Improvements in the Treatment of Sulphide of Ammonium Solutions with Carbonic Acid Gas for the Purpose of Obtaining Carbonate of Ammonia and Strong Sulphuretted Hydrogen.
Year: 1887

page_text: Date of Application, 31st Dec., 1887
Complete Left, 8th June, 1888
Complete Accepted, 13th July, 1888
Improvements in the Treatment of Sulphide of Ammonium Solutions
with Carbonic Acid Gas for the Purpose of Obtaining Carbonate
of Ammonia and Strong Sulphuretted Hydrogen.
We, EDWARD WILLIAM PARNELL, and JAMES SIMPSON, of 8 Rumford Place,
Liverpool, in the county of Lancaster, Manufacturing Chemists, do hereby declare the
nature of this invention to be as follows:-
When sulphide of ammonium in solution is subjected to the continuous action of
carbonic acid gas, carbonate of ammonia is formed with evolution of sulphuretted
hydrogen.
If dilute carbonic acid from a lime kiln or from the products of combustion is
employed, the nitrogen, and other inert gases with which it is mixed, dilute the
sulphuretted hydrogen which is evolved rendering it less suitable for conversion into
sulphur or vitriol or other use in the arts. Hence it is generally assumed that in
order to get strong sulphuretted hydrogen it is essential to use only pure or nearly
pure carbonic acid gas.
The object of our invention is to obtain strong sulphuretted hydrogen from
sulphide of ammonium solutions without necessarily incurring the expense of making
strong carbonic acid.
We find that in treating a solution of sulphide of ammonium with dilute carbonié
acid a large proportion of the latter will be absorbed without any considerable evolution
of sulphuretted hydrogen with the inert escaping gas. The amount of this evolution
of sulphuretted hydrogen varies according to the composition of the sulphide of
ammonium solution under treatment and the speed at which the carbonic acid gas
is passed through it.
In carrying our invention into practice we divide the treatment of the sulphide of
ammonium solution with carbonic acid gas into two operations.
In the first operation we treat it with dilute carbonic acid gas and continue the
treatment till an appreciable quantity of sulphureited hydrogen begins to be evolved
mixed with the diluting gases. This operation may be conducted in an open vessel

page_text: but for sanitary reasons we prefer to conduct the escaping gases to an oxide of iron
purifier or through damp sulphide of calcium in order that any trace of sulphuretted
hydrogen may be prevented from escaping into the atmosphere. By an open vessel
we mean a vessel communicating with the atmosphere either directly or through a
scrubber or purifier.
In the second operation we subject the solution which has undergone treatment
in the first operation to the further action either of the same quality of carbonic
acid as was employed in the first operation or of a stronger carbonic acid, if available.
This operation must be conducted in a closed vessel fitted with a pipe communi-
cating with a gas holder or other receptacle for the sulphuretted hydrogen which
is evolved by the action of the carbonic acid.
It is manifest that by means of the preliminary carbonation in the first operation
a considerable proportion of the nitrogen and other inert gases with which the
carbonic acid was diluted is removed, thereby increasing the percentage of sulphuretted
hydrogen in the total volume of gas given off in the final treatment.
This process is available for the treatment of any solution of sulphide of ammonium
for the purpose of obtaining sulphuretted hydrogen and carbonate of ammonia but
it is specially applicable to the manufacture of alkali by the processes patented by us
in Letters Patent No. 381 of the year 1885 and No. 47 of the year 1886 the carbonate
of ammonia being used to decompose common salt, as in the said processes strong
carbonic acid for the final treatment may be obtained in the conversion of the crude
bicarbonate of soda into monocarbonate. This strong acid may be used by itself or
mixed with weaker gases.
Dated this Thirtieth day of December 19:

page_text: Improvements in the Treatment of Sulphide of Ammonium Solutions
with Carbonic Acid Gas for the Purpose of Obtaining Carbonate
of Ammonia and Strong Sulphuretted Hydrogen.
We EDWARD WILLIAM PARNELL, and JAMES SIMPSON, of 8ª Rumford Place
Liverpool, in the county of Lancaster Manufacturing Chemists, 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:-
When sulphide of ammonium in solution, is subjected to the continuous action of
carbonic acid gas-Carbonate of ammonia is formed with evolution of sulphuretted
hydrogen.
If dilute carbonic acid, from a limekiln or from the products of combustion is
employed, the nitrogen and other inert gases with which it is mixed, dilute the
sulphuretted hydrogen which is evolved and render such sulphuretted hydrogen less
Hence
suitable for conversion into sulphur or vitriol or for other uses in the arts.
it is generally assumed, that in order to get strong sulphuretted hydrogen it is essential,
to use only pure or nearly pure carbonic acid gas.
The object of our invention is to obtain, strong sulphuretted hydrogen from sulphide
of ammonium solutions, without necessarily incurring the expense of making strong
carbonic acid.
We find that in treating a solution of sulphide of ammonium with dilute carbonic
acid, a large proportion of the latter will be absorbed without any considerable
evolution of sulphuretted hydrogen with the inert escaping gas. The amount of
this evolution of sulphuretted hydrogen varies according to the composition of the
sulphide of ammonium solution under treatment, and the speed at which the carbonic
acid is passed through it.
In carrying our invention into practice we divide the treatment of the sulphide of
ammonium solution with carbonic acid into two operations.
In the first operation we treat the said sulphide of ammonium with dilute carbonic
acid gas, and continue the treatment till an appreciable quantity of sulphuretted
hydrogen begins to be evolved mixed with the diluting gases. This operation may be
conducted in an open vessel, but for sanitary reasons we prefer to conduct the
escaping gases through an oxide of iron purifier, or through damp sulphide of
calcium, in order that any trace of sulphuretted hydrogen may be prevented from
escaping into the atmosphere. By an open vessel we mean a vessel communicating
with the atmosphere either directly or through a scrubber or purifier.
In the second operation we subject the solution which has undergone treatment in

page_text: the first operation to the further action, either of the same quality of carbonic
acid as was employed in the first operation, or to the action of a stronger carbonic acid
if available. This operation must be conducted in a closed vessel fitted with a pipe
communicating with a gas holder or other receptacle for the sulphuretted hydrogen
which is evolved by the action of the carbonic acid.
It is manifest that by means of the preliminary carbonation in the first operation a
considerable proportion of the nitrogen and other inert gases with which the carbonic
acid was diluted is removed, thereby increasing the percentage of sulphuretted
hydrogen in the total volume of gas given off in the final treatment.
This process is available for the treatment of any solution of sulphide of ammonium
for the purpose of obtaining sulphuretted hydrogen and carbonate of ammonia; but it
is specially applicable to the manufacture of alkali by the processes patented by us in
British Patents Nos. 381 and 478 the carbonate of ammonia being used to decompose
common salt as in the said process, strong carbonic acid, for the final treatment may
be obtained in the conversion of the crude bicarbonate of soda into monocarbonate.
This strong acid may be used by itself, or mixed with weaker gas.
:
In applying this process to the manufacture of alkali by the action of carbonic
acid on sulphide of ammonium and brine, we prefer, as an absorbing apparatus, both
for the preliminary and final carbonation, towers of the design patented by E. Solvay
No. 1525 in which the tower is divided into a series of compartments by diaphragms.
These towers may be employed in different manners.
First. The towers may be employed independently in which case they should be of
a height of about 60 feet, one tower being employed for the preliminary carbonating,
and the liquid transfered from it to a second tower for the final treatment. The
brine and sulphide of ammonium are fed into the top of the first tower, and dilute
carbonic acid gas is forced in at the bottom, until an appreciable quantity of
sulphuretted hydrogen is found to be escaping with the waste gases coming off at the
top. The speed of the gas entering should be so regulated that about one equivalent.
of carbonic acid to one equivalent of alkali shall be absorbed at the base of the tower
by the time an escape of sulphuretted hydrogen takes place with the waste gases.
Should the speed of the gas entering be too great, this point of carbonation will not
have been reached before the escape of sulphuretted hydrogen takes place. On the
other hand should the rate of the admission of the carbonic acid be too slow, more than
one equivalent of carbonic acid to one equivalent of alkali will have been absorbed,
at the base of the tower. In practice however the only objection to this is that the
tower will not have been employed to its full absorbing capacity.
The liquid at the base of the tower is drawn off as required and more brine and
sulphide of ammonium are fed in at the top, and the operation is repeated.
The liquid drawn off is fed into the top of the second tower for final carbonation,
and carbonic acid as strong as can be obtained is forced in at the bottom. The speed
of this gas is regulated so as to obtain sulphuretted hydrogen of a suitable strength
from the top. The liquid when fully carbonated is drawn off at the bottom.
Or the two carbonating operations may be conducted in two series of vessels
smaller than the towers, the vessels of each series communicating with each other,
and the gas passing through each vessel in succession.
7
Or the two carbonating operations may be conducted in one series of vessels
arranged and connected, so that while some of them are open to the atmosphere for
conducting the preliminary carbonation, the others will be closed except as regards
connection with the gasholder for conducting the second or final carbonation. In
this arrangement each of the carbonating vessels may be used for the first or second
carbonation, according to the way in which the gas escaping from it is conducted,
whether to the atmosphere or to the gasholder.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed we declare that what we
claim is.
The above described process for treating sulphide of ammonium in solution with

page_text: carbonic acid gas with production of carbonate of animonia and sulphuretted hydrogen
consisting essentially in two operations following each other namely. First the
treatment with dilute carbonic acid gas in a vessel, or series of vessels, from which the
final escaping gases, with or without washing and purifying, are allowed to escape
into the atmosphere; and Secondly the treatment with dilute or strong carbonic acid
gas in a vessel, or series of vessels, fitted with an outlet for conducting the sulphuretted
hydrogen where required.