US1129513A - Process of making compounds in electric furnaces. - Google Patents

Description

s. PEAGGGK.l PROCESS 0F MAKING COMPOUNDS IN ELEGISIG FURNACES.

, APPLIOATIQH'HLVED SEPT. 22, 1913. 1,129,51 3.' Patented Feb. 23, 1915.

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UNITED STATEs PATENT orricn 'SAMUEL ramones, or clarence, immers,A assertion-To INTERNATIONALQAGBICUIP- I TURA'L conromrron, or NEW Yoan, n. Y.; a oonzrona'ron or NEW YORK.

PROCESSO?? KAKING COMPOUNDS 'x mTBC EURNCES.

Specification of Letters iatent.

,Patented Feb. es, 1915.

Application and september e2', 191e. serial No. :191,129.

T all whom it may concern.'

Be it known that I, SAMUEL Pniicocn, a citizen of the United States, residing at Chicago, inthe county of Cook and State of Illinois, have invented certain new and useful 'Improvements in Processes of Making has for one of its objects to render morel eflicient similar processes heretofore pio.

posed.

ith this and other objects in view the invention consists in the novel combinations of steps constituting my process as will be more fully hereinafter disclosed and parn ticularly pointed out in the claims. v

In orderthat myvprocess may be more clearly understood, reference is had to a furnace suitable.. for carrying out my invention, which is illustrated in theaccompanying drawings forming a partof this specification in which like numerals designate like parts in all the views:-

1F igure 1 is a sectional view of a .furnace built in accordance with my invention; and, F ig. 2 is a sectional view, taken on the line 2 2 or Fig. i.

i indicates the electrodes, Which are preferably two in number and of a built-up construction, as shown.

2 indicates the body of the furnace, which may be of brick Work or other insulating material; 3, a steel jacket for said body portion; Ll, a metal section forming a continuation of the furnace 'shaft and chamber; 5, valved conduits for leading olf `they enit gases; 6, a continuation, of the section e provided with the hand feed opening 7, a section bolted to the member 6; 8, a rotatinggate or valve forming a gas tight connection with the furnace chamber and adapted to feed -measuredv quantities of charge material 9 tothe furnace chamber 10 Which is preferably tapered toward the bottom, 'as shown; l1 indicates oppositely disposed valved inlets for nitrogen, or producer gas, located belov,7 the electrodes l and preferably passing through the reduce portion 1S ofthe furnace bodyfas shown.

Said reduced portion 13 is also provided with a steel vcasing 14, and its-lower end opens into the conduitl or delivery passage 5,-preferably provided with the screw conveyer 16, 'and outlet or delivery 17, adapted to pass the material into any suitable receiver, not shown. Any suitable meansofor rotating the conveyer 16--may be provided,

andltl, is a gea:v for rotating valve or feed member 8.

'The furnace chamber 1i) square, or almost square in cross section, andthe area of each of' the opposed exposed faces of the electrodesv is preferably the rotating lmade at least as great as the area of said section, so that the path of least resistance through the molten material will be practically directly from one electrode face to the other; and therefore, the objectionable short circuiting and deflections of the current through said material, with the'consequent unequal heating thereof, now so annoying in furnaces of this type, are largely, if not entirely done away with. This@ con- Sider an important feature of my invention, and is conveniently secured by building up is preferably the electrodes l' from slabs of graphite, as

shown. The furnace is gas tight, when operating, as will be clear from the drawings, and by oppositely disposing the gas inlets 11 as illustrated, and thus causing the streams to meet inthe middle of the charge, an even and'steady flow of nitrogen through the reaction Zone is had, which would not be the case if only one vinlet vvas" employed.

The operation of my furnace will he clear from the foregoing, but may be briefly sumlmarized as follovvsz-The chamber l0 may be filled ywithacolre up to the electrodes, and then hot coke thrown in through the openingA 5,- the current turned on and the conveyer started while charge material is fed down through the chamber; or the said chamber may be filled with coke to a point above the electrodes, the current turned on and. when the coke becomes incandescent, it may be fed out through the conveyor While charge material is caused, to follow down into the reaction zone. Ineither case,

the turning of the feed valve or member S will cause charge material 9 to be uniformly fed to the reaction zone, and the turning of the Vscrew conveyor 16 will cause theV product to be uniformly removed from zone.

The current, in furnaces of this type, as iwell known, has heretofore been exceedingly difiicult to control, it being stronger through some parts of the charge than through others, and it hasresulted fromthis that the heating of the charge has not been uniform and the product as a consequence n vhas beenv liijregular in quality. In my 1nvention, however, not only does the large area of the `electrode faces above mentioned serve to remedy this grave defect, but I also preferably briquet my charge material 9, so that the original uniform distribution of conducting material is maintained inthe reaction zone, and. the current accordingly remains'more steady than heretofore. Not

produce a temperature of only say 15000. C.

in the reaction zone., which would be suit- 'ableV for producing calcium carbo-nitrid CaaNTCSN, for example, or I may put in less carbon and thus raise the temperature to 1900o C. and thus produce a temperature suitable for making a nitrid such as CMN?, "from .the same charge material.

I But, the above principles of operation are adapted Yfor the 'fixation of atmospheric nitrogenA whether one employs oXids, sulfidstetc., of metals, metaloids, or non-metals. They are also adapted for causing other chemical com'- binations in a. manner more efficient than Y heretofore, alllas will now be explained.

. conditions of treatment there formed double nitrids, suchas cyano-` It is'well-known that a large number of chemical-elements will combine with nitrogen to form nitride if the conditions of tem'- perature are favorable, and under varying may be .ntrids, carbo-nitrids, silico-nitrids, sulfonitrids, phospho-nitrids, etc. Further, it is known that theoretically atleast oxygen and calcium nitrids may be 'produced by heating calcium oXid in an atmosphere lof nitrogifgup to say 4000" C.; but these nitrids under these conditions are usually decomposedms 'fast as they areformed. On the othengihand, if We cause the oxygen of ,the calcium or other oxid to combine with t-carbon, or sulfur, etc., and to be removed lfrom the zone of reaction asfast as formed,

" then the metal, nietaloidfetc., will also combine with carbon or sulfur, etc., to form a carbid, or a suld, etc. Further, these carl5 bids or sulds thus formed are capable of dissociation in the presence o f gaseous n1- trogen to form nitrogen compounds according to the following illustrative equa- In fact a little consideration will show that vif R represents a metal, a non-metal, or

a metaloid radica-l, the principle of the above ,equations .hold in all RO, RS and similar brelations. But in applying these general prnciples'to commercial needsseveral limitations are at once encountered. The carbids, oxids, sulfids, etc., must be eX- posed to free nitrogen at the requisite temgen (O) or gas containing oxygen such as carbon dioXidtCOg) -water vapor (H2O), etc., may be present. Further, the exclusion of these gases must not materially increase the cost Aof the lproduct. Now all of these conditions are f lfilledv by my process. in the -xation of frenitrogen because,by 'attaching a `suction orfpther appartusto the pipes 5, and by regulating the valves in said pipes I can make the internal pressure Whatever may be desired, by regulating the amount of`carbon in the charge I can make the temperature whatever may be desired, and by keeping the voltage of the current downto say L1z0-or 50 volts, I can prevent any appreciable arcs'from forming .and

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peintures and in such a manner that no oXyc abnormally heating the charge in spots.

This will all be clearer upon considering the following concrete example :--S'uppose it is desired to form a double nitrid of phosphorus Vand calcium from a mixture of phosphate l rock andv iinely dividedA cokev and coal, and

that the ten'iperatureshould be maintained at! about 1400.O C. The change is made up with 70 to 7 5 of carbon, briqueted and fed to the furnace vwhereupon with a, current of about 50- volts, and a furnace having a chamber l twenty inches square, and `complying with the above disclosure.,- the 'above temperature will be found to be produced in the reaction zone; Again, suppose it is desired to produce a double nitrid of magnesium and carbon, and that the temperature should not 'rise above 1500o C., a suitable mixture of magnesium oxid Mg() and finely divided 'carbonis made up and the mixture made to contain 65% to 70% of carbon. 0n the other hand, if a temperature of 1900Q C. to 20000 C. is desired for the making of a calcium ora magnesium nitrid instead of the carbonitrid from the above charges, then the carbon content must be reduced to say 40% to45% carbon- The proper quantity of carbon n each'in? stance to produce lthe required temperature is determined by experiment and tabulated for future use.

By the above process, I am enabled to fix nitrogen as a carbo nitrid RCN2 instead of a nitrid R3N2, and this therefore enables me to fix the nitrogen at a lower temperature, as well as to fix three times as much nitrogen as would be possible if the temperature was permitted tov rise high enough to dissociate the said carbo-nitrid, and thereupon form a nitrid. But,` again, under some circumstances, it is more desirable to fix the nitrogen as a nitrid, and when these conditions exist, my lprocess enables one to readily ac-I commodate the plant to the existing requirements. 'When synthesizing other compounds, the same general remarks apply and it is therefore not deemed necessary to discuss a special example.

Especial attention is called to the fact, that by employing a very large percentage of conducting carbon in the charge, the temperature of said carbon when considered alone, will be practically constant, notwithstanding its motion past the electrodes; and the heat radiated from this carbon alone is a large factor in maintaining the temperature of the mineral portion of the charge material constant. In addition to this the said mineral portion of the charge material being in a comparatively small proportion, it is highly heated from this large proportion of carbon and rendered more uniform in its conductivity, so that it does not disturb the even iiow of current in its motion j past the electrodes to the extent that has been the case heretofore. In other words, my carbon really constitutes a moving resistor more or less mixed with mineral charge material; and it is evident from the above disclosure that by properly proportioning the v amount of carbon and the amount of mineral charge material, (the voltage remaining constant) that any desired high or low constant temperature may be at once attained. On the other hand, this result is conveniently attained by also so manipulating the voltage andl amperage as to produce this said temperature.

What I claim is l. The process of producing compounds containing nitrogen in an electric furnace which consists in preparing a charge containing carbon; regulating the amount of carbon in the charge according to the temperature desired in the reaction zone; pass-` ing said charge through' said reaction zone in the, presence of free nitrogen;.and maintaining the voltage of the current at a value too low to permit substantial arcs to be formed, vsubstantially as described.

2. The process of producing compounds containing nitrogen in an electric furnace `finished product from the furnace as fast as it is formed; and maintainingthe voltage of the current at a value too low to permit substantial arcs to be formed, substantially as described.

' 3. The process of producing compounds containing nitrogen in ari electric furnace provided with oppositely disposed electrodes which consists in preparing a charge containing carbon; regulating the amount of carbon in the charge according to the temperature desired in the reaction zone; passing said charge while having a cross section substantially equal to the cross section of said electrodes through said reaction zone in the presence of free nitrogen; drawing olf the gaseous products of the reaction fast as theyare formed; withdrawing the finished product as fast as it is produced; and maintaining the voltage'of the current at a value too low to permit substantial arcs to be formed, substantially as described.

4. 'Ihe process Aof producing uniform products in an electric furnace which consists in passing a predetermined quantity of conducting resistor material through a rea'ction Zone; passing a predetermined quantity of charge material mixed with said resistor material through said reaction zone; in maintaining the voltage of the current too low to permit of any substantial arcing; and in regulating the amperage to produce the required temperature, substantially as

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