Improved Means for Manufacturing and Recovering Cyanides, and Apparatus therefor.
Year: 1896

page_text: Date of Application 21st Sept., 1896
Complete Specification Lift. 18th June, 1897-Accept d. 31st July, 1897
PROVISIONAL SPECIFICATION.
Improved Means for Manufacturing and Recovering Cyanides, and
Apparatus therefor.
We GEORGE PEARCE LEWIS, of 2 Florence Villas, Helvetia Road, Catford in the
County of Kent, Engineer, and RICHARD AUGUSTUS CRIPPS of The Laboratory,
Hayward's Heath in the County of Sussex, Analytical Chemist, do hereby declare the
nature of this invention to be as follows:-
This invention relates to means for recovering cyanides from coal gas in the form of
sulphocyanides, ferrocyanides, or Prussian blue, as may be required.
The apparatus we employ consists of a rectangular vessel divided horizontally into
some four or more water-tight compartments or chambers.
Standing up from the floor of each compartment, is a broad tubular projection,
which forms a vertical passage for the gas to be treated.
Each of these passages is covered by an inverted trough, formed with inverted
lateral trough-like projections having comb-like edges.
These chambers are connected in such a manner that the gas to be treated is made
to bubble through the washing liquor in each chamber in succession.
Each of these chambers also contains a revolving screw, similar in character to that
of a ship's propeller, actuated by suitable gearing, and immersed in the washing
liquid, for the purpose of keeping it in active circulation. Means are also provided
for the inflow and outflow of the washing liquor from chamber to chamber.
Ferrocyanides or sulphocyanides in several forms can be produced, at will, by simply
changing the composition of the washing liquor.
Thus, we can obtain a sulphocyanide of an alkali, or an alkaline earth, by adding
to such alkali, or alkaline earth, preferably in the form of hydrate, some of the liquid
condensed from the "waste gases" evolved from ammoniacal liquor in the manufacture
of sulphate or muriate of ammonia, commonly known as devil liquor, and which
contains much sulphuretted hydrogen in solution, thereby converting the alkali or
alkaline earth into a sulphide.
The "devil liquor" sometimes contains ammonia, but, for the above purpose, it is
preferable that it should be free from it.
Alternatively, the same result may also be achieved by passing sulphuretted hydrogen,
or gases containing it, through the alkali in solution, or through water containing the
alkaline earth in suspension.
Flours of sulphur are then added to the mixture made by either of the methods
hereinbefore described.
The liquor, after being exposed to air for a day, is in a suitable condition for use as
a washing medium for recovering the cyanogen in the gas in the form of a solution of
a sulphocyanide of the alkali or alkaline earth employed.
Sulphocyanides may be produced by the use of a washing agent containing an
alkali in solution, or alkaline earth suspended in water, without such preliminary
treatment, but the effect of the before-mentioned process is to render the mixture
immediately effective for absorbing cyanogen, and more certain in its action.

page_text: A small percentage of oxygen in the coal gas to be treated assists the reactions in
recovering sulphocyanides by method described above.
For the production of ferrocyanides, we employ, as the washing liquor, a solution of
an alkali, such as roda, potash, or ammonia, containing sulphide of iron in suspension.
Thus, supposing we employ potash as the alkali, we obtain a solution of ferro-cyanide
of potassium.
The quantity of iron in suspension should be considerably in excess of the theoretical
quantity to form the salt.
A convenient way of preparing the sulphide of iron is as follows:-Dissolve scrap
iron in sulphuric or hydrochloric acid, and treat the resulting salt in solution with the
"devil liquor" hereinbefore described, or it may be run into a washer, and "waste
gases" also hereinbefore described passed through, producing insoluble sulphide of
iron, which is precipitated by the action of the sulphuretted hydrogen contained in
them..
The resulting solutions of sulphocyanides or ferrocyanides are evaporated and
crystallized in any suitable manner.
We can also produce Prussian blue by employing crude ammoniacal liquor con-
taining sulphide of iron in suspension, as the washing agent, giving a solution
containing ammonium ferrocyanide.
The liquor, after doing duty in the washer, is run into an ammonia still, and
distilled in the usual way by the addition of lime in the still, the effluent from which
contains calcium ferrocyanide by reason of the lime displacing the ammonia from its
combination with the ferrocyanide.
The effluent is run into a tank, and treated with a mixture of ferric and ferrous
salts, which produce an insoluble precipitate of Prussian blue.
Dated this 19th day of September 1896.
NEWTON & SON,
Agents for the Applicants.
COMPLE
Improved Means for Manufacturing and Recovering Cyanides and
Apparatus therefor.
We GEORGE PEARCE LEWIS of 2 Florence Villas, Helvetia Road, Catford, in the
County of Kent, Engineer, and RICHARD AUGUSTUS CRIPPS of The Laboratory,
Hayward's Heath in the County of Sussex, Analytical Chemist, do hereby declare the
nature of this invention and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement:-
This invention relates to means for recovering cyanides from coal gas in the forin
of sulpho-cyanides, ferro-cyanides, or Prussian blue, as may be required.
The apparatus we employ is shewn in the accompanying drawing,-
Fig. 1 being a longitudinal vertical section;
Fig. 2 being a transverse section; and,
Fig. 3 a sectional plan of the apparatus.
In these Figures, a is a rectangular vessel, divided horizontally into some four or
more watertight compartments b. Standing up from the floor of each compartment,
is a broad tubular projection c, which forms a passage for the gas to be treated.
Above each of these passages is a cover d, which extends over the greater part of
the compartment in which it is set, it being supported on brackets carried by the
sides of the compartment. This cover d is intended to receive, and spread through
the washing liquor, the gas under treatment. For this purpose, it is made with a

page_text: main central channel, from which project laterally, on both sides, passages closed
at their ends, and taking the form of inverted troughs, the lower edges of which
are serrated, to facilitate the escape of the gas into the washing liquor in minute
streams, that the gas may arise through the liquor in the form of globules.
The gas to be treated enters by the inlet pipe e, then up through the rectangular
pipe c into the inverted trough d, and from thence is caused to bubble through the
washing liquor, by passing through the serrations, and so on, from chamber to
chamber, in succession, until it finally leaves the apparatus by the outlet pipe f. The
liquor for use in the washer, prepared as hereinafter described, is run in through the
syphon pipe g, and overflows from chamber to chamber by means of the overflow pipes h,
and, when fully saturated with cyanogen, leaves the apparatus by the pipe j.
Each of these chambers also contains a revolving screw propellor k, actuated by
suitable gearing, and immersed in the washing liquid for the purpose of keeping it in
active circulation.
Ferrocyanides or sulphocyanides, in several forms, can be produced at will, by
simply changing the composition of the washing liquors.
Thus, we can obtain a sulphocyanide of an alkali, or an alkaline earth, by adding to
Buch alkali, or alkaline earth, preferably in the form of hydrate, source of the liquid
condensed from the "waste gases" evolved from an ammonia plant, for the manufacture
of sulphate
or muriate of ammonia, commonly known as "devil" liquor, and which
contains much sulphuretted hydrogen in solution, thereby converting the alkali, or
alkaline earth, into a sulphide. This "devil" liquor sometimes contains ammonia,
but, for the above purpose, it is preferable that it should be free from it.
Alternatively, the same result may also be achieved by passing sulphuretted
hydrogen, or gases containing it, through the alkali in solution, or through water
containing the alkaline earth in suspension.
Flowers of sulphur are then added to the mixture made by either of the methods
herein before described.
The liquor, after being exposed to the air for a day or so, should be in a suitable
condition for use as a washing medium for recovering the cyanogen in the gas in the
form of a solution of a sulphocyanide of the alkali or alkaline earth employed.
Sulphocyanides may be produced by the use of a washing agent containing an
alkali in solution, or alkaline earth suspended in water, without such preliminary
treatment, but the effect of the before-mentioned process is to render the mixture
immediately effective for absorbing cyanogen, and more certain in its action. A
small percentage of oxygen in the gas to be treated is necessary for the proper
re-actions to take place in recovering sulpho cyanides by the method described above.
For the production of ferrocyanides, we employ, as the washing liquor, a solution
of an alkali, such as soda, potash, or ammonia, containing sulphide of iron in suspension.
Thus, supposing we employ potash as the alkali, we obtain a solution of ferrocyanide
of potassium.
The quantity of iron in suspension should be considerably in excess of the
theoretical quantity to form the salt.
The sulphide of iron required is produced as follows:--
Dissolve scrap iron in sulphuric or hydrochloric acid, and treat the resulting solution
with the "devil liquor" hereinbefore described, or it may be run into a washer, and
"waste gases" also hereinbefore mentioned passed through, producing insoluble sulphide
of iron, which is precipitated by the action of the sulphuretted hydrogen contained
therein.
The resulting solutions of sulpho cyanides or ferro cyanides are evaporated, and
crystallized in any of the well-known methods.
We can also produce Prussian blue by employing crude ammoniacal liquor
containing sulphide of iron in suspension, as the washing agent, thereby obtaining a
solution containing ammonium ferrocyanide, which may be run through the ordinary
ammonia stills, and treated with lime in the usual way, producing calcium ferro-
cyanide in the effluent liquor.

page_text: The effluent is run into a tank, and treated for the recovery of Prussian Blue, by a
similar method to that described in Patent No. 5184.
Having now particularly described and ascertained the nature of our said Invention
and in what manner the same is to be performed, we declare that what we claim is :-
1. Treating alkaline solutions with "waste gases" containing sulphuretted
hydrogen, thereby producing a sulphide of the alkali for use in washing coal gas, and
recovering the cyanogen as a sulpho cyanide of the alkali, as above set forth.
2. In the recovery of ferrocyanides, producing the sulphide of iron required in a
convenient form for the use in the washer, by treating a solution of an iron salt with
"waste gases," as above described.
3. In the recovery of cyanides, the employment of apparatus constructed as above
described, whereby several forms of cyanide may be recovered from coal gas, as set
forth.
Dated this 18th day of June 1897.
NEWTON & SON,
Agents for the Applicants.