IMPROVEMENTS IN THE MANU FACTURE OF SODA AND POTASH
Year: 1857

page_text: LETTERS PATENT to William Gossage, of Widnes, in the County of
Lancaster, Chemist, for the Invention of "IMPROVEMENTS IN THE MANU
FACTURE OF SODA AND POTASH."
Scaled the 18th August 1857, and dated the 21st February 1857.
PROVISIONAL SPECIFICATION left by the said William Gossage at the
Office of the Commissioners of Patents, with his Petition, on the 21st
February 1857.
I, WILLIAM GOSSAGE, of Widnes, in the County of Lancaster, Chemist,
do hereby declare the nature of the said Invention for "IMPROVEMENTS IN THE
MANUFACTURE OF SODA AND POTASH," to be as follows:-
In the ordinary manufacture of soda and potash, the first stage in the
series of processes used is the production from sulphur of sulphuric acid,
which acid is employed for decomposing common salt, or some salt of potash
for the formation of sulphate of soda or sulphate of potash. The cost..
of native sulphur required for such production is greater than that of any
other material employed in such manufacture of soda or of potash.
The sulphate of soda or of potash thus obtained is decomposed by fluxing
it in mixture with carbonate of lime or caustic lime and small coal, and the
product obtained is called "black ash" or "ball alkali." This product is
lixiviated with water, and yields solution of soda or of potash which exists
therein, partly as carbonate, partly as caustic, and partly as sulphuret, and

page_text: a residuum is left undissolved, which contains the greater portion of the
sulphur (previously consumed to produce sulphuric acid) in the form of
sulphuret of calcium; it also contains carbonato of lime and carbon in the
state of coke. This residuum is known as "alkali waste," and is at present
thrown away as a worthless product.
One object of my Invention is to obtain sulphur from such "alkali waste,"
for the purpose of applying such sulphur to the production of sulphuric acid,
and subsequently of sulphate of soda, or sulphate of potash, and thus effecting
a most important saving in the cost of manufacturing soda and potash by
using sulphates so obtained, in place of sulphates obtained by the consumption
of native sulphur.
Another object of my Invention is to obtain carbonate of lime or caustic
lime or cement containing lime from such "alkali waste," when I use
carbonic acid for liberating sulphur therefrom.
Another object of my Invention is to obtain an increased proportionate
quantity of caustic soda or caustic potash, or of carbonate of soda or carbonate
of potash, in the usual manufacture of soda or potash. I decompose "alkali
waste," obtained in the manufacture of soda or potash, by the action of
carbonic acid or inuriatic acid thereon, and I thereby cause the evolution of
sulphur from sulphuret of calcium contained in such "alkali waste," which
sulphur is evolved in the state of sulphuretted hydrogen gas, and I cause such
gas to become mixed with sulphurous acid gas, or to be acted upon by liquid
sulphurous acid, uuder such circumstances as provide for the mutual decom-
position of sulphuretted hydrogen and sulphurous acid, and the consequent
production of free sulphur, which being collected is suitable to be applied to
the manufacture of sulphuric acid, and the production of sulphate of soda
or sulphate of potash, to be employed in the manufacture of soda or of
potash, in the manner usually adopted.
I obtain an increased quantity of caustic soda or caustic potash in the
manufacture of soda or potaslı, by using an increased proportionate quantity
of small coal in the mixture when decomposing sulphate of soda or sulphate
of potash, by fluxing, also by decomposing sulphuret of sodium or sulphuret
of potassium, contained in solutions obtained by lixiviation of "black ash"
or "ball alkali," by means of hydrated oxide of iron, of zinc, of manganese,
or of lead, thereby producing sulphuret of the metal employed, and caustic
soda or caustic potash. I decompose the metallic sulphuret thus obtained
by means of a suitable acid producing metallic solution, and liberating
sulphuretted hydrogen gas, from which gas I obtain sulphur for the manu-
facture of sulphuric acid.

page_text: I decompose such metallic solution by means of lime or magnesia, and
thus obtain hydrated metallic oxide, suitable for decomposing a further
quantity of sulphuret of sodium or of potassium, and thereby producing
soda cr potash in a caustic state.
I obtain an increased quantity of carbonate of soda or of potash by decom-
posing sulphuret of sodium or sulphuret of potassium, contained in solutions
obtained by lixiviation of "black ash" or "ball alkali," by means of hydrated
carbonate of iron, zinc, of manganese, or of lead, thereby producing
sulphuret of the metal employed, and carbonate of soda or of potash. I
decompose the metallic sulphuret, thus obtained, by means of a suitable acid
producing metallic solution, and liberating sulphuretted hydrogen gas, from
which gas I obtain sulphur for the manufacture of sulphuric acid. I decom-
pose such metallic solution by means of lime or magnesia, and I then inject
carbonic acid into the mixture to convert the hydrated oxide produced into
carbonate, or I decompose some of these solutions by means of carbonate of
lime or carbonate of magnesia, and I thus obtain carbonate of metallic oxide.
suitable for decomposing a further quantity of sulphurct of sodium or of
potassium, and thereby producing soda or potash in the state of carbonate.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said William Gossage in the Great Seal Patent Office on the
21st August 1857.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
GoSSAGE, of Widnes, in the County of Lancaster, Chemist, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-first day of February, in the year of our Lord
One thousand eight hundred and fifty-seven, in the twentieth year of Her
reign, did, for Ilerself, Her heirs and successors, give and graut unto inc, the
said William Gessage, Her special license that I, the said William Gossage,
my executors, administrators, and assigns, or such others as I, the said
William Gessage, 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 THE
MANUFACTURE OF SODA AND POTASH," upon the condition (amongst others) that

page_text: I, the said William Gossage, by an instrument in writing under my hand
and seal, 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 Gossage, do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement, reference being had to the Drawings hereunto annexed,
and to the letters and figures marked thereon (that is to say):-
In the ordinary manufacture of soda or potash, the first stage in the series
of processes commonly used is the production of sulphuric acid by the use of
native sulphur or of native pyrites, which acid is employed for decomposing
common salt or some salt of potash for the formation of sulphate of soda or
sulphate of potash. The cost of native sulphur or of native pyrites required
for such production is greater than the cost of any other material employed
or consumed in effecting such ordinary manufacture of soda or of potash.
Sulphate of soda or sulphate of potash thus produced is then decomposed,
by fluxing it in mixture with carbonate of lime, or caustic lime and small
coal, and the product so obtained is known as "black ash" or "ball alkali."
This product is lixiviated with water, and thereby yields solution of soda or of
potash, which soda or potash exists therein partly as carbonate, partly as
caustic, and partly as sulphuret. A residuum is left undissolved by such
lixiviation, and such residuum contains the greater portion of the sulphur
(which had been previously consumed in the said mauufacture for the pro-
duction of sulphuric acid) in the state of sulphuret of calcium. The said
residuum also contains carbonate of lime and carbon; it is known as "alkali
waste," and has hitherto been thrown away as a worthless product of such
manufacture of soda or of potash.
One object of my said Invention is to obtain sulphur from such "alkali
waste," for the purpose of applying such sulphur to the production of
sulphuric acid, and subsequently of sulphate of soda or sulphate of potash
and thus effecting a most important saving in the cost of manufacturing
soda and potash by using sulphates so obtained for such manufacture, in
place of sulphates obtained by the consumption of native sulphur or of
native pyrites.
I will firstly describe the means by which I effect this object of my said
Invention, so as to obtain sulphur from "alkali waste "..
In the Specification of an Invention for which I obtained Letters Patent,

page_text: bearing date the 17th day of August 1837, under the title of "certain
improvements in the processes or operations connected with the manufacture
of alkali from common salt, and with the use of the products obtained there-
from," I have stated as my discovery that carbonic acid gas can be employed
to effect the decomposition of sulphuret of calcium contained in "alkali waste,"
thereby causing the production of pure (or nearly pure) sulphuretted hydrogen
gas, which gas under certain circumstances can be used for the manufacture
of sulphuric acid in place of native sulphur. Notwithstanding the publication
of such discovery in the said Specification inrolled in the year 1838, "alkali
waste" has continued to be a valueless product (as its name implies), and
large expenses are at this time incurred in the manufacture of soda and
potash, in order to get rid of this hitherto worthless and most offensive product
of such manufacture. In effecting this part of my said Invention I cause the
decomposition of sulphuret of calcium contained in "alkali waste," and the
liberation of sulphur in the state of sulphuretted hydrogen therefrom, to be
accomplished by means of impure carbonic acid gas, and the sulphuretted
hydrogen gas so produced is consequently obtained in mixture with other
gases. Or l effect the decomposition of "alkali waste" by means of muriatic
acid, thereby obtaining sulphuretted hydrogen gas in mixture with carbonic
acid gas. The mixed, gases so obtained (by either of the said decompositions
of "alkali waste") are not suitable to be used for the direct manufacture of
sulphuric acid by the combustion of sulphuretted hydrogen contained therein
(as described in the Specification of my former Patent herein-before referred
to); therefore I cause such mixed gases to be subjected to certain processes or
operations herein-after described, in order to obtain sulphur therefrom.
When I use carbonic acid gas for effecting the said decomposition of
sulphuret of calcium, I prefer to obtain such gas by the calcination of lime-
stone with coke or coal in a limekiln, or by the combustion of coke or coal
with atmospherical air, using a furnace for such combustion having such a
bed of burning fuel on its fire grate as is sufficiently deep to provide for tne
whole, or nearly the whole, of the oxygen contained in such atmospherical
air becoming combined with carbon or hydrogen of the coke or coal burned.
1 conduct the gaseous products of such calcination or combustion through
an apparatus suitably arranged for cooling gases, and I then cause such
cooled gaseous products to filter through "alkali waste" (maintained in a
state of dampness) contained in suitable vessels or chambers, and I use such
a number of vessels or chambers (containing alkali waste) consecutively as I
find to be sufficient to effect the absorption of the greater part of the carbonic
acid so introduced therein and passing through. the same.

page_text: When I effect the decomposition of "alkali waste" by means of muriatic
acid, I prefer to employ for such purpose the means described in the
Specification of my former Patent, herein-before referred to.
I will now describe the construction and arrangement of apparatus which
I prefer to employ for effecting the decomposition of alkali waste when
using impure carbonic acid gas for such purpose; also for effecting the
decomposition of impure sulphuretted hydrogen gas, so as to obtain sulphur
therefrom:-
In the Drawings hereunto annexed, A is a limekiln, which is supplied with
limestone & coke or coal through an opening or doorway a. This opening or
doorway is closed with a door, to which is adapted a damper d for regulating
admission of atmospherical air into the upper part of the kiln A, so as to
effect combustion of carbonic oxide, which may be generated in the kiln A;
B is a vertical shaft or chimney through which gases generated in the kiln A
ascend. The shaft or chimney B is intersected horizontally by arches b,b,b;
such arches are perforated alternately at their outsides and middles, so as to
form a number of passages c,c. c, through which gases generated in the kiln A
must pass in their ascent up the shaft or chimney B. The direction of the
course of gases thus ascending is shown by arrows in the Drawings. The
vertical shaft or chimney B communicates through a pipe e with a cylindrical
iron vessel C closed at top, which vessel has a grating or false bottom D, on
which is supported such a quantity of pebble stones, each about the size of a
man's fist, as are sufficient to fill the said vessel within about two feet of the
top. A colander E is suspended or supported in the vessel C, and cold water
is supplied to such colander from a reservoir, so as to occasion streams of
water to pass through the vessel C over the stones contained therein, and to
escape therefrom through the pipe F, the end of which pipe is dipped into a
vessel containing water. G is a pipe conducting from the lower part of the
vessel C to the inlet passage of a ventilating fan H'; I' is a pipe conducting
from the outlet passage of the fan H' to the upper part of a square or oblong
chamber K¹. This chamber is constructed of brickwork, plastered so as to
make it sufficiently gas-tight. It has a number of perforated shelves k, k,
which may be formed of strips of wood resting on bearers. On each of these
shelves a layer of fresh "alkali waste," about one foot in thickness, is placed.
Doorways or openings T, T, capable of being closed sufficiently gas-tight by
moveable doors, are provided to the chamber K¹, through which alkali waste
is introduced on to the said shelves, and withdrawn therefrom. 1 is a pipe
conducting from the lower part of the chamber K' to the upper part of the
chamber K2. The chamber K2 is constructed similarly in all respects to the

page_text: chamber K¹, having perforated shelves for supporting "alkali waste," and
doorways or openings for introducing and withdrawing the same. The pipes
connected with the chambers K¹ and K are so arranged that the direction of
the current of gases proceeding to and from such chambers can be modified,
so that either of these chambers can be made to communicate in the first
instancewith the ventilating fan H', and subsequently with the other chamber.
Lis a pipe conducting gas from the chamber K2 (a similar arrangement is
provided for the chamber K¹); M is a branch pipe or flue from the pipe L,
communicating with the ash-pit of a furnace O. The pipe or flue M is fitted
with a damper m, by which the quantity of gas passing through the same may
be regulated. N is a branch pipe from the pipe L, communicating with the
upper part of the furnace O; this pipe N is fitted with a damper n, by which
the quantity of gas passing through the same may be regulated; O is a
furnace in which coke or coal is burned on its fire grate; the ash-pit of this
furnace is closed by a moveable door; P is a regulating damper, adapted
to such moveable door, through which air is supplied into the ash-pit of
the furnace O; Q is a flue for conducting gases from the furnace O to a
tower S; R is a damper for closing the passage of such flue when needful;:
J is a pipo connected with a steam boiler, through which steam is supplied
into the flue Q; S is a square or oblong tower formed of brickwork, and
plastered externally, also bound together with suitable iron bracings; the
tower S is intersected horizontally by a number of arches of brickworks, 8,6;
such arches are perforated so as to form a number of passages p, p, p, through
which gases flowing from the furnace O must pass; the said perforations
are made in the said arches alternately in the middle and at the outsides
thereof, as shewn in the Drawings hereunto annexed. The course of
passing through the said perforations is shewn by arrows marked on the
said Drawings. U is a pipe conducting from the tower S to a tower W.
The tower W is constructed of timber work lined with lead, and nearly
filled with pebble stones about the size of a man's fist, such pebble stones
being supported on a grating placed near the bottom of the same. Water
or other liquid is supplied into the tower W through a colander w suspended
or supported therein; such water or other liquid passes off through the
pipe X into a receiver Y. Z is a pipe conducting from the lower part of the
tower W to the inlet passage of a centrifugal fan H². The outlet passage
of such fan may communicate with a chimney for discharge of waste gases.
71, 72, are pipes communicating with a steam boiler, through which steam is
supplied to the chambers K1, K2, to communicate moisture to the "alkali
wast" contained therein.
gases

page_text: In effecting the first part of my said Invention by means of the apparatus
I have herein-before described, I introduce a mixture of limestone and coke
or coal (preferring to use coke) into the limekiln A (the contents of such kiln
being previously ignited), and I use such a proportion of coke or coal as will
ensure the complete or nearly complete combustion of the oxygen contained
in the air passing through the same. In such case I find usually that some
corbonic oxide gas is produced, and I allow some atmospheric air to pass into
the upper part of such kiln through the regulating damper d. Gases pro-
ceeding from the said kiln ascend through the perforations c, c, in the arches
b, b, of the vertical shaft or chimney B, and during such ascent such gases
become thoroughly mixed, so as to cause combustion of carbonic oxide and
oxygen gas contained therein. If I find on testing the gases proceeding
from the vertical shaft or chimney B that these contain a notable quantity
of oxygen gas, I restrict or close entirely the passages for air through the
regulating damper d, and if needful I use a larger proportionate quantity of
coke in the limekiln A, so as to obtain gases free or almost entirely free from
oxygen gas. I conduct gases from the chimney B through the pipe e into
the cooling tower C, through which I cause a sufficient supply of cold water
to be passed to reduce the temperature of such gases to about 180 degrees of
Fahrenheit, and by the pipe G the cooled gases are conducted to the inlet
passage of the ventilating fan H', which fan being driven by suitable power
causes atinospheric air to be drawn through the limekiln A, the chimney B,
and the cooling tower C, and the resulting gases (containing carbonic acid
gas) to be propelled through the pipe l'into the chamber K', in which such
gases percolate through layers of moistened "alkali waste" contained therein,
and the carbonic acid decomposes sulphuret of calcium contained in such
waste, evolving sulphuretted hydrogen gas by such decomposition. The
current of gases, having percolated through the layers of "alkali wasto".con-
tained in the chamber K', is conducted by the pipe 1 into the chamber K
containing other layers of "alkali waste," through which the said gases are
caused to percolate. I cause the said gases to pass through such a number of
layers of "alkali waste" as I find to be sufficient to abstract nearly all the
carbonic acid gas originally present in the mixed gases procceding from the
limekiln A; I thus obtain mixed gases containing much sulphuretted hydrogen
gas. I introduce gases proceeding from the limekiln, firstly, into a chamber
containing layers of " alkali waste" which has been previously acted upon by
carbonic acid, and thereby partiallydecomposed,and from thence into another
chamber containing layers of fresh "alkali waste." I conduct the said mixed
gases containing much sulphuretted hydrogen into a furnace O, on the grate

page_text: of which furnace I have a layer of burning coke or coal. I cause one portion
of the said mixed gases to pass into the ash-pit of the said furnace, and from
thence to percolate (together with a proper supply of atmospherical air
admitted through the regulating damper P) through such layer of burning
coke or coal, thereby producing sulphurous acid gas by the combustion of
sulphuretted hydrogen contained in such mixed gases, and I cause the other
portion of the said mixed gases to pass into the upper part of the furnace O;
the resulting gases pass from the said furnace through the flue Q into tho
nixing tower S at such temperature as may be communicated to them by
the combustion of coke or coal in the furnace O, and of sulphuretted hydrogen
therein. I modify such temperature by increasing or diminishing the supply
of coke or coal to the furnace O, and by increasing or diminishing the supply
of air through the regulating damper P; 1 regulate such supplies of coke of
coal and of air in the said furnace, so that the temperature of the mixed
gases passing into the mixing tower S shall not be less than 300 degrees of
Fahrenheit, and the temperature of the gases passing from such tower shall
not be less than 240 degrees of Fahrenheit. I have found that at such
temperatures a mutual decomposition takes place between sulphurous acid
gas and sulphuretted hydrogen gas, so as to produce uncombined sulphur
without causing the production of a certain acid compound of sulphur and
oxygen (known as "pentathionic acid "), which compound is produced when
such mutual decomposition is effected at ordinary temperatures, and such
acid compound is not capable of being decomposed by sulphuretted
hydrogen at such temperatures.
When I supply coke or coal to the furnace O, I let down the damper R to
prevent air passing into the mixing tower S. The mixing tower S is so
constructed that gases passing through the same are caused to be repeatedly
mixed together during such passage, and thereby the mutual decomposition
of sulphurous acid and sulphuretted hydrogen is facilitated and ensured.
After such decomposition is effected, the gases passing through the mixing
tower S contain in mixture therewith a quantity of free sulphur in a state of
minute division. I conduct such gases through the pipe U into the washing
tower W, and cause the same to percolate through the interstices existing
between the pebble stones placed in such tower, and at the same time I cause
a large supply of water or other liquid to pass in rapid currents down such
tower. The finely divided sulphur thereby becomes inixed with such liquid
(producing a turbid fluid), and flows therewith through the pipe X into the
receiver Y. I provide a suitable number of such receivers, and cause the
said turbid fluid containing sulphur to flow slowly through the same cou-

page_text: secutively, during which flowing sulphur becomes deposited in the said
receivers, and I elevate the supernatant liquor from the last receiver, and
cause this to flow again through the washing tower W. I collect the
deposited sulphur from the said receivers, and dry this to render it suitable
to be used for the production of sulphuric acid.
By means of the dampers m, n, I regulate the proportionate quantities of
mixed gases containing sulphuretted hydrogen, which I cause to pass through
the layer of burning coke or coal in the furnace O, and through the upper
part of such furnace in such manner that I may have a suitable proportion
of sulphurous acid produced from the gases passing through the said layer of
burning coke or coal to effect the decomposition of the sulphuretted hydrogen
contained in the gases passing through the upper part of the said furnace O.
I judge of such suitable proportion by testing the residual gases passing
from the washing tower W through the pipo Z. If I find ou introducing
a piece of bibulous paper soaked with a solution of sugar of lead into the
pipe that such paper becomes blackened, I know that an insufficient quantity
of sulphuretted hydrogen contained in the said mixed gases has been passed
through the said layer of burning coke or coal, or that an insufficient quantity
of air for its combustion has been admitted through the damper P; therefore
I either alter the position of the regulating dampers m and n, so as to admit of
the passage of a larger proportionate quantity of mixed gases through the said
layer of burning coke or coal, or I admit a larger quantity of atmospheric air
through the regulating damper P into the ash-pit of the furnace O. If I find
on introducing a piece of bibulous paper moistened with infusion of litmus
into the pipe Z that such paper becomes reddened, I know that an excessive
proportionate quantity of sulphuretted hydrogen contained in the said mixed
gases has become converted into sulphurous acid, and therefore I either alter
the position of the regulating dampers m and n, so as to occasion the passage
of a smaller proportionate quantity of mixed gases through the said layer of
burning coke or coal, or I diminish the admission of atmospheric air through
the regulating damper P into the ash-pit of the furnace O. Under any
circumstances I provide for the admission of sufficient atmospheric air into
the said furnace to maintain such a combustion of coke or coal and of sul-
phuretted hydrogen therein as will communicate to the said mixed gases the
elevation of temperature which I have herein-before mentioned. I prefer to
arrange the said regulation of dampers in such manner that I may find a very
slight indication of sulphuretted hydrogen in the gases passing through the
pipe Z rather than an indication of sulphurous acid therein.
In the manner which I have herein-before described, I effect the decom-

page_text: position of sulphuretted hydrogen contained in mixed gases obtained by
decomposing "alkali waste" with muriatic acid.
I also effect the decomposition of sulphuretted hydrogen contained in such
mixed gases obtained from "alkali waste," and consequent production of
free sulphur therefrom, by causing such mixed gases to become mingled
with hot sulphurous acid gas produced by the combustion of sulphur or of
pyrites with atmospherical air. I cause such mixture so obtained to pass
into the mixing tower S, and from thence into the washing tower W, so as
to separate uncombined sulphur (thereby produced) in mixture with water,
and I regulate the quantity of sulphur or of pyrites consumed, and conse-
quently of sulphurous acid employed, by such tostings as I have herein-
before mentioned as indicating the sufficiency or insufficiency of the quantity
of sulphurous acid so applied.
I can also effect the decomposition of sulphuretted hydrogen contained in
the said mixed gases obtained from "alkali waste," and consequent pro-
duction of free sulphur therefrom by the action of sulphurous acid thereon,
by causing such mixed gases to pass through the chamber of a furnace in
which a layer of coke or coal is undergoing combustion by atmospheric air.
In such case I regulate the quantity of atmospheric air admitted into such
furnace, so as to cause the production of such a quantity of sulphurous acid
by the combustion of sulphuretted hydrogen of the mixed gases as will be
sufficient to effect the decomposition of the remaining portion of such
sulphuretted hydrogen. I regulate the admission of atmospheric air by the
indications of such testings as I have herein-before mentioned. I also
regulate the quantity of coke or coal consumed in such furnace, so as to
communicate such a temperature to the gases proceeding from such furnace
as I have herein-before indicated as being suitable for the mutual décom-
position of sulphurous acid and sulphuretted hydrogen.
In this mode of working, I cause the gases proceeding from the furnace
employed to pass through the mixing tower S, so as to complete the said
mutual decomposition, and the washing tower W,so as to effect the separation
of sulphur therefrom by washing. I prefer to employ the mode of working in
which a portion of the said mixed gases containing sulphuretted hydrogen is
caused to pass through a layer of burning coke or coal with atmospheric air
to produce sulphurous acid,and such product is mingled with another portion
of the said mixed gases at a proper temperature, as herein-before mentioned.
A second object of my said Invention for "improvements in the manufac-
ture of soda and potash," is to obtain an increased proportionate quantity of
caustic soda or caustic potash, in the ordinary manufacture of soda or potash.

page_text: I effect this second object of my Invention, firstly, by using an increased pro-
portionate quantity of small coal in the mixture employed when decomposing
sulphate of soda or sulphate of potash by fluxing; thus, in place of using a
mixture for fluxing, containing three parts of sulphate of soda or sulphate
of potash, three parts of carbonate of lime, and one and a half to two parts of
small coal (which proportions are usually employed), I use nearly equal
weights of each of the said materials, reserving some part of the small coal to
be added as the fluxing proceeds. I thus effect the decomposition of some
part of the carbonate of soda or carbonate of potash produced by such fluxing,
and obtain an increased proportionate quantity of caustic soda orcaustic potash
in solution when I lixiviate the product of such fluxing; and secondly,Ieffect
this second object of my Invention by decomposing sulphuret of sodium or
sulphuret of potassium contained in solutions obtained by the lixiviation of
"black ash" or "ball alkali" by means of hydrated oxide of iron, of zinc, of
manganese, or of lead, thereby producing sulphuret of the metal employed,
and caustic soda or caustic potash. I effect such decomposition by adding to
the solution, obtained by such lixiviation at a boiling heat, such a quantity of
the metallic oxide as I find (by testing the solution with salt of lead) to be
sufficient to decompose the alkaline sulphuret contained therein. I collect
the metallic sulphuret thus produced, and after washing it with water I
.'decompose it by means of muriatic acid, or some other suitable acid producing
a solution of the metal employed. I decompose such metallic solution by
means of hydrate of lime or of magnesia, and I thus obtain hydrated metallic
oxide, suitable for decomposing a further quantity of sulphuret of sodium or
sulphuretof potassium, and thereby producing soda or potash in a caustic stato.
I have herein-before particularly described and ascertained the means
by which I perform my said Invention, but I do not confine myself in
performing the same to the precise details herein-before described, as these
may be modified to some extent without deviating from the nature of my
said Invention; nor do I claim an exclusive right to use such means, except
so far as such use may be comprised within the nature of my Invention, as
herein-after particularly defined. I claim, as my Invention of "improve-
ments in the manufacture of soda and potash," secured to me by the
herein-before in part recited Letters Patent,-
First, the obtainment of sulphur from "alkali waste" (which is constantly
produced in the ordinary manufacture of soda and potash), by decomposing
sulphuretted hydrogen gas (liberated from such "alkali waste") by means of
sulphurous acid gas, , under such conditions as prevent, either altogether or in
great part, the formation ofsuch acid compound or acid compounds of sulphur

page_text: which is or are not capable of being decomposed at ordinary temperatures
by sulphuretted hydrogen gas.
Secondly, the use of such an apparatus as I have herein-before indicated as
the "mixing tower S," for effecting the mixture and consequent mutual
decomposition of sulphuretted hydrogen gas (obtained from "alkali waste")
and sulphurous acid gas, at such temperatures as I have herein-before
indicated as suitable for effecting such mutual decomposition. Also, the
use of such an apparatus as I have herein-before indicated as the "washing
tower W," for effecting, by washing with fluid, the separation of sulphur
from the products of the mutual decomposition of such sulphuretted
hydrogen gas and sulphurous acid gas.
Third, the use of sulphur obtained by the decomposition of sulphuretted
bydrogen gas (liberated from "alkali waste") by incans of sulphurous acid
gas, for the production of sulphuric acid; which sulphuric acid is applicable
in the ordinary manufacture of soda and potash.
Fourth, the obtainment of an increased proportionate quantity of caustic
soda or caustic potash in the ordinary manufacture of soda and potash, by
the use of an increased proportionate quantity of small coal in mixture with
sulphato of soda or sulphate of potash, and lime or carbonate of lime,
subjected to fluxing in such manufacture so as to decompose some carbonate
of soda or carbonate of potash produced by such fluxing, and thereby pro-
duce caustic soda or caustic patash; also, by decomposing sulphuret of
sodium or sulphuret of potassium contained in solutions, obtained by the
lixiviation of "black ash" or "ball akali," by means of certain hydrated
metallic oxides, in the manner herein-before described.
In witness whereof, I, the said William Gossage, have hereunto set my
hand and seal, this Twentieth day of August, in the year of our
WILLIAM (L.S.) GOSSAGE.