AN IMPROVED PROCESS OF OBTAINING SULPHUR FROM SULPHURETTED HYDROGEN
Year: 1883

page_text: LETTERS PATENT to Carl Friedrich Claus, of Mark Lane, in the City of
London Chemist for an Invention of "AN IMPROVED PROCESS OF OBTAINING
SULPHUR FROM SULPHURETTED HYDROGEN
”
PROVISIONAL SPECIFICATION left by the said Carl Friedrich Claus at the
Office of the Commissioners of Patents on the 25th October 1883.
CARL FRIEDRICH CLAUS, of Mark Lane, in the City of London, Chemist,
"AN IMPROVED PROCESS OF OBTAINING SULPHUR FROM SULPHURETTED HYDROGEN
My invention relates to a process of obtaining sulphur from sulphuretted
bydrogen
In the Specification of a patent granted to me and dated July 29th 1882 (Nº 3608)
for obtaining sulphur from sulphide of hydrogen I have described a process in
which sulphide of hydrogen is passed with a quantity of atmospheric oxygen or
air equivalent to the hydrogen of the sulphide of hydrogen, through layers of
anhydrous oxide of iron whereby free sulphur is produced and the temperature
necessary for the continuance of the reaction is also maintained. This process is
applicable either when the sulphur produced is collected as such, or when it is
burned (by further admission of air) into sulphurous acid.
In carrying this process into effect with rich or pure oxide of iron I have found
that the heat developed by the reaction in some cases exceeds that most favourable
for its good working, and that in consequence, the oxide of iron is liable to form
clinkers or masses of the material fused together. To prevent this result I now
mix with the oxide of iron substances which will surround the particles of oxide
and keep them more apart but which will not interfere with the reaction in the
oxide of iron.
Many substances may be used for this purpose, for instance lime, magnesia,
or their carbonates, sulphates or sulphides, alumina, or silicate of alumina,
baryta or struntia or their carbonates, sulphates or sulphides, or metallic oxides,
such as oxide of chromium or manganese; or I may use finely divided charcoal.
According to another part of my present invention I use in the place of the
oxide of iron named in the said former Specification, other suitable pyrophoric or
contact substance capable of taking the place of oxide of iron or the sulphide of

page_text: iron momentarily formed when oxide of iron is used in the process such as an oxide
or salt in an anhydrous or dry state which may have the property of decomposing
sulphide of hydrogen at an elevated temperature, for example oxide of chromium,
the chromates of the alkalies and alkaline earths, or the chromates of metals, or
the oxides of cobalt, of silver, or of copper, or dry calcined sulphate of copper, the
manganates or permanganates of alkalies, or alkaline earths or metals, carbonate or
oxide of manganese and like materials.
I also use charcoal or platinum sponge or other substance which may have the
property of decomposing sulphide of hydrogen at the temperature which is
produced by passing the same mixed with air, or the quantity of oxygen which is
equivalent to the hydrogen of the sulphide of hydrogen, through layers of these
substances.
My invention consists not so much in the use of any particular one of the above
named substances for the purpose stated, but principally in passing a mixture of
atmospheric air and sulphide of hydrogen through these substances for the purpose
of maintaining the temperature necessary for the coutinuance of the reaction,
which converts the sulphide of hydrogen into free sulphur or (with a further
supply of air) into sulphurous acid.
I use these substances either in their pure state singly, or one or more mixed
together, or one or more mixed with the substances proposed to be mixed with
oxide of iron sucli as lime, magnesia or the like as above described.
The substances to be employed in a dry state for the decomposition of sulphide
of hydrogen should be in as porous a condition as practicable. They are broken
into pieces varying in size from that of walnuts to that of peas; they are placed in
layers of about six to twelve inches in depth on the perforated false bottom of a
closed iron tank lined with brick. Through one hole in the space below the false
bottom the sulphide of hydrogen enters and through another aperture air, in
quantity equivalent to the hydrogen of the sulphide of hydrogen, is admitted. The
temperature of the pyrophoric or contact substances when once raised to the
degree required for the reaction is maintained by the continued admission of air;
free sulphur is formed which escapes through an aperture of the iron box which is
situated above the layer of contact substances. The sulphur is conveyed thence
into suitable chambers and collected. It is obvious that by admitting more air
into the said box sulphurous acid may be produced instead of free sulphur.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
"
by the said Carl Friedrich Claus in the Patent Office on the 25th April 1884.
CARL FRIEDRICH CLAUS, of Mark Lane, in the City of London, Chemist,
"AN IMPROVED PROCESS OF OBTAINING SULPHUR FROM SULPHURETTED HYDROGEN
My invention relates to a process of obtaining sulphur from sulphuretted
hydrogen.
In the specification of former Letters Patent N° 3608 granted to me and dated
July 29 1882. I have described a process in which sulphide of hydrogen is
passed, with a quantity of atmospheric air containing oxygen equivalent to the
hydrogen of the sulphide of hydrogen, through layers of anhydrous oxide of iron,
whereby free sulphur is produced and the temperature necessary for the continuance
of the reaction is maintained.
In carrying this process into effect with rich or pure oxide of iron, I have found
that the heat developed by the reaction, in some cases, exceeds the degree most
favorable for the efficient working of the process, and that, in consequence, the
oxide of iron is liable to form clinkers or fused masses. To prevent this result I,
according to one part of my prosent invention, mix certain other substances with
the oxide of iron.
The substances employed for this purpose must be such as will not interrupt or
suspend the reaction between the oxide of iron, the sulphide of hydrogen and
atmospheric air.
It is obvious that the substances which answor or fulfil these requirements are
very numerous, for instance, Lime, Alumina, Magnesia Baryta, Strontia, oxide of
chromium, oxide of zinc, oxide of manganese, oxide of copper, or their carbonates,
sulphates, silicates, or sulphidos, or like substances. I employ either of these
substances, or a mixture of two or more thereof
The oxide of iron in a finely divided state should be intimately mixed with the
substance or substances thus employed, and the mixture may be moistened with
water to form a stiff pasty mass, which is dried, and, when dry, is reduced to pieces
of a size convenient for use. Minerals in which the oxide of iron exists intimately
mixed with any of the above named substances or others of a similar nature, may
be used without previous preparation.
According to another part of my present invention, I use, in the place of the
oxide of iron named in the said former specification, other suitable pyrophoric or
contact substance capable of taking the place of oxide of iron, that is to say, I use
an oxide or salt (in a dry state) which has the property of decomposing sulphide
of hydrogen at an elevated temperature, for example, oxide of chromium, the
chromates of the alkalies, and alkaline earths, the chromates of metals, or the
oxides of cobalt, of silver or of copper, or dry calcined sulphate of copper, the
manganates or permanganates of alkalies or alkalino earths or metals, or carbonate
or oxide of manganese, and like materials. I also use, instead of an oxide or salt,
finely divided platinum for the same purpose.
My invention consists not so much in the use of any particular one or more of
the above named substances for the purpose stated, but principally in passing a
mixture of atmospheric air and sulphide of hydrogen through such substance or
substances (which, under the described existing conditions, will be pyrophoric) for
the purpose of maintaining the temperature necessary for the continuance of the
reaction which converts the sulphide of hydrogen, by a continuous process, into
free sulphur.

page_text: In carrying out my invention, the materials hereinabove specified may be used
singly or mixed with one another.
The substances to be employed in a dry state for the decomposition of sulphide
of hydrogen should be in as porous a condition as practicable.
If soluble substances, such as sulphate of copper, sulphate of zinc or of iron, or
such as chromates or manganates are employed, then it is best to soak in (or
saturate with) solutions of these salts, fragments of burnt porous clay or pieces of
ganister brick, asbestos, pumice-stone, or similar materials, to dry these and to use
pieces of the same of convenient sizes. They are preferably broken into pieces
varying in size from that of walnuts to that of peas; the said pieces are placed in
layers of about from six to twelve inches in depth on the perforated false-bottom of
a closed iron tank lined with brick.
I have found the size of pieces of broken oxide of iron mixture or other so called
contact substance and the depth of the layers as stated above best suited for gns-
mixtures containing say from 15 to 25 per cent. of sulphide of hydrogen, but, for
richer or poorer gas-mixtures, the depth of layers may be increased or decreased.
For poorer gas, layers of six or more feet thick may be employed, but layers less
than 6 inches thick are not advisable even for the richest gas.
Fine powder should be avoided as the through-passage of the gases is thereby
impeded, and if the pieces are too large, say the size of a man's fist, though they
would not prevent the working of the process, a much larger bulk of the material
would be required, since the larger the surface exposed, the more perfect is the
action. It is most convenient to employ pieces of the size of a walnut even for
deep Inyers.
If more than one contact substance is to be used, or if such substances are mixed
with lime, alumina, magnesia, and like materials, they should be intimately mixed
in a finely divided state, made with water into a paste, the paste dried and broken
into pieces of a size convenient for use. Through one hole in the space below the
false-bottom of the above named iron box, the sulphide of hydrogen enters, and
through another aperture, air in quantity equivalent to the hydrogen of, the
sulphide of hydrogen is admitted. The temperature of the pyrophoric contact
substances, when once raised to the degree required for the reaction, is maintained
by the continued admission of air; free sulphur is formed which escapes through
an aperture of the iron box, which aperture is situated above the layer of contact
substances. The sulphur is conveyed thence into suitable chambers and collected.
The above described process is applicable to the production of sulphur from
sulphide of hydrogen from whatever source such sulphide of hydrogen may have
originated, whether in the manufacture of sulphate of ammonia from gas-iquor, or
in the mere application of heat to gas-liquor as practised in the purification of coal-
gas by ammonia, or in the process of recovering sulphur from alkuli waste by
acting on such waste by carbonic or other acid, or in the decomposition of metallic
or other sulphides by acids. It is possible, by means of the said procoss, to recover
the sulphur from gas-mixtures containing only a small quantity (say from 3 to 5
per cent.) of sulphide of hydrogen.
Having thus fully described my said invention and the manner of performing the
same I wish it understood that I claim :-
First. The above described continuous process whereby sulphur is produced from
sulphide of hydrogen in whatever manner the said sulphide of hydrogen may have
been generated or produced.
Second. In the production of sulphur from sulphide of hydrogen, the passing of
a mixture of air and sulphide of hydrogen in equivalent quantities either (a)
through a layer of oxide of iron which has been mixed with lime, alumina,
magnesia or similarly acting substanco or substances as above described, or (b)
through a layer of oxide of copper, oxide of manganese or other pyrophoric or
contact substance or substances which will decompose sulphide of hydrogen at the
ordinary atmospheric temperature or at an elevated temperature, substantially as
described.

page_text: Third-In the production of sulphur by the decomposition of sulphide of
hydrogen by means of the above named contact substances, the maintenance of
the temperature necessary for the continuance of the reaction by a regulated supply
of air to the sulphide of hydrogen, substantially as described.
In witness whereof I the said Carl Friedrich Claus have hereunto set my hand
and seal this Twenty second day of April in the year of Our Lord One thousand
eight hundred and eighty four.
CARL FRIEDRICH CLAUS. (LS.)