OBTAINING SULPHUR FROM FURNACE CASES
Year: 1885

page_text: We, EMIL HÄNISCH and MAX SCHROEDER of the Village of Neumuhl-Hamborn
near Oberhausen, in the Kingdom of Prussia, Engineers, do hereby declare the
nature of said invention for "OBTAINING SULPHUR FROM FURNACE CASES," and
in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement
72
The direct reduction of the sulphurous acid of furnace gases, or calcination, or
roasting gases, evolved from sulphur pyrites, blende, copper pyrites, galena and
other similar gaseous mixtures, by means of glowing fuel, has been frequently
attempted, but hitherto without any satisfactory result, this bemg due substantially
to the fact that for once heating the gases comparatively poor in SO³, consisting
chiefly of atmospheric nitrogen and oxygen, to the heat required for the reduction
of the SO³, a considerable quantity of fuel has to be expended Further, by
reason of the free oxygen contained in the gases a not inconsiderable portion of
the fuel employed in the reducing process, is uselessly consumed On the other
hand the large quantity of neutral gases have a very prejudicial influence on the
intensity of the reducing process, as also after the reduction on the yield of the
formed tinely divided sulphur Finally the process of reduction by this method
does not proceed with regularity, as whilst one portion of the SO³ molecules are
left completely intact another portion has been subjected to excessive reduction
so as to produce sulphide, consequently the yield in sulphur is very small
Substantially all these drawbacks are avoided by means of the process hereinafter
described for obtaining sulphur from furnace calcination or roasting gases
In this
process the sulphurous acid in the gaseous mixture does not pass direct to reduc-
tion but only after it has been separated from the injurious or neutral components
The separation of the sulphurous acid from the other gases accompanying it is
effected by causing the gaseous mixture to ascend a tower against, and in contact,
with a descending shower of cold water raining down therein The water absorbs,
the sulphurous acid and leaves the other gases (nitrogen, oxygen and carbonio
acid) mostly unabsorbed From the more or less rich watery SO' solutions
obtained in this manner according to the quality of the furnace gases under treat-
ment, the pure sulphurous acid is eliminated, the solutions being heated to boiling
point in a series of closed lead pans by blowing in steam or other suitable means
The water vapour evolved with the gas is separated therefrom in a worm or coil
of pipe
The sulphurous acid thus obtained is now passed on for subjection to the,
reducing process
,
As already indicated the process of reduction in passing the SO³ over or
through glowing fuel does not proceed entirely in accordance with the formula
SO+C=CO + S, but rather a gaseous mixture is obtained which consists
more or less of carbonic acid, carbonic oxide, sulphurous acud, sulphur vapour,,

page_text: carbonous oxysulphide, carburet of sulphur, and under certain circumstances-
when the fuel is gaseous-of sulphuret of bydrogen and water vapour By
employing a longer layer of fuel and effecting a slower passage past the same,
the SO contents would be diminished, but against this, the carburet of sulphur
and the carbonous oxysulphide increase in quantity, on the other hand in the case
of a shorter layer of fuel and quicker through passage, the latter appear in a lesser
degree, but against this also the greater portion of the sulphurous acid remains
unreduced By this means a satisfactory yield of S is never obtained when the
gaseous mixture is passed on to be cooled immediately after its passage past the
fuel, for the reason that a very considerable portion in the form of SO³, or on
the other hand as CS and COS is lost.
According to the experience of the inventors it is necessary in order to obtain a
better result, that the SO³ gases after their passage through a glowing bed of fuel
should remain a further period of time at a glowing heat excluded from any
additional reducing influence This may be effected by conducting the same
through a chamber charged or arranged with glowing fire brick or other suitable
fire proof material Here an alternating action ensues on the one hand of the
still present sulphurous acid, and on the other hand of the carbonic oxide, carburet
of sulphur and carbonous oxysulphide generated under the influence of the fuel,
from which action, when by proper regulation, the said gases are present in the
correct and easily obtained proportion, only carbonic acid and sulphur result By
employing a bed of reducing fuel with a neutral material a similar result may be
obtained,
Further for the purpose of reduction pure carbonic oxide gas or illuminating
In the employ-
gas may be employed instead of the coal, coke, or charcoal fuel
ment of carbonic oxide gas the SO gas is mixed with double its volume of CO,
and this mixture is conducted through a chamber charged or set out with a
neutral material at a glowing heat. Here the process proceeds according to the
formula SO + '00 - 2 CO³ + S The result is the same in the case of
illuminating gas, only then water is present
The necessary quantity of sufficiently pure carbonic oxide gas is obtained, by
the withdrawal of one half of the carbonic acid obtained in this process after
deposition of the sulphur, and conducting it through a pipe charged with
glowing fuel
The portion of the resulting CO* not again used is mixed with
hot air or with the glowing roasting gases from the furnace so that the small
quantities of SO³, CS, COS and S present in the carbonic acid may be carried
collectively over again into SO³, and in common with the furnace calcining or
roasting gases pass off for fresh absorption by water
The means for performing the reducing process is shewn in the accompanying
drawing in which Fig 1 is a half vertical cross section through the line A B, and
a half vertical cross section through the line CD of Fig 2, and Fig 2 is a vertical
longitudinal section taken partly through the line EF and partly through the
line G H of Fig 1.
The sulphurous acid passes through the pipe a into the cylinder b constructed
of fire proof material and charged with coal, coke or charcoal fuel, which cylinder
18 played upon and heated to glowing heat by generator gases coming through the
passage o The sulphurous acid reduced by one half mixed with the formed sulphur
vapours and the correspondingly produced carbonic oxide gases, etcetera, passes
through the connecting pipe d into the cylinder e filled with intact glowing
material such as fire brick The cylinder e is played upon and heated by the
hot gases of the cylinder b which come through the apertures Going through
the glowing mass downwards the second half of the sulphurous acid passes with
sulphur vapour and carbonic acid into the preliminary condensing chamber g and
then into the main condensing chamber h at the end of which the carbonic acid
gases pass out.
The hot gases impinging against the cylinder e descend through the side
away to the chimney through the passage k. The
225
A and
carried

page_text: condensed liquid sulphur collects in the lower parts of the condensing space, from
which it is drawn off through the pipe o or run into moulds or forms
The same apparatus may also be employed for the direct reduction of the SO'
by carbonic oxide gas Here one half of the CO coming from the condensing
chamber through the pipe a enters by the aid of a fan In ascending through the
glowing bed of fuel in b the 1 volume of the CO* is reduced to 2 volumes of
carbonic oxide, and then the latter is mixed with 1 volume of the sulphurous acid
admitted through the pipe The two components of this gaseous mixture then
in passing through the glowing layers of fire proof material in e react upon each
other and yield 1 volume of sulphur vapours to 2 volumes of 00* The sulphurous
gases are condensed in the condensing chamber whilst of the escaping CO³ one half
18 used over again
When illuminating gas is employed for the purpose of reduction, the cylinder
charged with fuel is dispensed with
As in the operation SO' + 2 CO 2 COS, as also in the other aforesaid
operations, a great deal of heat is liberated which here is not diminished by trans-
ference to admixed neutral gases, only a comparatively small addition of heat from
outside sources is necessary for maintaining the fire brick mass at a glowing heat
This addition is supplied by adding to the reducing material out of the container p
by means of Archimedean screw mechanism which is fed throug the pipe q and
passes the additional fuel through the pipe g' into the cylinder b
The pipe 9 18
relieved from any clogging material by means of the stoking iron r
of the ash residuum is accomplished by means of Archimedean screw mechanism
The removal
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, 18
1 Obtaining sulphur from furnace gases of calcination, or roasting, or from
similar gaseous mixtures in the manner that the sulphurous acid contained in
these gases 18 first absorbed in water, then separated from the watery solution
under the form of gas, and then reduced by means of glowing fuel, substantially
as herein before described with reference to the accompanying drawing
2 The process for maintaining at a glowing heat in a suitable chamber or vessel,
the gases containing sulphurous acid after they have been passed through a glowing
bed of fuel, under exclusion of additional reducing media, for the purpose of
obtaining an alternating action or reaction of the sulphurous acid still present
on the one hand, and of the carbonic oxide, carburet of sulphur, and carbonous
oxysulphide on the other hand, substantially as described and illustrated
3 The collecting together of the gases containing sulphurous acid, with carbonic
acid gas, illuminating gas, or other suitable gaseous bodies rich in carbon for the
purpose hereinbefore specified, substantially as described with reference to the
accompanying drawing
4 Obtaining carbonic oxide gas for carrying out the object of claim 3 by means
of the carbonic acid produced in the reduction of the sulphurous acid to sulphur,
in the manner that the carbonic acid is conducted through a bed of glowing fuel
substantially as described