US1278493A - Production of cyanogen compounds. - Google Patents

Description

PRODUCTION-OF CYANQG'EN GOMEOUNDS.

No Drawing.

-' Production of Cyanogen Compounds, of

which the following is a specification.

My invention relates to that class in which a cyanogen compound is produced through the combination of an initially combined metal of the alkaline group, :With carbon and With nitrogen, which may be initially free, or admixed with other gases and in which the solid materials employed are first finely comminuted and then mixed to gether With or Without a catalytic material, suitable for lowering the temperature for the combination of the active elements, and is directed among other things, toward pro- Xiding such an extended surface of the component materials for instant contact with the nitrogen as to reduce the time required for the completion of the chemical reactions involved, to an inconsiderable period, and to the intermittent removal of the treated material from the reducing chamber while .in a plastic condition and without substantial interruption, of the continuity of the process.

An examination of the art shows that in the production of cyanogen compounds by combining free nitrogen with an initially combined alkali metal and carbon, iron was used as a catalytic agent to reduce the temperature at which the reaction occurred, as far back as in 1835), when a mixture of coke, cinder or coals potassium carbonate, (potash or pearl ash) and iron turnings ground to a coarse powder were employed by Lewis Thompson for the production of potassium cyanid by heating the mixture in the presence of atmospheric air, (English periodical, The Mechanics Magazine No. 822 p. Here by the powdering of the iron an extended catalytic surface was obtained.

The proportions in which the solid materials were used have since been only slightly varied.

This (Thompsons) process consists in igniting a mixture of two parts potash, two parts coke or bituminous coal (steinkohlen) and one partiron turnings in an open vessel Specification of Letters Patent.

iatented ent. 31%, i ilfd.

Application filed June 30, 1917. Serial l lo. 171363.

permitting the access 013 air. Erdmann and Marchand in the Jomnal Pro/ttsobc @hcm-ic vol. 26, page 413.

This formula has since been varied only by increasing the proportion of powdered iron.

Where an iron tube is used as a catalyt c agent as in Siepermann s' process English Patents 13,697 of 1889, 935-0 and 9351 of 1906 the mixture is in the )roportion of one part of sodium carbonate to two parts of charcoal.

In the manufacture of cyanamids and also of cyanide Where the reaction takes place with the alkali compound in a plastic condition, that is below the fusion point of the material, an absorption method is used for fixin the nitrogen in the mass of? material which is placed in a large retort and the nitrogen is introduced therein under slight pressure. T he methods are described as ioL lows:

in the manufacture of cyanamid: The calcium car-bid is reduced to the consistency of flour and thereafter the process deriates into two distinct lines of treatment. At Odda (Norway) the crushed carbid placed in cylimlricai vertical roorts holding 3()0500 kilos. The absorption of nitrogen proceeds for thirty to forty hours, and is known to be complete by reading the controlling: meter. 7 i

"William Barbour, London {1M5} pp. (31%33.

At l esterreg'eln, Pians di'lrta and other Continental works the process of manufacture is quite i'liil'ercnt. Here the powdered carbid is placed in horizontal retorts similar to the retorts used in making coal gas: these are heated externally to 800-1000 C. by being placed in a grasiircd furnace while a stream of nitrogen forced i no the retorts for absorption by the cal-bid" Idea/"2 p.

in Buchers process U. 5%. Patent 1,120.68? he uses the absorption metmad employing a briqueted material, the preparation oi which he describes at length assigning the follow ing reasons for abandoning the use of powdered material: page 3, line 35 and follow ing Flt is hence more advantageous to use the charge in briqucted form to avoid the disadvantages inherent in the use powders since wi h the latter there is a liability to the clogging of the small openings which admit the nitrogen, with the consequent disturbance of the process: while further a sintered charge in the retort may be somewhat difficult to remove.

Upon trial of powdered charges of the' above description, in continuously acting furnaces of the type hereinafter described, the difficulties were found to be much greater than were subsequently encountered when briqueted charges were used: while further with the powder, under mechanical force, including the action of gravity, the heated charge became compact or gradually briqueted so that after cooling it was very diflicult to remove it with an iron chisel and hammer. The advantage of the use of powdered material over a briqueted mass or bulk such as he employs is stated by Bucher (p. 2 line 92) as follows: In the first of my copending applications, it is shown that the cyanid formation takes place very rapidly when the charge used is in form of powder f thus showing that proximity of the particles of carbon to those of iron is not an essential to rapid or complete reaction between the active materials. a,

In all of these absorption methods for fixing the free nitrogen or ammonia gas in combination, the capacity of the furnace is limited by the time required for the nitrogen gas to permeate the mixture.

- At the Westerregeln and other Continental works above cited, the overheating of the walls ensues, and the cyanamid, on cooling, sets to a rocklike mass on the walls of the retorts and has to be forcibly knocked out. Hence the retorts are subjected to a severe wear and tear. I mlustrial Nitrogen Cora wands (owl ]L';c )l0sivcs, page (33.

From this review of the state of the art it is evident that the use of powdered materials in the proportions of tWo parts of carbon to one of the alkali compound and of iron in requisite quantity to exert a catalytic effect. in lowering tem 'ierature, is not novel; up to the present time however the absorption of nitrogen into a bulk of material with its attendant disadvantage of enormous consumption of time for the completion of the process has been and is necessary where the reaction is effected with the materials unfused.

And no practical way of removing the product from the retort when a powdered ,material is fed therein has been discovered.

I will now illustrate my process as applied to the production of sodium cyanid. In this case the mixture will preferably comprise one part of soda ash or sodium carbonate (Na CO,,), three parts of powdered iron and three parts of a carbonaceous substance, such as charcoal or coke, which materialS are first reduced to a fine powder therewith, and I re ulate the and then thoroughly mixed. The soda ash will be found to have coated the particles of iron and carbon, thus presenting an ex tended surface for contact with the nitrogen gas when they are raised to a suitable temperature for con'ibination, while maintained in a diffused mass.

In order to secure contact of the nitrogen with the active materials under'these conditions I prefer to utilize an elongated section of iron pipe, or tube, which is p0si= tioncd vertically and preferably has a height of 50 feet or thereabout and a di ameter or cross-section so limited that the heated material while descending by gravity from the upper part of the tube will substantially all of it engage with and adhere to the inner wall of the tube. When it is desired to increase the tonnage capacity of the tube the cross-section or diameter may be increased and the tube mounted to be variably positioned at, a very slight angle in any direction from the vertical center.

. I deliver a supply of the powdered mixture into such tube at or near its upper end so that it will descend, by gravity, in a diffused mass until it contacts with the inner wall of the tube and adheres thereto. I also deliver a supply of nitrogen, into the tube, at or near its lower end: the nitrogen being preferably preheated to the temperature of combination for the carbon and the sodium content' of the sodium carbonate temperature of the nitrogen supply so that when tliehe'at of combination, generated by the chemical reactions occurring in the heat zone of the tube, is released, the temperature therein shall not be substantially increased thereby. In practice I prefer to maintain a temperature of about 1000 to 1100 0., though the temperature may be varied and yet produce the cyanid in commercial quantities, I also supply heat externally to the furnace as necessary to maintain the required temperature.

As when heated, the sodium carbonate and cyanid product becomes plastic and viscid, I take advantage of their adhesive quality to cause the heated particles of the mixture to contact with the inner wall of the tube in the course of their descent and adhere thereto, as heretofore explained thus accumulating and forming an inner skin or coating thereon. Owing to the enormously extended surface of the active materials exposed for contact, with the nitrogen, when pulverulent materials are used, the reaction is effected as to substantially all of the material before the particles become fixed by adhesion to the wall and is completed as to all thereof in an inconsiderable period thereafter. \Vhen it is desired to remove treated material from the wall and chamber I preferably assure the effective treatment of all of the adhering remove the heated material While in a plasticcondition through a suitable valve at the bottom of the tube thus rendering the commercial treatment of powdered material effective andpractical by continuous proc 055. which is not substantially interrupted by these steps -for the detachment and re moval of material.

I am filin on the same date herewith an appli 'ation 101' U. Letters Patent for an apparatus for producing cyanogen com-- pounds wherein I show a practical. method for the removal. of the plastic material from the inner face of the chamber Wall and for its removal from the chamber While in a plastic condition, but do not confine myself to the method there shown any suitable structure may be used and any suitable me chanical device for handling the plastic material and for its removal from the chamber without substantial interruption of the continuity of the process. Upon removal from the retort the treated material is given such further treatment in any usual manner as required to separate the cyanid content from the other material.

In the practice of my process I retain the.

. of a cyanamid, the catalytic agent and car loon being omitted and a finely comminuted carbid of the alkali'metal being employed. In such case, necessary temperature conditions arc observech the reaction will substantially occur while the .rnaterial is dif fused in the body of the reducing chamber or adhering to the Wall thereof, and the time required for completing: the operation will be reduced to an inconsiderahle period. The material is removed from the Wall and Vil7l1- drawn from the tube at appropriate inter- VttlSWVllilG in a plastic condition, as heretofore described.- {h'ude cyanamid of the same metal may be added as a catalyzing agent.

I do not confine myself to the use of iron as catalytic agent as it is well known that several other elements and substances may he used in. the place'thereof but ll find iron is the most economical for use on a commer- C" 1 l 12m ween? k p l preterablytuse decarnurized iron, it is known that the reaction involved in the producing of a cyanid of an alkali metal in the presence of carhurized iron results in decarhurization and likewise that when clecarhurized iron is used the iron undergoes no perceptible change and may be usec. repetite-ally.

My process may be varied by the use of hriquets such as described in the Bucher process heretofore referred to and, as thus applied, the pulverulent materials mixed in the desired proportions are first briqueted and then continuously delivered to heated zone and permitted to descend gravity therein, but before suea desceutis completed, they are caused to adhere to the inner Wall of the reducing chamber, a continuous supply of nitrogen is delivered into the chamber. a reducing temperature maintained therein. As the time. element is extended ly the necessity for the absorption of the nitrogen by the briquets. the coating on the Wall of the chamber is removed from the Wall and the'furnace, at more extended intervals but is so removed While in a plastic condition, thus obviating the difficulties encountered in the practice of his process.

Having thus specified, shown and. described the same, I claim as novel and my invention v 1. A process for the production. of a cyanogen compound from an initially combined alkali metal, initially free nitrogen and carbon, or a carbonaceous material, in the preseuceof a catalytic agent. which in cludes the pulverizing and mixing of the solidv materials in such pi-rportions as to supply suliicient carbon for combination with the alkali metal present when brought into the presence of free nitrogen and sufficient quantity of a suitable catalytic agent to effectively reduce the temperature for combination of. active participants in the reaction to form a cyanogen compound and in effecting such. reaction by bringing a continuous supply of the mixed material While in a diiiuscd mass into the presence of free nitrogen in a zone heated to the tem perature of combination for the active elen'ients and in causing such diffused mass during its descent in the reducing chamber limiting such zone and in toe presence of such nitrogen supply to adhere to the inner Wall of such chamber and in removing the adhesive mass from the wall and the chambox, at appropriate intervals, While yet in a plastic conditiom substantially as described.

2. A process for the production of a cyanogen compound from an initially combined alkali metal, nitrogen admixed. with.

other gases and carbon, or a carbonaceous material, in the presence of a catalytic agent, which includes the pulverizing and mixing of the solid materials in such proportions as to supply sufficient carbon for combination with the alkali metal present when brought into the presence of such nitrogen and sufiicient quantity of a suitable catalytic agent to effectively reduce the temperature for combination of the active participants in the reaction to form a cyanogen compound and in effecting such reaction by bringing a continuous supply of the mixed material while in a diffused mass into the presence of such nitrogen in a zone heated to the temperature of combination for the active elements and in causing such diffused mass during its descent in the reducing chamber limiting such zone and in the presence of such nitrogen supply to adhere to the inner Wall of such chamber and in removing the adhesive mass from the wall and the chamber, at appropriate intervals, while yet in a plastic condition, after sealing such chamber and showering into a reaction space an inii:

supplying nitrogen thereto under for a short time, substantially as descri 3. The process of producing carbon-nine gen-metal compounds which comprises mixture comprising an alkali metal pound and carbonaceous matter, main ing in said reaction space an atmosphere consisting largely of nitrogen, heating said reaction space to a temperature sufficient to promote a nitrogen fixing reaction among the materials, causing the product of said reaction to adhere to the Walls bounding the reaction space and removing 'tiie accumulations of reaction product from the Walls at intervals.

Signed at New York, in the county of New York and State of New York, this seventh day of December, A. D. 1916.

JOHN DIX MORGAN.

Witnesses:

E. ROBERTS LEWIS, LAURA E. SMITH.