IMPROVEMENTS IN THE MANUFACTURE OF SULPHATE OF SODA AND " SULPHATE OF POTAON, AND IN APPARATUS USED IN THE SAID MANUFACTURE
Year: 1874

page_text: LETTERS PATENT to William Hunt, of Castleford, near Normanton,
in the County of York, Manufacturing Chemist, for the Invention
of "IMPROVEMENTS IN THE MANUFACTURE OF SULPHATE OF SODA AND
"
SULPHATE OF POTAON, AND IN APPARATUS USED IN THE SAID MANUFACTURE,"
"
PROVISIONAL SPECIFICATION left by the said William Hunt at the
Office of the Commissioners of Patents, with his Petition, on the
6th March 1874.
I, WILLIAM HUNT, of Castleford, near Normanton, in the County of
5 York, Manufacturing Chemist, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN THE MANUFACTURE OF SULPHATE OF SODA and
: SULPHATE OF POTASH, AND IN APPARATUS USED IN THE SAID MANUFACTURE,” to
be as follows:-
•
My Invention has reference to the manufacture of sulphate of soda
O and sulphate of potash by the action on chloride of sodium and chloride
of potassium of a mixture of sulphurous acid gas, steam, and atmo-
spheric air.

page_text: In the ordinary method of conducting the said manufacture the
chloride to be operated upon is put into chambers and the gascous
mixture is drawn in succession through a series of the said chambers,
the said gaseous mixture being made to pass by a descending course
through the said chambers, that is, the gaseous mixture is introduced
into each chamber at the top and passes out at the bottom.
In conducting the process according to my Invention I pass the
gaseous current of sulphurous acid gas, steam, and atmospheric air
through the series of chambers in an alternately upward and downward
direction, that is, if the current pass downwards in the first chamber it
passes upwards in the second, downwards in the third, upwards in the
fourth, and so on. After a time the gaseous current is reversed, that is,
it is passed upwards in those chambers in which it had previously passed
downwards, and downwards in those chambers in which it had previously
passed upwards. By this method of conducting the process the contents
of the chambers are more uniformly acted upon than when the gaseous
current is passed through the chambers in the ordinary way. Thero is
'also this further advantage that the draught required to pass the gaseous
current through the chambers is less than that required when the said
current has to pass from the bottom of one chamber through a flue or
pipe to the top of the next chamber.
.
In constructing apparatus for conducting the said manufacture I
arrange the chambers in a circle, and I ercct at the centre of the circle
a conical tower. The heat given out during the decomposition of the
chloride in the chambers gives to the gaseous current in the said tower
sufficient ascending power to produce the required draught through the
chambers without the use of a steam jet which is ordinarily employed.
From the top of the said conical tower the gaseous current passes to the
condenser.

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Sixth day of March, in the year
of our Lord One thousand eight hundred and seventy-four, in the
thirty-seventh year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said William Hunt, Her special
license that I, the said William Hunt, my executors, administrators,
and assigns, or such others as I, the said William Hunt, my exe-
cutors, administrators, and assigns, should at any time agree with,
and no others, from time to time and at all times thereafter during
the term therein expressed, should and lawfully might make, use,
excrcise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN THE MANUFACTURE OF SULPHATE OF SODA AND SULPHATE OF
POTASH, AND IN APPARATUS USED IN THE SAID MANUFACTURE," upon the
condition (amongst others) that I, the said William Hunt, my exe-
cutors or administrators, by an instrument in writing under my,
or their, or one of their hands and seals, should particularly describe
and ascertain the nature of the said Invention, and in what manner
the same was to be performed, and cause the same to be filed in the
Great Scal Patent Office within six calendar months next and imme-
diately after the date of the said Letters Patent.
:
NOW KNOW YE, that I, the said William Hunt, do hereby declare
the nature of the said Invention, and in what manner the same is
to be performed, to be particularly described and ascertained in and
by the following statement thereof, that is to say:-
My Invention has reference to the manufacture of sulphate of soda
and sulphate of potash by the action on chloride of sodium and chloride
of potassium of a mixture of sulphurous acid gas, steam, and atmo-
spheric air.
In the ordinary method of conducting the said manufacture the
chloride to be operated upon is put into chambers and the gaseous
mixture is drawn in succession through a series of the said chambers,
the said gaseous mixture being made to pass by a descending course
through the said chambers, that is, the gascous mixture is introduced
into cach chamber at the top and passes out at the bottom.
In conducting the process according to my Invention I pass the
gaseous current: of sulphurous acid gas, steam, and atmospheric air

page_text: through the series of chambers in an alternately upward and downward
direction, that is, if the current pass downwards in the first chamber it
passes upwards in the second, downwards in the third, upwards in the
fourth, and so on. It is preferred to pass the gaseous current upwards in
the first chamber. After a time the gaseous current is reversed; that is,
it is passed upwards in those chambers in which it had previously passed
downwards, and downwards in those chambers in which it had previously
passed upwards. By this method of conducting the process the contents
of the chambers are more uniformly acted upon than when the gaseous
current is passed through the chambers in the ordinary way. There is
also this further advantage that the draught required to pass the gaseous
current through the chambers is less than that required when the said
current has to pass from the bottom of one chamber through a flue or
pipe to the top of the next chamber.
In constructing apparatus for conducting the said manufacture I
arrange the chambers in a circle, and I crect at the centre of the circle
a conical tower. The heat given out during the decomposition of the
chloride in the chambers, together with the heat of the gases leaving
the chambers, warms the tower and gives to the gaseous current in the
said tower sufficient ascending power to produce the required draught
through the chambers without the use of a steam jet which is ordinarily
employed. From the top of the said conical tower the gaseous current
passes to the condenser.
Having explained the nature of my Invention, I will proceed to
describe, with reference to the accompanying Drawings, the manner in
which my Invention is performed.
Figure 1 represents in elevation an appartus for the manufacture of
sulphate of soda or sulphate of potash constructed according to my
Invention, and Figure 2 represents the same partly in plan and partly in
horizontal section, different parts of the sectional portion being taken at
different levels.
Figure 3 represents in plan an arrangement in which the chambers
are arranged around the central tower or shaft in a nearly rectangular
figure, the said chambers being nearly rectangular in horizontal section.
The arrangement, Figure 3, is essentially the same as that represented in
Figures 1 and 2, but instead of the arrangement, Figure 3, a row of
circular or other shaped chambers may be disposed on either side tho

page_text: tower, the base of which in this case is oblong, and extends nearly from
side to side of the apparatus.
;
Figure 4 represents a vertical section of two adjacent chambers of the
apparatus, Figures 1 and 2, and shows details of the arrangement of
parts by which the gascous current is made to pass from one chamber to
the next.
Figure 5 represents a vertical section of one of the chambers and the
central tower or shaft, and illustrates the details of the arrangement of
parts by which the gascous current is discharged into the central tower,
as well as the arrangement of parts by which the gaseous current is
introduced into the bottom of the chamber from the gas flue under the
apparatus.
:
The parts of the horizontal section, Figure 2, are taken at the
following levels:-The chambers a, b, are taken on the level of the floor
of the said chambers; the chamber g is a section taken on a level with
the slotted bottom or grating; the chambers e, f, are taken on a level
with the lids on the tops of the said chambers, and the chamber d is
taken on a level with the boxes covering the luting, and the chamber c
is a plan of the top of the apparatus.
I will describe my improvements in the manufacture of sulphate of
soda and sulphate of potash, in connection with my improved apparatus
represented in the accompanying Drawings.
I prefer to employ a series of seven chambers, marked respectively
a, b, c, d, e, f, g, but the number may be varied. I build these chambers
with brick or large blocks. I make the chambers circular by preference,
but they may be made of other shapes. I arrange the chambers by
preference in a circle, or nearly in a circle, and in the centre of the
circle I construct a conical tower or shaft h, built with bricks, laid in a
mixture of tar and fine sand. The hot gases from the chambers a, b, c,
d, e, f, g, entering the tower h make it hot, and thereby produce draught.
The chambers a, b, c, d, e, f, g, and tower h are built inside an encasing
or boundary wall i, and the space between this wall i and the
chambers a, b, c, d, e, f, g, as well as the space between each chamber
and the tower or shaft is filled with fine ground rock salt or any other
material that will prevent air drawing into the chambers or gas escaping
out of them. The material in the said spaces also tends to keep the

page_text: .
.
chambers warm. Before putting the ground rock salt or other material
between the chambers and the wall the latter is well plastered with fine
coke mixed with a little lime or sulphate of lime or other material
suitable to prevent loss of heat. The top of each chamber is covered
with a cast-iron plate k (or with an arch of brick), which has openings ?
for the convenience of charging and discharging the chamber. These
openings are stopped up whilst the chambers are working. When a brick
arch is employed it is plastered over with a thick coating of sulphate of
lime, a layer of salt is put upon that, and then a quantity of spent bark
or coke dust, and a layer of bricks upon that to prevent loss of heat.
There are two moveable plates at the front and near the bottom of each
chamber for the convenience of discharging the chamber. When the
chambers are working the two plates are a little distance apart, and the
space between them is filled with dust or fine sand, to prevent the
leakage of gas or air drawing in. An annular flue m, into which steam
is admitted near the sulphur burners, passes under the series of
chambers a, b, c, d, e, f, g, and conducts the products of the sulphur
burners and atmospheric air and steam by means of branch vertical
pipes n to the several chambers, or to some of the chambers, the gaseous
current being admitted to or stopped off from any chamber as required.
I prefer working only six chambers at a time, so as to leave the seventli
for discharging and charging. The chambers are connected with each
other at top by means of flues p (see Figure 4), and at bottom by flues 1.
The communications are opened and closed by means of dampers p², p²,
and. There are also flues q with dampers q² (see Figure 5) com-
municating with the tower h, for taking away the muriatic acid arising
from the action of the sulphurous acid, air, and steam on the salt. The
gas is conducted from the top of the tower h through pipes to the
ordinary condenser for condensation. The dampers dip into sand placed
in the seats represented for preventing the escape of gas. There is a
small cap on or near the top of the tower, to permit of the testing of the
state of the gas with respect to moisture. An excess of steam is
objectionable, as it lowers the temperature of and dilutes the gases..
.
1
Having described the apparatus I will now explain the manner of
conducting the manufacture of sulphate of soda or sulphate of potash
therewith by means of sulphurous acid gas, air, and steam.
The chambers a, b, c, d, e, f, g, and sulphur burners are first heated
with fires kept in them for some time before charging them. The salt

page_text: or potash is damped and laid on drying flues and dried and thereby
made hard, it is then broken up into lumps about the size of a hen's egg
and the chambers are filled with the lumps of salt within a foot or two
of the top. The salt in the chambers is heated by hot gases arising
from the burning of coke in the sulphur or pyrites burners. This is
continued till the salt in the first chamber is brought to a very dull red
heat; then I begin to burn pyrites in the burners, the gas from which,
with a little steam and air circulating amongst the lumps of salt or
muriate of potash produces muriatic acid and sulphates, the muriatic
acid gas goes forwards up the tower h and away through earthen pipes
to the condensing tower. To make a free passage for the gases in the
bottom of the chambers I use for supporting the material in the
chamber cast-iron plates & slightly curved to give strength. These
plates have slots in them so as to form a grating through which the
gases readily pass. I make these plates of a convenient size to move:
These plates are supported about a foot from the floor and in the most
favorable way for conveying the gas to all parts of the chamber. Each
piece of casting rests upon cast-iron wedges or bearers which when
moved from under the castings cause the latter to drop from the
salt cake, and they can be taken out when the chambers have to be
discharged.
>
...
When a chamber has been disconnected from the gas flue on account
of its contents being finished before discharging the chamber I raise the
damper q² of the fluc q which communicates with the tower h in order
to draw off the gases remaining in the salt cake; I prefer that the top
of the burners should be at least three or four feet below the floors of
the chambers to help the ascent of the gases, and I build the burners as
near the chamber's as possible. The annular flue m under the chambers
is divided into two parts, one part supplying three of the chambers
with gas, and the other supplying four chambers, but these flues can be
connected with the burners or disconnected from them at pleasure. The
sulphur burners are situated at the part marked A of the apparatus, and
by means of flues are connected with the two parts of the annular
flue m..
When the chomhous

page_text: to receive gas from the burners then the other flue is stopped off from
the burners and that under the chambers d, e, f, g, is opened and
becomes connected with the burners.
Before changing any of the dampers I plaster up the doors of the
sulphur burners and put the dampers close in the.burners to prevent the
gas going along the flues while the dampers at the chambers are being
changed.
:
For some time before changing the gas from one flue to another I
heat the flue from a fire-place which is situated at B on the opposite side
of the chambers to the sulphur burners at A, which fire-place can be
cut off from the flue m or connected therewith as circumstances may
require, and this flue or either of the flues can be connected with the
chimney draught. The object of heating the flues for some time before
introducing the gas is to heat the gas before entering the chamber.. The
top or cover of the chamber is made with segments of iron having flanges
which are screwed together with screw pins. I plaster a coating of
gypsum of about an inch and a half thick on the cast-iron cover when
the latter has been fixed, and on the said coating put a coating or layer
of salt, and on the coating or layer of salt I put spent bark or. any
other imperfect conductor of heat. The cover has finally a coating of
bricks placed upon it. On the top of the conical tower / I place two or
more cast-iron elbow pipes to connect with other iron or earthenware
pipes to carry the muriatic acid to the condenser.
Where the apparatus is constructed to burn pyrites poor in sulphur I
heat the sulphurous acid gas produced by the burning of the pyrites by
means of stoves built in the spaces between. the chambers. The fire of
the said stoves is made to pass through and heat iron pipes, around
which the gaseous mixture from the pyrites burner is made to circulate
and becomes further heated before it passes into the chambers. The
same arrangement of pipes also heats the gascous mixture as it passes
from one chamber to the next. After a chamber has been discharged it
is recharged as soon as possible, and the salt or contents of the chamber
is heated by the heat from a portable stove before the gaseous mixture
is introduced into the last charged chamber. The portable stove I
employ has a flue at its back, which flue is introduced into the bottom
part of the chamber. One of the openings at the top of the chamber
is opened, and a draught is thereby produced, by means of which the

page_text: -hot air from the portable stove circulates about the lumps of salt and
heats them preparatory to the sulphurous gases being introduced. Coke
is burned in the portable stove referred to.
By the construction and arrangement of the parts of the apparatus I
am enabled to conduct the process of manufacturing sulphate of soda or
sulphate of potash in the manner herein-before referred to, the gaseous
current being taken direct from one chamber into the next; and passing
alternately upwards and downwards in the adjacent chambers, the
direction of the current being changed from time to time. so as to cause
it to pass upwards in those chambers in which it had previously passed
downwards, and downwards in those chambers in which it had previously
passed upwards. By thus conducting the process the contents of the
chambers are much more uniformly acted upon than by the ordinary
method; and there is this further advantage in my method of conducting
the process that as the gases pass direct from one chamber to the next
without the ordinary ascending flue much loss of heat is avoided, and
there is less resistance to the passage of the gaseous current. The
steam jet ordinarily employed for producing the required draught
through the apparatus is unnecessary, the tower or shaft and the
condensers supplying sufficient draught for the effectual conducting of
the process.
Having now described the nature of my Invention and the manner in
which the same is to be performed, I wish it to be understood that I do
not limit myself to the precise details herein described and illustrated,
as the same may be varied without departing from the nature of my
Invention, but I claim as my Invention,―
First. The improvements in the manufacture of sulphate of soda and
sulphate of potash, herein-before described and illustrated in the accom-
panying Drawings, that is to say, passing the gaseous current of
sulphurous acid gas, steam, and atmospheric air in an alternating upward
and downward direction through the series of chambers in which the
said gaseous current operates upon the chloride of sodium or chloride of
potassium contained in the said chambers, and afterwards reversing the
direction of the gaseous current so that it passes upwards in those
chambers in which it had previously passed downwards, and downwards
in those chambers in which it had previously passed upwards, substan-
tially as described and illustrated.

page_text: Secondly. The improvements in apparatus to be used in the manu-
facture of sulphate of soda and sulphate of potash, herein-before
described and illustrated in the accompanying Drawings, that is to say,
_ arranging the chambers in which the manufacture of sulphate of soda
or sulphate of potash is effected around or about a tower or shaft for
determining a draught through the apparatus, and so constructing and
arranging the parts of the said apparatus that the gaseous current may
be passed direct from one chamber to the next or to the central tower
or shaft, and the direction of the gaseous current reversed at pleasure,
substantially as described and illustrated.
In witness whereof, I, the said William Hunt, have hereunto set
my hand and seal, this First day of September, in the year of
our Lord One thousand eight hundred and seventy-four.
Witness,
GEORGE SHAW.
WILLIAM HUNT. . (L.S.)