IMPROVEMENTS IN APPARATUS FOR THE MANUFACTURE OF SULPHATE OF Soda and SulphatE OF POTASH
Year: 1873

page_text: LETTERS PATENT to William Hunt, of Castleford, near Normanton,
in the County of York, Manufacturing Chemist, for the Invention of
"IMPROVEMENTS IN APPARATUS FOR THE MANUFACTURE OF SULPHATE OF Soda
and SulphatE OF POTASH."
Sealed the 7th November 1873, and dated the Sth September 1873.
PROVISIONAL SPECIFICATION left by the said William Hunt at the
Office of the Commissioners of Patents, with his Petition, on the
8th September 1873.
I, WILLIAM HUNT, of Castleford, near Normanton, in the County of
York, Manufacturing Chemist, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN APPARATUS FOR THE MANUFACTURE OF
SULPHATE OF SODA AND SULPHATE OF POTASH," to be as follows:-
In the manufacture of sulphate of soda and sulphate of potash from
chloride of sodium and chloride of potassium respectively, by introducing
[into chambers containing the said chlorides a mixture of sulphurous acid
gas, atmospheric air and steam, the chambers and other parts of the
apparatus in and by which the process is conducted are made of cast
iron,

page_text: These chambers are costly in construction, and are injured by the
action on the iron of the evolved hydrochloric acid gas.
The object of my Invention is to remedy these defects in the said
chambers, and consists of the improvements in constructing the said
chambers herein-after described.
By my Invention the construction of the said apparatus is much less
costly than that of apparatus constructed in the ordinary way and is
less liable to injury by chemical action than the ordinary apparatus.
5
I construct the said chambers of brick, blue brick being preferred.
Ordinary bricks or fire-bricks may however be used. In building the 1
chambers I employ in place of ordinary mortar, clay or other cement
not acted upon by hydrochloric acid gas.
I build the said chambers of one thickness of brick. The space
between the exterior of the brick chambers and the wall enclosing the
said chambers I fill with chloride of sodium or common salt.
1
I prefer to use rock salt ground to a fine powder, but do not confine
myself to any particular kind of chloride of sodium, as chloride of
sodium from any source, provided it be in fine powder, answers the
purpose. The powdered chloride of sodium is pressed or rammed in the
space between the brick chambers and outer wall. The chloride of 2
sodium in a short time consolidates into a compact mass and forms an
air-tight packing between the chambers and outer wall. The chloride
of sodium is unacted upon by the hydrochloric acid gas evolved, and
should any of the mixture of sulphurous acid gas, air, and steam come in
contact with it a superficial coating of sulphate of soda is thereby a
formed, but the efficiency of the apparatus is not thereby interfered
with.
The chloride of sodium may either be used alone or mixed with clay
or sand.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
-
filed by the said William Hunt in the Great. Seal Patent Office on
the 4th March 1874.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
HUNT, of Castleford, near Normanton, in the County of York, Manu-
facturing Chemist, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eighth day of September, in the year of our
Lord One thousand eight hundred and seventy-three, in the thirty-
seventh year of Her reign, did, for Herself, Her heirs and successors,
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 executors,
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, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS IN
APPARATUS FOR THE MANUFACTURE OF SULPHATE OF SODA AND SULPHATE OF
POTASH," upon the condition (amongst others) that I, the said William
Hunt, my executors 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 Seal Patent Office within six calendar months next and
immediately 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 :-
In the manufacture of sulphate of soda and sulphate of potash from
chloride of sodium and chloride of potassium respectively by introducing
into chambers containing the said chlorides a mixture of sulphurous
acid gas, atmospheric air and steam, the chambers and other parts of the
apparatus in and by which the process is conducted are made of cast
iron.

page_text: These chambers are costly in construction and are injured by the
action on the iron of the evolved hydrochloric acid gas.
The object of my Invention is to remedy these defects in the said
chambers, and consists of the improvements in constructing the said
chambers herein-after-described.
By my Invention the construction of the said apparatus is much less
costly than that of apparatus constructed in the ordinary way, and is
less liable to injury by chemical action than the ordinary apparatus.
5
I construct the said chambers of brick, blue brick being preferred.
Ordinary bricks or firc-bricks may however be used. In building the 1
chambers I employ in place of ordinary mortar, clay or other cement
not acted upon by hydrochloric acid gas.
I build the said chambers of one thickness of brick. The space
between the exterior of the brick chambers and the wall enclosing the
said chambers I fill with chloride of sodium or common salt.
1
I prefer to use rock salt ground to a fine powder, but do not confine
myself to any particular kind of chloride of sodium, as chloride of
sodium from any source, provided it be in fine powder, answers tho
purpose. The powdered chloride of sodium is pressed or rammed in the
space between the brick chambers and outer wall. The chloride of 2
sodium in a short time consolidates into a compact mass and forms an
air-tight packing between the chambers and outer wall. The chlorido
of sodium is unacted upon by the hydrochloric acid gas evolved, and
should any of the mixture of sulphurous acid gas, air, and steam come in
contact with it a superficial coating of sulphate of soda is thereby 2
formed, but the efficiency of the apparatus is not thereby interfered
.with.
The chloride of sodium may either be used alone or mixed with clay
or sand.
In place of chloride of sodium sulphate of soda, or gypsum, or a
sulphate of baryta, or burnt clay, or loam may be employed, but I use
chloride of sodium or common salt in preference to any other material.

page_text: Figuro 1 represents partly in plan and partly in horizontal section an
apparatus for the manufacture of sulphate of soda or sulphate of potash
constructed acccording to my Invention; Figure 2 represents the same
in side elevation.
Figure 3 represents a vertical section of one of the chambers of the
said apparatus taken on the line X, Figure 1; and Figure 4 is a vertical
section of two of the chambers drawn to a larger scale, the said section
being taken on the line Y, Figure 2. The same letters indicate the
same parts in the several Figures of the Drawings.
a, b, c, d, e, f, g, and I are eight chambers for containing the chloride
of sodium which is to be converted into sulphate of soda by treatment
with a mixture of sulphurous acid gas, steam, and air; i is the outer wall
within which the cight chambers are enclosed. The common salt or
packing material by which the chambers and passages are for the most
párt surrounded and protected is markod / in the several Figures of the
Drawings.
Before describing the way in which I build up the apparatus I will
explain its gencral construction and manner of using the same. I is the
main flue which conducts the mixture of sulphurous acid gas, steam, and
air to the apparatus. This main extends between the two rows of
chambers, and is provided with openings & opposite cach of the
chambers.
The construction of the chambers will be best understood by an
examination of Figure 4. Each of the said chambers has three large
openings m, m³, m³, in its top. Two openings only in each chamber, one
shewn in Figure 4; the positions of the third are seen in Figure 1. The
central opening m serves for introducing the charge of salt to be operated
upon, while the outer openings m², m³, serve for connecting the chambers
with each other and with the main flue as occasion may require.
When the openings m, m³, m², are not in use they are closed air-tight
by caps m³, m' (see Figuro 4). The top of each chamber is also provided
with a series of small holes or openings marked n in Figure 1. These
holes or openings n are used for the introduction of a rod for stirring or
loosening the material in the chambers when necessary, and may be
closed when not in use by stoppers or covers. Near the bottom of each
of the chambers a grating of bars p is supported as represented, and an

page_text: q
opening continued through the outer wall i is made near the bottom
of each of the chambers. The sides of the opening 7 are provided with
rests 1, on which a horizontal bar can be supported. On this horizontal
bar the workman can place and support any rod or tool which he may
introduce into the opening a for breaking up and raking out the material
in the chamber.
Small horizontal openings s, s, made of cast-iron pipes, supported at
their ends by the outer wall i and the wall of the chamber, are situated
at the positions represented, through which openings a bar or tool may
be introduced for loosening the contents of the chamber. The openings
8, 8, may also be used as sight holes. The construction of these openings
8, 8, will be understood by an examination of the Drawing. The contents
of the chambers are removed at the openings q. t, t, are flues below
the ground level, and running outside and parallel to the longer walls i
of the apparatus. These flues communicate with the lower part of each
chamber and with the ordinary condenser, and convey the hydrochloric
acid gas evolved together with the unabsorbed gases and vapours to the
şaid condenser, a stcam jet being used to produce the required draught
through the apparatus. The way in which the lower part of each
chamber is connected with and disconnected from one of the flues & will
be understood by reference to Figure 4. When the top of the vertical
branch of the flue is covered by the plate u the chamber is disconnected
from the said flue, and the opening 7 communicates with the external
air, and the charge of the chamber can be readily withdrawn.
"
When it is wished to close the opening 2 and direct the gas from the
bottom of the chamber into the top of the next one a cast-iron plate is
placed against the inclined faces of the rests r, and the space in front of
this plate is filled with salt or packing material to make the junction
air-tight.
When it is required to put the chamber in communication with the
fluo the plate is removed from the rests r; the plate u is also taken
away and a vertical plate is fixed at v, which plate is made air-tight by
luting so as to close the communication between the chamber and the
outer air. The gases or vapours in this case escape into the flue t and
from thence to the condenser.
By reference to Figure 1 it will be seen that each of the chambers has
at its bottom a horizontal branch flue w, upon which branch flue w a

page_text: vertical flue x (see Figure 3) is built. These branch flucs w, w, and
vertical flues x, x, are for the purpose of conducting the gases and
vapours from the bottom of one chamber to the top of the next. The
communication between the top of the flues & and the openings m³ in
the tops of the chambers is effected by means of semicircular tubes or
junction pieces marked y. Similar junction pieces are used to connect
the openings m¹ of the chambers with the openings in the flue / con-
veying the mixture of sulphurous acid gas, air, and steam to the apparatus.
One of the last named junction pieces is represented at 7 in Figure 4,
which Figure 4 also illustrates the nature of the junction between the
said junction pieces and the openings they serve to connect. The flue /
is made of brick, but the openings in the said flue to be connected
to or disconnected from the openings m² in the tops of the chambers
consist of short vertical cast-iron pipes (see Figure 4) opening into a
short horizontal cast-iron arch, which constitutes on each of the openings
the upper part of the fluc 1, the upper part of the brickwork of the
flue at these parts being removed to permit the insertion of the arched
metal portion of the junction piccc.
The course of the mixed gases and vapours through the apparatus will
be understood by an examination of Figure 1. The gaseous mixture
passes from the flue through the junction piece y² into the top of the
chamber a, from the bottom of the chamber a through the horizontal
fluc w up the vertical flue a and connecting piece y into the top of the
chamber 6, and so on through the series of chambers until it reaches the
bottom of the chamber h, from whence it passes by the fluc t to the
condenser.
When the contents of the chamber a have been decomposed the said
chamber is disconnected from the flue 1, the opening in which is closed
by a cap, and the said chamber a is emptied and recharged.. The
chamber 6 is now connected with the flue 1, and constitutes the first of
the series, and afterwards the chambers c and d, and so on are connected
with the flue l, and constitutes respectively for the time being the first
of the series. Similarly the last of the series is connected with the
flue t, each of the chambers becoming in its turn the last, the contents
of all the chambers, or all the chambers excepting onc, being under
operation at the same time, the one not in operation being either in
process of charge or discharge. Opposite those of the vertical flues

page_text: which are near the outer wall i I make in the said wall an opening
continued by a pipe through the packing material into the said vertical
flues x. Through these openings the temperature of the gascous current
can be ascertained and the process regulated accordingly. The said
openings are closed by plugs when not in use.

page_text: draught by leakage of air. Chambers constructed of brick without the
said packing are not sufficiently air-tight for the successful working of
the apparatus.
In order more effectually to make the apparatus air-tight I prefer to
plaster the inside of the vertical walls i, i, with a plaster composed of
gypsum and water, and I also coat the exterior of the vertical ascending
flues with a like plaster. The outsides of the chambers may also be
similarly plastered.
Although the arrangement of apparatus illustrated by the accom-
panying Drawings is that which I prefer to use, yet I do not limit myself
to any particular shape of chambers nor to the method of connecting
them together, and with the flues which respectively convey the gascons
mixture to the chambers and the resulting gaseous mixture to the
condenser, as other arrangements may be adopted with like effect.
Although for the sake of brevity I have herein described my Invention
with reference to the manufacture of sulphate of soda by treating
chloride of sodium with a mixture of sulphurous acid gas, steam, and air,
yet my said Invention is equally applicable to the treating of chloride of
potassium in a similar manner for the manufacture of sulphate of
potash.
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 the improvements in apparatus
for the manufacture of sulphate of soda and sulphate of potash, hercin-
before described and illustrated in the accompanying Drawings, that is
to say, making the said apparatus of a series of chambers and flues
mainly of brick, and making the said brick chambers and flues air-tight
or practically air-tight by means of a packing powder or material sur-
rounding or enveloping the said chambers and flues, the said packing
material consisting of powdered common salt or other substances, cither
with or without admixture with common salt, which are not injuriously
affected by the gases or vapours employed or evolved in the manufacture
of sulphate of soda or sulphate of potash by acting on chloride of sodium

page_text: or chloride of potassium with a mixture of sulphurous acid gas, steam,
and air, substantially as described and illustrated.
In witness whereof, I, the said William Hunt, have hereunto set
my hand and seal, this Twenty-cighth day of February, in the
year of our Lord Ono thousand eight hundred and seventy-
four.
Witness,
•
GEORGE SHAW.
WILLIAM HUNT. (L.S.)