US1035727A - Process of producing compounds of aluminum, carbon, and nitrogen. - Google Patents

Description

S. PEAGOCK. PROCESS 0F PRODUGING COMPOUNDS OF ALUMINUM, GARBON,`AND NITROGEN.

APPLIATION FILED SEPT. 23, 1911.

vPatented Aug. 13, 1912.

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SAMUEL PEAcOcx, OP CHICAGO, ILLINOIS, AssIGNOn "ro E. I. nu PON'r DE NEMOURS POWDER COMPANY, A CORPORATION or NEW JERSEY.

Specification. of Letters Patent.

Patented Aug. 13, 1912.

y Application led September 23, 1911. Serial No. 650,973.

To all 'whom it may concern v Be it known that I, SAMUEL PEACoCK, a 4citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Processes of Producing Compounds of Aluminum, Carbon, and Nitrogen; and I do hereby declare the following to be a full, clear, and exact description of theinvention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to the production of a nitrid having the formula AIZCSNG, and has for its object to provide a process for making this product in an efficient and expeditious manner.

To these ends the invention consists in the .novel steps constituting my invention which is more fully hereinafter disclosed and `particularly pointed out in the claims.

Referring to the accompanying drawings forming a part of this specification, the figure is a diagrammatic sectional illustration of a furnace suitable for carrying out my invention.

1 indicates` any suitable supply for the mixed carbon and alumina, 2 valves controlling the same, 3 a furnace provided with a refractory lining 4, 5 a resistor of graphite or other suitable material, 6 a second resistor, 7 supports for said resistor, 8 rings on the outside of the furnace connected with said supports 7 and adapted to make contact with the brushes 9, 10, 11 and 12 included in suitable electric circuits not shown.

The furnace is supported by any suitable I means as for example the rollers 14, and is revolved as by the means 15. 16 representsl an air-tight connection between the receptacle 1 and the larger end of the furnace,

\ while 17 represents a similar connection between the exit 18 and the smaller end of the furnace. The shape of the furnace is preferably conical with its lower side horizontal,

` and. when rotated it therefore carries the `material 20 in small particles upwardly on its inner side, and drops'the same down at a point nearer the smaller end than it wasbe- A fore. AIn thls way, the material is continuously fed through and evenly heated in the 'furnace as it rotates.'

In order to allow for the` expansion-'and lnecessary to disclose more of its details,

contraction of the resistors, I preferablyprovide spring supports 22 which may be suitably made of carbon or other refractory conducting substance.

23 represents a suction pipe for the pump 24, which communicates with the interior of the connection 16 as shown, and 25 represents a suitable vacuum gage, which is provided with contacts, not shown, connecting with the wires 26.

27 represents any suitable electro-magnetic device adapted to be operated from the gage 25 and controlling the exit valve 28 of the pump, although my processmay be carried out at atmospheric pressure, or even above, if desired.

Since the above apparatus forms no part of my present invention, I do not deem i an only refer to it here in order to make clearer the process now to be described.

Briefly stated, this process consists in taking advantage of the relation which exists between the equilibrium tem erature and pressure of the formation o the nitrid, AlgCaNn, and preferably in causing said nitrid to form at a temperature in the neighborhood of 1500 centigrade or lower, while the internal pressure of the furnace is below that of the atmosphere, or at say 500'millimeters of mercury or lower.

In carrying out my process, I take finely divided and dry alumina and finely divided dry carbon,I preferably coke or charcoal, in the ratio of 102 parts by weight of the former to 72 parts of the latter, thoroughly mix the same, and feed the mixture into the furnace as illustrated. I find in practice that the process is facilitated if an excess of/carbon ove'i` that required to satisfy the eduation below, and sometimes as lhigh at-25 or 30 per cent. is used, since it prevents the formation of aluminum nitrids such as A12N2, which contains a much lower percentage of nitrogen than do the nitrids of my process. -Said'excess of carbon also insures the more nearly complete conversion of the aluminav to the form distinguished by the formula Al,CsN, said excess of carbon not being injurious to the process. After the mixed alumina and carbon is in the furnace, I preferably subject 4 it under the conditions above mentioned, by means of the resistor 5 to a temperature of about 1.500 C., which effects the formation of the nitrid in accordance with the following equation As thenitrid, however, is formed and the material fed by the furnace under the electrode 6, less total-heat units are required to keep up the reaction temperature, because the reaction lessens in velocity and less heat is absorbed. Therefore, I preferably include the resistor 6 in an independent circuit, and pass. only suilicient current therethrough to supply the necessary heat in the lfurnace to correspond with the selected pressure of gas that is -being ,main` tained. The vmaterial is next cooled and i discharged from the furnace by any suitable means.

' Any carbon monoxid C0 which may be liberated Vfrom the charge, will be forced forward by the nitrogen, as well as sucked forward by the pump, and therefore it will -not reach the nit-rid in suiiicient pro or- 4.tions to cause any damage.

The suc g forward of this carbon monoxid necessarily lessens its partial pressure, aud therefore hastens the reaction. And, since the whole pressure in .the furnace ma be as A10WA :as 500 mm. it also necessari y results that Y the real partial' pressure of the carbon an advantage to maintain as low-a pressure.

and tem erature inside the furnace as will bringl a out the desired reaction, because any silica or other impurities that may be present will not be fused and therefore, the

walls of the furnace will not be gummed upl as would be the case with higher temperatures. n

It will 'be observed that my product A12CNa contains six parts= ofrfixed nitrogen by weight to two parts of aluminum, whereas if I. allowed the formation-ofalliminum were' nitrid, AlzNg, to take place, only two parts of fixed nitrogen to two parts of alummum would beobtamed.

The product of this vprocess' forms the subject of my copending application #650,972 of even date herewith.

It is obvious that those skilled in theart may vary the details of my process without departing 'from the spirit thereof, and therefore I do not wish to be limited tol the above disclosun'e except as may be required by the claims. v

What I claim is 1. The process of'producing ling" the formula AliCaN, which consists in heating at a pressure below 500 millimeters of mercury 1n 'the presence 4of nitrogen alumina with suicient' carbon and to a temperature suiiicient to produce said compound, substantiall as described. 2. The process o'fyproducing a nitrid havling the formula-A12C8N8, whlch consists in ,heating alumina in the presenceof nitrogen A. at pressure less than that of the atmosphere with suiiicient carbon and to a temperature requisite vto form said compound, substantially as described.

3. The process of' producing a nitrid which consists in vmixing finely divided a nitrid havv lalumina with carbon, the latter being in excess of that required to produce said nitrid; yand subjecting the mixture under a pressure less than 500 millimeters of mercury in an atmosphere of lnitrogen to the tem erature necessary nitrid, substantially as described.

4. The process of producing a nitrid,

which consists in mixing finely divided alumina with carbon, the latter being in excess of that required to produce said nitrid; and subjecting the mixture in an atmosphere of nitrogenunder a pressure less than that of the atmosphere to the temperature 4necessary to produce lsaid nitrid, substantially as descrlbed. Y

In testimony whereof, I aifix my signature, in presence of two witnesses.

j sL rEAcocK. Witnesses: l T. A. WrrrooN,

Y Gao. Prrrs.

to produce said

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