, (which it received in the blast-furnaee,) yet the loss by oxidation is about twenty per cent. of the metal. To obviate this waste the pneumatic process was adopted, which consists in running the iron into a chamber, and there without the use of separate fuel, blowing blasts of air, either hot or cold, up and through the liquid-iron; the oxygen in the air combining with the carbon in the iron, causing a greatly increased heatand boiling in the metal, thus decarbonizing the iron. In this process the carbon in the metal serves as fuel to the oxygen of the blast and greatly expedites the operation, but still there is a considerable waste by oxidation, amounting to about twelve per cent. in removing five per cent. of carbon.

My improvement is designed to obviate this loss of iron by the use of a bath ofmclted oxide ofiron in the following manner: When the refinery is ready, the coke or other fuel is put in and lighted, and the blast being applied, the furnace is thoroughly heated. The metal to be refined, having been melted in a cupola or air furpace, is run into the chamber of the refinery. Melted oxide of iron is then run in until it lies to the depth of ten or twelve inches on top of the melted iron, being of less specific gravity; and the coke, being still lighted,

floats on top of the melted oxide. The mouths of the tuy ercs being about on a level with the top of the-melted.

iron, and below the surface of the oxide, the blast enters the mass of metal, and uniting with the carbon decalbonizes it'and causes a violent agitation. This ebullition results in the admixture of some of the melted oxide with the mass of iron, which has the effect of scouring itand removing such earthy or metallic impurities as may be mechanically admixed with the metal. The melted oxide,,which separates the fuel from the iron, serves to protect it efi'ectually from admixture with the carbon'of the fuel, so that the benefits of the heat caused by the fuel are secured without the deleterious effect of the constant earbonizing of the metal resulting from the presence of the fuel, when not thus separated from the meta-1. It is true that the carbon in the metal is sufficient to keep up a great heat, while the oxygen of the air is passing through it, without the use of other fuel,

but so soon as the carbon is eliminated or burned out the fuel is gone, and the metal at once begins to chill, so that it is'necessary at once to run it out of the chamber or vessel in which it has been treated by the pneu-.

matic process. By my improvement, howeverJ am enabied, by means of the coke on top of the bath of melted oxide, to keep up the heat in the iron after the carbon has been removed for thepurpose. of treating the iron with carbide of iron or otheriv ise, in order to produce thcrequircd degree of carbcnization for the grade of steel to be manufactured, or for the further refining of themetal it being important-to the qualityof the steel that the carbide introduced after the de'carbonization has been clfected should fo'rmh chemical combination, and not a mere mechanical union with the iron, as is apt to be thecase where separate fuel is not'einployed.

In the varibus processes of refining iron or stcel herctoi'or in use, oxygen is employed as the agent for producing the ii'eee'ssary.decarbonization. I propose,however, to use, either in place of the o xygen or in combination with it, hydrogen, which I have found to possess several advantages peculiar to itself. Oxygenfisfin itself, the cheapest element which can be used, owing to its presence in atmospheric air; but its strong affinity for iron renders its use a source of great waste. Hydrogen, on' the other hand, possesses the necessary afiinity for carbon to render it an efficient agent for decarbonizing iron, while it has little or no a flinity for the iron, and prodnces'no injurious efi'ect on that metal; it is also peculiarly adapted to the refining of iro'n ivhieh contains sulphur and phosphorugby its afiinity for those substances. The pneumaticprocessot refining ir on before referred to,-;dcpending, as it does, on the use of oxygen, will not remove those impurities (sulphur and phospho res) from the metal. If the phosphorus be combined ivith the iron ore as phosphate of lime it will pass off in the slag of the blast-furnace, but'ifprcsent as phosphoric acid, the action of the blast-furnace-is to cause it to com-- blue with the metal asa phosphuret. Now, as oxygen has ainuch larger affinity for iron at 3,000 Fahrenheit, (the working point of iron,) than it has for phosphorus, would be necessary to oxidize all the iron before the phosphorus would beeliminateil, and thus it arises that steel made by thepne'umatic process-contains as much phosphorus after treatment as before. I If, however, hydrogen be used for the deearbonization of the metal, having no aiiinity for their-on, it combines freely with the phcsphorus forming by chemical union P. H passing off as phosphnrettcd hydrogen. Althou;;h sulphur sublimes at 170 Fahrenheit, thejmaximum temperature at which it va-porizes is about 185 Fahrenheit,- so'that at the heat of melted iron or steel it \villnot pass off as vapor; its afiinity for oxygen also diminishes as the temperature increases above 170 Fahrenheit, so that at 3,-000 Fahrenheitto 5,000 Fahrenheit itis impossible to separate it from the iron by means of oxygen. Hydrogen, however, unites with sulphur at a high temperature, forming a chemical union as S H, and passed of from the iron assulphuretted hydrogen. I v

Thus, it happens that hydrogen, when applied'to the refining of iron or steel, cnrriesofi" from it two of the foreign substances which are most injurious to the steel, and \yhich it is almost impossible to remove by the use of the pneumatic process. In using hydrogen as the agent for decarbonizing and refining molten cast iron or stecl i employ the. refinery fire before described, together with the bath of oxide, blowing-hydrogen gas or the veporlof hydrocarbon fluid, such as petroleum, benzole, andgnsoline, into the melted metal through the tuyeres in the same manner as already described in roferenceto the use of an atmospheric blast. ,In this case the fuel on top of the melted oxide serves to kcepup the requisite heat, the hydrogen unites with the carbon of the metal and carries it oh burning, when it reaches the coke above the oxide bath. It also unites with and eliminates the sulphur-and phosphorus, thus ridding the metal of these injurious elements, while the bath of oxide prevents the carbon of the fuel from imiting with'the metal, and retardingthe process of decarbonization.

In thisprocess, and that before described, the only'change needed in the construction of the refinery furhaee increase the depth o'i' boshes so nsto accommodate the bath of oxide without reducing the working capacity the firrnaee The hydrogen to be used-for my process maybe. procuredin any ordinary or convenient method Asa hydrocarbon vapor answcrs'tlrc purpose very well, the well-known hydrocarbons before nientionedmay be conveniently and economically employed. Lil-ho light hydrocarbons, benzole and gasoline, are extremely cheap, and-the-lighter the grade of hydrocarbon thelarger proportion of hydrogenit contains, so that by choosing the lighter cizheavicroils, or hydrocarbon fluids producedt'rom petroleum, the required proportion of carbon and hydrogen may be secured. The quantity of hydrogen required for any specified charge of metal of known quality may be ascertained with sufficient accuracy as follows: Suppose a charge of ten thousand pounds of metal containingfive per cent or five hundred pounds carbon, one per cent. or one hundred pounds sulphur, one-half per cent-or fifty pounds phosphorus. N'dugasone atom of hydrogen unites with six atoms of carbon, or with six teenatoms oi sulphur, or with thirty-one atoms of phosphorus, forming respectively carburetted hydrogen, sulphuretted hydrogen, and phosphuretted-hydrogcn, the entirceharge would theoretically require, for fiv hundred pounds carbon, eighty-three and onc halt' pounds hydrogen; for one hundred pounds sulphur, six and one-quarter pounds hydrogen for'iifty pounds phosphorus, fire pounds hydrogem'equal to ninety-four and threequarter pounds hydrogeiigorabout'twcn'ty pounds of hydrogen'to each ton of metal; but as in practice the hydrogen cunnotibe all u til-ized, it-is bettertoprovidc for fifty pounds of hydrogento each ton of iron. The hydrogen may be conveniently applied in the form of hydrocarbon vapor, by vaporizing the light hydrocarbon fluids before mentioned, or otherwise, as may be desired; it being safer not to use the liquid hydrocarbons without eveporination, as the enormous expansion on being suddenly exposed to so high a heat might he attended with dangerous results. i v

Ihave described the use of m oxide bath in a refinery furnace in connection with a'blast of atmospheric air,.and also with a blast of hydrogen or of hydrocarbon vapor; but as both atmospheric air and hydrogen or hydrocarbon vapor or gasmay be employed with a refinery at the same time, llwill proceed to explain the nrannci ofi'such use.

The refinery being heated usbei'orc described with coke, and the blast of air turned on, the melted metal ass-so isinin' -intr'ona thecnpple, and then the melten ozid is introdnced nntil it lies to the depth of tenor twelve ineh es between the coke sham The hlest oletrnesph'erie sir causes'e violent egitotion of the metal, mixing sport of the-melted oxide withthe mess, but notlp'ermi tting the carbon of the fuel to reach the iron below the ox ide; While the processMxdec'erhonizng v i s-progressingsay in ten minutes or so after the commencement,

elstrealn of. hydrogen, as a. gas, or of hydrocarbon oporis introduced into the metal through the some or other gnyeres. The sheet of this is that while the oxygen is" re moying the cerhond'i-ornthe metal, the hydrogen removes the sulphur nndphosphorusieii before described and by. their joint ection the metal is refined, purified,

and edn'ced from etude castiron tocas't-siteel. After, the operation has been'eentinned for the sp'ace of thirty.

or forty -minutes theyiole'nt agitation m an d'lf steml-steeljsgeguirfad the metal is immediately tapped o'nt bls w ds osing 'h'e taph e. "'lllhe' oxidei-eniniiiing iii-th s 'lnrnecev xyill nnswerlfonsevernl heats; Whenhyd'roge'n is aepara'te chninher may he resortedtennd the refineryfire dispensed viitlnnnd the amount of. hydrogen necessary for the process wilL be considerably diminished,asitschief nnrpose, when used withoxygen, is to e er'nov'e' the sulphur and phosphornsffrom the iron'. I

' Having thus described my improved process for-refining iron andsteel, I'do not claim the use of a blnstof atmospheric air in a refining fnrneee with coal or coke as fuel, as that is an old onjd well-known method.

Neither do I claim refining iron, or steel in erfnrnnee with a hlnst of atmospheric nil without the-use of additio'nnl fuel, known as the pneumatic process. I t t Nor do. I new claim 'a petent for the use of hydrogen gas or liquid hydrocarbons for the deoxidizin\ of metallic oxides in e. molten condition, as I have previously obtained Letters Patent therefor. t

' But what I do claim its my invention, and desire to secure hy -Letters Pntent, is-- efheing taken-to step theflow as soon as'themethlebeases and the-oxide begins tip-appear,

1 ldyed' ee thegjiui ifying egent; Oine fuel, as coke, mnsthe employed, bhtwhen oxygen is'also nsed iii con' jo -n9; ion-with thehydro'gen,tny .prooess of 'deca'rbonizing and purifying iron by hydi o geu nmy'be.snccesst'dlly nndndventageously exnployed without othenfnel than that supplied by the'eei'bon' in their-on. Inthis case the l 1. Refining iron, steel, and other metals, by means of a. blast of etmosphericair or other decnrbonizing.

blast in a. refinery or furnajce heated with coke or other cerhonaceous fuel, when a. layer of metallic oxides is interposed between the fuel and the metal under treatment, for thepurposes hereinbefore set forth.

2. The use of a. covering of metallic oxide forprotecting metals from the influence of carbon, substantially as hereinbeforedescribed.

8.- The use of hydrocarbon liquid, vepor, or gas, in the process of refining iron or steel, in the mannersuhstontially as hereinbefore described.

' 4. The rise sh 'arembsn liquid, ye'nor, or gas, for the purpose of removing sulphur nnd-phosphorus, or

either of them, from iron, steel, or other metals in the process of refining, substantially ashereinbefore described. 1 1 V 3 In testimony whereof I, the said JABOB REESE, have hereunto set my hand in presencc'ofi JACOB REESE.

Witnesses:

A. S. NIeno'LsoN, Gso. HQ 'Gnms'irv.