IMPROVEMENTS IN THE MANU FACTURE OF CARBONATE OF SODA
Year: 1855

page_text: LETTERS PATENT to George Louis Stott, of. St. George's, in the County
of Gloucester, for the Invention of "IMPROVEMENTS IN THE MANU
FACTURE OF CARBONATE OF SODA."
Sealed the 23rd May 1856, and dated the 27th November 1855.
PROVISIONAL SPECIFICATION left by the said George Louis Stott, at
the Office of the Commissioners of Patents, with his Petition, on the
27th November 1855.
I, GEORGE LOUIS STOTT, of St. George's, in the County of Gloucester, do
hereby declare the nature of the Invention for IMPROVEMENTS IN THE MANU-
PACTURE OF CARBONATE OF SODA, to be as follows:-
My improvement consists in a new mode or process for freeing the liquor
containing the sulphuret of sodium, known in the process of alkali making
from chloride of sodium as "vat liquor," from the sulphur held in combination
therein.. This I effect chiefly by placing such liquor in a suitable covered or
closed vessel, and forcing, pumping, or otherwise compelling carbonic acid gas
to enter and combine with the said liquor under pressure, whereby the greater
part if not all the sulphur contained in such liquor will be precipitated, and the
alkali therein converted into carbonato of soda, from which, by evaporating to
the proper strength and cooling, crystals of carbonate of soda from the vat
liquor so treated may be at once obtained. Secondly, where the object may
not be to obtain the carbonate of soda in crystals, but in what is termed in

page_text: commerce soda ash, or soda ash liquor, for soap-making, alkaline lees and
other purposes, I employ the oxides of certain metals, that is to say, the oxide
of iron, the oxide or peroxide of manganese, and the oxide of zinc, or either or
all of them; and these oxides of metals, in the most minute state of mechanical
division to which I can bring them, I, mix and combine by agitation into the
solution of sulphuret of sodium.or vat .liquor, whereby the sulphur will be
taken into combination with the oxide of the metal employed, and the alkaline
solution left free, either to bo afterwards combined with carbonic acid for the
production of crystals of carbonate of soda, or evaporated and dried into the
salt known as soda ash, or rendered caustic, so as to be used at once to combine
with resinous; oleaginous, and fatty matters in the manufacture of soaps,
and for other purposes; or I use the two processes herein described in
combination, that is to say, I employ first carbonic acid gas in closed vessels
and under pressure, and afterwards the oxides of one or more of the metals
named; or I employ first the oxides of one or more of the metals named,
and afterwards the carbonic acid gas in closed vessels and under pressure,
and I employ either or both until I find the vat liquor or solution of sulphuret
of sodium freed from its sulphur, and fit for all the purposes to which
alkaline liquor free from sulphur is usually applied; and I afterwards recover
the metals employed from their combinations with the sulphur of the alkali by
roasting and other means, well known to metallurgists, whereby they will
become re-oxidised, and capable of being again employed to desulphurize other
"vat liquor," as at first.
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SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said George Louis Stott, in the Great Seal Patent Office on
the 27th May 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
LOUIS STOTT, of St. George's, in the County of Gloucester, send greeting.
WHEREAS Her most Excellent Majesty. Queen Victoria, by Her. Letters
Patent, bearing date the Twenty-seventh day of November, in the year of our
Lord One thousand eight hundred and fifty-five, in the nineteenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, tho
said George Louis Stott, Her special licence that I, the said Georgo Louis
Stott, my exccutors; administrators, and assigns, or such others as I, the said
George Louis Stott, my executors, administrators, and assigns, should at any
time agree with, and no others, from time to time and at all times. there-

page_text: after 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 CARBONATE OF SODA," upon the condition (amongst
others) that I, the said George Louis Stott, 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 Inven-
tion, 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 George Louis Stott, 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 improvement consists in a new mode of freeing liquor containing
sulphuret of sodium, known in the process of alkali making from common salt
as "vat liquor," from the sulphur therein held in combination or solution.
This I effect by adding to such solution, whilst it is being evaporated to the
usual crystallizing strength, metals in the state of oxides, that is to say, the
oxide of iron, the oxide of manganese, and the oxide of zinc, either or all of
them separately or combined (especially the oxide of zinc, which I prefer as
acting the more readily), and I employ these in the most minute state of
division in which they can be obtained. These oxides I mix and combine by
agitation. with and into the solution containing sulphuret of sodium or "vat
liquor," until upon trial with the usual tests all trace of sulphur has dis-
appeared, it having combined and formed a sulphuret with the metal or metals
employed, which sulphuret or sulphurets are readily separated by subsidence
and filtration, leaving the liquor fit to be carbonated so as to produce
crystallized carbonate of soda, as herein-after described, or to be evaporated in
proper pans or furnaces, as heretofore, into soda ash, or rendered caustic for soap-
making, or for other purposes to which alkali or alkaline liquor is usually
applied. But when the object is to obtain carbonate of soda in crystals or in
a crystalline state, I then inject into or otherwise combine with the alkaline
liquor (desulphuretted by the use of the oxides of the metals, as before
described,) carbonic acid gas obtained from any of the usual sources, until the
caustic alkali or soda is thoroughly saturated and combined therewith, and
become converted into solution of carbonate of soda, when being evaporated to
its proper strength or gravity it is filtered and passed into the crystallizing
vessels, and I afterwards collect the sulphurets of the metals resulting

page_text: from the oxides of the metals so employed in desulphurizing vat liquor
containing sulphuret of sodium in solution, and by roasting in a current of air,
or by other means, well known to metallurgists, I drive off or expel the
sulphur with which the metal or metals had combined, so as to recover or
obtain the oxides of the said metals, and render them capable and fit for
desulphuretting other vat liquor or solutions containing sulphuret of sodium,
as at first; and I would remark that the oxide of the metal may be used in
the state of carbonate of the oxide where it is more readily obtained in this
state, and in this case a smaller quantity of carbonic acid gas will afterwards
be necessary to complete the conversion of the soda into carbonate of soda.
My claim is for the use or employment of the oxides of certain metals, that
is to say, the oxide of iron, the oxide of manganese, and the oxide of zinc, for
the purpose of freeing "vat liquor," or solution containing sulphuret of sodium,
from the sulphur held in solution or combination therein, as herein described..
In witness whereof, I, the said George Louis Stott, have hereunto set
my hand and seal, this Twenty-sixth day of May, in the year of our
Lord One thousand eight hundred and fifty-six.
Witness,
S. CARPMAEL
GEORGE LOUIS STOTT. (L.S.)