IMPROVEMENTS IN THE MANUFACTURE OF SILICATE OF SODA, OR SILICATE OF POTASH, AND IN THE MANUFACTURE OF ARTIFICIAL STONE
Year: 1862

page_text: LETTERS PATENT to Charles Thomas, of the City of Bristol, Soap
Manufacturer, for the invention of "IMPROVEMENTS IN THE MANUFACTURE
OF SILICATE OF SODA, OR SILICATE OF POTASH, AND IN THE MANUFACTURE OF
ARTIFICIAL STONE."
Sealed the 21st January 1863, and dated the 13th October 1862.
PROVISIONAL SPECIFICATION left by the said Charles Thomas at the
Office of the Commissioners of Patent, with his Petition, on the 13th
October 1862.
I, CHARLES THOMAS, of the City of Bristol, Soap Manufacturer, do hereby
declare the nature of the Invention for "IMPROVEMENTS IN THE MANUFACTURE
OF SILICATE OF SODA, OR SILICATE OF POTASH, AND IN THE MANUFACTURE OF
ARTIFICIAL STONE," to be as follows:-
This Invention has for its object "Improvements in the Manufacture of
Silicate of Soda, or Silicate of Potash, and in the Manufacture of Artificial
Stone."
In the manufacture of these substances it is usual to digest the silica with
the potash or soda in a close boiler, in which mechanical stirrers have in some
cases been arranged. According to my Invention 1 mount the boiler so that
it can rotate or oscillate. The boiler is kept in motion during either the
whole or a portion of the time occupied in the process of digestion, and in

page_text: this manner there is produced a friction between the several particles of silica
sufficient to rub off the gelatinous coating formed by the action of the caustic
alkali on the same, and thus the process of solution is greatly facilitated,
clean surfaces being constantly presented to the action of the soda or potash.
I prefer to use a jacketted boiler heated by steam, rotating or oscillating
horizontally. In some cases I make the boiler stationary, and cause the cage
within the boiler containing the silica to revolve or oscillate independantly of
the boiler or dissolving vessel. In manufacturing artificial stone, I combine
a solution of silicate of soda with the refuse produced in the process of alkali
making, and commonly known. as "black-ash waste," or with "burnt iron
pyrites," ground or pulverized, or with a mixture of these two materials.
These substances will when mixed with silicate solution form a hard stony
mass, and the composition whilst soft may be moulded into any desired form,
or made into large or small blocks suitable for building or other purposes.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Charles Thomas in the Great Seal Patent Office on the
13th April 1863.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, CHARLES
THOMAS, of the City of Bristol, Soap Manufacturer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirteenth day of October, in the year of our Lord
One thousand eight hundred and sixty-two, in the twenty-sixth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Charles Thomas, Her special licence, that I, the said Charles Thomas,
my executors, administrators, and assigns, or such others as I, the said
Charles Thomas, 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 SILICATE OF SODA, OR SILICATE OF POTASH, AND IN THE
MANUFACTURE OF ARTIFICIAL STONE," upon the condition (amongst others) that
I, the said Charles Thomas, my executors or administrators, by an instru-
ment 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

page_text: 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 Charles Thomas, 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 Invention has for its object improvements in the manufacture of silicate
of soda, or silicate of potash, and in the manufacture of artificial stone.
In the manufacture of silicates of soda or of potash it is usual to digest the
silica with the potash or soda in a close boiler, in which mechanical stirrers
have in some cases been arranged. According to my Invention, I mount the
boiler so that it can rotate or oscillate. The boiler is kept in motion during
either the whole or a portion of the time occupied in the process of solution,
and in this manner there is produced a friction between the several particles
of silica sufficient to rub off the gelatinous coating formed by the action of the
caustic alkali on the same, and thus the process of solution is greatly facilitated,
clean or fresh surfaces being constantly presented to the action of the soda or
potash. I prefer to use a jacketed boiler heated by steam, rotating or
oscillating horizontally; such a boiler is shown on Sheet 1 of the annexed
Drawings, and to use an alkaline solution of a specific gravity ranging from
1100 to 1200 degrees. In some cases I make the boiler stationary, and
cause a cage within the boiler containing the silica to revolve or oscillate
independently of the boiler or dissolving vessel, such an arrangement is shown
on Sheet 2 of the annexed Drawings. The process, as far as the strength of
the alkaline solution and the quantity of silica is concerned, is conducted in
the ordinary manner of producing silicates of potash and soda by solution, and
the process is continued until by drawing samples the alkali is found to be
sufficiently saturated with silica. In order to heat the digesting vessel I prefer
to employ steam of a pressure of about fifty pounds per square inch. In
manufacturing artificial stone, I combine a solution of silicate of soda with
the refuse produced in the process of alkali making, and commonly known as
"black-ash waste," or with "burnt iron pyrites," ground or pulverized, or
with a mixture of these two materials. The black-ash waste and burnt iron
ore will when mixed, either separately or conjointly with silicate solution, form
a hard stony mass, and the composition whilst soft may be moulded into any
desired form, or made into large or small blocks suitable for building or other
purposes. I prefer to use the silicate solution of a density of 1750, and in

page_text: the proportion of from 20 to 30 per cent. of the weight of the black-ash waste
or burnt iron pyrites, or of those two substances in equal parts. The mixture
may be most conveniently effected in a mortar pug mill. The compound on
coming out of the mill should be at once moulded to the form required.
In witness whereof, I, the said Charles Thomas, have hereunto set my
>hand and seal, this Tenth day of April, in the year of our Lord One
thousand eight hundred and sixty-three.
Signed, sealed, and delivered by the
above-named Charles Thomas in
..the presence of
W. BRITTAN,
CHARLES THOMAS. (L.S.)
Solicitor, Bristol.