AN IMPROVED METHOD OF DECOMPOSING CHLORIDE OF SODIUM AND OTHER COMPOUNDS BY MEANS OF STEAM
Year: 1866

page_text: LETTERS PATENT. to Walter Weldon, of Park Villa, West Hilll, Highgate,
in the County of Middlesex,. for the Invention of "AN IMPROVED METHOD
OF DECOMPOSING CHLORIDE OF SODIUM AND OTHER COMPOUNDS BY MEANS OF
STEAM."
Sealed the 16th April 1867, and dated the 26th October 1866.
PROVISIONAL SPECIFICATION left by the said Walter Weldon at the
Office of the Commissioners of Patents, with his Petition, on the
26th October 1866.
I, WALTER WELDON, of Park Villa, West Hill, Highgate, in the County
of Middlesex, do hereby declare the nature of the said Invention for
IMPROVED METHOD OF DECOMPOSING CHLORIDE OF SODIUM AND OTHER COMPOUNDS BY
MEANS OF STEAM," to be as follows:-
This Invention has for its object the decomposition of chloride of sodium
and other compounds by means of steam. As regards chloride of sodium, or
common salt, it is well known that steam is capable of decomposing that
compound, but prior to the present Invention there had not been devised any
arrangements by means of which that decomposition could be effected on a
manufacturing scale. It can be conducted on any scale, however, by means of
my present Invention, in carrying which into effect I hoat the salt to the
ונס..מ

page_text: point at which the steam will react upon it, instead of by simply applying heat
externally to the vessel containing the salt, either wholly or at least partially,
by causing to come in direct contact with the salt itself either atmospheric
air or any suitable gas or mixture of gases previously heated to the
requisite temperature. I thus pass into the vessel or oven or furnace con-
taining the salt, not only steam, but also highly heated air, or a highly heated
gas or mixture of gases, whereby I keep the salt (which may first, when pre-
ferred, have been heated as far as practicable by other means) at the tem-
perature most suitable to the end to be attained. In order to cause the steam
and hot air or gas or mixture of gases to come into contact with the whole
of the salt, I either cast the salt into blocks of large surface and support these
in the vessel or oven in which the decomposition is to take place, in such wisc
that the hydrate of sodium which is one of the products of the decomposition
shall run down their sides as it is formed, collecting on the bottom or floor of
the vessel or oven, and so continually exposing a new surface of un-
decomposed salt to the action of the steam and hot air, or hot
gas or mixture of gases; or I support the bottom or floor of the vessel or
oven on a hydraulic ram or other ready means of altering its elevation at will,
place the salt upon this moveable bottom or floor, provide at a certain level
inclined platforms, down which the hydrate of sodium as it is formed may run
or be swept by mechanical means into suitable reservoirs, and as fast as the
salt at the surface is decomposed and the resulting hydrate of sodium removed
so elevate the moveable bottom or floor as to bring a new surface of salt
under the action of the steam and hot air, or hot gas or mixture of gases.
By first casting the salt into solid blocks I can similarly expose it at the sides
as well as at the bottom of the vessel or oven, making the sides as well as the
bottom moveable as above described; or I can expose it at the sides only,
and not at the bottom at all. When it is not convenient to have either the
sides or the bottom of the vessel or oven moveable, I either pass the steam
and hot air or hot gas or mixture of gases through the whole mass of the salt,
or I pass them over or inject them upon the surface of the salt, and from time
to time sweep off the hydrate of sodium formed, and so expose a new surface
of salt to decomposition. It is a good plan to first heat the salt
to fusion in a separate furnace, and pour it into the decomposing vessel or
oven in the molten condition. Its decomposition is then effected much more
rapidly than when the salt is charged cold, and requires less hot air or hot gas
or mixture of gases, steam alone indeed, when a moveable bottom is used and
the oven is charged with highly heated salt, sometimes being sufficient.
Usually, however, a heating agent will be required as well as the steam; and

page_text: when I do not use for this purpose simply hot atmospheric air, I prefer to use, if
I desire to obtain hydrate of sodium, the mixture, consisting chiefly of nitrogen
and carbonic oxide, which results from passing atmospheric air through a
sufficient excess of incandescent carbonneous fuel; or, when I desire to obtain
carbonate of sodium, the mixture, consisting chiefly of nitrogen and carbonic
acid gases, which is got by passing atmospheric air through incandescent
carbonaceous fuel in proportions the reverse of those just mentioned. When
I desire to produce silicate or aluminate of sodium, I mix the chloride of
sodium with silica or alumina, and then proceed as with the simple chloride;
and so, likewise, in other similar cases.
I have spoken above more particularly of chloride of sodium, but fluoride
of sodium is decomposible in precisely the same way, and the plan above
described is moreover applicable in all its essential features to other salts of
sodium, and also to many compounds of other bases. I need only add that
with some salts it is a good plan to place them in a revolving furnace, and to
pass through that the required steam and hot air or hot gas or mixture of
gases.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Walter Weldon in the Great Seal Patent Office on the 25th
April 1867.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WALTER
WELDON, of Park Villa, West Hill, Highgate, in the County of Middlesex,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-sixth day of October, in the year of our
Lord One thousand eight hundred and sixty six, in the thirtieth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Walter Weldon, Her special licence that I, the said Walter
Weldon, my executors, administrators, and assigns, or such others as I, the
said Walter Weldon, 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 "An
IMPROVED METHOD OF DECOMPOSING. CHLORIDE OF SODIUM-AND-OTHER-COMPOUNDS BY
MEANS OF STEAM," upon the condition (amongst others) that I, the said
Walter Weldon, my executors or administrators, by an instrument in writing

page_text: 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 Walter Weldon, do hereby declare
the nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement:-
This Invention has for its object the decomposition as a manufacturing
process of chloride of sodium and other compounds by means of steam. As
regards chloride of sodium, or common salt, it is well known that steam is
capable of decomposing that compound, but prior to the present Invention
there had not been devised any arrangements by means of which this decom-
position could be effected on a manufacturing scale. It can be conducted on
any scale, however, by means of my present Invention, in carrying which into
effect I heat the salt to the point at which the steam will react upon it
instead of by simply applying heat externally to the vessel containing the salt,
either wholly or at least partially, by causing to come in direct contact with
the salt itself either atmospheric air or any suitable gas or mixture of gases
previously heated to the requisite temperature. I thus pass into the vessel
or oven or furnace containing the salt, not only steam, but also highly heated
air or a highly heated gas or mixture of gases, whereby I keep the salt (which
may first have been heated as far as practicable by other means) at the tem-
perature most suitable to the end to be attained. In order to cause the steam
and hot air or hot gas or mixture of gases to come into contact with the whole
of the salt, I either cast the salt into blocks of large surface, and support
these blocks in the vessel or oven or furnace in which the decomposition is
to take place in such wise that the alkaline compound, which is one of the
products of the decomposition, shall run down their sides as it is formed,
collecting on the bottom or floor of the vessel or oven, and so continually
exposing a new surface of undecomposed salt to the action of the steam and
hot air or hot gas or mixture of gases; or I support the bottom or floor of the
vessel or oven or furnace (which bottom or floor may conveniently
be made of iron, the other parts of the vessel or oven or furnace
being made of refractory brick) upon a hydraulic ram, a powerful screw, cr
any other ready means of altering its elevation at will, place the salt upon
this moveable bottom or floor, provide at a certain level 'suitable receptacles
into which the alkaline compound resulting from the decomposition of the

page_text: By first
salt may either run as it is formed or from time to time 'be swept by means
of a rake or other suitable appliance; and as fast as the salt at the sur-
face is decomposed, and the resulting film or layer of alkaline compound is
removed, so elevate the moveable bottom or floor of the oven or furnace as
to bring a fresh surface of salt into the position in which it can best be acted
upon by the steam and hot air or hot gas or hot mixture of gases.
casting the salt into solid blocks I can similarly expose it at the sides as well
as at the bottom of the oven or furnace, making the sides as well as the
bottom moveable as above described; or I can expose it in the manner set
forth at the sides only, and not at the bottom at all. When it is not convenient
to have either the sides or the bottom of the vessel or oven or furnace move-
able as above described, I pass the steam and hot air or hot gas or hot
mixture of gases through the whole mass of the salt, or I pass them over or
inject them upon the surface of the salt, and from time to time sweep off the
alkaline compound formed, and so expose a new surface of salt to decom-
position. Whether I proceed in this manner or in the manner previously
described, I prefer to highly heat the salt in a separate vessel or furnace
before introducing it into the vessel or furnace in which its decomposition is
to take place. This expedient enables the decomposition to be effected far
more readily and with a much less expenditure of hot air or hot gas or hot
mixture of gases, than when the salt is charged cold; indeed, by the aid of
this expedient, especially when using also the moveable floor described above,
I can decompose the salt by steam without mixing the steam with hot air or
hot gas or mixture of gases. It is greatly preferable, however, to use a
heating agent as well as the steam; and when I do not use for this purpose
simply highly heated atmospheric air I prefer to use, if I desire to obtain
hydrate of sodium, the products of combustion of a furnace, the carbonaceous
fuel burnt in which escapes from it chiefly in the form of carbonic- oxide; or
when I desire to obtain carbonate of sodium, the products of combustion of a
furnace in which the carbon of the fuel consumed is for the most part con-
verted into carbonic acid. When I desire to produce silicate or aluminate of
sodium, I mix the chloride of sodium with silica or alumina, and then proceed
as when using the chloride only.
I have spoken above only of chloride of sodium, but my Invention is appli-
cable-also-to-both fluoride-of sodium and nitrate of sodium, and moreover to
various other sodium salts, including the sulphate, and to a great number of
compounds of other bases.
Having now described the nature of my said Invention, and the manner in
which the same is to be performed, I claim as my Invention, and desire to be

page_text: secured to me by the herein in part recited Letters Patent, the decomposition
of chloride of sodium and other compounds by means of steam, substantially
as is above described.
In witness whereof, I, the said Walter Weldon, have hereunto set my
hand and seal, this Twenty-fifth day of April, in the year of our Lord
One thousand eight hundred and sixty-seven.
WALTER WELDON. (L.s.)