AN IMPROVED PROCESS FOR UTILIZING GAS LIQUOR IN THE MANU-. FACTURE OF CARBONATE OF POTASH AND OTHER SALTS AND SULPHURIC ACID, AND IN APPARATUS THEREFOR, WHICH APPARATUS IS ALSO APPLICABLE FOR OTHER LIKE PURPOSES
Year: 1877

page_text: LETTERS PATENT to Roger William Wallace and Carl Friedrich Claus, both
of the Chemical Works, Southall, in the County of Middlesex, for the Invention
of "AN IMPROVED PROCESS FOR UTILIZING GAS LIQUOR IN THE MANU-.
FACTURE OF CARBONATE OF POTASH AND OTHER SALTS AND SULPHURIC ACID,
AND IN APPARATUS THEREFOR, WHICH APPARATUS IS ALSO APPLICABLE FOR
OTHER LIKE PURPOSES."
Sealed the 22nd January 1878, and dated the 25th July 1877.
PROVISIONAL SPECIFICATION left by the said Roger William Wallace and
Carl Friedrich Claus at the Office of the Commissioners of Patents on the 25th
July 1877.
"
ROGER WILLIAM WALLACE and CARL FRIEDRICH CLAUS, both of the Chemical
Works, Southall, in the County of Middlesex. AN IMPROVED PROCESS FOR
UTILIZING GAS LIQUOR IN THE MANUFACTURE OF CARBONATE OF POTASH AND
OTHER SALTS AND SULPHURIC ACID, AND IN APPARATUS THEREFOR, WHICH
APPARATUS IS ALSO APPLICABLE FOR OTHER LIKE PURPOSES."
Our Invention relates to a novel process whereby gas liquor or gas water is
utilized in the manufacture of carbonate of soda, carbonate of potash, and other
salts, also in the manufacture of sulphuric acid, and the said Invention comprises
improvements in the construction of parts of apparatus employed for the above and
similar purposes.
Gas liquor is a mixture partly consisting of ammonia, sulphide of ammonium, and
sulpho-cyanide of ammonium.
In the manufacture of sulphate of ammonia or muriate of ammonia from gas
liquor, it is well known that the gas liquor is pumped or run successively through a
number or series of covered tanks or boilers, or towers filled with coke or other like
vessels, whilst steam or a mixture of steam and ammoniacal vapour (that is to say,
vapour of aminonia, carbonate of ammonia, and sulphide of ammonium) passes
in an opposite direction through the same vessels. In its passage through these
31

page_text: tanks, boilers, or towers, the steam or the mixture of steam and ammoniacal vapour
becomes gradually enriched with ammoniacal compounds, and when sufficiently
charged therewith, and after passing the last tower into which the fresh gas liquor is
caused to flow, the ammoniacal vapours are conducted into a covered tank lined
with lead or made of stone or other suitable material, partly filled with sulphuric
acid or hydrochloric acid. This vessel is called the saturator. In it, and by the
contact with the sulphuric or hydrochloric acid, the ammoniacal vapours are absorbed
and decomposed in such a manner as to form sulphate of ammonia or muriate of
ammonia (which is sold as such), and carbonic acid and sulphide of hydrogen gas is
set free, and escapes through a pipe in the top of said saturator. These gases in the
form or condition in which they are at present obtained are a nuisance to the
manufacturer, and are not utilized in any manner, and the only way to render the
same innocuous is to pass them through fires and to burn the same, or to heat them
by the well-known oxide of iron process.
The main object of our Invention is to so conduct this operation and combine the
manufacture of carbonate of potash and carbonate of soda from the sulphides of
these alkalies with the manufacture of the salts of ammonia, as to obtain valuable
bye-products. This object we accomplish in the following ways, that is to say:
We prepare a solution of sulphide of potassium or sulphide of sodium either by
decomposing the sulphates of these alkalies by means of sulphide of barium or solu-
tions thereof, or by decomposing the sulphates by means of heat with an excess of
carbonaceous matter, as herein-after explained, and dissolving the product in water.
We pass the aforesaid gases, consisting of carbonic acid and sulphide of hydrogen
after they leave the saturator, through the solutions of sulphide of potassium or
sulphide of sodium, either in another set of covered tanks or boilers (similar to those
used in the manufacture of the sulphate of ammonia), or in towers filled in the
triangular pieces of iron or the like, as described in the Specifications of former Letters
Patent, and referred to in the Specification of our Letters Patent, dated 20th January,
No. 272, but this construction forms no part of our present Invention.
By the action of the carbonic acid contained in the mixture of gases the sulphide
of potassium or the sulphide of sodium becomes converted into carbonate of potash
or carbonate of soda, whilst a gas containing nearly pure sulphide of hydrogen
makes its escape instead. The carbonate of potash or carbonate of soda solution we
boil down and calcine into salts ready for the market, and the sulphide of hydrogen
being now rich enough to be utilized we burn it in suitably constructed burners into
sulphurous acid, which may be conducted into lead acid chambers to produce the
sulphuric acid required for the manufacture of sulphate of ammonia; or it may be
conveyed into solutions of sulphide of ammonium obtained in any other suitable
manner. By decomposing this hyposulphite of ammonia by means of acids we obtain
sulphurous acid which may be utilized in the purification of gas from sulphide of
hydrogen.
We prefer, however, to proceed in the following manner, namely, we cause the
ammoniacal vapours after they leave the covered tanks, boilers, or towers, and before
they enter the saturator, to pass through the solutions of sulphide of potassium or
sodium in another set of tanks, boilers, or towers, as described.
The carbonate of ammonia in the said vapours decomposes the sulphides of
potassium or sodium forming carbonate of potash or soda, which remains in the
boilers, tanks, or towers, whilst sulphide of ammonium, which is formed simul-
taneously, and which is volatile, escapes from the hot liquor and passes on to the
saturator to be there decomposed, as above described, into sulphate of ammonia or
muriate of ammonia, and into sulphide of hydrogen. The latter being rich is
utilized, the carbonate of potash or carbonate of soda is boiled down and calcined, as
above described.
A third method of proceeding is to mix the solutions of alkaline sulphides with
the crude gas liquor as it enters the apparatus. By so doing the carbonate of potash
formed will be found in the residual liquors, but in too diluted a form and
contaminated with sulpho-cyanide of potassium. Any ammoniacal compound

page_text: remaining in the liqour may be volatilized in a separate vessel and passed into the
saturator.
In making solutions of sulphide of potassium or sodium we use such solutions
over again several times to dissolve fresh quantities of sulphate of potash or soda
before adding fresh quantities of sulphide of barium, so as to obtain these sulphide
solutions in a more concentrated form.
When preparing sulphide of potassium or sodium by heating the respective
sulphides in the presence of an excess of carbonaceous matter, we use furnaces or
apparatus constructed of materials which are comparatively indestructible, and we
prefer to use for this purpose blocks or bricks made of the mineral called bauxite or
wochenite, or the substance of which it is composed, namely, alumina.
Our improved process is chiefly designed for the economical manufacture of
carbonate of potash, but it may be very advantageously employed for the manufacture
of carbonate of soda or other salts.
The sulphide of hydrogen evolved in the process above described we also utilize
in other ways, for instance, we use the same for the purification of sulphuric acid
from arsenic, and for the precipitation of copper, silver, and lead, from its solutions,
either acid, neutral, or alkaline.
For the purification of acid from arsenic we also use the sulphide of hydrogen as
produced by the ordinary process of inanufacturing sulphate of ammonia.
The free carbonic acid, as produced in the process described, we use also for decom-
posing sulphide of barium, producing carbonate of baryta. And for these purposes
we prefer to use apparatus constructed of the above specified materials.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Roger William Wallace and Carl Friedrich Claus in the Great Seal
Patent Office on the 25th January 1878.
ROGER WILLIAM WALLACE and CARL FRIEDRICH CLAUS, both of the Chemical
Works, Southall, in the County of Middlesex. "AN IMPROVED PROCESS FOR
UTILIZING GAS LIQUOR IN THE MANUFACTURE OF CARBONATE OF POTASH AND
OTHER SALTS AND SULPHURIC ACID, AND IN APPARATUS THEREFOR, WHICH
APPARATUS IS ALSO APPLICABLE FOR OTHER LIKE PURPOSES."
Our Invention relates to a novel process whereby gas liquor or gas water is
utilized in the manufacture of carbonate of soda, carbonate of potash, and other
salts, also in the manufacture of sulphuric acid, and the said Invention comprises
improvements in the construction of parts of apparatus employed for the above and
similar purposes.
Gas liquor partly consists of carbonate of ammonia, sulphide of ammonium, and
sulpho-cyanide of ammonium.
In the manufacture of sulphate of ammonia or muriate of ammonia from gas
liquor it is well known that the gas liquor is pumped or run successively through a
number or series of covered tanks or boilers, or towers filled with coke, whilst steam
or a mixture of steam and ammoniacal vapour (that is to say, vapour of ammonia,
carbonate of ammonia, and sulphide of ammonium) passes in an opposite direction
through the same vessels. In its passage through these tanks, boilers, or towers,
the steam or the mixture of steam and ammoniacal vapour becomes gradually
enriched with ammoniacal compounds, and when sufficiently charged therewith and
after passing the last tank into which the fresh gas liquor is caused to flow, the
ammoniacal vapours are conducted into a covered tank lined with lead or made of
stone or other suitable material, partly filled with sulphuric acid or hydrochloric acid.
This vessel is called the "saturator." In it, and by the contact with the sulphuric
or hydrochloric acid, the ammoniacal vapours are absorbed and decomposed in such
a manner as to form sulphate of ammonia or muriate of ammonia, and carbonic acid,
and sulphide of hydrogen gas is set free and escapes through a pipe in the top of
said saturator. These gases in the form or condition in which they are at present
obtained are a nuisance to the manufacturer, and are not utilized in. any manner,
and the only way to render the same innocuous is to pass them through fire, and to
burn the same or to treat them by the well-known oxide of iron process.
The main object of our Invention is to so conduct the operation, and combine the
manufacture of carbonate of potash and carbonate of soda obtained from the sulphides
of these alkalies with the manufacture of the salts of ammonia, as to obtain valuable
bye-products. This object we accomplish in the following ways, that is to say-We
prepare a solution of sulphide of potassium or sulphide of sodium either by
decomposing the sulphates of these alkalies by means of sulphide of barium or
solutions thereof, or by decomposing the sulphates by means of heat with an excess
of carbonaceous matter, as herein-after explained, and dissolving the product in water.
We pass the aforesaid gases, consisting of carbonic acid and sulphide of hydrogen,
after they leave the saturator through the solutions of sulphide of potassium or
sulphide of sodium, either in another set of covered tanks or boilers (similar to those
used in the manufacture of the sulphate of ammonia), or in towers filled with
triangular pieces of iron or the like, as described in the Specifications of former
Letters Patents, and referred to in the Specification of our Letters Patent dated
20th January 1877, No. 272, but this construction forms no part of our present
Invention.
By the action of the carbonic acid contained in the mixture of gases the sulphide
of potassium or the sulphide of sodium becomes converted into carbonate of potash
or carbonate of soda, whilst a gas containing nearly pure sulphide of hydrogen is

page_text: thus produced. The carbonate of potash or carbonate of soda solution we boil down
and calcine into salts ready for the market, and the sulphide of hydrogen being now
sufficiently pure (that is to say, free from carbonic acid) to be utilized we burn it in
suitably constructed burners into sulphurous acid, which may be conducted into lead
acid chambers to produce the sulphuric acid required for the manufacture of sulphate
of ammonia, or the sulphurous acid may be conveyed into solutions of sulphide of
ammonium obtained in any other suitable manner, whereby hyposulphite of
ammonia is produced. By decomposing this hyposulphite of ammonia by means of
acids we obtain sulphurous acid, which may be utilized in the purification of gas
from sulphide of hydrogen.
We prefer, however, to proceed in the following manner, namely, we cause the
ammoniacal vapours after they leave the covered tanks, boilers, or towers, and before
they enter the saturator, to pass through the solutions of sulphide of potassium or
sodium into another set of tanks, boilers, or towers, as described.
The carbonate of ammonia in the said vapours decomposes the sulphides of
potassium or sodium, forming carbonate of potash or soda which remains in the
boilers, tanks, or towers, whilst sulphide of ammonium, which is formed simultaneously
and which is volatile, escapes from the hot liquor, and passes, on to the saturator to
be there decomposed, as above described, into sulphate of ammonia or muriate of
ammonia, and into sulphide of hydrogen. The latter being rich is utilized. The
carbonates of soda or potash are boiled down and calcined, as above described.
A third method of proceeding is to mix the solutions of alkaline sulphides with
the crude gas liquor as it enters the apparatus. By so doing the carbonate of potash
formed will be found in the residual liquors, but in too diluted a form and contaminated
with sulpho-cyanide of potassium. Any ammoniacal compound remaining in the
liquor may be volatilized in a separate vessel and passed into the saturator.
In making solutions of sulphide of potassium or sodium we use such solution over
again several times, to dissolve fresh quantities of sulphate of potash or soda before
adding fresh quantities of sulphide of barium, so as to obtain these sulphide solutions
in a more concentrated form.
When preparing sulphide of potassium or sodium by heating the respective
sulphates in the presence of an excess of carbonaceous matter, we use furnaces or
apparatus, constructed of materials which are comparatively indestructible, and we
prefer to use for this purpose blocks or bricks made of the mineral called bauxite, or
the substance of which it is chiefly composed namely, alumina.
The sulphide of hydrogen evolved in the process above described we also utilize
in other ways; for instance, we use the same for the purification of sulphuric acid from
arsenic, and for the precipitation of copper, silver, and lead, from its solutions, either
acid, neutral, or alkaline.
For the purification of acid from arsenic we also use the sulphide of hydrogen
as produced by the ordinary process of manufacturing sulphate of ammonia.
The free carbonic acid, as produced in the ordinary process of manufacturing
sulphate of ammonia, we use also for decomposing sulphide of barium, thus pro-
ducing carbonate of baryta; or after having taken the sulphide of hydrogen away by
any convenient process, we use the carbonic acid for the manufacture of carbonate
of soda and potash by the ammonia process.
Having thus fully described the said Invention, and the manner of performing the
same, we wish it understood that we claim,-
First. The manufacture of carbonate of potash, carbonate of soda, and other salts,
from the sulphides of the above-named alkalies by either of the processes herein
specified.
Second. The production of pure or nearly pure sulphuretted hydrogen for the
uanufacture of sulphuric acid and for other purposes, as above set forth.
Third. The utilization of the carbonic acid in gas liquor, as above described, and
for the purposes set forth.
Fourth. The use of the sulphide of hydrogen evolved in the manufacture of
sulphate of ammonia for the purification of acids from arsenic.

page_text: Fifth. The employment of the material known as bauxite in the construction of
the above-described furnaces or apparatus, for the purpose specified.
In witness whereof, I, the said Roger William Wallace, for myself and on
behalf of the said Carl Friedrich Claus, have hereunto set my hand and seal,
this Twenty-fourth day of January, in the year of our Lord One thousand
eight hundred and seventy-eight.
R. W. WALLACE. (LS.)