IMPROVEMENTS IN THE MANUFACTURE OF CERTAIN SALTS OF SODA
Year: 1853

page_text: LETTERS PATENT to Thomas Cottrill, of West Bromwich, in the
County of Stafford, for the Invention of "IMPROVEMENTS IN THE
MANUFACTURE OF CERTAIN SALTS OF SODA."
Sealed the 16th March 1853, and dated the 11th January 1853.
PROVISIONAL SPECIFICATION left by the said Thomas Cottrill at
the Office of the Commissioners of Patents, with his Petition, on
the 11th January 1853.
I, THOMAS COTTRILL, of West Bromwich, in the County of Stafford, do
hereby declare the nature of the said Invention for "IMPROVEMENTS IN
THE MANUFACTURE OF CERTAIN SALTS OF SODA" to be as follows:-
My Invention refers to the treatment of the vat liquor obtained by
the solution of the products obtained from the furnaces known as black
ash furnaces in the manufacture of "soda ash," and consists of the
addition to the said liquor of the poto-carbonate of iron, whereby the
sulphuret of sodium contained in the said liquor is decomposed, and
the carbonate of soda is formed.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Thomas Cottrill in the Great Seal Patent Office
on the 11th July 1853..
TO ALL TO WHOM THESE PRESENTS SHALL COME, I,
THOMAS COTTRILL, of West Bromwich, in the County of Stafford, send
greeting.
WHEREAS Iler most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eleventh day of January, in the year of
our Lord One thousand eight hundred and fifty-three, in the sixteenth
year of Her reign, did, for Herself, Her heirs and successors, give and
grant mito nic, the said Thomas Cottrill, Her special licence that I, the
said Thomas Cottrill, my executors, administrators, and assigns, or such
others as I, the said Thomas Cottrill, 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 CERTAIN SALTS OF SODA," upon the condition (amongst others) that I,
the said Thomas Cottrill, by an instrument in writing under my hand
and scal, 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 J, the said Thomas Cottrill, 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 refers to the treatment of the vat liquor obtained by
the solution of the products obtained from the furnaces known as black
ash furnaces in the manufacture of "soda ash," and consists of the
addition to the said liquor of the proto-carbonate of iron, whereby the
sulphuret of sodium contained in the said liquor is decomposed, and
the carbonate of soda is formed.
The method now usually employed in the manufacture of carbonate

page_text: of soda, after decomposing the sulphate of soda in a reverberatory fur-
nace by means of coal and lime stone, or the like, is to lixiviate the
black ash balls so produced in vats or tanks, to boil to a strength the
liquor obtained from these balls, afterwards to salt it down in other
pans, as is well understood, and bring it to a dry state in reverberatory
furnaces. The produce is what is known in the trade by the termi
"soda ash," but it sonictimes undergoes a second process of dissolving,
salting down, and furnacing to purify it still further. To produce "soda.
that crystallized carbonate of soda, the soda ash from the first process
is re-dissolved, filtered, and crystallized. In the method which I employ
I lixiviate the black ash balls in the usual way, but to the liquor thus
produced, either before or after it is boiled to a strength, I mix the
native carbonate of iron (proto-carbonate) finely powdered in such
quantities as may be necessary to purify the liquor sufficiently, which
is readily ascertained by testing a quantity of the liquor with acetate
of lead, and if the precipitate is black it indicates that sufficient
of the carbonate of iron has not been applied, and then in the usual
way boil the liquor to strength, run it into pans to crystallize, to make
"soda," or by the usual process of salting down and furnacing convert
it into "ash" for sale.
The quantity of the native carbonate of iron it is found necessary to
employ varies with the quantity of the liquor from the black ash balls,
but I find from experience that about half a ton of native carbonate of
iron of good quality is generally sufficient for one ton of dry "ash" of
52° in strength to purify the liquor for making "soda" and "soda ash."
In witness whereof, I, the said Thomas Cottrill, have hereunto set
my hand and seal, this Eleventh day of July, in the year of our
Lord One thousand night hundred and fift. thune
Witness,
S. CARPMAEL.
THOMAS COTTRILL. (L.S.)