IMPROVE- MENTS IN THE MANUFACTURE OF SODA
Year: 1875

page_text: LETTERS PATENT to James Mactear, of Glasgow, in the County of
Lanark, North Britain, Chemist, for the Invention of "IMPROVE-
MENTS IN THE MANUFACTURE OF SODA."
Sealed the 26th October 1875, and dated the 8th May 1875.
PROVISIONAL SPECIFICATION left by the said James Mactear at the
Office of the Commissioners of Patents, with his Petition, on the
8th May 1875.
I, JAMES MACTEAR, of Glasgow, in the County of Lanark, North
Britain, Chemist, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN THE MANUFACTURE OF SODA," to be as follows, that is
to say :-
This Invention relates to an improved combination of processes
whereby, in the manufacture of soda, a part of the operations hitherto
required may be dispensed with, whilst soda sulphate is more completely
separated from the products and profitably utilised.

page_text: In applying the Invention in the case of the ordinary vat liquor of the
soda manufacture, this liquor is by preference first treated with carbonic
acid until the caustic soda is carbonated, and silica, alumina, and iron,
thrown down. Any excess of carbonic acid may be taken up by the
addition of untreated liquor. The separated liquor, if not already strong
enough, is then boiled or concentrated so as to crystallise on cooling,
and is constantly stirred or agitated whilst cooling, so that the soda may
separate in a granulated condition. The granulated soda, after being
separated from the remaining liquor, is washed and most of the
impurities not left in the liquor are thereby removed. The remaining
liquor after being again treated with carbonic acid if necessary is to be
boiled down to the salting point and again agitated whilst cooling, so as
to obtain a further supply of granulated soda, which is to be purified by
washing like the first. The same treatment may be repeated a third time
if found desirable. The liquor still remaining and which will contain
most of the soda sulphate and impurities may be again boiled down
nearly or altogether to dryness, and the resulting salts may be
decomposed in the ball furnace, as commonly practised with fresh soda.
sulphate.
In a similar manner what are known as "red" liquors and also the
mother liquors from which soda crystals have been separated, may be
first treated with carbonic acid, any excess of which can be taken up by
adding more untreated liquor, and then after boiling down, if necessary,
be agitated whilst cooling or crystallising, so as to yield the soda in a
granulated condition as before.
The boiling down and granulation is to be repeated until most of
the soda is withdrawn, after which the remaining liquor containing
principally soda sulphate is to be boiled down and the salt decomposed
as before directed.
The washed or unwashed granulated soda obtained as herein-before
described may
be subsequently treated in various ways, a calcination and
attendant processes being in all cases saved as compared with existing
processes. Thus the washed granulated soda may be sold in that
condition, or it may be redissolved and crystallised for sale; or the
washed granulated soda may be calcined for the purpose of forming
soda ash of high strength; or it may be used for making caustic soda
which may in this way be obtained of very high strength. .

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said James Mactear in the Great Seal Patent Office on
the 6th November 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
MACTEAR, of Glasgow, in the County of Lanark, North Britain, Chemist,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Eighth day of May, in the year of our
Lord One thousand eight hundred and seventy-five, in the thirty-eighth
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said James Mactear, Her special licence that I,
the said James Mactear, my executors, administrators, and assigns, or
such others as I, the said James Mactear, 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 MANU-
FACTURE OF SODA," upon the condition (amongst others) that I, the
said James Mactear, 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 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 James Mactear, do hereby declare
the nature of my said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the
following statement in writing, that is to say:
My said Invention relates to an improved combination of processes
whereby, in the manufacture of soda, a part of the operations hitherto
required may be dispensed with, whilst soda sulphate is more completely
separated from the products and profitably utilised.
In applying my Invention in the case of the ordinary vat liquor of the
soda manufacture this liquor is by preference first, treated with carbonic

page_text: acid until the caustic soda is carbonated, and silica, alumina, and iron
thrown down. Any excess of carbonic acid may be taken up by the
addition of untreated liquor. The separated liquor, if not already strong
enough, is then boiled or concentrated so as to crystallisc on cooling, and
is constantly stirred or agitated whilst cooling, so that the soda may
separate in a granulated condition.. The granulated soda, after being
separated from the remaining liquor, is washed and most of the
impurities not left in the liquor are thereby removed. The remaining
liquor after being again treated with carbonic acid if necessary is to be
boiled down to the salting point and again agitated whilst cooling, so as
to obtain a further supply of granulated soda, which is to be purified by
washing like the first. The same treatment may be repeated a third
time if found desirable. The liquor still remaining and which will
contain most of the soda sulphate and impurities may be again boiled
down nearly or altogether to dryness, and the resulting salts may be
decomposed in the ball furnace, as commonly practised with fresh soda
sulphate.
In a similar manner what are known as "red" liquors and also the
mother liquors from which soda crystals have been separated may be
first treated with carbonic acid, any excess of which can be taken up by
adding more untreated liquor, and then after boiling down, if necessary,
be agitated whilst cooling or crystallising, so as to yield the soda in a
granulated condition as before.
The boiling down and granulation is to be repeated until most of
the soda is withdrawn, after which the remaining liquor containing
principally soda sulphate is to be boiled down and the salt decomposed.
as before directed.
The washed or unwashed granulated soda obtained as herein-before
described may be subsequently treated in various ways, a calcination and
attendant processes being in all cases saved as compared with existing
processes. Thus the washed granulated soda may be sold in that
condition, or it may be redissolved and crystallised for sale; or the
washed granulated soda may be calcined for the purpose of forming soda
ash of high strength; or it may be used for making caustic soda which
may in this way be obtained of very high strength.
Having thus particularly described my said Invention and the manner
of performing the same, I have to state that what I believe to be novel

page_text: and original, and claim as secured to me by the herein-before in part
recited Letters Patent is,-
1. The obtaining of granulated soda in the manner herein-before
described.
2. The application of granulated soda obtained as herein-before
described in making soda ash of high strength, or in making caustic
soda.
3. The separating of sulphate of soda from the carbonate in the
manner herein-before described.
In witness whereof, I, the said James Mactear, have hereunto set
my hand and seal, this Fifth day of November, in the year of
our Lord One thousand eight hundred and seventy-five.