US1496467A - Apparatus and method for the thermochemical treatment of materials - Google Patents

Description

June 3 1924. 1,496,467

C. B. JACOBS APPARATUS AND METHOD FOR THE THERMOCHEMICAL TREATMENT OFMATERIALS Original Filed June 28, 1919 3 Sheets- Sheet 1 A INVENTOR APPARATUS AND METHOD FOR THETHERMOCHEMICAL TREATMENT OF MATERIALS 3 Sheets-Sheet 3 Ofiginal Filed June 28 1919 C. 5. Jacos Jame 3 9 192% 3,496,437

C. B. JACOS APPARATUS AND METHOD FOR THE THERMOCHEMICAL TREATMENT OF MATERIALS Original Filed June 28, 1919 3 Sheetg-Sheet 3 WW Z2 2M INVENTOR ATTORNEY Patented June 3, 1924.

entree stares 1,496,467 PATENT 'oFFIcE.

CHARLES E. JACOBS, OF WILMINGTON, DELAWARE; ASSIGNOR TO E. I. DU FONT DE NEMOURS & COMPANY, OF WARE.

WILMINGTON, DELAWARE, A CORPORATION OF DELA- APPARATUS AND METHOD FOR THE THERMOCHEMICAL TREATMENT OF MATERIALS.

Application filed To all 10h am it may concern.

Be it known that I, CHARLES B. Jaooes, a citizen of the United States, and a resident of Wilmington, in the county of New Castle and State of Delaware, have invented a certain new and useful Apparatus and Method for the Thermochemical Treatment of Materials, of which the following is a spec1- fication.

This invention relates to apparatus for use in the performance of thermochemical operations, and has for an object the provision of apparatus by the use of which such operations can be carried out in an efficient, economical and commercially practicable manner. It also relates to a method of performing certain thermochemical operations, preferably while making use of such apparatus, and has for another object the providing of such a method.

To the ends set forth and also to improve generally upon apparatus and methods of the character indicated, my invention consists in the following matters hereinafter described and claimed.

In general, in chemical processes involving thermochemical reactions, it is desirable to carry out the operations in a continuous manner. In many instances, however, the nature of the materials used and the conditions necessary for successfully carrying out the reactions involved, do not lend themselves to the conditions necessary for continuous operation. It is in the treatment of such materials that apparatus and methods,

involving the present invention find their most direct application.

Without restricting my invention thereto, I describe it by reference to the apparatus illustrated in the accompanying drawings, with reference to the production of alkalimetal cyanides. In order to more plainly bring out the advantages of apparatus and of methods embodying my invention, I shall first briefly discuss the production of alkalimetal cyanides and the difficulties to be encountered and overcome In practically all of the processes extant for the formation of alkali-metal cyanides, in which free or elemental nitrogen in a pure state, or free or elemental nitrogen in nitrogen-bearing gases, is caused to combine directly with compounds of the alkali metals and carbon to form alkali-metal cyanides,

June 28, 1919, Serial No. 307,456. Renewed November 12, 1923.

the chemical reaction involved is expressed empirically by the following equation:

Alkali-metal cyanides are formed according to the above equation when intimate mixtures of an alkali-metal carbonate and carbon are subjected to the action of free or elemental nitrogen at temperatures ranging from below 900 C. to above 1000 C., and morereadily when the mixtures of alkalimetal carbonate and carbon treated, contain certain catalyzing substances which aid in the fixation of the nitrogen as alkali-metal cyanides.

In the formation of alkali-metal cyanides, irrespective of the exact composition of the charge or of the temperature required to bring about the reaction, it is desirable to carry out the operation in as nearly a continuous manner as practicable and with this object in view, many efforts have been made to design and construct furnaces for the continuous production of alkali-metal cyanides. But substantially all of these efforts have failed to produce a furnace which gave satisfactory results under the conditions necessary for operation on a commercial basis.

The more important conditions favorable to, and the precautions necessary for, the eflicient production of alkali-metal cyanides from free or elemental nitrogen, carbon, and compounds of the alkali-metals may be stated as follows:

Intimate contact is required between more than the theoretical amount of nitrogen and the other elements of the reacting mass, so constituted physically that a large surface of the other reactive elements is exposed to contact with the nitrogen. This condition is usually met by maintaining thecharge in a porous condition in order that the nitrogen shall not only have free access to all parts of the reactive mass and become fixed but also in order that the excess of nitrogen may sweep out and expel the carbon monoxide given off by the reaction and thus effect a high concentration of the nitrogen in contact with the other active elements throughout all parts of the charge.

The charge at the temperature required for the cyanide reaction is in a more or less plastic condition and any movement or agitation such as would be caused by pressure necessary for the movement of the charge through a stationary retort or furnace or the agitation caused by rotating the retort or furnace tends to compact the charge, destroys its porosity and causes the nitrogen to form channels and flow along these paths of least resistance with consequent failure to come into intimate contact with all parts of the reacting mass.

The nitrogen supp y should preferably be preheated to the temperature required for the reaction before being admitted to the charge, in order not to check or slow up the reaction by cooling the contact points of the nitrogen and the other elements of the re-' acting mass below the temperatures at which the reaction takes In operating with producer gas as .the source of nitrogen, certain additional precautions are necessary. Carbon dioxide destroys cyanide rapidly even at high temperatures, and the producer gas used must contain the minimum quantity of carbon dioxide. The cyanide charge cannot be allowed to cool off in producer gas, since the equilibrium while giving almost pure CO above 900 (3., lower temperatures yields a mixture which is largely CO Now, the above conditions are most easily maintained in operating what is technically known as a batch process, e., a process in which the charge is placed in a retort or furnace and kept stationary and undisturbed until the reaction is complete, cooled, removed and the operations repeated). For by this method of procedure the charge can be maintained in a porous condition and an intimate and uniform contact of nitrogen maintained; the nitrogen supply can be readily preheated to the reacting temperature before it is introduced into the charge; and, if producer gas is the source of nitrogen, the charge may be cooled in the absence of producer gas by simply shutting off the supply during the cooling period.

But,- in the batch process as ordinarily carried out a long period is required to cool the finished charges, which entails a multiplicity of furnaces or retorts to insure sufficient plant capacity, and also entails a verylarge. expenditure of fuel in order to reheat the cooled furnaces or retorts to the reacting temperatures. Hence it is desirable to operate the cyanide process in as nearly a continuous manner as practicable.

Unfortunately, however, the character of the charge and the temperature required for the reaction are not favorable to continuous operations in which any movement of the charge takes place. In the continuous types of shaft furnaces or retorts', vertical or inclined, in which the charge is fed in place most energetically.-

at the top and discharged at the bottom, the pressure necessary for the movement of the charge tends'to compact it with the attendant disadvantages pointed out above, unless the charge contains such 'a small proportion of alkali-metal compounds as to make the yield of cyanide obtained commercially unprofitable. In the rotary types of continuous furnaces-the agitation ofthe charge by rotation has the same disadvantageous effects.

A further disadvantage type of furnace for cyanide production is the fact that it is difiicult to use producer gas as the source of nitrogen, since the carbon monoxide in the producer gas coming in contact with the cooled parts of the charge as it is fed towards the outlet of the furnace is converted into carbon dioxide to such an extent as to destroy a large part of the cyanide already formed. Unless the furnace is divided into heat zones and the producer gas only allowed to come into contact with the charge in the zone in which the temperature is above 900 C. pure nitrogen must be used for the reaction. Now the apparatus and method of the present invention provide for the retention, in the production of alkali-metal cyanides, of the desirable conditions of the batch method, and permit of substantially the same output and fuel consumption as if the charges were fed continuously through the furnace or retort.

Briefly stated, the method involving my invention preferably includes enclosing the charge in a thin iron envelope, or secondary retort, perforated at the bottom, which re tort is slipped inside a retort proper which latter remains permanently in a furnace heated to the reacting temperature. The nitrogen is delivered to the charge through a perforated bottom in the envelope. after passing down through the annular chamber formed by the clearance between the inside walls of the permanent retort and the removable envelope. The products of the reaction are expelled from the charge through an opening in the top of theenvelope. As to the apparatus e In the accompanying drawings Figure 1 is a horizontal section, substantially on line B-B of Figure 2, of a furnace having a plurality ofretorts incorporated therein in accordance with my invention;

Figure 2 is a vg'rtical section taken substantially on the line A-A of Figure 1;

Figure 3 is a vertical. diametrical section of an outer retort member:

Figure 4 is a vertical, diametr'ical section of an inner envelope member;

Figure 5 is a vertical, diametrical section of an inner envelope member and a retort member assembled;

Figure 6 is a vertical, diametrical section, substantially at right angles to that of Fig.

of the continuous 5. of a retort member and an inner envelope member assembled. together with the clamp for holding the two members in fluid tight relation, and

Figure 7 is a top plan view of the asselpbled apparatus.

(In Figures 3 to 6 the retort and envelope are broken out to econoinize space, while indicating .that the parts are of considerable length as compared to their diameters.)

Referring now to the drawings A retort member 1, of any suitable size, and constructed desirably of such metal as will resist oxidation by the furnace gases, or, say, of wrought iron protected by a fire clay jacket, is adapted to be received, pref erably permanently, in the furnace F. head 2 (desirably of cast steel) is carried at the upper end of the retort and presents opposite passages 3 and 4, the passage 3 serving as an inlet and the passage 4 serving as an outlet. As shown, the passage 4 opens through the upper surface of the head, for connection with a cooperating pascage 5 provided by the head of the inner envelope member, now to be described.

The envelope, or secondary retort, 6 is preferably of thin wrought iron. It is the immediate receptacle for the batch and is designed to be slipped inside the primary retort 1. This envelope is designed to be filled with the batch, introduced into the retort 1, and, at the conclusion of the treatment, removed, together with the contained batch. It will be seen that the apparatus thus provides for the treatment of the charges in such a way as to retain the advantages of the batch method, while, at the same time, the advantages of continuous feedinglarge output and small fuel consumption-are obtained. For, an envelope with i a new batch can be introduced to the retort 1 immediately upon the withdrawal of an envelope containing a finished batch. Also, the retort proper 1 is kept constantly at operating temperature, thus avoiding the deterioration due to alternate expansion and contraction to which it would be subjected if removed from the furnace to cool, with its contents, to room temperature. Also, the expenditure of the heat necessary to raise the heavy retort from room temperature to reacting temperature is now avoided and confined to the heatnecessary to raise the light sheet iron envelope 6 to operating temperatures.-

The envelope 6 is of somewhat less diameter than the retort 1, thereby to provide an annular passage, or chamber, 7 and, as shown, is provided with perforations 8, in its bottom 6 and with series of perforations 8 extending any desired distance above the bottom. As shown the bottom 6 is detachably connected with the side wall of the envelope, by the bolts 6*. A head or top A when the envelope is 9, preferably of cast steel, is' carried at the upper end of the envelope 6 and is horizontally extended to be carried bythe head 2 of the retort.1, thereby to supp rt and suspend the envelope 6 within the retort 1. The head 9 presents a chamber 10 in communication with the envelope 6 proper. The before referred to passage 5 connects the chamber 10 and the outlet passage 4 in the head 2. As shown, the inlet passage annular passage 7. It will be noted that the chamber 10 is of restricted cross-sectional dnnensions, compared to the envelope 6 proper, thus the chamber serves to protect the entrance to passage 5 from clogging being filled from the bottom.

With this arrangement, in operation, nitrogen is introduced through the passage 3 and follows the path indicated by the arrows (Figs. 5 and 6). The excess nitrogen and the carbon monoxide pass off through the passage 4, and desirably the passage 4 is connected to a gas main leading to a gas holder, since in commercial operation the escaping gas is valuable for fuel on account of the carbon monoxide it contains. Desirably this escaping gas may be used in heating' the furnaces.

In order that the envelope 6 may be closed from air leaks into the charge, when the envelope and the charge are removed from the furnace, a valve 11 is provided in the passage 4, of any suitable form. As here shown, it is merely of the rotary plug type.

It will be seen that, with the parts assembled as described, the nitrogen in its passage down from the top of the heated annular chamber 7 formed between the inside walls of the retort and the envelope containing the charge, becomes preheated to the reacting temperature by the time it reaches the entrance to the charge in the bottom of the envelope, thus aiding in supplying heat to the charge from the heat transmitted throughout the charge by the hot nitrogen, the charge being heated internally and externally instead ofonly externally as in the ordinary batch method. Also, the reaction will not be checked by the introduction of cold nitrogen to the hot charge as is the case to a certain extent in the ordinary batch method of operation.

A chamber element 12, conveniently in the character of a tube closed at the lower end, suspended from the head 9, and lying in the passage 13, permits the insertion of the thermocouple of a pyrometer. A

The detailed construction of the apparatus may be of any convenient or desired character. In the illustrated s'tructurez-The head 2 is connected to a flange 14, unitary with the retort 1, by stud bolts 15. In a similar way the head 9 is connected by 3 in the head 2 communicates with the if desired).

stud bolts 16 to a flange 17 unitary with the envelope 6, such flange 17 having a passage 5' to register with, and form an extension of, the passage 5. The head 9 comprises a separate portion 18, bolted to the body of the head by bolts 19, and exteriorly threaded 1 to carry a collar 20. This collar presents upstanding ears 21, 21,- having holes 22, 22, provided for receiving a bar for lifting the envelope from the retort member 1, say by means of a travelling crane (not shown). Also, the collar 20 presents a peripheral groove 23. Trunnions 24, 24, are slidably mounted in the groove 23 and serve as a mounting for a locking member, or clamp, designated generally as 25 (Fig. 7).

This member comprises sides 26, 26, mounted on the trunnions and carrying, pivoted between their down-turned ends, latch members 27, 27. These latches are adapted to catch beneath the shoulder 28 of the head 2. The latches and the upper surface of the head 9 are cooperatively bevelled as indicated at 9 and 27, 27. The collar 20 is split and may be tightened upon the threads of the member 18, as by bolts 29.

With the above described arrangement, after the envelope 6 has been placed in the retort 1, the latches 27, 27, are brought beneath the shoulder 28, and the collar 20 screwed upward on the member 18, say by a handle bar inserted in the holes 22, 22. This forces the heads 2 and 9 into gas tight relation (suitable packing 30 may be used The desired relation obtained, the collar 20 may be clamped in position by bolts 29 to lock the parts in position. Upon moving the collar 20 downward, the bevels 9, 9, and 27 27 cooperate to throw the latches 27, 27 free of the shoulder 28.

Desirably, the head 9 may be provided with passages 31 and 32 for cleaning, or other desired purpose, and closed by plugs 33 and 34, when not in use.

It will be seen that I have provided an apparatus in which charges may be treated with the advantages of the batch method, and which provides for a speed substantially equal to, and a fuel consumption substantially no greater than, thoseobtained by a continuous process, without the attendant disadvantages of a continuous process.

The retort, envelope, etc., may be of any suitable dimensions, having in view a sufficient length of the retort 1, envelo e 6 and the chamber 7 to furnish the desire amount of preheating of the nitrogen, and so forth.

In carrying out the processes for the production of sodium cyanide in the above arrangement of apparatus. the method pursued in practice is desirably as follows: The permanent retorts 1, placed in the furnace F (Figures 1 and 2), are heated to between 950 C. and 1000 C. and the inner envelopes 6 each previously filled with a charge, consisting of, for example: of sodium carbonate 40% of carbon 15% of oxide of iron of sodium chloride are placed inside the permanent retorts 1, and the heads properly clamped together as shown in Figures 6 and 7. When a charge has reached the proper temperature, nitrogen, either pure or in the form of producer gas, is introduced through the inlet 3, preferably under a pressure of about two atmospheres absolute. The nitrogen passing down through the annular chamber 7 as indicated by the arrows, enters the charge through the perforations 8 and 8 at the bottom of the envelope at a temperature equal to, or slightly greater than, the temperature of the charge, where it reacts with the elements of the charge, forming sodium cyanide. The carbon monoxide given off in the reaction, and the excess of nitrogen, pass on up through the charge, the excess of nitro n sweeping the CO with it and expelling it through the outlet of the inner envelope at 5, valve 11 being open.

When the reaction is complete the supply of nitrogen is shut off, the outlet valve 11 closed, and the clamp, 25, loosened and the inner envelope 6 and its contents lifted out of the retort proper 1. Then, another envelope, immediately and without loss of heat from the retort 1, and containing a fresh charge, is put in place by means of a travelling crane or overhead hoist, not shown in the drawing, and the operation repeated. The hot envelope 6 containing the finished charge is dropped into a cooling can not shown, but, struction to the retort 1, except that it is made of thin sheet iron, and water is flowed over it to hasten the cooling of the charge. The envelope with its cooled charge is removed to the extraction plant and the charge extracted for the production of cyanide or hydrolyzed for the production of ammonia as the case may be.

It will be understood that I may depart widely from the exact arrangement of the apparatus and the details of manipulation without departing from the spirit of the invention.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

1. In an apparatus for the thermochemical treatment of materials, in combination,

say, of similar conan outer retort member adapted to be 2. In an apparatus for the thermochemical treatment of materials, in combination, an outer retort member adapted .to be mounted in permanent relation to a heating means, and an inner envelope member removably receivable in said retort member, there being provided a passage for the introduction of fluids t0,-and a passage for the escape of fluids from, said envelope member, said escape passage being located and arranged for the conducting away. and isolation, from the envelope member of fluids issuing from said envelope member.

3. In an apparatus for the thermochemical treatment of materials. in combination, an outer retort. member adapted to be mounted in permanent relation .to a heating means, an inner-envelope member removably receivable in said retort member, there being passage means for the flow of fluid through said envelope member, and means independent of said outer retort member for preventing such flow on occasion whereby said envelope member may be cooled while removed from said retort member without the flow of fluid therethrough.

4. In an apparatus for the thermochemical treatment of materials, in combination, an outer retort member adapted to be mounted in permanent relation to a heating means, an inner envelope member removably receivable in said retort member, there being passages provided for the introduction of fluids to, and escape of fluids from, said envelope member, and a valve in one of said passages to close said passage and prevent entrance of fluids to said envelope through such passages on occasion.

5. In an apparatus for the thermochemical treatment. of materials, in combination. an outer retort member adapted to be mounted in permanent relation to a heating means,

an inner-envelope member removablv reeeivable in said retort member, there being passage means for the flow of fluid through said envelope member with such means including provisions for the conducting away, and isolation, from the envelope member of fluids issuing from the envelope member, and means independent of said outer retort member for preventing such flow on 00-- casion, whereby said envelope member may be cooled while removed from said retort member without the flow of fluid there through.

6. In an apparatus for the thermochemical treatment of materials, in combination, an

outer retort member adapted to be mounted in permanent relation to a heating means, and an inner envelope member removably receivable in said retort member, said members being adapted for vertical arrangement, there being provided a passage for the introduction of fluids into said envelope member adjacent to the bottom thereof, and a passage for the escape of fluids from such member adjacent to the top thereof, said escape passage being located and arranged for the conducting away, and isolation, from the envelope member of fluids issuing from said envelope member. v

7. In-an apparatus for the thermochemical treatment of materials, in combination, an outer retort member adapted to be mounted in permanent relation to a heating means, an inner envelope member removably reeeivable in said retort member, there being passages provided for the introduction of fluids to, and escape of fluids from, said envelope member, and means in'controlling relatlon to one of said passages for closing the same thereby to prevent entrance of fluids to saidenvelope through such passages on occaslon.

8. In an apparatus .for the thermochemical treatment of materials, in combination, an outer retort member-and an inner envelope member received in. said retort member, said envelope member being smaller than said retort member, thereby to provide a fluid chamber between said members, therebeing a fluid inlet passage to said chamer, a fluid outlet passage from said envelope member, anda fluid passage between said two members, said various passages being relatively located to rovide for the passage of fluid into said 0 amber, through a charge contained in said envelope, and out of said envelope.

9. In an apparatus for the thermochemical treatment of materials, in combination, an outer retort member and an inner envelope member received in said retort member, said envelope member being smaller than said retort member, thereby to provide a fluid chamber between said members, there being a fluid inlet passage to said chamber adjacent to one end thereof, a fluid outlet passage from said envelope member ad jacent to the end thereof in proximity to the said mentioned end of said chamber. and a fluid passage between the ends of-said chamber and said envelope member remote from said first mentioned end of said chamber; whereby fluid introduced through said inlet passage shall pass along said chamber and against the wall of said envelope member, into and along said envelope member, and from said envelope member.

10. In an apparatus for the thermochemical treatment of materials, in combination, an outer retort member and an inner envelope member, both tubular in character, the envelope member being of less crossdimensions than said retort member and so adapted to be received therein as to present a chamber between the walls of said members, there being a fluid inlet passage to said chamber, a fluid outlet passage from said envelope and a passage adjacent the end of said envelope remote from said outlet passage and placing said chamber and the interior of said envelope in communication.

11. In an apparatus for the thermochemical treatment of materials, in combination, an outer retort member, an inner retort member, both tubular in character with the envelope member having a smaller crossdimension than said retort member and adapting it to fit within the retort member,

and means for supporting said envelope member within said retort member with the lower end of said envelope member spaced from the adjacent end of said retort, the said end of said envelope member being provided with perforations connecting said chamber and the interior of said envelope, and there being a fluid inlet passage to said chamber and an outlet passage from said envelope. 1

.12. In an apparatus for the thermochemical treatment of materials, in combination, a pair of members the one to be received within the other, to be suspended therein and fastened thereto, and means for suspending and fastening the received member,-

such means comprising structure upon said receiving member presenting a rest surface, a flange upon the received member and located to rest upon said rest surface, and means for forcing together and connecting said rest-surface structure and flange.

13. In an apparatus for the thermochemical treatment of materials, in combination, a pair of members the one to be received within the other, to be suspended therein and'to be fastened thereto, and means for so suspending and fastening said received member, such means comprising a head upon the receiving member and presenting a rest-- surface, a flange upon the received member and locatedto rest upon said rest-surface, a head received upon said flange, and means for forcing saidheads toward each other and into contact with said flange.

,14. In an apparatus for the thermochemical treatment of materials, in combination, an outer retort member adapted to be mounted in permanent relation to a heating means, and an inner envelope member removably receivable in said retort member,

there being passage means for the flow of fluid through said envelope member, and said envelope member being provided with an individual closing top, independent of said outer retort member, whereby said envelope member may be removed from said retort member without the opening of said envelope member.

15. In an apparatus for the thermochemi-- cal treatment of materials, in combination, an outer retort member adapted to be mounted in permanent relation to a heating means, an inner envelope member removably receivable in said retort member and havrestricted rec ss meme? ing an openin and a removable closure therefor, space from the hereafter named top longitudinally of said envelope member, there being passage means for the flow of fluid relative to said envelope member and said envelope member being provided with a top having a recess of a cross section -ma-teria-lly less than that of the envelope member proper, and said assa e means opening into said recess Where y s'aid protects said passage during filling 0 said envelope through said opening.-

16. In an apparatus for the thermochemical treatment of materials, in combination, an outer retort member adapted to be mounted in permanent relation to a heating means, an inner envelope member removably receivable in said retort member and having a removable bottom, there bein passage means for the flow of fluid relative to said envelope member, and said envelope member being provided with a top having a recess of a cross section materially less than that of the envelope member proper, and said passage means opening into said recess whereby said restricted recess protects said passage from the bottom.

17. In an apparatus for the thermochemical treatment of materials, in combination, a pair of members each presenting a head, one of said heads presenting a latch-receiving means and the other a locking-membersupporting means, and means for locking said heads together, thereby to connect said members, such means comprising a locking member carried by said supporting means and having a latch.

18. In an apparatus for the thermochemical treatment of materials, in combination, a pair of members each presenting a head, oneof said heads presenting a latch-receiving means and the other a locking-membersupporting means, and means for locking said heads together, thereby to connect said members, such means comprising a locking member carried by said supporting means and having a latch, and provision for clamping said latch to said latch-receiving means when said locking member is moved in one direction relatively to said supporting means and for automatically freeing said latch when said locking member is moved in another direction relatively to said supportingmeans.

19. In an apparatus for the thermochemical treatment of materials, in combination,

during filling of said envelope an inner member and an outer member, each having a head, one of said members also having a flange to lie between said heads, each said head and said flange presenting each a passage section, said heads and flange and said passage sections being so 10- cated as toprovide a continuous passage, the we meats? passage section of one head communicating with the interior of that head, the passage section of the other head communicating with the exterior of that head, and the passage section of said flange connecting the passage sections of the heads.

20. The method of thermochemically treating a batch of material which comprises making use of an inner-and-outerreceptacle apparatus with the outer receptacle fixed in a heating means, introducing the inner receptacle into the outer receptacle, thermochemically treating the batch while contained in the inner receptacle to bring about chemical reaction in the batch, removing the inner receptacle while hot, together with the batch, and cooling the batch while unassociated with the outer receptacle.

21. The method of thermochemically treating a batch of material which comprises making use of an inner-and-outer-receptacle apparatus with the outer receptacle fixed in a heating means, introducing the inner receptacle into the outer receptacle, thermochemically treating the batch while contained in the inner receptacle to bring about chemical reaction in the batch, removing the inner receptacle while hot, together with the batch and cooling the batch without access of fluid while unassociated with the outer receptacle.

22. The method of treating batches of material which comprises making use of a plurality of inner receptacles and an outer receptacle, with the outer receptacle fixed in a heating means, introducing an inner receptacle into the outer receptacle, treating a first batch while contained in the inner receptacle, removing such inner receptacle while hot, together with the batch, without substantial cooling of the outer receptacle, and introducing a second batch contained in a second inner receptacle, into the said outer receptacle while such receptacle retains the heat acquired in the treatment of the first batch. i

23. The method of thermochemically treating a batch of material which comprises making use of an inner-and-outer-receptacle apparatus with the outer receptaclefixed in a heating means, introducing the inner receptacle into the outer receptacle, treating the batch by heating and addition of reactive material while contained in the inner receptacle to bring about chemical reaction in the batch, removing the inner receptacle while hot, together-with the batch, and cooling the batch While unassociated With the outer receptacle.

24. The method of thermochemically treating a batch of material which com-.

prises making use of an inner-and-outer receptacle apparatus with the outer receptacle fixed in a heating means, introducing the inner receptacle into the outer receptacle, treating the hatch by heating and the addition of reactive material while con tained in the inner receptacle to bring about chemical reaction in the batch, removing the inner receptacle while hot, together with the batch, and cooling the batch without access of fluid while unassociated with the outer receptacle.

25. The method of thermochemically treating batches of material which comprises making use of a plurality of inner receptacles and an outer receptacle, with the outer receptacle fixed in a heating means, introducing an inner receptacle into the outer receptacle, treating a first batch by heating and addition of reactive material while contained in the inner receptacle to bring about chemical reaction in the batch, removing such inner receptacle while hot, together with the batch, without substantial cooling of the outer receptacle, and introducing a second batch, contained in an inner receptacle, into the outer receptacle while such receptacle retains the heat acquired in the treatment of the first batch.

26. The method of thermochemically treating batches; of material which comprises making use of a plurality of inner receptacles and an outer receptacle, with the outer receptacle fixed in a heating means, introducing an inner receptacle into the outer receptacle. thermochemically treating a hatch while contained in the inner receptacle, to bring about chemical reaction 1n the batch, removing such inner receptacle while hot, together with the batch, without substantial cooling of the outer receptacle, and introducing a second batch, contained in an inner receptacle, into the outer receptacle while such receptacle retains the heat acquired in the treatment of the first batch.

27. The method of producing alkali metal cyanides which consists in making use of an inner-and-outer-receptacle apparatus with the outer receptacle fixed in aheating means, placing a batch of a suitable mixture of alkali metal compound and carbon in the inner receptacle, introducing such receptacle into the outer receptacle, subjecting such receptacle to heat and passing nitrogen into the batch, removing the inner receptacle while hot, together with the batch. and cooling the batch while unassociated with the outer receptacle.

In testimony whereof I afiix my signature.

CHARLES B. JACOBS.

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