US741396A - Production of nitrogen compounds. - Google Patents

Description

:PATJENTED 001?. 13, 1903.

G; DE GHALMOT.

PRODUCTION OF NITROGEN COMPOUNDS.

APPLICATION TILED JAN. 23.1896.

3 SHEETSSHEET 1.

N0 MODEL.

INVENTOR:

FIG. 2.

(luclmiw (liq By his Al/or'ueys,

No. 741,396. PATENTED OCT. 13, 1903.

G; DE GHALMOT. PRODUCTION OF NITROGEN GOMPOUNDS.

APPLIOATION FILED JAN. 23. 1896.

N0 MODEL. 3 SHEETS-SHEET 2.

I ''FIG. 3.

PATENTED OCT. 13, 1903.

G. DE GHALMOT. PRODUCTION OF NITROGEN COMPOUNDS.

\ APPLIOATION FILED JAN. 23. 1896.

3 SHEETS-SHEET 3.

NO MODEL.

WITNESSES:

By his Alzomeys,

GUILLAUME DE CHALMOT,

TO THE WILLSON LABORATORY CORPORATION OF WEST VIRGINIA.

- Patented October 13, 190s.

PAT NT Fries;

or LEA'KSvILLE, NORTH CAROLINA, ASSIGNOR COMPANY, OF NEW YORK, N. Y., A

- PRODUCTION OF NITROGEN COMPOUNDS.

SPECIFICATION forming part of Letters Patent No. 741,396, dated October 13, 1903.

Application filed January 23, 1896. Serial No. 576,521- (No specimens.)

To all whom, it may concern:

Be it known that 1, GUILLAUME DE CHAL- M01, 2. subject of the Queen of the Netherlands, (having declared my intention of becoming a citizen of the United States,') residing at Leaksville, in the county of Rocking ham and State of North Carolina, have invented certaiu new and useful Improvements in the Production of Nitrogen Compounds,

- IO of which the following is a specification.

This invention relates to the production of nitrids of metals or metalloids in the electric furnace and the production of ammonia from such nitride.

If oxids or salts of metals or metalloids are mixed with carbonaceous matter and heated in the electric furnace while a current of nitrogen is passed through the material, the metals or metalloids take upa considerable 2o amounto" nitrogen, which is bound in the form of nitrids almost wholly, with occasional traces of cyanids. There can thus be Obtained nitrids of calci n, (Oa N of barium, (Ba N Of aluminium, (AlN, and of titanium, (TiN In suchtests'I has a found the nitrids mixed with carbids, oxids, and graphite or other-form of carbon. Definite formulae for the reactions which take place cannot therefore be given. I have founu that in these reactions it is not sufficient to pass the nitrogen Over the mass in the furnace; but it is practically essential that it shall be forced through the mass. In the case of fused material it becomes exceedingly difficult in the electric furnace to effect a passage of the nitrogen through the mass so as to bring about an extensive contact between it and the molten material because of the extreme fluidity of the material at the excessively high temperature attained. One purpose of my invention is to overcome this difficulty. To this end I conduct the reaction with an excess of carbon, whereby the material is rendered very porous, and thus the nitrogen can be forced through the entire porous mass and brought into intimate contact with all the reduced metal. In fact, such a perfection of porosity is-thus attained as to render it feasible to introduce nitrogen on top of the mass in the furnace and cause it to circulate downward through the mass. In order to obtain ammonia. -from these nitrogen compounds, they are treated with steam at red heat. The steam should first be superheated; but if not it will become so by contact with the hot compounds. In the case of barium, calcium, and other basic elements the ammonia is easily obtained in this manner from their nitrids or cyanids. In the case of titanium itis preferable to mix its nitrid with a basic o'xid and then subject the mixture to superheated steam.

The treatment of the nitrids with steam for recovering the ammonia might be efiected at any time by heating the nitrid and then pass ing the superheated steam over or through it.

It is,-however, practically of great advantage to carry out this treatment while the nitrogen compound is still'exposed to the heat of the electric furnace. I

My invention'therefore provides not only that the nitrogen shall be forced through the porous highly-heated mass in the furnace,' but also that superheated steam shall at the same time be forced through the mass in order that the nitrogen which is fixed as a nitrid shall almost immediately afterward be converted into ammonia. This Operation is greatly facilitated by the porosity of the mass in' the furnace, which renders it feasible to institute a downward circulation of the gases through the mass.

My invention further provides forasubstantiallycontinuous treatment in the furnace by feedingit continuallywith fresh material from above and causing the material under action to slowly descend at a rate to insure that the greater part of the material shall be acted upon and reduced by the electrically-generated heat in the furnace, the nitrogen being introduced at the top of the furnace and circulated downward past the electrodes, and the superheated steam being introduced preferably beneath the electrodes, the combined gases being thus circulated downward through the porous mass and drawn 0d at any convenient point beneath, while the entire mass is caused to gradually descend and is finally removedat the bottom of the furnace. I have devised 'anapparatus for carwitha basic" oxid, preferably caustic lime, and also mixed with carbonaceous material,-

preferably coke or' charcoal. The mixture is subjected to theheat of an electric arc, and

nitrogen is forced through the semimolten' material. While still quite hot, steamis forced into the mixture. -The carbids and nitrids which were firstformed' are thus decomposed, and the originaloxids--that is, titanium oxid and caustic li ine.-are again obtained. The nitrogen forms ammonia and the carbon forms carbon monoxid, while hydrogen is at the same time liberated from the decomposition of ,the steam. The lime and titanium oxid can then be mixed anew with carbon and used a second time. As some titanic acid is liable to be carried over with the gases which pass out of the furnace and as this acid is somewhat expensive the gases are conducted through settling-rooms and fines and washing apparatus, where all the titantum oxid'dust can settle. Some of the dust thus recovered is titanium nitrid, which is volatilized in the arc.

Instead of titaniumoxid other oxidsmay be used. Alumina has given me especially favorable results. Instead of lime other bases, like'sodaor potash,would be equally efiective; but these are subject to the objections of being too expensive, too'volatile, and of acting on the bricks of the furnace.

I will now describe the apparatus which I havedevis'ed for carrying out my new process and which I believe is the best adapted to that end.

Figure lot the accompanying drawings is a vertical mid-section .through the electric furnace. Fig. 2 isahorizontal section thereof on the .line 2 2 in Fig. 1. Fig. 3 is a vertical section on the line 3 3 in Fig. 2, showing the dust-separatorand ammonia-absorber. Figs. 4 and 5 are fragmentary sections showing two modified constructions for the lower part of the furnace shown in Fig. 1'. Fig. 6 is a sectional elevation showing a'modified construction. i

7 Referring to Fig. 1, let A indicate an upright shaft, stack, or chimney, which may be made of masonry. In the upper part of this stack is formed a chamber B, constituting the chamber of the electricfurnace/ Into this.

chamberproject electrodes C, consisting of bars, slabs, or pencils of carbon and which are constructed to be relatively movable through openings in oppositesides of the fur nace-wall in order to vary the length of the are or the quantity of material interposed between the pencils and acted upon by the electric current passing between them. Both may be movable or one fixed and the other movable: Above the chamber B is mounted a hopper D, having a con trolling slide or feeddoorEatits'bottom. Thishopperisdesigned to contain the pulverized and mixed material to be fed to the furnace. Beneath the electrodes C O thefurnace-chamber B is preferably contracted 'or formed with a hopper-bottom, as shown at B, and from this portion the chamber extends downward, preferably, as an upright chamber of uniform cross-section. This chamber is designated F. In this chamber F, I have shown in Fig.1 a piston G, mounted .to work freely up or down in the chamber. and supported on a rod 9, which is engaged between rollers g g one of which is preferably formed with cog-teeth to engage corresponding rack-teeth on one side of the rod g, so that by turning the wheels g g the piston may be raised or lowered. A pit g is provided for receiving the rod 9 when the piston is lowered. The lowermost position of the piston is indicated indotted lines at G. Just abovethis position the stack is formed with an opening H, closed-by a suitable door.

A nitrogen pipe I enters the upper part of the furnace -chambe'r B for introducing nitrogen thereinto. In practice I prefer to employ atmospheric nitrogen in the form of what is'known as producer-gas or generatorgas consisting'of a, mixture chiefly of nitrogen and carbon monoxid. I have shown in Fig. 1 a gas-producer J of ordinary construction'and a blower K for forcing air through it, the producer being fed withcoal which is brought to'incandescence and the air then forcedthrough-it in the well-known manner. The producer-gas thus generated is introduced into the chamber B and caused to flow downthrough the mass of material. At any suitable point or points in they lower part of the chamber B or upper part of the chamber F openings or twye'rs a a are provided for introducing superheated steam. Steam is-fed to these openings through pipes S S, Fig. "2, which communicate with passages a in the masonry, from which passages the twyers aa branch. ft

For permitting the escape of the gases from the chamber the furnace is formed on one or both sides with a perforated plate or partition I), from which leads an opening or space 0 in the masonry, and from this extends a pipe d, which leads to the dust-separator L, Fig; 2. I have shown the outlets bed as arrangedon'two opposite sides of the furnace. The plates b b may be made of porcelain or of metal, (ironl) In the formercase they may and in the latter case they must be cooled by the circulation of cold water through them. In Fig. 2 I'haveshownthe left-hand plate I) as made hollowfr this purpose. The right-hand plate (show n in plan) is supposed to be similarly constructed. Both plates are connected at the other side with an outlet water-pipe W. The water-current should be rapid bycircu lating the water under high pressure.

The dust-separator may be variously constructed. The construction shown in Fig. 3 consists of a casing L, into which the gases enter by pipes ddat the top on opposite sides, are thence deflected downward by partitions'e e, and flow thence upward to the inlet of'a pipe f, which carries the gases down out of the separator and delivers them to the gas-washer and ammonia-absorber.

For washing the gas it is caused to pass from the pipe f into a chamber g, which is sealed in water, so that the gas has to pass beneath the water seal and bubble up through,

the water on the opposite side of a partition which separates this chamber from the chamber h. By this means any particles of dust which have not been caused to settle to the bottom of the dust-separator L are washed out or arrested and retained in the water seal beneath the chambers g h.

For separating the ammonia from the gas any suitable kind of ammonia-absorber may. be employed--such, for example, as any construction commonly used in gas-works for separating ammonia from illuminating-gas. I have shown' at M one construction of ammonia-absorber that may be employed. It consists of an upright casing in which is ar ranged an alternating series of inclined shelvesz'i, extending each from one side across part way toward the other. In the construction shown the chamber 7i, already referred to,

constitutes the bottom chamber of this absorber. Cold water is introduced by a pipe j and falls on the upper shelf 2', flowing across this shelf and falling onto the next, flowing over this and falling onto the next below, and

so on, the water thus having a zigzag course down the casingfand finally fallinginto the water seal at the bottom in the chamber h. The gas which bubbles up into the chamber 72 is caused to circulate in an 'upward zigzag path, so that it-flows over the streams of water on the shelves 1 t' and flows through. the successive waterfalls at the lower edges of these shelves, so that the gas continuously comes in contact with. fresher and cooler water, by which the ammonia contained in the.

rated plates b. The titanic oxid or other me tallic oxid, the lime or other base, and the carbon having been pulverized and mixed together are placed in the hopper D. Suificient material is caused to fall fromthis hopper into the chamber 13 to fill the furnace up to and around the electrodes 0 C. The furnace operation can then begin. The electrodes C 0 being connected at the opposite. terminals of an electric circuit fed by a suitable generator or transformer, (either continuous or f air beingsucked into the furnacethat is to say, its pressure is slightly more than that of the atmosphere. The suction-blower N is set in operation, being driven at such speed as to generate just sufficient suction to draw the gas through the mass of pulverulent material inthe furnace and through the dust-separator L and ammonia absorber M. Consequently the gas introducedat I under substautially atmospheric pressure is drawn down through the porous mass by suction.

The action of the electrically-generated heat in the furnace is'to reduce the metallic oxid and the basicloxid, the incandescent reduced materials being'expo'sed to the nitrogen of the producergas, and thereby converted partly into nitrids and partly into carbide.

As fast as this reduction occurs the piston G should be lowered by turning the wheels g 9 and fresh material should be introduced from the hopper D by opening the. slide E.

Any other means for feeding the'm'aterial maybe substituted-for this slide.v In this way a sufficient mass of unreduced material is kept piled above the electrodes,while the nitrids and carbids are continually caused to descend to positions opposite the twyers aa'and outlet-openings b b. As soon as the nitrids,&c.,

have come to the level of the twyers superheated steam should be turned on through the pipes S S and injected through these twyers into the material. This steam decomposes the nitrids, generating ammonia and hydrogen, which, with the residue of the producer-gas, is drawn off through the perforations b-and passed through the dust-separator, where any particles of dust 'or ashes, in-- cluding particles of titanic acid, are caused to settle. The gases th'en pass'down through the pipe f to the water-chamber-g, where they are forced throughwater to takeout any further particles ,of dust. The gases then pass upward through the ammonia-absorber,where the ammoniais taken up by the water. The remaining gas then passes out through the pipe 7c and blower N and beinga combustible gas sustantially devoid of nitrogen it may be conducted to gas-burners or anyap-l paratus in which such gas can be :utilized. Thefurnaceoperation continues as described until the piston G has descended toits lowest position G, whereupon the furnace operation IIC is stopped, and as soon as the mass is suliiciently cooled the door H is opened and the material is drawn out through this door. This material consists of substantially the original mixture of metallic oxid and lime and may :be used again by grinding it and mixing it again with carbon.

which is required chemicallyto eflect'the re-' duction of the metallic oxid the reduced ma terial in the-furnaceis made very porous.

This-is especially important in the use of titanium, since its nitrid has all the properties ofa metal and has a very high fusing-point,

so that it is very desirable to keep its particles apart. The porosity is further promoted by the mixture of "titanium oxidwith lime,

whichafterreduction forms a mixture of ti-' tanic nitrid, calcium carbid, and calcium nitrid. The steam on coming in contact with the calcium carbid and nitrid decomposes these compounds at once, formingcalcium oxid and gases like carbon monoxid, carbon dioxid, hydrogen, ammonia, &c; The drivihg ofi of these gases makes the material still more porous, since .the calcium oxid which is thus reconstituted is not hot enough to run together. The resulting porosity of the material allows the steam to come also into contact with the titanic nitrid, which would not occur if this latter were alone present, since in that case thewater-vaporwould act only on the surface of this nitrid, forming titanic acid, which would withstand the further action of the vapor. It is also probable that the presence of the base (lime) furthers the decomposition of the titanic ni'trid by uniting with a part of the resulting titanic acid;

, The reaction between superheated steam and titanium nitrid is Ti N -l-6H Q=3TiO +etNH The. efiect of adding a base, as soda oriim'e,

' is that it unites with the titanic oxid that is set free by the steam and forms a salt called a titanate', (titanic oxid having acid. properties,) the reaction being as follows, with soda:

ner'shown in Fig. 4 by constituting a screw conveyer P for the piston G, this conveyer acting to continuously or intermittently dig out the material from the bottom of the chamber F, so that the process may be made, in

is suggested in Fig. 5 may beemployedgwhere the mass settles down to the bottom of thechamber F and can be shoveled out through eifect, continuous, or such a construction as v a door Q, its descent being facilitated by polzing through a poke-opening Q.

Fig; 6 shows a'modified construction of furnace wherein a tubular carbon pencil C is used as one electrode and an iron plate 0 forming the bottom of the furnace-chamber and covered with a layer of carbon, constitutes the other electrode, these being connected iln circuit with a dynamo or other generator Din the ordinary manner. Nitrogen orproducer-gas is introduced through a pipe being conducted under control of valves 10 and 11 through a'flexible pipe R to thehol- 'Iand superheated steam through apipe-S', either of these in alternation or bothtogether low in the carbon pencil 0', the gases flowing down through this carbon pencil to the bottom thereof and then ascending through the mass of material in the furnace and passing out through a piped, which leads to any suitable dust-separator and ammonia-absorber.

This apparatus may-he. operated by first circulating nitrogen through the furnace during the maintenance of the are and then discontinuing the arc and circulating superheated steam through the highly-heated mass in the the operations altercarrying out the process... It is within my invention to effect the preliminary heating of the materials by heat otherwisev generatedas, for example, in any ordinary furnace heated by combustion-thus raising the materials to "as high a temperature as is practicable by such means and then subjecting them to the action of an electric arc to further raise the temperature to that necessary to accomplish the conversion of the oxid or u salt into a nitrid, cyanid or carbid..

This process has the advantage of saving a part of the electrically-generated heat, which is' expensive, and substituting for it heat generated fromfuel.

I claim as my invention the following'defined novel features, substantially as hereinbefore specified, namely:

1. The process which consists-in heating the oxid or salt of a metal or metalloid with an" excess of carbonaceous matter in an electric furnace, so as to reduce the, metal or metalloid while forming a porous permeable mass,and passing nitrogen through the heated porous mass at so high a temperature as to form a nitrid rather than a cyan'id of the metal or metalloid. Q

2. The process which consists in heating the oxid or salt of-a metalor metalloid with anexcess of carbonaceous matter in an electric furnace, so'as to reduce the metal whileforming'a porous permeable .mass, simultaneously passing nitrogen through the heated. porous'mass while maintaining so high a tern;- perature as toformfa nitrid rather than a cyanid of the metal or metalloid, and 'subsequently passing superheated steam through the porous; mass to decompose-t the nitrid and form ammonia. 1

.3 -The process which c'onsistsin heating theo'xidior salt of a metal or metalloid with carbonaceous matter in an electric furnace so as to reduce the metal or metalloid, passingnitrogen th ough the heated mass awhile maintainingso igha temperature as to form a nitrid rather than acyanid of the metalor metalloid, and while the massis stillhighly heated passing superheated steam through" it 3 to decompose the nitridand form ammonia. I

4, The process which consists in heating thejoxid' or salt of a metal or metalloid with an added base and, with carbonace'ousimatter in an electric furnace,' so as. to reducethe metal or metalloid and convert the baseinto a earbid, simultaneously passingnitrogen.

throughv the material'while maintaining: so

high a temperature as toform a nitrid rather than a cyanid, and subsequently exposing the material to superheated steam to dQCOUI'. pose the nitrid and form ammonia.

5. The process which consists in heatinga titaniferous compound with an added base I and carbonaceous matter in an electric furnace, so as to reduce the titanium, and passmaintaining so high a temperature as to form a mixture of titanic and basic nitrids (rather than cyanide) or carbids, and subsequently exposing these'to superheated steam to de- I compose the nitrids andform ammonia,-

'.cyanid of the metal. i

9. The processivhich consists in exposing 7. The process which consists in heating a titaniferouscompound with lime and carbonaceons matter in an electric furnae; passing nitrogen through the material in the'furnaceunder so high atemperature asto formgfaii trids, whereby. is formed a mixfiifiiot titanic and calcic nitrids and .galcium carbid, and

subsequently exposing these to superheated steam to decompose the nitridsand form ammonia. I

8. The process which consists in exposing a mixture of .the oxid or salt of a metal or metalloid with. carbonaceous matter to the heat generated by the passage of an electric current between electrodes, whereby the metal is' reduced, causing the mass to dc scend inproportionas the reduction takes I efiect to bring fresh material within the action of the current, and to lower the reduced materiaLb'eyond the electrodes, and passing a current-of nitrogen downwardly through the mass, whereby it is brought into contact with the metal or metalloid, at the instant of its reduction; while maintaining so high a-tem perature as to form a'nitrid rather than a a m-ixture of the oxid or salt of a metal or metalloid with carbonaceous matter v to the heat generated by the passageofan electric current between electrodes, whereby the metal or metalloid is reduced, causing the mass to descend in proportion as the reduc tion takes eflect to bring fresh material withl in the action of the current, and to lower the reduced material beyond the electrodes, passing a current of nitrogen downwardly through the mass, whereby it is brought intoco'ntact with-the metal or metalloid attheinstant'of its reduction while maintaining so,high a temperature as to form a nitrid rather than a cyanid of the metal or metalloid, and simultaneously introducing superheatedsteam into the: mass in contact with the newly-formed nitridto decompose the same and form ammon ia.

In witness whereofI have hereunto signed my name in'the presence of two subscribingw witnesses. I

V GUILLAUME DE- CHALMOT. I Witnesses: I

E. B. KING,

CA VIN SHARP.

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