US1086019A - Economic metallurgical and chemical process. - Google Patents

Description

J. E. BUGHER. ECONOMIC METALLURGICAL AND OHEMIGAL PROCESS.-

APPLICATION FILED FEB. a, 1 912.

"1,086,019. Patented Feb. 3, 19145 5 Woe, W607, 4ST $04. @51 0114 213;

Wikuwoao UNITED STATES Pam FFICE.

JOHN E. nonnn, or COVENTRY, nnonn ISLAND, assleuon T mrnoenn rnonuc'rs COMPANY, A oonronA'rIoN or arons ISLAND.

ECONOMIC METALLURGICAL AND, CHEMICAL PROCESS.

Specification of Letters Patent.

Patented Feb. 3, 1914.

Application filed February 8, 1912. Serial No. 626,339.

To all whom it may concern:

Be it known that I, JOHN E. BUCHER, a citizen of the United States, residing at Coventry, in the county of-Kent and State of Rhode Island, have invented certain new and useful Improvements in Economic Metallurgical and Chemical Processes, of which the following is a full, clear, and exact deof manufacture,

scription.

.-This invention relates to a novel process one aspect of which pertains to the purification of metals generally, and more particularly iron, with the formation of other commercially valuable products and by-products incident thereto.

With the exception of aluminum, iron is probably the most abundant metal in the earth, but its important ores are nearly all oxygen compounds. In practice it is nearly always obtained by reducing these ores with carbon in a blast furnace, or the like. The crude iron thus obtained, known in the art as pig-iron, is very. impure and frequently contains only about ninety-two per cent. of iron.

phosphorus, sulfur, manganese, slag, occluded gases, and other substances. These impurities come partly from the ore and partly from the materials used in the manufacture of the iron. During the pasthundred years considerable progress has been made in the removal of these impurities, but notwithstanding these advances in the art, really pure iron is not yet prepared on a large commercial scale' This is due partly to the difficulty or expense of removing certain constituents from the iron.

The processes of purification,.which are now in use, such as the Bessemer, basic Bessemer, basic open-hearth, acid' open-hearth, and paddling, practically all depend on oxidation; the oxygen being usually obtained from the air or from iron ore (Fe O or its equivalent. or from air and oxid; and in substantially all of these processes, oxygen is the active element used in the purification, and'the elements carbon, silicon, manganese, sulfur and phosphorus, are oxidized and thus eliminated in the escaping gases, or else in the form of slags. These processes, while serving admirably in many respects are attended with many serious disadvantages;

The impurities in the pig-iron con' sist of variable quantities of carbon, silicon,

, the

such as requiring the ores, the metal treated, and the furnace linings, and the like, to be of certain compositions in many cases. As the degree of oxidation must necessarily be limited inmost, if not all of the methods used at present, for economic and other consi-derations, the removal of the impurities is practically never complete; and in some cases these methods even result in entire failure to remove the most objectionable impurities. Slags are formed and these sometimes interfere with the process. In some cases, excessive loss of metal or time is involved. In certain processes the energetic oxidation causes serious injury to the metal and thusnecessitates the use of deoxidizing agents such as manganese or SlllCOIl. Indeed, it sometimes becomes necessary to add somewhat expensive alloys" or materials containing such elements as manganese or silicon, in order to maintain the required high temperature during the process of oxidation. When .air, which contains only about one volume of oxygen to four volumes of nitrogen, is used as the source of oxygen, an eno1' mous volume of inert nitrogen is carried along with the oxygen necessary for the process. The large volume of inert gas thus introduced into a given process necessitates the use of extensive pumping machinery and unduly large furnaces and converters. The nitrogen, which in such processes is useless, is raised to a high temperature during the purification operations, which causes an excessive loss or waste of heat. For example, in the Bessemer process roughly about seventy-five per cent. of the heat produced by combustion of carbon. to carbon monoxid is lost on account of the waste nitrogen. this waste of energy and contemplates in its preferred form heating the metal or material which is .to be treated or purified, 73.6., iron, with a mixtu e (or compound) comprising nitrogen (or a nitrogenous com pound) and one or more powerful reducing elements, such for example asthe metals of the alkali or alkaline earth groups; or compounds of such elements. In other words, I may use a' mixture-comprising nitrogen and one or more of these reducing elements, e. g.

sodium and magnesium; or I may use a com pound of nitrogen and one more of these ele- My process practically eliminates suming that sodium be the metal used, by

esium nitrid; or a nitrogeand one or more of these reducing elements, etc. 7

My invention also contemplates the use in the process when desired of alloys containing a powerful reducing elementor ele ments.

Sodium and potassium are particularly ments, 6. 9. ma

well adapted for my novel process on account of their chemical activity and volatility; while sodium has the added advantage of cheapness. While these recited elements are preferred, I do not desire, however, to be limited thereto in any sense, since any suitable material which may be characterized as a powerful reducing agent, or element, is regarded as within the purview of y ture of the impurlties present in the substance treated, and the, extent towhich it is'desired to remove these impurities. As-

Way of illustration, so little thereof may be involved int-he process, in some cases, that the mixture, for example, with nitrogen, may comprise but a trace of the sodium; Indeed, invsome cases the nitrogen may be used alone- This aspect of the inventionis distinguished from he usual processes, in

' that, in such case, the nitrogen is the active purifying agent, in contradistinction to oxygen. In et-her cases it will sometimes be desirable to use "so little nitrogenous matter that the reagentswill consist substantially of, for example, alkali. or. alkaline earth metals. It will, be understood, however,

' that while the sodium, for example, may

have independent functionsv or actions of its own; and in like manner the nitrogen 'may have independent functions, there is yet. a peculiar relationship between such elements whereby they conjointly serve to efi'ect decarburization of the material treated. Considered from this point of view,

cordingly do not attempt to cover these separate and independent actions of the elements employed, specifically.

As above indicated, instead of using free metals of, for example, the alkali or alkaline earth groups, someof their compounds which are reactive in my process and which will furnish in such case an alkali or alkaline earth metal, and in some cases a certain invention. The relative proportions of the elements used in the process may be Widely varied, and depend upon the na-.

' cases,

amount of nitrogen in addition, for example, may be used. Cyanamids, such as disodium cyanamid, and amids, such as sodium amid, etc, are among the compounds of this type which may be used in the process. Thenitrogen used in my process may also be obtained from such nitrogenous compounds as ammonia, nitrids, and the like,

or mixtures of such substances; and it may be, and in many cases preferably is, free nitrogen. If nitridsare used they may, desired, be produced from nitrogen by the addition of nitrid forming elements to the 1 metal or substance which is to be treated.

When aii is injected into molten iron, as in known processes, theoxygen is so much more active than the nitrogen that the latter is practically inert; as it is generally considered. It is, hence, desirable in most when conducting my novel process, to exclude air. It is also desirable usually to, as far as practicable, exclude water and water-forming constituents from participation in the reactions involved in the process. A certain amount of these may be unavoidj ably present in the substance to betreated 'orpurified, but such cannot in many cases be helped, and all that can be done is to avoid the wilful introduction of suc'hcompounds as hydrates, for example, which contain certain water forming constituents.

The above statements conclusively show that the principles of my process for the purification decarburization thereof, are distinctivelydifferent fromthose of the present commer; cial processes.

element, in the purification. On the other of iron, and especially for the These known-processes, com

sidered as a'whole, are oxidation processes, and they depend upon oxygen for the active 7 hand In rocess is a reduc'tlon, rocess a y P v P which makes use of nitrogen alone in certain aspects of the same, ing elements, such as the alkali or alkaline earth metals, in other aspects of. the same, and yet further, gen or nitrogenous matter and such reducing elements, the latter more particularly for decarburization purposes. This distinction is fundamental, as even the basic processes which are now in commercial use arereally strictly oxidation processes in which baslc materlal is used primarily to remove the phosphorus. In my process free nitrogen,

which, in the present commercial processes which use oxygen of the air, is an undesirable inert element which cannot conveniently be avoided, not only becomes an active participant in further becomes fixed and absorbed more or less completely to form nitrogenous conipounds such, for example, as cyanogen compounds or nitrids. On account of these radical diiferences my process overcomes very many of the disadvantages of those of a combination of nitro-.

the reactions involved; but

and of powerful reduc I heretofore in use for purifying iron and the like, and it also has many other and even more .novel advantages. For example: it

not only allows the fixation of atmospheric bon dioxid, or carbonates, I obtain cyanid,

for example. This latter production may be represented by the equations:

2Na+2O+N :2NaG N+about 51,900 enories 2K+2G+N =2KCN+about 66,900 calories.

These reactions are strongly exothermic; and therefore may furnish a newmeans of getting the high temperature necessary in a modified Bessemer or similar process.

Owing to the fact that it is unnecessary in my process toheat up a relatively enormous bulk of inert nitrogen, and owing to the powerful exothermic reactions involved, it should become possible for heating purposes, to utilize the carbon, present in the charge, much more advantageously than in many known processes. My experiments have demonstrated that it is possible to augment this heating effect by the addition of carbon; while the heating eflect will still further be intensified by introducing sodium or other suitable reducing metal in the form of a vapor, either alone, or in a hot gaseous or vaporous blast. This blast, for example, may consist of hot nitrogen and sodium vapor. I am of the opinion that this will do away with the necessity for using iron rich in silicon and manganese, in the Bessemer process, and of metals rich in phosphorus and low in silicon for the basic Bessemer process. This should be of great value because the Bessemer processes are very exacting, in that they require definite composition in the iron ores used for the preparation of the metal. These ores are expensive, and the herein described process will hence probably enable the use of cheaper ores.

Carbon in any form, even as graphite, or as carbids, e. 9. iron carbid, may be readily and completely removed from iron by my process; or it may be removed to substantially any desired extent. Carbon or graphitized carbon may also be removed from a mixture-of powdered or otherwise finely divided iron and carbon by this method. As to just what reactions and inter-reactions take place resulting in the carbon present, from whatever source, uniting with the nitrogen to form the radical CN,

I am unable to positively state. Apparently, an iron carbid, or in some cases, a

solution-of carbon in iron, is first formed, which carbid, or solution, together with the iron carbid already present, if any, then reacts with nitrogen and sodium, or like metal or element present which is capable of forming the base of a cyanogen compound which is stable at the temperature of the operation, and substantially pure metallic iron is produced. The solution of carbon in ironmay, of course, be'either in solid. or molten form; and it will be apparent, of course, that the quantity of iron present is considerably in excess of the carbon actively present. The foregoing, however, is merely .my theory, and I do not wish to be limited thereto in an way. The removal of graphitic carbon is of especial importance in that the presence of this substance in iron materially impairs its strength. Itmay here be noted also that I find that carbon in other forms 6. g. silicon carbid may be successfully removed by my process. Indeed not only is thecarbon of such a compound removed, but'the silicon itself is also eliminatedv from the metal treated.

Phosphorus in steel causes brittleness under shock and a general cold shortness. It has also been shown thateven .005 per cent. increase in phosphorus decreases the wearing qualities of the cutting edges of tools to a sensible extent; and in general, the presence of relatively minute quantities of this impurity seriously impairs some of the mostvaluable characteristics of ironor steel. Phosphorus is not removed to any extent by acid oxidation processes because the phosphorus pentoxid formed is again reduced, thus re-phosphorizing the iron. It'

has therefore heretofore been necessary to employ basic processes, such as the basic openhearth, or basic Bessemer, which are usually more troublesome, and in some cases, expensive than the ordinary Bessemer process. The basic Bessemer process requires high phosphorus and low silicon on account of the basic lining, and further on account of the desirability of producing a high temperature and a slag rich in calcium phosphate. In my process, the phosphorus, so far as I have been able to ascertain, is completely removed, presumably in the form of a phosphid, and as the temperature can be maintained by the formation of cyanids from carbon, there is no need of a definite composition of the iron used in the process. The basic Bessemer process was invented especially to remove phosphorus, and I am ioo of the opinion that my herein described process may afford a substitute for it.

Sulfur is perhaps the most injurious impurity foundin iron, and, to the best of my knowledge, no completely satisfactory commercial method for its removal has been found. In some cases the percentage of sulfur in the metal is even increased during As this reaction is also powerfully exothermic, the sulfur is removed very energetically and completely. This action is hence of very great importance, since sulfur in steel causes red shortness, interferes with welding, and, therefore, may cause imperfections in apparently sound castings.

' I am'also of the opinion that sulfur and phosphorus have been the cause of many of the mysterious failures of structural steel, and of many serious accidents due to the breakage of. railways rails; and faults due to the same cannot always be avoided, even by careful heat treatment; nor can they always be detected, even by careful tests or inspection. Thesefacts demonstrate the value of my process wherein sulfur, phos phorusand carbon, which, so far as I am aware, cannot be removed completely by the commercial oxidation processes of today without undue loss of iron by oxidation, can be removed completely because the iron is not attacked by nitrogen, nor by the metals of, for example, the alkali or alkaline earth groups.

In such a modified Bessemer process as I have referred to, said process would not need to be interrupted promptly at a certain time as the metal treated cannot become oxidized; so that the process could, in effect, he forced to completion'without danger to the productor products. In the present Bessemer process it is commonly necessary to add ferro-manganese or similar substances to take away the excess of oxygen. In the contemplated process the current of sodium vapor and nitrogen should remove oxygen if it is present in combinations such as Fe(), CO, and similar substances, or in the form of slags. Thus it should be possible to effect a recovery of iron,'instead of having to sustain a loss of about 13 to 17 per cent., as is frequently the case with the basic Bessemer process. I have not been able, as yet, to ascertain exactly in what order the impurities are removed from the metal to be treated, but I .am of the opinion that theobjectionable elements sulfur and phosphorus, are among the first to be removed, rather than among the last. If I am correct, this will result in a very great advantage, since it should not then be necessary to remove all of the carbon and then to recarburize the iron as is done in known processes.

bined reduction-oxidation process.

- I have above referred to the independent action of nitrogen in the process, and am of the opinion that the nitrid-forming elements, such as silicon, titanium, vanadium, and similar elements, may be removed under suitable treatment, through the instrumentality of the nitrogen alone; the reactions between such elements and the nitrogen probably forming nitrids. Such nitrids may be heated with steam "or with caustic alkalis, or -they may be treated by other suitable methods to recover the fixed nitrogen in the form of ammonia, for example.

I I have previously referred to the reduced volume of gas which might be used in such a modified Bessemer process, which should permit of the use of much smaller appa' ratus, such as pumping machinery, furnaces and converters, than are at present in use. This is principally due to the fact that the volume of nitrogen required to remove carbon as cyanid is only about twenty per cent.

of the volume of air required in the Bessemer process to remove the carbon as carbon monoxid; 'This percentage may vary down to none at all in the case of operations relating to the removal of such elements as sulfur and phosphorus alone. The reduced volume of gaseous matter whichwould be passed through a charge would also reduce spattering of material and loss of heat.

.It is also evident that my process may be used in conjunction with processes at present,in commercial use, thus giving a combined oxidation-reduction process, or a com- Iron may also be recovered from slag, for example, by -means of the herein described method; the oxids being reduced at proper temperatures. The following equations serveto illustrate. this phase of my 'inventionz i.

" FeO+2Na:Fe+Na O FeO+Mg:Fe+MgO be obtained therefrom, for example, by the addition of carbon or carbonaceous matter .to the molten metal.

, The proces'smay also be applied to relatively impure materials, such as metallic regulus.

In large measure,

the blow holes in iron.

argon for this purpose.

or steel are caused by carbon monoxid which is soluble in hot metal and separates partly when the metal solidifies, or which is formed by the reaction of oxids, such as FeO, in the slag with carbon. For example:

The reactions almost immediately above be present it will be reduced with production of free carbon as per the following equations:

I am of the opinion also that the nitrogen or nitrogen and argon current will displace or sweep out the-carbon monoxid as well as other gases and volatile substances, just as such currents remo e the latter substances from a water solution.- In this connection it should be noted that a proper efiectuation of my process will afford a cheap and plenti ful supply of argon, of which there is an abundance in the atmosphere, since approximately one per cent. of the latter consists of this apparently absolutely inert gas. At present practically no use is made of this element, but if-it can be marketed at a low cost, undoubtedly uses will be found for it. I contemplate one use of the said element in connection with the present process. I have just stated that the nitrogen, or nitrogen and argon current should displace or sweep out carbon and volatile substances from the melt, and I may here state that I contemplate in some cases using a current of substantially pure The statements in the literature indicate that the'continued exis.ence of nitrogen in molten iron is very uncertain, and even should I use the current of nitrogen without any supplemental flow of relatively p'ureargon, I believe that the nitrogen would inprobably no case be occluded in any material quantity in the molten metal. Should it be found that any appreciable quantity of nitrogen is occluded in the metal, however, it may be readily removed by the addition of nitrid forming elements. It may,=also, be removed by the addition of carbon U elements which would form cyanids according to the reaction:-

It is obvious, of course, that this phase of'my process would apply more particularly to molten metals, and especially to iron, and it may be carried out in many forms of apparatus; converters very similar to those used in the basic Bessemer procmonoxid and other gases with sodium or similar pling 8. The nipple cook 13, afiords a b ess being suitable, and I have hence not attempted to illustrate apparatus wherein this cluded. I have successfully carried out my herein described process at temperatures below the melting point of metals which are to be purified, and will now proceed to describe with particularity the nature of the apparatus which I have used in. this connection. It is to be understood, however, that the said apparatus is but one of many by means ofwhichmy process may be carried out, and I hence do not desire to be limited in any particular as to either the manner or means by or in which said process maybe eflectuated' I While the particular exemplification '01 my process hereinafter described relates more particularly to the treatment of metals or substances at temperatures below the melting point of such substances or metals, I reiterate that I regard the treatment of metals or substances at temperatures above their melting points as within the purview of. my invention, and hence do not desire to be limited to operations conducted at relatively low temperatures, except where the claims specifically so state. tention is justified is practically proven by my experiments wherein, in some cases, iron which I have treated has been formed into globules of substantially pure iron during the course ofthe cyanid forming operation.

Referring to the drawing which forms a part hereof and in which like reference characters designate like parts in the respective views: Figure 1 is a side elevation of an apparatus wherein my process may be carried I out, one side of the muffle surrounding the retort beingremoved for purposes of illustration. Fig. 2v is a section of said apparatus, taken on line II-II of Fig. 1.

A section of heavy wrought iron pipe 1 is provided at either extremity thereof with a reducing cap 2, the reduced extremities of these caps being respectively connected to plpes 3 and '4, preferably'of considerably smaller diameter than the section 1. A T 5 is connected to the outer extremity'ofthe small pipe ornipple 3, and a nipple 6 of the same diameter may be tapped into the opposite side of T 5. Nipple 6 is connected to a cock 7 which in turn is connected to a couor pipe section 4 is also correspondingly connected to a coupling 9. Two Ts l010, one-of which is disposed upon either side of the retort formed by the tube 1 are connected respectively with the couplings 8 and 9 in any suitable manner, while a U-shaped pipe connection. 11, having t erein a coupling 12 and -pass around the retort.

That this contervals along the and laterally extending from the T 10 isa burners 18, ,which for convenience may be mounted upon a known manner.

able vents-21, for

.paratus; the decarburizationr being so per- Downwardly extending from the T 5 is-a pipe'connection 14 having therein acock"15 connection 16 in which is a cook 17 The retort 1 may be heated in any suitable manner, as by means of a series of Bunsen trogen which passes "tort 1 that if the'ironbe finely divided, e. 9., pulverulent orfibrous, that the reactions are effected more'rapidly than if the said metal be solid. Dhave successfully, however, do; carburized solid masses of steel in'this apfeet that I hav'e'been unable to find a traceof carbon after the treatment; while I have also successfully treated pig iron herein. The metal-may be introduced into the retort by unscrewing one of the reducers 2, and I similarly introduce at one end' of the retort a quantity of some powerful; reactive metal, 6. g-., sodium. Nitrogen is introduced into the retort via apipe 24, which is in communication with the "i' 10, upon the left hand side of the device, as shown in Fig. 1; and if the cooks 7 and 17 be; opened, and cocks 1'3 and 15 be closed, the gaseous-nitrogen will if that be the reducing pass through the coupling 8, and connected parts, directly int'o the retort. Herein it is rapidly heatedt'o sit-temperature preferably approximating the'boiling point of sodium,

metal used. As the. hot nitrogen passes over the sodium, designated 25, the latter vaporizes thereinto and passes together with the nitrogent'hrough or over the metal 23 to be treated. In the de-' vice shown, twenty burners have been somewhat; diagrammatically indicated, and in practice a few of theseat the extremity of the retort from which the current of nitrogen emerges are unlighted. Thus for example, fifteen gas jets may be ignited, and five burners may be left cold. As a result, the said extremity of the retort from which the nitrogen emerges is cooler than other portions of the same, and is preferably at a temperature below the boiling point of so.- dium, so that any sodium which passes through the mass of metal to be treated,-e. g., iron, will, upon entering this relatiyelycool end of the retort, be deposited; This pro-- cedure results in a saving of the-reducing metal which accumulates in this relatively inaaoia cool extremity of the retort and is there held until the current of nitrogen is reversed, in

should preferablybe quite pure, with the exception, perhaps, of the argon present, and as it passes oil through the cook 17 it may be collected in any suitable manner to avoid waste. After substantially all the sodium,

if sodium be the reducing metal employed,

has been transferred from one end of the retort to the other, the cooks 7 and 17 are closed and those designated 13 and 15 are opened. Thereafter the nitrogen will pass downwardly from T 10 and around a by pass 11 to T 10', and thence through the re in a reverse direction to thatin which it previously flowed therethrough. It will the manner hereinafter described. The n1-- through the apparatus be understoodvthat before so reversing the current of gas .the burners 18, which had previously been unlighted, are now lighted, and a'corresponding number at the other extremity of the retort are turned off. As a result, the cool section or portion of the retort is transferred from one extremity of the latter to the-other, so. that the previously deposited sodium, for example, will be reevaporated and will again be carried through or over the metal to be treated, by the nitrogen current, to be deposited thereafter at the end of the retort from whence it originally came. The flow of nitrogen through the retortmay thus be reversed at intervals until the metal to be treated has been substantially completely purified, or until all of the reducing metal has been used up. It is obvious that this metal may be in troduced into the retort or vessel either in liquid or in solid form, or it may be introduced as a vapor. My experiments indicate that the higher the temperature of the oper-' ation, the more rapid the eflectuation of the process. There are probably, however, limits beyond which it would be undesirable to go. In operating the apparatus herein particularly described, the temperature was maintained by means of the burners at from 700 to 800 C. I have found, however, that wherethe iron was in finely divided condition, and especially where additional carbon,

preferably in the'form of graphite, had been supplied to the mass to be treated, the reactions took place so vigorously that some of the iron was melted into globules, which would indicate thatthe' temperature of so: of the iron had been raised to the neighborhood of 120'0' (3., at least, and probably to 1500 (1,. or more. Under these last mentioned conditions the demand for nitrogen is so great that a rapid stream of the same must be flowed into the retort as the reactions tend to form a partial vacuum therein, and it is necessary in such case further to guard against a How of gas back through the cock 17. To this end, a liquid seal 26, or

, nitrogen flows, to such an extent that the .course, from atmospheric nitrogen, and it is assumed that this latter has been obtained by separating it from the oxygenof the air by any-suitable-process, of which several commercially practicable ones are known to me. Where an excess of nitrogen passes through the apparatus, it may, as I have previously stated, be collected; and may thus be used repeatedly until .it has all been consumed. Should it be found in practice that any waste of sodium, for example, is taking place, it is merely necessary to refrigerate, asby means, for example, of currents of air,

theextremity of the retort from which the temperature of the same will be materially below the boiling point of the reducing metal. It may be here observed, too, that it is advantageous, in some .cases, to carry out the process under a pressure considerably above atmospheric. This feature is of especial advantage, for example, when the nitrogen current must be forced through the metallic mass being treated. I have found that steel treated by the herein described process is much less rapidly attacked by by drochloric acid (20% solution) than it'originally was, the steel and the j becomes, being respectively subjected to the acid at a temperature from '80 to C; In other words, I have found that the prac= tically pure iron produced by theherein described process dissolves very slowly in said acid and is far less subject to corrosion than untreated iron. It is obvious also that cast? ings maybe treated in accordance with the said process so that the carbon may be taken, if desired, only from the outside thereof virtually rendering the outside of the castings malleable. When the metal treated is in solid, or relatively solid form, the action' seems to be that the carbon in whatever form it. is present diffuses from the interior portions toward the surface of the metal, there to re-act with the nitrogen and sodium to form cyanid. Iron is completely decalburized when heated to redness in an atmosphere of nitrogen and sodium vapor for a sufficient length of time, substantially pure sodium cyanid being formed.- The process may even be used to separate a mixture of finely divided carbon and iron in the form of filings, powder and similar states of division.

lVhen the operation is conducted at or around a red heat, the cyanid will collect upon the surface of the metal treated, and can readily be obtained therefrom by lixiviat-ion, cyanid being very soluble in water, and

iron, as it really but a small quantity of this latter fluid there fore su'tficing to expeditiously recover this valuable product in the form, if desired, of a concentrated cvanid solution.

In treating solid bodies of iron such as castings, for example, obviously the carbon only at the surface of such bodies is first removed, but as the process is. continued it is progressively removed from the inner portions of the castings, or the like. It is possible, therefore, to produce a material consisting of initially integrally connected layers of iron and steel, for example, which may even be alternated, since it is possible to recarburize a surface by known cementation processes. Thus, for example, a block .decarburized, for example, to a depth of oneeighth of an inch, and finally the surface only may be recarburized again, if desired. Again, other material than carbon may be introduced into the decarburized metal.

Thus vapors, for example, containing sulfur or phosphorus, or compounds thereof, or of such elements as silicon could be brought into contact with a hotsurface of a metalwhich is to be treated, and thereby be caused to impregnate the same.

If finely divided iron is placed in the retort and treated in the manner above described, the product is a spongy mass, which When compressed appears as a shining or highly lustrous, coherent, metallic substance which is very soft being readily hammered or worked at ordinary temperatures. The spongy material above referred .to is so readily compressedthat it becomes coherent and lustrous even when rubbed merely with a horn spatula, or the finger nail. Such finely divided sponge-like iron may be molded, compressed, hammered, or otherwise suitably worked, with or ithout the assistance of other substances, such as carbon. The objects thus formed may then be given any desired heat treatment, thus form-' ing by molding processes objects equivalent to castings, pipes, ingots, sheets and bars of any desired composition.

Steel and other objects, such as sheets of metal, wire, bars, nails, or posts, may be treated by this method so as to soften or purify the surface layers alone, by selecting suitable conditions in accordance with the foregoing, the surfaces to be treated being brought into" contact, for example, with sodium and nitrogen, and the articles being heated fora sufiicient length of time to permit of decarburization to the desired amount and depth. If desired, iron or steel objects the rate of diffusion of such impurities through the solid mass to be treated, .at the temperature of the operation. The metal surface thus obtained is very resistant to corrosion. This phase of the process is especially'adapted forthe removal of impurities from sheet iron before tinning, galvanizlng or sherardizing, as it removes not only the usual impurities, but also the com-.

paratively large quantity of phosphorus which is present in the metal to prevent too great stickiness of the sheets in the rolling processes. The metal so treated is, therefore, free from-,the, greater part of the impurities which at present-cause so much corrosion of tinned iron.

The value of the-herein described process will therefore be almost selfevident, and it. is anticipated that it will have an important effect upon many industries. In view of the importance of the said process, and in view of the novelty residing therein, I hence desire to be limited only by the scope of the appended claims.

It will be understood that the word puri-' fying as used herein is a general term and is-intended 'to covereither partial or complete purification; while the term iron as used in the claims in connection with the said word purifying, or words of similar import, refers to wrought iron, cast iron, steel, and the like, or to alloys containing iron. In like manner the expression changing the physical condition of a compound is intended to cover volatilization, lixiviation, etc. Where the word reaction ocours in said claims, unless qualified by the adjective direct or the like, I intend it to be understood that such term not only includes a simple or direct reaction but a compleX reaction wherein possibly several subsidiary reactions occur; this provision being obviously necessitated by the lack of exact knowledgeas to justhow the molecules of the several elements involved behave with respect to each other.

"pended claims the term light metal has becnused as a generic terin for such metals of relatively low specific gr'avity as sodium,

potassium, suitable alkali-earth metals, and the like. Where, also, in certain of the claims the reaction set forth involves iron or its equivalent, it is to be understood that in such case the iron may actively participate in the reaction, 2'. 6. enter into or be removed from chemical compounds, as in the case of carbid, or it may participate catalytically, as in the casewhere it acts as a solvent for the carbon in the manner previously referred In the following apto. In other words, such claims are to be regarded as of sufficient scope to cover iron, or its equivalent,'either as an active participant or as a catalyst. The term 11011 ferrous has been applied in certain of said claims to metals other than iron, steel and the like.

Having described my invention, I claim:

1. The process of purifying a 1r etal which comprises eifecting' a reaction in which the metal to be treated, a powerful reducing element and nitrogen participate.

2. The process of purifying a metal which comprises efi'ecting a reaction in which the metal to be treated, a powerful reducing element, and the elements carbon and. nitrogen participate. 4

3. The process of purifying iron which comprises effecting a reaction in which the iron to be treated, a powerful reducing element and nitrogen participate.

4.-The processof purifying iron containing carbon, which comprises combining a portion at least of said carbon with nitrogen and a non-ferrous metal, to form a cyanogen compound.

5. The process of purifying iron containing carbon which essentially comprises combining' a portion at least of said carbon with an element capable of being united with said carbon to form an oxygen free radical, and

with a second element capable of acting as the base of a compound containing said radical.

6. The metallurgic process of decarburiz- 10 0 ing iron, whichincludes effecting a reaction 1n the presence ofthe iron to be purified, in which free nitrogen, carbon from said iron, and a light metal participate to form a cyanid of said light metal.

7 The process of obtaining metal from a mass containing said metal and carbon, whichessentially comprises combining a portion at least of said carbon with an ele- 'ment capable of being united with said carbon to form an oxygen free radical, and with a second element capable of acting as thebase of a compound containing said radical, to form said compound, and removing said compound from said metal by lixiviation.

8. The process of obtaining iron from a mass containing iron and carbon whichessentially comprises combining a portion at least of said carbon with an element capable of being united with said carbon to form a radical, and with a second element capable of acting as the base of said compound containing' said radical, to form said compound.

9. The process of obtaining iron from a 126 mass containing iron and carbon which essentially comprises combining a portion at least of said carbon with an element capable of being united with-said carbon to form an oxygen free radical, and with a second ele- 13k ment capable of acting as the base of a com pound containing said radical, to form said compound, and separating said iron from said compound by changing the physical condition of said compound. 7

10. The metallurgic process of decarburizing iron which essentially comprises com; bining a portion at least of said carbon with an element capable of being united with said carbon to form an oxygen free radical, and with a light metal capable of acting as the base of a compound containing said radical, to form said compound of said light metal.

11. The process of treating a substance containing carbon initially in solution in an element of the iron group which is capable of directly uniting with free carbon, which essentially comprises combining a portion I at least of said carbon with nitrogento form cyanogen, and with a second element capa- 5 ble of acting asthe base of a cyanogen compound, by elevating the temperature'of said substance containing carbon to a point where some at least of-said carbon may be *reacted upon by said nitrogen and said secondelement to form said compound. I

' 12. The process of treating a substance containing carbon and an element of the iron group which is capable of directly uniting with free carbon to obtain said element therefrom, which comprises combining said carbon with nitrogen to form cyanogen, and with a second element capable of acting as the base of a cyanogen compound, by elevating the temperature of said substance containing carbon. to a point where sub-' stantially all of said carbon may be reacted upon by said nitrogen and said sec nd element to form said compound.

13. The process of treating a relatively extensive body of iron having carbon therein to eifect the removal of at least a portion of said carbon, which comprises elevating the temperature of said iron at leastto a point where said carbon may diflnse there through, and reacting upon the ir n and carbon with a nitrogenous reagent and a nitrogenous reagent and a non-ferrous metal, which is capable of forming the base of a cyanogen compound, to form said cyanogen compound, cooling the heated mass and dissolving said cyanogen compound in a menstruum for the'same.

15. The process of treating a mass containing as constituents thereof, carbon and a free metallic element which is capable of directly uniting with free carbon to form a carbid, to separate carbon from said mass, said process comprising heating said mass and reacting exothermically on-some at least of the carbon therein with an element capable of uniting therewith to form an oxygen free radical, and with a second metal capable of combining with saidradical to form a compound stable at the temperature of the operation.

16. The process of treating a mass containing as constituents thereof, carbon and a free metallic element which is capable of directly uniting with free carbon to form a carbid, to separate carbon from said mass, said processcomprising heating said mass and reacting exothermically on'some at least of the carbon therein with an element capable of uniting therewith to form an oxygen free radical, and with a second metal capable of combining with said radical to form a compound stable at the temperature of the operation, and separating said compound from saidtreated metal by changing the physical condition of said compound.

17. The process of treating a mass'of ma terial containin carbon in solution in an element norma ly incapable ofdirectly uniting with free nitrogen, to separate can bon therefrom, which comprises eifectingan exothermic reaction in which some, at least, of said carbon, an element capable of com bining with said carbon to form an oxygen free radical, and an element capable of.act

ing as the base of a compound containing said radical, participateto form said compound.

18. The process of treating a mass of material containing carbon in solution in an element normally incapable of directly unit-' ing with free nitrogen, to separate carbon therefrom, which comprises effecting an exothermic reaction in which some at least of ical, an element capable of acting as the vbase of a compound containing said radical,

and said first mentioned element, participate to form said compound.

19. The process of treating a mass of material containing carbon in solution in a carbid-forming element normally incapable .of directly uniting with free nitrogen, which comprises effecting an exothermic reaction in which some at least of saidcarbonfan element capable of combining with said carbon to form an oxygen free radical, an element capable of acting as the base ofa com .110 said carbon, an element capable of combinmg1 with said carbon to form an oxygen free pound containing said radical, and said carbid-forming element, participate to form said compound.

20. The process of treatlng a mass of mater1al containing carbon in solution in an ing with free carbon and nitrogen,

element normally incapable of directlyunitnitrogen, to separate carbon therefrom, which comprises efiecting an exothermic reaction, at an elevatedtemperature, in which at least some of said carbon,

the elementnitrogen, an element capable of.

compound containing and said first mentioned element, participate to form said compound.

21. The process of treating carbon in soluti'on in a relatively extensive body of an element capable of directly uniting with free carbon to form a carbid, to separate said carbon from said element, which comprises efi'ecting a reaction, atsa temperature at which said carbon ma freely diffuse through said body and in which reaction said carbgn, the element nitrogen, an ele-- ment capable of acting as .thebase of a compound containing .carbon and nitrogen, and said first mentioned element, participate .to form said compound, and separating said compound from the residue by changing its physical condition. I 22. The process of treating a mass of material containing carbon intimately associacting as the base of a ated with an element normally incapable of;

directly uniting with free nitrogen, to separatecarbon therefrom, which comprises ef- I fecting an exothermic reaction, at an eleva-ted temperature, in which at least some of caid carbon, the velement nitrogen, .a free metal capable of' acting as the base of a compound containing .carbon and nitrogen in the form of a radical, and said first mentioned element, participate to form said comound. a

23. The process of treating carbon in solution in 'a relatively extensive body of an element capable of directly uniting with free carbon to forma carbid, to separate said carbon from said element, which comprises efiecting a reaction, at a temperature at which saidflcarbon may freely 'difiuse which reaction said carbon, free nitrogen, an element capableof actin as the base of a compound cont ining car on and nitrogen in the form of a radical, and said first mentioned ele-,

ment, participate to form said compound,

7 and separating said compound from the residue by changing its physical condition.

24:. The process of treating a mass of material containing carbon in solid solution in an elem'entcapable of directly uniting .with free carbon, but incapable of directly uniting with free nitrogen, to separate carbon therefrom, which comprises eifecting an eXotheI'mic reaction at an'elevated temperature, in which at least some of saidcarbon, the element nitrogen, an element capable of acting as the base of a compound contain;

ing carbon and nitrogen, and said first mentioned element, participate to. form said compound. 25. 'The process of treating a mass of material containing carbon in solid solution in an element normally incapable of directly uniting with free nitrogen, to separate carbon therefrom, which comprises eflecting a reaction at an elevated temperature, in which at least some ofsaid carbon, free nitrogen, an initially uncombined; light metal which is capable of acting as the base of'a compound containing carbon and nitrogen, and said first'mentioned element, participate to form said compound.

26. The'process of treating a mass of material containing carbon and an element capable of directly uniting with free carbon to'form aflcarbid, to separate carbon therefrom, which comprises effecting a reaction, at an elevated temperature, in which at least some of said carbon, free nitrogen, an element capable of acting as the base of a compound containing carbon and nitrogen, and said ,first mentioned element, participate to form said compound, and separating said compound afrom .the residue by changing its physical condition.

2.7. The proc'essof treating a substantially undivided andrelatively extensive mass of material containing ,ca-rbon in solution in an element normally incapable'of directly uniting with free nitrogen, to separate carbon therefrom, which comprises effecting a reaction at a temperature. above 500 0., in which at least some of said dissolved carbon, free nitrogen, an element capable of acting as the baseof a compound containing carbon and nitrogen in the form of a radical, and said first mentioned element, participate to form said compound and continuing said reaction .by the diffusion of said carbon,

which is as yet uncombined, to a surface of said mass at which ,contact may be effected with said free nitrogen and said ,base form-- 'ing element.

28. The metallurgic process ofdecarburizing iron which includes effecting a reaction in which free nitrogen, carbon in solution in the iron to be purified, and a light metal participate ;to form a cyanid of said light metal. 7

29. --l;he process oftreating a mass of material containing carbon dissolved in solid iron, to separate carbon therefrom, which comprises .effectinga reaction at an elevated tempera ure in Which at least some of said carbon, ,the element nitrogen, an element s initially ,present in free or molecular condi- -tion and'capable of acting as the base of acompound containing carbon and nitrogen in the form of a radical, and iron participate.

30. The process of treating a mass of ma terial containing carbon dissolved in solid iron, to separate carbon therefrom, which comprises effecting a reaction, at .an elevated temperature;-in-which -at leastsome of said carbon, free nitrogen, a free metal capable of acting as the base of a compound containing carbon and nitrogen in the form of a radical, and iron participate.

'31. The process of treating a mass of material containing carbon in solution in iron, to separate carbon therefrom, which comprises effectingan exothermic reaction at. an elevated temperature in which atleast some of said carbon, free nitrogen, a light metal capable of acting as the base ofa compound containing carbon and nitrogen in the form of a radical, and iron participate.

32. The process of treating a mass of material containing carbon in solution in an element normally incapable of directly. uniting with free nitrogen, to separate carbon therefrom, which comprises effecting an exothermic reaction at an elevated temperature, in which at least some of said carbon, the element nitrogen, a light metal capable of acting as the base of a compound containing carbon and nitrogen, and said first mentioned element, participate to form said compound, said first mentioned element being present in relatively large quantityas compared to the amount of active carbon present.

33. The process of treating a mass of material containing carbon in solution in an element normally incapable of directly uniting With free nitrogen, to separate carbon therefrom, which comprises efi'ecting an exothermic reaction at an elevated tempera ture, in which' at least some of said carbon, the element nitrogen, an alkali metal capable of acting as the base of a compound containing carbon and nitrogen, and said first mentioned element, participate to form said compound.

34. The metallurgic process of decarburizing iron which includes effecting a. reaction in which free nltrogen, carbon'in solution in the iron to be purified, and sodium participate to form sodium cyanid.

35. The process of purifying a metallic mass having impurities therein, one of which comprises carbon, and one of which comprises an element capable of being directly united with a powerful reducing element, which includes supplying said last mentioned element and the element nitrogen to said mass and effecting a plurality of reactions-in which said powerful reducing ele- Inent-and some of said impurities participate to form compounds of said reducing element,

carbon taking part in one of said reactions and yielding cyanogen.

36': The process of removing impurities from a substance which comprises effecting an exothermic reaction in which the substance to be treated, a powerful reducing ele- 'ment, and the elements carbon and nitrogen participate.

37. The process of removing impurities from a substance wh1ch comprises efl'ecting an exothernuc reaction 1n Which the sub stance to be treated, a powerful reducing element, the element carbon, and molecular nitrogen participate.

38. The process of rem ving an impurity from a substance, which comprises subjecting said substance'to contact with a powerful reducing element in vaporous form, and effecting a reaction in which the substance to be treated said reducing element, and the elements car on and nitrogen participate.

39. The process of removing an impurity from a substance which includes effect-ing an exothermic reaction in the at a temperature above 500 0., in which an element capable of being combined with carbon and nitrogen to form a cyanogen compound, stable at the temperature of the operation, the element nitrogen,and carbonaceousmatter in non-gaseous form, participate, substantially as described. 40. The metallurgic process of treating iron in bulk to remove an impurity therefrom which includes effecting a reaction at a temperature below that of the electric furnace, but above 500 C., in which an element capable of being combined with carbon and nitrogen to form a cyanogen compound,

presence of, iron,

stable at the temperature of-the operation,

and the elements iron, nitrogen and carbon participate, the iron being present in relatively large quantity as compared to the amount of carbon actively present, and be having as a catalytic agent, substantially as described.

41. The metallurgic process of removing an impurity from a substance which includes effecting a reaction, through the instrumentality of heat, in which an initially free element capable of being combined with carbon and nitrogen to form a cyanogen compound,

stable at the temperature of the operation,

the elements iron and nitrogen, and carbonaceous matter in non-gaseous form participate, while substantially excluding water and. Water forming constituents from-pan ticipation in 'said reaction.

42. The metallurgic process of removing an impurity from a substance which includes effecting a reaction, through the instrumentality of heat, in which an initially free element capable of being combined with carbon and nitrogen to forma cyanogen compound, stable at the temperature of the operation, the elements iron uncombined with oxygen participate, while substantially forming constituent-s from participation in said reaction. I

and nitrogen, and carbon,

excluding water and Water with a second element 48. The process of purifying iron containing carbon which comprises combining a ortion at least of said carbon with nitrogen and ametal other than iron, to form a cyanogen compound, and separating said cyanogen compound from, the; iron-con taining residue.

1 44. The process of purifying iron containing carbon which comprises combining a portion at least of said carbon with an element capable ofbeing'united with said carv bon'to'form an oxygen free radical, and capable of acting as the base of a compound containing said radical, by efiecting a reaction, at a temperature below the melting point of the iron .to be treated, in which said iron and the said elements participate.

45. The process of obtaining, iron from a mass containing iron and carbon which comprises combining a portionat least of said carbon with an element'capable of bein united with said carbon to forma radica, andwith a second element capable of acting as. the base of said compound containing said radical, to form said compound,

the operationbeing conducted at a temperaing with free nitro gen,

therefroml whi-ch comprises effecting a returc substantially of cast iron, I

4:6, The process of removing carbon from iron which comprises combining a portion at below the melting point least of said carbon with an element capable of being unitedwith said carbon to form an oxygen free radical, andwith-a light metal capable of acting as the base ofa compound;

containing said radical, tdform said com:v

pound of said light metahand separating said compound from the. iron-containing residue. I

1 47. The process-of treating a mas's of niatei'i-al containing carbon in solution-in an "element-normally incapable ofdirectly unit- 'action in' iwhi'ch some, at least, of said carbon, an element capable ofcombinin'g with to separate carbon said carbon toform an oirygen free radical,

and an element initially present in free or 1 molecular condltion and capable of acting as i the base of a compound containing sai radical, participate to formv said compound.

48,. The process o fitreating a mass of material containing carbonin solution in iron,

to separate carbon therefrom, which com-- prises. effecting a I'QdCillOIly at an elevated 3 temperature, in which at least some of said carbon,- free nitrogen, of acting as the'base of a compound cona free. metal capable tainingcarbon andnitrogen in the form of a radicalg a hd iron participate,and separating, at'leash'theradical forming constituents of said compound, while'in chemical combination. with each, other, mass. I

. 4.9; The process of treating a mass of mafrom said terial containing carbon intimately associated with iron, to separate carbon there from, I thermic reaction at an elevated temperature inwhich at least some of said carbon, free nitrogen, a light metal capable of act-,. ing as the base of a compound containing carbon and nitrogen in the form of a radical, and iron participate, the ironbeing present in relatively large quantity as compared to the amount of carbon actively present. y

50. Theprocess of removing impurities from a substance which comprises effecting a: reaction in which the substanceto be treat- ,ed, a powerful reducing element, andthe -elements, ca'rbon and nitrogen participate, 'andseparating the two last mentioned elements, at least, while "n chemical combination with each other, from said substance.

In witness whereof, I subscribe my signature, inthe presence of two witnesses.

JOHN E. BUCHER. Witnessesi I Wnnno M. CHAPIN, JAMES DAn'romo.

which comprises effecting I an exo- I

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