IMPROVED PROCESSES FOR OBTAINING SULPHUR FROM SULPHIDE OF HYDROGEN
Year: 1882

page_text: LETTERS PATENT to Carl Friedrich Claus, of Mark Lane, in the City of London,
Chemist for an Invention of "IMPROVED PROCESSES FOR OBTAINING SULPHUR
FROM SULPHIDE OF HYDROGEN,'
PROVISIONAL SPECIFICATION left by the said Carl Friedrich Claus at tho
Office of the Commissioners of Patents on the 29th July 1882.
CARL FRIEDRICH CLAUS, of Mark Lane, in the City of London, Chemist,
PROVED PROCESSES FOR OBTAINING SULPHUR FROM SULPHIDE OF HYDROGEN
"
"IM-
My invention relates to processes for obtaining sulphur from sulphide of
hydrogen.
Hydrated oxide of iron has been used commonly for the absorption of sulphide
of hydrogen from gases containing the same. The oxide of iron, becomes, at the
ordinary temperature, by the action of the sulphide of hydrogen upon it, converted
into sulphide of iron. Such sulphide of iron, when exposed to atmospheric air and
moisture, becomes reconverted into a mixture of hydrated oxide of iron and free
sulphur, that is to say, it becomes what is termed "revivified." This mixture is
then capable of again absorbing fresh quantities of sulphide of hydrogen, and so on
over and over again until the hydrated oxide of iron is so diluted by the admixture
of sulphur that it becomes comparatively inactive. The sulphur is then driven off*
by heat, in a separate process, and utilized. The residual oxide of iron, having by
this heating process become converted into anhydrous oxide of iron, is no longer
applicable for the absorption of sulphide of hydrogen in the ordinary manner and
has therefore to be replaced by fresh bydrated oxide, generally "bog ore."
Now according to a part of my present invention the said anhydrous oxide of
iron inay be used over and over again for the absorption of sulphide of hydrogen,
by either heating the oxide of iron itself or the gases containing the sulphide of
hydrogen, or by maintaining an elevated temperature in the vessels in which the
operation is carried on.
I also treat "spent oxide" by passing sufficiently heated air, deprived of oxygen,
through the spent oxide to drive off the sulphur, to sublime its sulphur, and to

page_text: collect it in chambers or vessels. The nitrogen of the air may be collected in a gas
holder and used again and again for the same purpose by forcing it, by the pressure
in the gas-holder or compression pumps, through heated pipes or blast heating
plant of other description, and thence into and through the spent oxide, through
the sulphur-condensing chambers, to be again collected in a gas-holder, and so on
continuously.
After the sulphur is driven off by hot air, the sulphide of hydrogen gases are
again admitted into the apparatus containing the oxide of iron, whilst the latter is
still hot.
My invention also has for its object the "revivification" of the oxide of iron
simultaneously with or during the absorption of sulphide of hydrogen. An
anhydrous oxide of iron, such as that obtained in the manner above described, or
"spent pyrites," may be used, or the operations may be commenced with ordinary
bog ore or similar hydrated oxides of iron (natural or artificial). To revivify the
oxide of iron, or to convert the sulphide of iron, almost directly after its formation,
back into oxide of iron and free sulphur, I pass along with the sulphide of hydrogen,
or the mixture of sulphide of hydrogen with other gases, as much atmospheric air
as is found necessary. The air, so admitted or forced into the sulphide of hydrogen,
or mixture of the latter with other gases, I use either hot or cold according to the
quantity of sulphide of hydrogen contained in the mixture, that is to say,
according to the richness of the gas in sulphide of hydrogen, or according to
the initial temperature of the gases. Thus, if sulphide of hydrogen not much
diluted by other gases is passed into anhydrous oxide of iron together with the
requisite quantity of atmospheric air, and the oxide of iron is heated to begin with
to dull red heat or thereabout, the gases as well as the atmospheric air may be
injected or passed into the vessel containing the oxide of iron at the ordinary
temperature of the air; the chemical reaction will afterwards maintain the required
temperature or even increase it, without applying extraneous heat, for an almost
unlimited time, if, however, the sulphide of hydrogen is much diluted, either the
air,. or the sulphide of hydrogen, or both should be admitted in a heated state.
The effect of this process is that the sulphide of hydrogen becomes converted
into free sulphur, which, at the heat produced by the chemical reaction, passes in the
shape of vapor and in a continuous stream away from the oxide of iron and is
sublimed, and in this state 1 collect the same in suitable chambers or vessels for
practical use.
The above described processes are applicable, for instance, to the recovery of
sulphur from sulphide of hydrogen when the latter has been liberated by the action
of hydrochloric, carbonic, or other acid, or by chloridė of magnesium, from alkali
waste, or other sulphides of alkalies, or alkaline earths. They are also applicable to
the production of sulphur from sulphide of hydrogen, when the latter has been
liberated from sulphide of ammonium in gas liquor, either by the action of heat or
by the action of carbonic or other acids upon the same. But they may also be
applied to the recovery of sulphur from sulphide of hydrogen obtained from other
sources.
If the sulphide of hydrogen is sufficiently pure to produce sulphurous acid, for
the manufacture of sulphuric acid, and it is desired to convert the same into sul-
phurous acid, it is only necessary to admit sufficient air into the absorption apparatus
to burn the sulphur passing off therefrom.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Carl Friedrich Claus in the Great Seal Patent Office on the
29th January 1883.
"
CARL FRIEDRICH CLAUS of Mark Lane in the City of London Chemist.
IMPROVED PROCESSES FOR OBTAINING SULPHUR FROM SULPHIDE OF HYDROGEN."
My invention relates to the production or obtaining of sulphur from sulphide of
hydrogen by processes which yield a continuous stream of free sulphur, and in
which the sulphide of hydrogen (or the gases containing the same), together with
atmospheric air, pass into, and through, layers of nonhydrated or anhydrous oxide
of iron, whilst the said oxide of iron is kept in a heated condition.
This process is especially intended for the production of sulphur from sulphide of
hydrogen obtained from crude gas-liquor by the application of heat thereto, as
described in the Specification of Letters Patent N° 1369 of 1868 and mentioned in
the Specification of Letters Patent N° 2838 of 1881, or by the action of carbonic
acid gas, as described in my Provisional Specification of 29th September 1882
No 4644. But the said process is also applicable to the recovery of sulphur from
sulphide of hydrogen produced by the action of acids, or of chloride of magnesium,
upon the sulphides of alkalies or of alkaline earths.
Hydrated oxide of iron has been commonly used for the absorption of sulphide
of hydrogen from gases containing the same, more especially in the purification of
ceal a
gas. Such oxide of iron, after it has become "spent" and the sulphur is driven
from it by heat, is converted into anhydrous oxide of iron, which is no longer
applicable for the absorption of sulphide of hydrogen in the usual manner and has
therefore to be replaced by fresh hydrated oxide of iron.
Now according to a part of my present invention the anhydrous oxide of iron
may be used repeatedly for the absorption of fresh quantities of sulphide of
hydrogen.
I obtain this result by maintaining in the apparatus in which the anhydrous
oxide of iron is exposed to the action of sulphide of hydrogen, a temperature of
not less than 200° or 220° Fahrenheit.
:
A much higher temperature, though it will not prevent the absorption of the
sulphur of sulphide of hydrogen, will not be so favorable to the satisfactory;
working of the process.
When working in the above described manner the oxide of iron is changed into
sulphide of iron, which I revivify in the ordinary manner by exposure to air; the
sulphur is driven from it by the application of heat or the sulphur is burned off
from the sulphide of iron. The residual anhydrous oxide is used over again in the
same manner.
The maintenance of the necessary temperature in the oxide of iron may obviously
be effected in various ways; for instance by the application of extraneous heat to
the vessels containing the oxide of iron, or by heating the sulphide of hydrogen, or
the gases containing the sulphide of hydrogen.
According to another part of my invention I mix with the sulphide of hydrogen
(or mixture of sulphide of hydrogen and other gases) a sufficient quantity of air to
oxidize, and combine with, the hydrogen of the sulphide of hydrogen. In this
manner sufficient heat is produced to keep the oxide of iron at a suitable tem-
perature. The requisite quantity of air is added to the gases containing the
sulphide of hydrogen previous to their entering the oxide of iron.
The air so admitted may be used either hot or cold according to the quantity of
sulphide of bydrogen contained in the mixture of gases, that is to say, according to

page_text: their richness in sulphide of hydrogen, or according to the initial temperature of
the gases. Thus, if sulphide of hydrogen not much diluted by other gases is passed
into anhydrous oxide of iron together with the requisite quantity of atmospheric
air (the oxide of iron at starting being heated to the required temperature, say to
220° Fahrenheit or 300° Fahrenheit or thereabouts), the gases, as well as the
atmospheric air, may be passed, without being heated, into the vessel containing the
oxide of iron; the chemical reaction taking place in the oxide will afterwards,
without extraneous heat, maintain for an almost unlimited time the required
temperature and will even increase it.
If, however, the sulphide of hydrogen is much diluted the necessary temperature
must be maintained by the continuous application of extraneous heat, either to the
oxide of iron, to the gases containing sulphide of hydrogen, or to the air to be
admitted.
The effect of this procedure is that the sulphide of hydrogen becomes converted
into free sulphur, which, at the heat produced by the chemical reaction, passes in
the free state in a continuous stream away from the oxide of iron; and in this state
I collect the same in suitable chambers or vessels.
For carrying my invention into practice I find it advantageous to use an iron
receptacle (lined with bricks) having a perforated false bottom, on which a layer of
oxide of iron is placed. The oxide may be the ordinary material now used in gas-
works, in which case the operation may be commenced and continued without
external heat; or it may be anhydrous oxide, in which case it must be heated to a
temperature of say from 200° to 250° Fahrenheit at starting.
The sulphur which leaves the oxide of iron is carried forward in a finely divided
state and is, as already stated, deposited in suitable chambers.
Having thus fully described my said invention, and the manner of performing
the same, I wish it understood that I Claim:-the above described processes or
operations for obtaining sulphur from sulphide of hydrogen, that is to say :-
First The use of heated anhydrous oxide of iron for the absorption of sulphide
of hydrogen as above described.
Second-The admixture of cold or heated air in regulated quantities with the
sulphide of hydrogen before it is passed through the anhydrous oxide of iron, for
the purpose of obtaining free sulphur in a continuous stream, as above described.
Third: The maintenance of the necessary temperature for causing the anhydrous
oxide of iron to absorb the sulphide of hydrogen by the admixture of air with the
gases and the consequent carrying forward of the sulphur, as above described.
Fourth-The series of operations forming a continuous process or method of
obtaining sulphur from sulphide of hydrogen by means of anhydrous oxide of iron
as above described.
In witness whereof I the said Carl Friedrich Claus have hereunto set my
hand and seal this Twenty ninth day of January in the year of our Lord
One thousand eight hundred and eighty three.
CARL FRIEDRICH CLAUS (L.S.)