A NEW METHOD OR PROCESS AND A NEW COMBINATION OF PROCESSES AND APPLIANCES FOR OBTAINING FROM SULPHIDE OF SODIUM AND SULPHIDE OF POTASSIUM EITHER SILICATES OR ALUMINATES OF SODA AND POTASH AND EITHER FREE SULPHUR OR SULPHUROUS ACID
Year: 1876

page_text: LETTERS PATENT to Walter Weldon, of Abbey Lodge, Merton, in the County
of Surrey, for the Invention of "A NEW METHOD OR PROCESS AND A NEW
COMBINATION OF PROCESSES AND APPLIANCES FOR OBTAINING FROM SULPHIDE
OF SODIUM AND SULPHIDE OF POTASSIUM EITHER SILICATES OR ALUMINATES OF
SODA AND POTASH AND EITHER FREE SULPHUR OR SULPHUROUS ACID"
PROVISIONAL SPECIFICATION left by the said Walter Weldon at the Office
of the Commissioners of Patents on the 28th August 1876.
WALTER WELDON, of Abbey Lodge, Merton, in the County of Surrey "A NEW
METHOD OR PROCESS AND A NEW COMBINATION OF PROCESSES AND APPLIANCES
FOR OBTAINING FROM SULPHIDE OF SODIUM AND SULPHIDE OF POTASSIUM EITHER
SILICATES OR ALUMINATES OF SODA AND POTASH AND EITHER FREE SULPHUR
OR SULPHUROUS ACID."
In certain other Specifications which will be deposited at the Patent Office on the
same day as this I have described certain Inventions relating to the manufacture of
sulphide of sodium and sulphide of potassium, whereby I believe that those bodies can
henceforth be produced so economically as to permit of their being applied to a
number of new and very important purposes. My present Invention has reference
to their application to the manufacture of silicates and aluminates of soda and
potash.
It will be convenient to speak below only of sulphide of sodium and of silicate
and aluminate of soda, but whatever is said of these compounds will be equally
applicable to the corresponding compounds of potassium.
Sulphide of sodium manufactured in accordance with my other Inventions afore-
said will be produced in a cylindrical furnace placed horizontally, arranged so as to
be capable of revolving on its longer axis, and having an opening at each end to
permit of the entry into it and of the passage throught it of products of combustion
or other gases or vapours For the purpose of my present Invention such cylin-
drical or "revolving" furnace must have connected with it at one end an apparatus
for producing superheated steam, and at the other end an apparatus for treating
sulphuretted hydrogen.

page_text: The application of my present Invention commences when the said revolving
furnace contains a charge of sulphide of sodium which has either been produced
therein, or has been otherwise produced and afterwards charged thereinto. In order
to convert such sulphide of sodium into silicate or aluminate of soda I add to the
said sulphide either silica or alumina, accordingly as it is silicate or aluminate that
I desire to produce, and I then send into the furnace superheated steam. While
superheated steam is thus passing into it I keep the furnace in revolution, so that
the steam shall come into contact with all parts of its contents. Under these con-
ditions the steam reacts on the sulphide of sodium, forming on the one hand
sulphuretted hydrogen, which passes off as gas, and on the other hand caustic soda,
which at the moment of its formation combines with the silica or alumina present,
forming silicate or aluminate of soda, as the case may be
The sulphuretted hydrogen produced in tho operation just described can
be treated
in either of two ways It will pass off mixed with steam, and the mixture should
preferably first be cooled so as to condense the steam out of it, leaving the sul-
phuretted hydrogen nearly or quite pure The sulphuretted hydrogen can then either
be simply burnt into sulphurous acid or treated for the obtainment of its sulphur in
the free state by the Invention. for which Her Majesty's Letters Patent, Numbered
2008, and bearing date the 31st July 1871, have been granted to me. But in
applying that method of obtaining sulphur from sulphuretted hydrogen to the sul-
phuretted hydrogen obtained in manufacturing silicate or aluminate of soda as above
set forth, I prefer to employ for the absorption of the sulphuretted hydrogen either
such apparatus as that which is described for the absorption of dilute chlorine in
the Specification of an Invention filed in pursuance of the conditions of Letters
Patent dated the 16th July 1873, and Numbered 2449, or such new apparatus as will
be described in another Specification which will be deposited at the Patent Office on
the same day as this
The steam to be used as above described may be superheated most conveniently
by means of what is known as a Siemens-Cowper stove.
The method of applying the steam may be modified by applying it in another
apparatus than the revolving furnace aforesaid. In such case the silica or alumina
should be mixed with the sulphide of sodium in the revolving furnace; the mixture
should then be withdrawn fiom that furnace and allowed to cool, and then broken
up into small lumps, these lumps being then changed into vertical cylinders, and
therein treated by the superheated steam
The proportions of silica or alumina to be employed per given quantity of sulphide
of sodium must be governed, as will be well understood, by the consideration of
what kind of silicate or aluminate, whether very acid, and therefore insoluble, or
less acid and soluble it may be desired to produce.
The method above described for producing silicate and aluminate of soda may be
modified by using instead of superheated steam a blast of hot air This modification
of the said method yields the sulphur of the sulphide directly as sulphurous acid, but
the sulphurous acid so yielded is less pure and more dilute than that obtained by
burning sulphuretted hydrogen produced by means of superheated steam.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Walter Weldon in the Great Seal Patent Office on the 7th February
1877.
WALTER WELDON, of Abbey Lodge, Merton, in the County of Surrey. "A NEW
METHOD OR PROCESS AND A NEW COMBINATION OF PROCESSES AND APPLIANCES
FOR OBTAINING FROM SULPHIDE OF SODIUM AND SULPHIDE OF POTASSIUM EITHER
SILICATES OR ALUMINATES OF SODA & POTASH & EITHER FREE SULPHUR OR
SULPHUROUS ACID."

page_text: This Invention consists in a new method or process, a combination of this method
or process with certain other methods or processes, and a combination of appliances,
whereby I transform sulphide of sodium into silicate and aluminate of soda, and
sulphide of potassium into silicate and aluminate of potash, and at the same time
obtain the sulphur of the said sulphides either as free sulphur or as sulphurous
acid.
In describing my said Invention it will be convenient to speak only of sulphide
of sodium and of silicate and aluminate of soda; but all that will be said of these
compounds will be equally applicable to sulphide of potassium and silicato and
aluminate of potash.
The said new method or process consists in mixing sulphide of sodium, preferably
in the state of fusion, with either silica or alumina accordingly as it is silicate or
aluminate which is to be produced, and then treating the mixture by superheated
steam. The steam reacts on the sulphide of sodium, liberating its sulphur as sul-
phuretted hydrogen, which passes off as gas, and forming caustic soda, which caustic
soda then reacts on the silica or alumina, forming silicate or aluminate, as the case
may be.
I combine this method of obtaining silicate or aluminate of soda with one or other
of two methods of utilizing the sulphuretted hydrogen which is produced at the
same time. The said sulphuretted hydrogen passes off mixed with steam. By one
method of utilizing it I simply pass the mixture of sulphuretted hydiogen and steam
through cooling pipes or other convenient apparatus, whereby I separate the steam
by condensation, and then burn the sulphuretted hydrogen directly to sulphurous
acid; I prefer however to treat it for the obtainment of its sulphur in the free state
by a former Invention, for which Letters Patent bearing date the Thirty-first of
July 1871, and Numbered 2008, have been granted to me
To carry into effect the above stated method of obtaining silicate or aluminate of
soda, together with that method of treating the resulting sulphuretted hydiogen
which I believe to be the most advantageous, I employ a combination of appliances,
the central element of which is a revolving furnace lined with blocks of carbon, pre-
ferably though not necessarily such as are produced by artificially agglomerating
coke under my Invention, the Letters Patent for which are Numbered 3382, of the
year 1876. As required only for the conversion of sulphide of sodium into silicate
or aluminate of soda, this furnace need differ from the revolving furnaces at present
in nearly general use among manufacturers of alkali only in being lined with blocks of
cai bon instead of with fire-brick; but when the furnace is to be used not only for the
conversion of sulphide of sodium into silicate or aluminate as aforesaid, but also for
the manufacture of the sulphide itself, it may have likewise the further peculiarities
which are described for a revolving furnace for the manufacture of alkaline sul-
phides in the Specification of my Patent Numbered 3380, of the year 1876. With
one end of the said carbon lined revolving furnace I connect any suitable apparatus
for the production of highly superheated steam, which apparatus may conveniently
be that which is known as the Siemens-Cowper stove, and the other end of it I
connect with such apparatus for the treatment together of a gas or gases and a
liquid, as is described in the Specification of my Patent Numbered 3389, of the year
1876. To these appliances must be added an "oxidizer," such as is used in my
well-known process for the regeneration of the manganese employed in the manu-
facture of chlorine.
The mode of working is as follows:-When the revolving furnace contains a
charge of sulphide of sodium which has either been produced therein, or having
been produced in other apparatus has been charged thereinto, such sulphide being
preferably in the state of fusion, I add thereto silica or alumina, accordingly as
it is silicate or aluminate that I desire to obtain, and I then put the furnace in
revolution and send into it a blast of highly superheated steam. As long as steam
is going into it I keep the furnace in revolution in order that the steam inay come
into contact with all parts of its contents. When sulphuretted hydrogen ceases to

page_text: be evolved the entrance of the steam is interrupted, and the charge having now
become converted into silicate or aluminate, as the case may be, is withdrawn from
the furnace, and the furnace is then recharged for a fresh operation.
The sulphuretted hydrogen which is ovolved during the operation just described
passes on leaving the furnace into the first of a series of closed vessels or "absorbers,"
each of them partially filled with a mixture with water of finely divided oxide of
iron or of manganese. Almost any oxide of either of these metals may be used, but
I prefer to employ precipitated and therefore hydrated sesquioxide of iron. Each
vessel of the said series is furnished with a mechanical agitator consisting of a
number of arms attached at right angles to an axis or shaft placed horizontally, and
these agitators are so arranged and kept in such rapid motion as to maintain in the
upper part of each vessel a continual rain or spray of the mixture with water of
oxide of iron or other oxide, as aforesaid. The sulphuretted hydrogen enters the
first vessel of the series at its upper part, and there comes into contact with an
enormous surface of the said rain or spray. It comes into contact at the same time
with the continually renewed surface of the mixture of metallic oxide and water m
the lower part of the vessel. Under these conditions much of the sulphurotted
hydrogen first dissolves in the water of the said mixture, and then reacts upon the
metallic oxide therein, its sulphur entering into combination with the metal of the
said oxide, and its hydrogen with the oxygen thereof. That part of the sulphuretted
hydrogen which has not time thus to react upon the mixture of oxide and water in
the said fist vessel, and thus to become absorbed in that vessel, passes on into the
upper part of the second vessel of the series, where a further portion of it reacts,
and thereby becomes absorbed as aforesaid, what is not absorbed in this second
vessel passing on into the upper part of the next vessel of the series, and so on
until evory trace of the sulphuretted hydrogen has been absorbed. If the size of
the absorbers be properly adjusted to the size of the revolving furnace and to the rate
at which sulphuretted hydrogen is produced therein, from four to six absorbers will
suffice for its complete absorption, but much will depend in this respect upon the
speed at which the agitators are worked. When the oxide of iron or other oxide in
the mixture thereof with water with which the first vessel was charged has been
completely converted into sulphide, the contents of that vessel are withdrawn there-
from, and the contents of the second vessel are transferred to the said first vessel,
those of the third vessel are transferred to the second vessel, and so on throughout
the series, the last vessel when its contents have been transferred to the last but one
being recharged with fresh mixture of oxide and water. The mixture of metallic
sulphide with water which has thus been withdrawn from the first vessel of the
series is put into an "oxidizer" or deep cylindrical vessel, connected with a blowing
engine by a pipe conveying air therefrom, which pipe terminates near the bottom
of the oxidizer in an arrangement of smaller pipes or other suitable appliance for
disseminating as thoroughly as possible through the contents of the vessel the air
which may be injected into it. Therein the said mixture of metallic sulphide with
water is treated by air until the sulphide in such mixture is reconverted into oxide,
its sulphur being at the same time set free. The product of this operation is a
mixture with water of metallic oxide and free sulphur. This mixture can be used
again for the absorption of more sulphuretted hydrogen instead of fresh mixture of
oxide and water, and with intermediate treatment by air it can thus be employed
several times successively, becoming continually richer and richer in sulphur. When
it contains such proportion of sulphur as may be preferred, it may be treated by
hydrochloric or other suitable acid so as to dissolve the oxide out from it, leaving
free sulphur; or the mixture of oxide and free sulphur may be separated from the
water it is mixed with or suspended in, and be drained and dried, and may then
have its sulphur burnt off fiom it as sulphurous acid, us will be well understood.
Applied in this last-mentioned manner the said mixture gives sulphurous acid gas
as little diluted as can be obtained by burning the best brimstone, and far less dilute
than that obtained by burning pyrites, seeing that the sulphur in the said mixture
is all in the free state and not combined, and that the metal in the mixture is

page_text: already fully oxidized, and so absorbs no oxygen in the operation of burning off
the sulphur.
Instead of performing in a revolving furnace, as aforesaid, the above described
treatment by superheated steam of a mixture of sulphide of sodium and silica or of
a mixture of sulphide of sodium and alumina, that treatment may be performed in
other apparatus, but the means of performing it which are above described I beleive
to be the best.
Another method consists in mixing the silica or the alumina with the sulphide of
sodium while the latter is in the state of fusion, then allowing the mixture to cool
and solidify, and then breaking it up into small lumps, charging these lumps into
vertical cylinders, and passing the steam through and among them as contained
therein
The treatment as above described of mixtures of sulphide of sodium with silica or
alumina may be modified by using a blast of highly heated air instead of super-
heated steain. This method yields directly as sulphurous acid the sulphur of as
much of the sulphide as becomes thereby converted into silicate or aluminate, but
the sulphurous acid so obtained is extremely dilute, and much of the sulphide,
instead of being enabled to react on the silica or alumina is always oxidized to
sulphate.
The proportions of silica or alumina per given quantity of sulphide of sodium to
be used in the mixtures to be treated under the present Invention must be governed,
as will be well understood, by the consideration of what kind of silicate or aluminate,
whether very acid and therefore insoluble, or less acid and therefore soluble, it may
be desired to obtain.
Having now described the nature of my said Invention, and in what manner the
same is to be performed, I claim as the Invention to be secured to me by the herein-
before in part recited Letters Patent,―
Firstly. The new method or process for transforming sulphide of sodium into
silicate or aluminate of soda, and sulphide of potassium into silicate or aluminate of
potash, which is above described.
And, Secondly. The combination of processes and appliances whereby, substan-
tially as is above set forth, I transform sulphide of sodium into silicate or alumi-
nate of, soda, & sulphide of potassium into silicate or aluminate of potash, and at
the same time obtain the sulphur of the said sulphides either as free sulphur or as
sulphurous acid.
In witness whereof, I, the said Walter Weldon, have hereunto set my hand
and seal, this Thirtieth day of January, in the year of our Lord One
thousand eight hundred and seventy-seven.