IMPROVEMENTS IN THE " METHOD OF AND IN APPARATUS FOR EXTRACTING SULPHUR AND SULPHUROUS ACID FROM PYRITES
Year: 1884

page_text: I ARTHUR CHARLES HENDERSON of 47 Museum Street Oxford Street in the
Parish of Bloomsbury and county of Middlesex Civil Engineer and Patent Agent
do hereby declare the nature of the said Invention for "IMPROVEMENTS IN THE
"
METHOD OF AND IN APPARATUS FOR EXTRACTING SULPHUR AND SULPHUROUS
ACID FROM PYRITES a communication to me from abroad by Léon Labois Civil
Engineer of the city of Paris in the Republic of France to be as follows :-
The process herein referred to is the economical manufacture of sulphur from
pyrites and it consists in distilling a portion of the sulphur contained in the
mineral, in a special furnace, in condensing it into flour or stick, and immediately
afterwards making use of the residues still rich in sulphur for manufacturing
sulphurous acid and its derivatives especially sulphuric acid.
The following description of the apparatus shows how the process is carried on,
and how a practical solution of obstacles is met with.
Fig 1 represents a transverse section of an apparatus for distilling, the mineral,
condensing the sulphur vapour, and roasting the residues. Fig 2 is a plan section
through the longitudinal axis of the retort; a distilling furnace is placed above a
roasting furnace of the Malétra type.
Distillation is effected separately from the roasting; and heat should not be
withdrawn from the roaster if the same quantity of acid is to be made with a
sufficient desulphuration of the cinders, as to still leave them of commercial value
in metallurgy, the amount of fuel used for the purpose being relatively insignificant,
so that without reducing the temperature the maximum production of distilled
sulphur is effected.
:
The roasting furnace may be of other types than that indicated, nevertheless
what is here described exhausts the mineral better and supersedes others in novelty
of construction.
The distilling furnace F, contains a horizontal retort a, heated by return of
flame; charging and discharging at b, the vapours escaping through a tube k, which
escape is regulated by a butterfly valve p, governed by a crank m Fig 1. .

page_text: A sheet iron strainer o, either fixed or movable if necessary not to interfere with
working at the furnace connects the discharge with the opening, communicating
with the roasting furnace f.
This strainer or filter c is surmounted by a flap valve c', also of sheet iron with
hinge c³, and sight hole c³. This arrangement is to prevent sulphur vapours and
sulphuric acid from spreading in the work shops whilst discharging.
The opening a, is hermetically closed by a conical valve, or better still by &
valve g, opening inwards by aid of a lever g³ and counter weight worked by hand
and pivoting on the axis g¹.
The counterpoise lever g³ whatever its position is outside the filter, and in reach
of the operative, this arrangement has the advantage of quickening the escape of
the gas into cc, the moment the valve is opened and then closing the aperture
hermetically.
Discharge could be made through an aperture inside the retort but then a filter
or strainer would be required round the furnace, this would lead sulphurous acid
into the condensing chamber, and would diminish the heating surface which is
already restricted.
The following is the modus operandi :-
When distillation is to be effected, the lower furnace being charged the operator
pushes back the valve c¹, by turning the key o*, he then opens the retort a, then
closes the valve and opens the aperture x, by means of the lever g², and stirs
through the opening c³, to cause the residues to fall; having done this he closes the
valve by aid of a lever and removes the filter c, and the valve c¹ which as before
described are movable,
Condensation cannot be conducted in chambers too heavy or large to be placed
on the furnaces: draught should be regulated without interruption and production
should be constant, as it should not be overlooked that distillation by this process
works periodically with the roasting.
The condenser described above and represented Figs 1. 2 and 3 complies with
these requirements. It consists of a case of sheet iron with double sides divided
inside by divisions also double sided in which cold water circulates.
The double side of the case or envelope, or the divisions alone may suffice if the
quantity of vapour to be distilled does not require much cooling. In the case of the
employment of the simple divisions, the envelope may be of wood brick or any
other appropriate material.
The following description and enumeration of its parts will show its construction.
d. refrigerating divisions.
e. refrigerating envelope.
h. conduit by which the refrigerating current is led.
dpipes distributing the current to the divisions.
e pipes for the envelope of the case.
d regulating taps of the refrigerating current.
i joint to pipes to allow of removal of divisions.
d pipes for the escape of the overflow of the divisions.
d exit pipe of the refrigerating current.
k sulphur vapour inlets.
, bolted lid admitting of its removal.
safety valve Fig 3.
n, guides to the divisions.
o. T iron supporting the divisions.
9. aperture for the exit of the sulphur.
Fig 4, is a modification in which the divisions are tubular, and especially
intended for large chambers, although more expensive they are better suited for
the purpose when intended to bear greater pressure.
It will be seen that the case is divided into a certain number of divisions, which
are increased in accordance with the number of distilling furnaces of the condenser.

page_text: The matter to be condensed circulates freely round these divisions as already
mentioned with a sufficient number of divisions the refrigerating envelope can be
dispensed with. Each division may be regulated by pipes and special taps so as to
graduate refrigeration or equalize the temperature.
They may be flat, tubular and of any suitable material, oblique, or horziontal,
fixed or movable so that their number can be increased.
The draught can be regulated by means of the butterfly valve p, and the
condensing temperature can be regulated by the tap dui.
Perfectly dry flour sulphur can thus be made, which can be used in this condition
or run into sticks.
In cases where the building and arrangements of the works will not admit of
placing the distilling furnaces above the roasting furnaces, distillation must be
separately conducted and the residues removed by means of a carriage of special
construction in order to avoid loss of heat as much as possible.
Fig 5 represents a side view of a carriage or barrow of this description. It
consists of a cylindrical vessel m, borne on two wheels h, Its height is such that
the orifice in the lid m³, directly leads to the point of discharge of the retort. It
can be inclined on the axis of the wheels h. This carriage is moved by the
handles k.
The bottom m³ of the vessel or recipient m, is hinged and held firm by a chain i,
which is hooked to a fixed point and is unbooked when the carriage is brought
above the opening x of the roasting furnace, to discharge its contents.
When the barrow or carriage is drawn by ropes the handles are replaced by ears
or some equivalent.
Heating the air for roasting-To effect a proper combustion in the roasting
furnace to desulphurate the cinders in such a manner that they can be sold for
metallurgic purposes, the greatest amount of heat is required.
The pyrites impoverished by distillation naturally reach the roasting furnace less
rich in combustible matter. This is obviated
1st in passing a certain quantity of sulphur to the roasting furnace.
2nd In utilizing the waste heat of distillation and condensation of the gases as
they leave the roasting furnace, or in employing these three sources of heat
combined for heating the air before its introduction into the roasting furnace.
Fig 6 merely represents the process of reheating as an explanation of the principle
of utilizing the waste heat of the gases from a Malétra furnace R, and from the
exit of the distilling furnace. Finally a third arrangement passes air instead of
water into the condenser where it takes up a certain amount of heat and is then
transferred to the reheater. These methods can be used singly or in conjunction.
The reheaters are tubular, lenticular or parallelopiped, connected together by
pipes. The quantity of air introduced is necessarily regulated by the draught of
the roasting furnace.
Description of Fig 6.

page_text: The Malétra furnace has been selected merely as a type which is much used, the
principle of the invention can be applied to all roasting furnaces provided
modifications are made to suit each case.
What is claimed is
1st The exclusive property of the process above described with regard to the
drawings, consisting in heating a charge of pyrites in a special distilling furnace, in
extracting from it a certain quantity of sulphur, in condensing it, and producing
sulphuric acid from the reduced residues.
2nd The apparatus for this purpose.
3rd Arranging the distilling furnaces above the roasting furnace.
4th The fixed or movable strainer with discharging valve.
5th The method of closing the orifice of the roasting furnace.
6th Condensing by the circulation of water, as applied to the extraction of
sulphur from pyrites; and in conjunction with the condenser referred to.
The circulation of vapour round the divisions containing a current of cold water
or refrigerating liquid or gas of some sort, constitutes a novelty which is claimed
for all its applications in refining rough or native sulphur or pyrites.
7. Although less economical, claim is made to the construction of the charging
recipient for taking the residues to the roaster when distillation is conducted
separately.
8. Finally heating the air used in desulphurating by passing it to a reheater of
some sort placed in the smoke box of the furnace, or in the condenser, or at the
exit of the gas from the roasting furnace, or by all these means combined for the
purpose of utilizing the waste heat,
I ARTHUR CHARLES HENDERSON of 47 Museum Street, Oxford Street in the
Parish of Bloomsbury and county of Middlesex, Civil Engineer and Patent Agent
do hereby declare the nature of the said Invention for "IMPROVEMENTS IN THE
METHOD OF, AND IN APPARATUS FOR EXTRACTING SULPHUR AND SULPHUROUS
"
ACID FROM PYRITES a communication to me from abroad by Léon Labois, Civil
Engineer of the city of Paris in the Republic of France and in what manner the
same is to be performed, to be particularly described and ascertained in and by
the following statement:-
The process herein referred to is the economical manufacture of sulphur from pyrites,
and it consists in distilling a portion of the sulphur contained in the mineral, in
a special furnace, in condensing it into flour or stick, and immediately afterwards

page_text: making use of the residues still rich in sulphur for manufacturing sulphurous acid
and its derivatives especially sulphuric acid..
The simple extraction of the quantity of sulphur readily distillable by heat
(14 to 16 per cent of the weight of the mineral) with a loss of the remainder, being
more expensive, cannot favorably compete with native sulphur. To economically
obviate this drawback, works in use for manufacturing sulphuric acid must be
employed for the manufacture of sulphur into a sub product without disturbing
their arrangement; material, or hinder their ordinary production. The following
description of the apparatus shows how the process is carried on, and how a
practical solution of obstacles is met with.
t
Fig 1 represents a transverse section of an apparatus for distilling the mineral,
condensing the sulphur vapour, and roasting the residues.. Fig 2 is a plan and
horizontal section through the longitudinal axis of the retort; a distilling furnace
is placed above a roasting furnace. f, with slabs or hearths of the Malétra type.
Distillation is effected separately from the roasting-as an apparatus employed
for two purposes never works regularly and heat should not be withdrawn from
the roaster if the same quantity of acid is to be made with a sufficient desul-
phuration of the cinders, as to still leave them of commercial value in metallurgy,
the amount of fuel used for the purpose being relatively insignificant, so that
without reducing the temperature the maximum production of distilled sulphur is
effected.
The roasting furnace may be of other types than that indicated nevertheless
furnaces for burning to dust exhaust the mineral better and supersede others in
novelty of construction.
When the distilling retort is situated in the roasting furnace as seen in Fig 5 so
that it is heated by direct combustion of the pyrite, this arrangement only works
well when hot air is introduced to replace that used. This will be hereafter
reverted to. The distilling furnace F Figs 1 & 2 contains a horizontal retort a
heated by return of flame charging and discharging at b, the vapours escaping
through a tube K which escape is regulated by a butterfly valve p, or register
governed by a crank p¹.
A sheet iron strainer c, either fixed or movable if necessary not to interfere with
working at the furnace connects the discharge with the opening x communicating
with the roasting furnace f.
4
This strainer or filter o is surmounted by a flap, or clac valve c', also of sheet iron
with hinge c, and sight hole c³, this arrangement is to prevent sulphur and acid
vapours from spreading in the workshops whilst discharging.
The opening is hermetically closed by a conical valve, or better still by a
valve g opening inwards by aid of a lever g³ and counter weight worked by hand
and pivoting on the axis g¹.
The following is the modus operandi :-
When distillation is to be effected, the lower furnace being charged, the operator
pushes back the valve c', by turning the key c', he then opens the retort α, then
closes the valve, and opens the aperture, by means of the lever g, and stirs
through the opening c³, to cause the residues to fall, having done this he closes the
valve g by aid of a lever, and removes the filter c, with its valve c', which as
before described are movable so as to clear the front of the furnace.
This arrangement is necessary not only for the reasons above described but is
'necessitated by the position of the calcining furnaces, which being generally placed
in numbers or batteries only admit of this way of charging and working the
distilling furnace placed above them.
Nevertheless discharge can be effected through an aperture pierced in the retort.
This arrangement is easily applied by coupling the furnaces two and two as shown
in the longitudinal and transverse sections by Figs 3 and 4 so that the furnace F
has its opening between the two discharge pipes ac, As in this case the discharge
pipe terminates some inches from the top slab or hearth of the roasting furnace,
care must be taken to have it always full of distilled pyrites,

page_text: The workman who has the charge of spreading the mineral on the hearth or slab
of the furnace also regulates its descent. The pyrite left in the pipe c, acts as a plug.
There is no need to open the retort, the lid remains fixed and distillation is carried
on uninterruptedly in a closed vessel.
A rake covered with refractory matter rests near the bottom of the retort,
the handle passes through the lid, a little cement suffices to make it hermetical.
This retort is charged through a tubular sieve T, perpendicular to the axis of the
sphere S or conical stopper of refractory clay, which forms the plug.
Working the apparatus is as follows:-When distillation is considered to be
complete, the operator rakes the pyrite. with his rake to the discharge pipe x, the
dimensions of which is calculated to receive two or three charges, he then opens
the charging sieve T, and the fresh charge falls and spreads on the botton of the
retort, reaching to the edge of the opening a, regulating the descent and spreading
the mineral out with his rake as before described.
Condensation can be effected in condensers placed at the side or upon furnaces.
Moreover the draught must be regular, without interruption, and production
constant, as distillation by this process works periodically with the roasting.
A condenser must therefore be used kept perpetually cold. It is or may consist of
a small case or chamber of sheet iron or lead constantly watered by a distribution
of water.
If large masses of vapour are condensed in a very narrow space, the condenser
represented by Figs 1 & 2 will serve the purpose; it consists of a sheet iron box 8,
with double sides divided internally with hollow and perfectly tight divisions in
which the water circulates. The double side of the casing or envelope, or the
divisions alone may suffice, if the quantity of sulphur vapour to be distilled does
not require too great a refrigeration.
In the case of simple divisions the casing may be of wood, brick, or any other
suitable material. h represents the supply pipe of the refrigerating current which
spreads in the divisions d by aid of the pipes d, and in the case or envelope e, by
the pipe e dare taps regulating the refrigerating current-d' are the overflow
pipes of the divisions see Fig: 2.
The sulphur vapours extend to K, is the bolted lid allowing of removal.
11 safety valves-n guides to the divisions-o, T irons supporting the divisions,
and
the opening for the exit of the sulphur-i, i, are the joints of the pipes
allowing of the removal of the divisions.
The divisions d, may be tubular, especially for large chambers. The matters to
be condensed circulate freely round the divisions d, which can be regulated by
pipes and special taps, so as to graduate the refrigeration, or maintain an equal
temperature.
These divisions may be flat or tubular of any suitable material, vertical, oblique
or horizontal, fixed or movable. By means of the butterfly valve p, the draught
may be regulated; in the same manner the condensing temperature can be
regulated by the tap d¹¹.
In cases where the building and arrangements of the works will not admit of
placing the distilling furnaces above the roasting furnaces, distillation must be
separately conducted, and the residues removed by means of a carriage of special
construction, in order to avoid loss of heat as much as possible.
Fig 6 represents a perspective view of a carriage or barrow of this description.
It consists of a cylindrical vessel m, borne on two wheels m¹. Its height is such
that the orifice in the lid m³ directly leads to the point of discharge of the retort.
It can be inclined on the axis of the wheels. This carriage is moved by two
handles m³. The bottom m' of the vessel or recipient is hinged and held firm by
a chain m which is hooked to a fixed point, and is unhooked when the carriage is
brought above the opening x, of the roasting furnace to discharge its contents.
When the barrow or carriage is drawn by ropes the handles m³ are replaced by
ears or some equivalent,

page_text: Heating the air for roasting-To effect a proper combustion in the roasting
furnace to desulphurate the cinders in such a manner that they can be sold for
metallurgic purposes, the temperature must be gradual and constant.
The pyrites impoverished by distillation naturally reach the roasting furnace less
rich in combustible matter. This is obviated 1st in passing the same quantity of
sulphur into the roasting furnace, 2nd in utilizing the waste heat of distillation and
condensation of the gases leaving the roasting furnace, or these three sources of
heat combined for heating the air before its introduction into the roasting furnace.
It has been observed that if the retort was placed in the roasting furnace as
shown by Fig 5. the heat of the furnace would not be sufficient to effectively
distill the pyrite and burn the residues, the two operations being antagonistic,
there would be an imperfect desulphuration, and an insufficient distillation. But
by the introduction into the roasting furnace at r of a current of air at a
sufficiently high temperature the temperature for combustion can be re-established.
In this case the hot air would be given from a special heater.
The retort is placed on the upper slab or hearth of the roasting furnace the air
introduced to the lower slab through the register r, is previously heated to a high
temperature by means of a tubular apparatus, or with divisions, or a Siemens
heater, which in this case would supply one or a number of batteries of furnaces.
Fig 8 merely represents the process of reheating as an explanation of the
principle of utilizing the waste heat of the gases from a Malétra furnace R, and
from the exit of the distilling furnace.
Finally a third arrangement passes air instead of water into the condenser,
where it takes up a certain amount of heat, and is then transferred to the reheater.
These methods can be used singly or conjointly.
The reheaters are or may be tubular, lenticular, or parallelopiped, connected
together by pipes. The quantity of air introduced is necessarily regulated by the
draught of the roasting furnace.
The following is a description of the several parts of the Figure 8
A. Distilling furnace of the pyrites.
M Malétra furnace for the sulphurous acid.
.C Condenser of the sulphur vapours.
R, Reheater utilizing the heat of the sulphurous acid and gas leaving the Maletra
furnace.
R¹ Reheater utilizing the heat of the gases of combustion of the distilling furnace.
8. Air conduit leading from the condenser C to the reheater R.
t. Air conduit leading from the reheater R to the reheater R'.
u. Air conduit leading the reheated air to the air entry of the Malétra furnace.
v. Orifice of entry of the sulphurous acid gas into the reheater R.
Orifice of exit of sulphurous acid gas of the reheater R.
w. Conduit leading the gas of combustion to the reheater R¹.
w Conduit of escape of the gas of combustion into the chimney.
In following this description the principle and general arrangement will be
readily understood, it may however be varied to suit different works, for furnaces
although of one type do not always have all their parts similarly arranged.
The Malétra furnace has been selected merely as a type much in use, the
principle of the invention can be applied to all roasting furnaces provided modifi-
cations are made to suit each case.
The circulation of vapour round the divisions containing a current of cold water,
or refrigerating liquid, or gas of some sort constitutes a novelty which is claimed
for all its applications in refining rough or native sulphur or pyrites.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is
1st The method of, and means employed for heating a charge of pyrites in a
special distilling furnace, in extracting from the charge a certain quantity of

page_text: sulphur, in condensing it, and in producing sulphurous acid from the impoverished
residues, in the manner herein specified.
2d The mode of constructing apparatus for effecting the above objects, such as
represented by the Figs 1. 2. 3. 4 and 5.
3rd The method of placing the distilling furnace above the roasting furnace as
represented by Figs 1 and 2.
4th The method of constructing the fixed or movable strainer with discharging
valve as shown by Figs 1 and 2.
5th The method of closing the orifice of the roasting furnace with a lever valve
as shown by Figs 1 and 2.
6th The method of charging and discharging in a closed vessel as shown by
Figs 3 and 4.
7th The method of condensing by the circulation of water as applied to the
extraction of sulphur from pyrites, and in conjunction with the condenser referred
to, and shown by Figs. 1. 2. and 7.
8th The method of constructing the charging recipient for taking the residues to
the roaster when distillation is conducted separately as shown by Fig. 6.
9th The method of heating the air used in desulphurating the residues or cinders
by passing them to a reheater of some sort placed in the smoke box of the furnace,
or in the condenser, or at the exit of the gas from the roasting furnace, or by all
these means combined, for the purpose of utilizing the waste heat as shown by
Fig 8.
10th The method of placing the distilling retort in the roasting furnace the air
for effectively producing desulphuration of the residues or cinders being heated by
a special reheater, which reestablishes the temperature of the roasting furnace to a
degree sufficient for effecting a suitable distillation, and a complete desulphuration
as hereinbefore explained and as represented by Fig 5. The whole as and for the
purposes substantially as herein described and as illustrated by the accompanying
drawings.