US1347518A - Method of making hydrocyanic acid and cyanids - Google Patents
Method of making hydrocyanic acid and cyanids Download PDFInfo
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- US1347518A US1347518A US319702A US31970219A US1347518A US 1347518 A US1347518 A US 1347518A US 319702 A US319702 A US 319702A US 31970219 A US31970219 A US 31970219A US 1347518 A US1347518 A US 1347518A
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- acid
- hydrocyanic acid
- ferrocyanid
- copper
- cyanids
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- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01C—AMMONIA; CYANOGEN; COMPOUNDS THEREOF
- C01C3/00—Cyanogen; Compounds thereof
- C01C3/02—Preparation, separation or purification of hydrogen cyanide
- C01C3/0262—Preparation, separation or purification of hydrogen cyanide from cyanides
- C01C3/0287—Preparation, separation or purification of hydrogen cyanide from cyanides from simple or complex cyanides of other transition metals, e.g. from iron cyanides
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- the present process constitutes in a sense an improvement on the aforesaid method Dewrance' and Yi/williams being based on the discovery that in place of a kcopper salt (eitlierfcuprous or cupric), finely divided metallic copper may be employed, with a number orp advantageous results, as JWill be presently pointed out.
- a 'further object of the process viz. the speeding up of the reaction, Where ac s other than hy- Specificaton of Letters Patent.
- drochloric acid are used to bring about the conversion of ferrocyanid's to hydrocyanic acid and cyanids, is accomplished by the addition ol a small chlorid or other chloi'id. is the maintenance ot' the concentrationo't the convertiii'gr acid within proper limits, such limits being relatively narrow.
- material utilized in the present process Will ordinarily be a sludge, such as ⁇ obtained in the socalled Bueb process (see U. S. Patent No. 625,964, dater. May 30, 18,99) by treating the oven gases betere removing the ammonia therefrom with a solution of iron sulfate, or copperas.
- Bueb process see U. S. Patent No. 625,964, dater. May 30, 18,99
- the present improvements are not limited but may be advantageously used with forrccyanid' compounds derived from various sources.
- the familiar part of the apparatus such as will be employed in the 4production ol' Eueb sludge, comprises, scrubber l in which the gas containing cyanogen compounds and ammonia is treated livitha solution oi a ierrous salt such as ferrous sulfate.
- a pump 2 serves 'to circulate the absorbing liquid through such scrubber, or to transfer the same in whole or part, when absorption hasv proceeded sulicientl y, to u neutralizing tanlr
- the solution is neutralized with an acid, such as sulfuric acid, to precipitate the soluble errocyanid, after which the mixture is elevated by of apunip flto a filter press 5 or equivalent apparatus adapted to separate out su l1 precipitate.
- This special apparatus' comprises, in association with said still 10, a tank 11 containing sulfuric acid and connected to supply the latter to said still as desired; a combined condenser and fractioning column 12 where the steam evolved with the acid from 'said still is condensed and any hydrocyanic acid absorbed by the condensed steam is again .distilled off before the condensed steam .is discharged from the apparatus; and an absorber 13 connected with the upper part of said condenser, a fan 14 ⁇ connectedwith said absorber serving to keep the latter, together with the condenser and still, under a slight vacuum, and thus prevent escape of hydrocyanic acid in case of any ⁇ leak developing.
- he lower end o the fractioning column 12 is connected by a trapped discharge pipe 15, so that the water condensin and collecting in saidcolumn may be ischarged.
- the water discharged from the latter will accordingly be practically free of the acid.
- the base of the still is connected with a which its contents, when the proper stage is reached, may be run into a ⁇ settling tank or preferably through suitable filters 17 as shown, whereby the insolublefcopper cyanid formed, as will presently be more fully explained, is. separated out.
- the residual solution consisting of ferrous sulfate, ammonium sulfate, free sulfuric acid and a slight amount of copper salts, is then ⁇ run through a tank 18 filled with scrap iron on which the copper is deposited as the metal.
- the solution overflowing from tank 18 is collected in a tank 19 and then transferred by pump 20 back to scrubber 1, to be used over again.
- a small amount of ammonium' chlorid, or other chlorid as heretofore indicated, is preferably added.
- a small quantity of metallic copper is then also added to said distilling vessel, such copper being preferably in a finely divided state, and thereupon the contents of the vessel are brought to boiling.
- the ferrocyanid compound is added gradually from tank 8, together with a further measured quantity of acid, to bring about the liberation of the hydro cyanic acid.
- the amount of free acid originally charged into the distilling vessel is maintained substantially constant by thus adding more acid along with the ferrocyanid compound, and by regulating the amount of heat applied and the quantity of water vapor driven off, the concentration ⁇ of such acid in the distilling vessel willv likewise remain substantially -constant.
- the ferrocyanid ⁇ material used contains impurities such as'tar or sulfur these impurities will gradually accumulate in the copper cyanid .residue rendering the copper cyanid less ac- ⁇ not available for re-use directly.
- metallic copper in place of a cpper salt alsovhelps to counteract the action ofatmospheric oxygen or erric compounds in oxidizing cuprous to cupric con pounds. The reaction is thus accelerated, since such cuprous compounds are much more active than the cupric compounds.
- the concentration oi' the acid may be readily maintained within the proper narrow limits, c'. e. high enough so that the reaction will proceed at a good speed, and yet not so high as to cause partial decomposition of the hydrocyanic acid evolved. At the same time I am able to avoid excessively diluting the alkali in which the hydrocyanic acid is absorbed. Finally it will be noted that by adding the errocyanid compound gradually, only a small amount of such compound remains undecomposed at' any time, thus avoiding the effect of long continued boiling, which renders such compound more and more diiicult to decompose into hydrocyanic acid.
- the arrangement of the still, condenser and fractioning column permits the condensed water to flow through the fractioning column, be freed from hydrocyanic acid'and then discharged from the apparatus instead of returning to the still. In this way, the capacity of the still is increased and a more concentrated solutiong of ferrous sulfate and ammonium sulfate obtained.
- i. ln a method of converting ferrocyanids to hydrocyanic acid and cyanids, the steps which consist in placing metallic copper with an acid capable of reacting with such i'errocyanid, gradually adding the ferrocyanid along with a further quantity of such acid approximately suiiicient to react with such ferrocyanid, whereby the amount of free acid present is maintained substantially constant, and distilling off the hydrocyanic acid thereupon set free.
- Steps l which consist in placing metallic copper with an acid capable of reacting with such errocyanid, gradually adding the ferrocya iid along with a further quantity of such aiid; distilling off the hydrocyanic acid thereupon set free, and subsequently recovering the copper from the solution.
- steps which consist in placing metallic cop- 1 per With a suitable acid, gradually adding the ferrocyanid along with a further quantity of such acid, distilling oi the ⁇ hydrocyanc L.acid thereupon set free, separating out the insoluble copper cyanid in such bsolution, and then recovering the copperin metallic form from the copper compounds remaining in such solution and utilizing both such copper cyanid and metallic copper over again in such distilling step.
Description
Y tilled with a dilute mineral acid, onl
NITED STATES PATENT OFFICE.
MAX E. MUELLER, 0F YOUNGSTOWN, CHIC).
METHOD 0F MAKING HYDROCYANIC ACID ANI) CYAN IDS.
Application filed August 25, 1'5'19.
useful improvement in Methods of Making llydrocyanic Acid and Cyanids, of which the following is a specification, the principle of the invention being. herein eX- plained and the best mode in which I have contemplated applying that principle, so as to distinguish it `from other inventions.
lt has been recognized that to obtain cyanid from ferrocyanid .in the Wet Way by distilling such ferrocyanid with an acid, and absorbing the evolved hydrocyanic acid in' a caustic alkaline. solution, involves unexpected and peculiar dilliculties. Une of these (see H. E. TWilliams U3/mogen 00mpo'zwwis, p. 272, et seg.) is the dificulty that r/henanallali metal ierrocyanid is disy lifty per cent. of the total cyanogen is evolved as 'hydr-ocyanic acid, the remainder being precipitated, as the insoluble ferrous potassio {or'sodic7 etc.)V errocyanid. llloreover,` in sonia methods oextracting cyanids from gases the cyanogen is combined in a .conipound similar to the insoluble double ferrocyanid, from which only traces of hydro# oyanic acidare evolved by distillation with mineral acid. For the purpose ot' overcoming these diiiiculties, Feld Worked out a process which consisted in addingv roerv curio chlorid to the 'lerrocyanid whereby, un er proper conditions, the whole of the c: logen content or" such iferrocyanid is converte into mercurio cyanid, from which the cyanogen may be recovered as hydrocyanic acid by distilling it with a suitable acid. Subsequently it was discovered by Dewi-ance and llilliains {see British Patent No. 28,- 074/08) that a small or ou'irio in conjunction with a suitable acid etlected the same result.
The present process constitutes in a sense an improvement on the aforesaid method Dewrance' and Yi/williams being based on the discovery that in place of a kcopper salt (eitlierfcuprous or cupric), finely divided metallic copper may be employed, with a number orp advantageous results, as JWill be presently pointed out. A 'further object of the process, viz. the speeding up of the reaction, Where ac s other than hy- Specificaton of Letters Patent.
proportion of cuprous Patented July 27, 1920. Serial No. 319,702.
drochloric acid are used to bring about the conversion of ferrocyanid's to hydrocyanic acid and cyanids, is accomplished by the addition ol a small chlorid or other chloi'id. is the maintenance ot' the concentrationo't the convertiii'gr acid within proper limits, such limits being relatively narrow.
To the accomplishment of thel foregoing and related ends, the invention, then, con- A sists of the steps hereinafter fully described and particularly pointed out in the claims, the annexed drawingand the following description setting forth in detail certain means and one Inode of carrying out the invention, such disclosed means and niode illustrating, however, but one of various Ways in which the principle of the invention may be used.
ln said annexed drawings* rlie single figure there appearing'is a diagrammatic representation of an apparains designed for carrying out my presentiinprcred process.
Where employed in conjunction, with a coke byproducts recover plant, material utilized in the present process Will ordinarily be a sludge, such as `obtained in the socalled Bueb process (see U. S. Patent No. 625,964, dater. May 30, 18,99) by treating the oven gases betere removing the ammonia therefrom with a solution of iron sulfate, or copperas. lt Will be understood, however, that the present improvements are not limited but may be advantageously used with forrccyanid' compounds derived from various sources. p
Referring to the aforesaid drmving, the familiar part of the apparatus, such as will be employed in the 4production ol' Eueb sludge, comprises, scrubber l in which the gas containing cyanogen compounds and ammonia is treated livitha solution oi a ierrous salt such as ferrous sulfate. A pump 2 serves 'to circulate the absorbing liquid through such scrubber, or to transfer the same in whole or part, when absorption hasv proceeded sulicientl y, to u neutralizing tanlr Here the solution is neutralized with an acid, such as sulfuric acid, to precipitate the soluble errocyanid, after which the mixture is elevated by of apunip flto a filter press 5 or equivalent apparatus adapted to separate out su l1 precipitate. The filtrate,
amount of ammonium A further object to use with this particular material,
quired into a suitable distilling vessel 10,
the latter marking the beginning of the apparatus of special interest in connectionl with the process in hand.
This special apparatus' comprises, in association with said still 10, a tank 11 containing sulfuric acid and connected to supply the latter to said still as desired; a combined condenser and fractioning column 12 where the steam evolved with the acid from 'said still is condensed and any hydrocyanic acid absorbed by the condensed steam is again .distilled off before the condensed steam .is discharged from the apparatus; and an absorber 13 connected with the upper part of said condenser, a fan 14`connectedwith said absorber serving to keep the latter, together with the condenser and still, under a slight vacuum, and thus prevent escape of hydrocyanic acid in case of any` leak developing.
he lower end o the fractioning column 12 is connected by a trapped discharge pipe 15, so that the water condensin and collecting in saidcolumn may be ischarged. Provision is also made for injecting, steam into the base ofA said `column as by a-valvecontrol pipe 15a in order to drive up into the upper condenser part thereof such hydrocyanic acid as is carried by such water l f discharge pipe 16, by means of as it passes down the column. The water discharged from the latter will accordingly be practically free of the acid.
The base of the still is connected with a which its contents, when the proper stage is reached, may be run into a` settling tank or preferably through suitable filters 17 as shown, whereby the insolublefcopper cyanid formed, as will presently be more fully explained, is. separated out. The residual solution, consisting of ferrous sulfate, ammonium sulfate, free sulfuric acid and a slight amount of copper salts, is then` run through a tank 18 filled with scrap iron on which the copper is deposited as the metal.
The solution overflowing from tank 18 is collected in a tank 19 and then transferred by pump 20 back to scrubber 1, to be used over again.
The general operation of the a paratus just described in exemplification o my improved process may now be set'forth as Jneed not be described in detail.
follows, viz. The distilling vessel 10 is charged with sulfuric (or hydrochloric),
acid of the proper strength from tank 11.
In case sulfuric acid is used, a small amount of ammonium' chlorid, or other chlorid as heretofore indicated, is preferably added. A small quantity of metallic copper is then also added to said distilling vessel, such copper being preferably in a finely divided state, and thereupon the contents of the vessel are brought to boiling. When this stage is reached, the ferrocyanid compound is added gradually from tank 8, together with a further measured quantity of acid, to bring about the liberation of the hydro cyanic acid. vIn other Words, the amount of free acid originally charged into the distilling vessel is maintained substantially constant by thus adding more acid along with the ferrocyanid compound, and by regulating the amount of heat applied and the quantity of water vapor driven off, the concentration` of such acid in the distilling vessel willv likewise remain substantially -constant. i
The manner in which the hydrocyanic acid that is freed by the reaction in the still is collected and separated, has been sufficiently indicated in connection with the description of the apparatus. T hel solution in the still-will of course become gradually more and more concentrated with iron sulfate or chlorid, depending Qn which acid is used, and will have to beremoved from such vessel after a time. As this condition is approached, no more acid is added with the ferrocyanid compound, the addition of the latter, however, being continued as fast as 'it is decomposed and hydrocyanic acid given off. In this way most ofthe acid originally charged into the distilling vessel is utilized, so that the final solution in such vessel contains very little free acid. No attempt is made to distil off the hydrocyanic acid 'completely as after the ferrocyanid compound has been decomposed with the formation ofcuprous cyanid the evolution of hydrocyanic acid becomes extremely slow unless a further supply of ferrocyanid compound is added. The reaction is carried only so far until no ferrocyanid compounds remain undecomposed at which time considerable .cyanogen will still remain coins bined as cuprous cyanid. Under these conditions the insoluble material remaining in the still which is essentially cuprous cyanid is easily separated from the solution by settling or filtration whereas any undecomposed ferroc anid compounds remain, the material sett es very slowly and is diiiicult to filter. Y
Instead of recovering the copper in solution'in the tank 18 by introducing metallic iron, it may be recovered electrolytically, as,
his metallic copper, as well as the copper cyanid from the filters 17, is returned to the still for subsequent operation of the latter. 1f the ferrocyanid `material used contains impurities such as'tar or sulfur these impurities will gradually accumulate in the copper cyanid .residue rendering the copper cyanid less ac- `not available for re-use directly. The employment of metallic copper in place of a cpper salt alsovhelps to counteract the action ofatmospheric oxygen or erric compounds in oxidizing cuprous to cupric con pounds. The reaction is thus accelerated, since such cuprous compounds are much more active than the cupric compounds.
Due to the manner in which the distillation is conducted by adding, along with the errocyanid compound, the proper quantity of acid for conversion of same, the concentration oi' the acid may be readily maintained Within the proper narrow limits, c'. e. high enough so that the reaction will proceed at a good speed, and yet not so high as to cause partial decomposition of the hydrocyanic acid evolved. At the same time I am able to avoid excessively diluting the alkali in which the hydrocyanic acid is absorbed. Finally it will be noted that by adding the errocyanid compound gradually, only a small amount of such compound remains undecomposed at' any time, thus avoiding the effect of long continued boiling, which renders such compound more and more diiicult to decompose into hydrocyanic acid.
Finally, the arrangement of the still, condenser and fractioning column permits the condensed water to flow through the fractioning column, be freed from hydrocyanic acid'and then discharged from the apparatus instead of returning to the still. In this way, the capacity of the still is increased and a more concentrated solutiong of ferrous sulfate and ammonium sulfate obtained.
Other modes of applying the principle of my invention may be employed instead of the one explained, change being made as regai-ds the method herein disclosed, provided the step or -steps stated by any of vthe following claims or the equivalent of such stated step or steps be employed.
I therefore particularly -point out and distinctly claim as my invention f 1. The method of converting errocyanids to hydrocyanic acid and cyanids, which consists in treating the ferrocyanid with metallic copper in conjunction with an acid capable of reacting with such ferrocyanid and distilling oit the hydrocyanic acid thereupon set free.
2. The method of converting ferrocyanids tohydrocyanic acid and cyanids, whichconsists in treating the ferrocyanid with iinely divided metallic copper in conjunction. with an acid capable of reacting with such ferrocyanid and distilling oiln the hydrocyanic acid thereupon set free.
3. In a method of converting errocyanids to hydrocyanic acid and cya-nids, the steps which consist in placing metallic copper with an acid capable of reacting with such errocyanid, gradually adding the ferrocyanid along with a further quantity ot such acid, and distilling off the hydrocyanic acid thereupon set free.
i. ln a method of converting ferrocyanids to hydrocyanic acid and cyanids, the steps which consist in placing metallic copper with an acid capable of reacting with such i'errocyanid, gradually adding the ferrocyanid along with a further quantity of such acid approximately suiiicient to react with such ferrocyanid, whereby the amount of free acid present is maintained substantially constant, and distilling off the hydrocyanic acid thereupon set free.
5. In a method of converting ferrocyanids to hydrocyanic' acid and cyanids, the steps which consist in placing finely divided metallic copper with a quantity of sulfuric acid admixed with a small amount of ammonium chlorid, gradually adding tiie iterrocyanid along with a further quantity of such acid,
and distillingv oli' the hydrocyanic acid thereupon set free.
6. In a method of converting ferrocyanids to hydrocyanic acid and cyanidsa the steps which consist in placing finely dijvidcd metallic copper with a quantity of sulfuric acid admixed with a small amount of ammonium chlorid, gradually adding the ferrocyanid along with a further quantity of such acid approximately suiicient to react with such ferrocyanid, whereby the amount of free acid present is maintained substantially con. stant, and distilling oii' thehydrocyanic a'cid thereupon set free.
7. 1n a method of converting ferrocyanids to hydrocyanic acid and cyanids, the steps which consist in placing metallic copper with an acid capable of reacting with such ferrocyanid, gradually adding the ferrocyanid along with a further quantity of such acid approximately sufficient to react with such ferrocygid, whereby the amount of reacting acid p .sent is maintained substantially constant, and distilling olf the hydrocyanic acid set free, the addition of such further quantity of reacting acid being discontinued when the solution becomes concentrated With the iron salt of such acid.
8. In a method of converting ferrocyanids to hydrocyanic acid and cyanids, the Steps l which consist in placing metallic copper with an acid capable of reacting with such errocyanid, gradually adding the ferrocya iid along with a further quantity of such aiid; distilling off the hydrocyanic acid thereupon set free, and subsequently recovering the copper from the solution.
9. In a method oficonverting ferrocyanids to hydrocyanic acid and cyanids, the steps which consist in placing metallic copper with an acid capable of reacting With such ferrocyanid, gradually adding the ferroeyanid along with a further quantity of such acid, distilling off the hydrocyanic acid thereupon set free, separating out the insoluble copper cyanid in such solution, and then recovering the copper in metallic form from the copper compounds remaining in such solution.
l0. In a method of converting errocyap nids to hydrocyanic acid and cyanids, the
such acid, distilling od'the hydrocyanic acid thereupon set free, and subsequently recovn ering the copper from the solution, and
utilizing the same over again in such dis-V tilling step.
11. In a method of converting ferrocyanids to hydrocyanic acid andyanids, the
steps which consist in placing metallic cop- 1 per With a suitable acid, gradually adding the ferrocyanid along with a further quantity of such acid, distilling oi the` hydrocyanc L.acid thereupon set free, separating out the insoluble copper cyanid in such bsolution, and then recovering the copperin metallic form from the copper compounds remaining in such solution and utilizing both such copper cyanid and metallic copper over again in such distilling step.
' Signed by me this 20th day of August, 1919. Y i
MAX E. MUELLER.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US319702A US1347518A (en) | 1919-08-25 | 1919-08-25 | Method of making hydrocyanic acid and cyanids |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US319702A US1347518A (en) | 1919-08-25 | 1919-08-25 | Method of making hydrocyanic acid and cyanids |
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| Publication Number | Publication Date |
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| US1347518A true US1347518A (en) | 1920-07-27 |
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| Application Number | Title | Priority Date | Filing Date |
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| US319702A Expired - Lifetime US1347518A (en) | 1919-08-25 | 1919-08-25 | Method of making hydrocyanic acid and cyanids |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2462638A (en) * | 1945-02-15 | 1949-02-22 | Du Pont | Corrosion inhibiting process |
| WO1997045369A1 (en) * | 1996-05-30 | 1997-12-04 | E.I. Du Pont De Nemours And Company | An improved process for preparing anhydrous hcn |
-
1919
- 1919-08-25 US US319702A patent/US1347518A/en not_active Expired - Lifetime
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2462638A (en) * | 1945-02-15 | 1949-02-22 | Du Pont | Corrosion inhibiting process |
| WO1997045369A1 (en) * | 1996-05-30 | 1997-12-04 | E.I. Du Pont De Nemours And Company | An improved process for preparing anhydrous hcn |
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