AN IMPROVED PROCESS FOR EXTRACTING CAUSTIC SODA AND POTASH AND THE CARBONATES OF THE SAME FROM THEIR SOLUTIONS.
Year: 1870

page_text: LETTERS PATENT to William Robert Lake, of the Firm of Haseltine,
Lake, & Co., Patent Agents, Southampton Buildings, London, for
the Invention of "AN IMPROVED PROCESS FOR EXTRACTING CAUSTIC SODA
AND POTASH AND THE CARBONATES OF THE SAME FROM THEIR SOLUTIONS.".
A communication from abroad by François Marie Bachet, of Paris,
in the Empire of France, Banker.
Sealed the 14th February 1871, and dated the 2nd September 1870.
PROVISIONAL SPECIFICATION left by the said William Robert Lake at
the Office of the Commissioners of Patents, with his Petition, on
the 2nd September 1870.
I, WILLIAM ROBERT LAKE, of the Firm of Haseltine, Lake, and
Company, Patent Agents, Southampton Buildings, London, do hereby
declare the nature of the said Invention for "AN IMPROVED PROCESS FOR
EXTRACTING CAUSTIC SODA AND POTASH AND THE CARBONATES OF THE SAME PROM
THEIR SOLUTIONS," a communication, to be as follows:-
When a liquid holds in colution code in a souatio condition

page_text: by the evaporation of the liquid solvent. This process requires peculiar
vessels, and becomes more tedious and costly in proportion to the extent
to which the solution is diluted.
The following process is greatly more simple and economical :—The
bicarbonate of soda is a salt relatively very soluble, and the Inventor has
found that it is excluded in a very remarkable manner from acqueous
solutions by the other more soluble salts of soda, especially the chloride
of sodium (sea salt), which when the liquid is completely saturated with
it precipitates almost the whole of the bicarbonate.
On
Starting with this fact I subject the liquid to be treated to the action
of carbonic acid while cold, either under pressure or by the continuous
passage of a current of the gas to transform into bicarbonate all the
caustic soda or all the carbonate of soda held therein in solution.
-the-other-hand-I-dissolve-therein-sea-salt, maintaining-this-solution-at-
the point of saturation. The bicarbonate of soda is precipitated and I
draw it off by decantation, then subject it to filtration, pressure, and
washing as required. This bicarbonate when subjected to the action of
heat is easily converted into perfectly pure carbonate of soda.
The other salts of soda more soluble than the bicarbonate, such as the
nitrate, the sulphate, and others, may be used in this operation in place
of the chloride of sodium, and will act more or less in a like manner.
The same system is applicable to the precipitation of caustic potash
and carbonate of potash from their solutions under the form of
bicarbonate.
The above process produces almost entirely the precipitation and
isolation of the soda and potash in the form of bicarbonate, but it leaves
as a residue the same quantity of liquid as existed originally charged to
the maximum degree with the precipitant salt employed. Ordinarily it
will be necessary to withdraw this salt to re-employ it and consequently
vaporize all the liquid. The advantage in this case will be only the
having to treat salts of a more easy crystallization and not having to
employ therefor vessels of a special or peculiar character; but where
the advantage will be found considerable, and equal to the saving of all
the expences of evaporation, is where there is to be the direct employ-
ment of the liquid residue charged to the maximum degree with the
precipitant salt.
Moreover, this process is applicable with great advantage as a com-

page_text: the Twenty-ninth day of March, A.D. 1869, No. 939, which has for its
object the production of soda by the reaction of the oxide of lead in the
presence of water and lime upon chloride of sodium with the regeneration
of the chloride of lead or oxide. I thereby obviate entirely the great cost
of evaporation which is necessary for the extraction of the soda formed
in liquids necessarily poor. The liquids satuated with sea salt and cold
which are left as a residue have an immediate re-employment for recom-
mencing the reaction by the oxide of lead and the lime. It is only
necessary previous to this re-employment to stir them with a little lime
to liberate from them the carbonic acid which they hold.
It is necessary to avoid leaving the soda liquids to be thus treated in
contact with organic substances as the soda would enter more or less
into combination with these substances, and such combination will not
be destroyed by the carbonic acid.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said William Robert Lake in the Great Seal Patent
Office on the 1st March 1871.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
ROBERT LAKE, of the Firm of Haseltine, Lake, & Co., Patent Agents,
Southampton Buildings, London, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Second day of September, in the
year of our Lord One thousand eight hundred and seventy, in the
thirty-fourth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said William Robert Lake, Her
special licence that I, the said William Robert Lake, my executors,
administrators, and assigns, or such others as I, the said William Robert
Lake, 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 PROCESS FOR EXTRACTING CAUSTIC SODA AND POTASH AND THE
CARBONATES OF THE SAME FROM THEIR SOLUTIONS," a communication to me
from abroad by François Marie Bachet, of Paris, in the Empire of

page_text: France, Banker, upon the condition (amongst others) that I, the said
William Robert Lake, 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 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 William Robert Lake, 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:-
When a liquid holds in solution soda in a caustic condition or in the
form of a carbonate its extraction has been hitherto effected com-
mercially_by_the_evaporation-of-the-liquid solvent; this process requires
peculiar vessels, and becomes more tedious and costly in proportion to
the extent to which the solution is diluted.
The following process is much more simple and economical. The
bicarbonate of soda is a salt relatively very slightly soluble, and the
Inventor has found that it is excluded in a very remarkable manner from
aqueous solutions by the more soluble salts of soda, especially the
chloride of sodium (sea salt), which when the liquid is completely
saturated with it precipitates almost the whole of the bicarbonate.
Starting with this fact I subject the liquid to be treated to the action
of carbonic acid while cold, either under pressure or by the continuous
passage of a current of the gas, to transform into bicarbonate all the
caustic soda or all the carbonate of soda held therein in solution. . On
the other hand I dissolve therein sea salt, maintaining this solution at
the point of saturation. The bicarbonate of soda is precipitated, and
I draw it off by decantation; I then subject it to filtration, pressure,
and washing, as required. This bicarbonate, when subjected to the
action of heat is easily converted into perfectly pure carbonate of
soda.
.
The other salts of soda more soluble than the bicarbonate, such as
the nitrate, the sulphate, and others, may be used in this operation
in place of the chloride of sodium, and will act more or less in a
like manner. The same process is applicable to the precipitation of
caustic potash and carbonate of potash from their solutions under the
form of bicarbonate.

page_text: The above process produces almost entirely the precipitation and
isolation of the soda and potash in the form of bicarbonate, but it leaves
as a residue the same quantity of liquid as existed originally charged to
the maximum degree with the precipitant salt employed. Ordinarily it
will be necessary to withdraw this salt, to re-employ it, and consequently
vaporize all the liquid. The advantage in this case will lie solely in
having to treat salts of a more easy crystallization, and not having to
employ therefor vessels of a special or peculiar character; but where
the advantage will be found considerable, and equal to the saving of all
the expenses
of evaporation, is where there is to be the direct employment
of the liquid residue charged to the maximum degree with the precipitant
salt.
Moreover this process is applicable with great advantage as a com-
plement to that for which I have obtained Letters Patent bearing date
the Twenty-ninth day of March A.D. 1869, No. 939, which has for its
object the production of soda by the reaction of the oxide of lead in the
presence of water and lime upon chloride of sodium with the regeneration
of the chloride of lead or oxide; I thereby obviate entirely the great
cost of evaporation, which is necessary for the extraction of the soda
formed in liquids necessarily poor. The liquids saturated with sea salt
and cold, which are left as a residue, have an immediate re-employment
for recommencing the reaction by the oxide of lead and the lime. It is
only necessary previous to this re-employment to stir them with a
little lime to liberate from them the carbonic acid which they hold.
It is necessary to avoid leaving the soda liquids to be thus treated in
contact with organic substances, as the soda would enter more or less
into combination with those substances, and such combination will not
be destroyed by the carbonic acid.
Having thus fully described the said Invention, as communicated
to me by my foreign correspondent, and shewn how the same may be
conveniently and advantageously carried into practice, I wish it under-
stood that I claim, the cumulative use of carbonic acid and salts of soda
or potash more soluble than the bicarbonates of these two bases to act
upon liquids containing soda or potash in a caustic condition or in the
state of carbonates for the purpose set forth.
I also claim the cumulative use of carbonic acid and chloride of
sodium to act upon liquids containing caustic soda or carbonate of soda

page_text: for the purpose set forth, and the application of this process in connection
with that described in the aforesaid former Specification.
In witness whereof, I, the said William Robert Lake, have hereunto
set my hand and seal, this First day of March, in the year of our
Lord One thousand cight hundred and seventy-one.
Witness,
E. C. JACKSON.
WILLIAM ROBERT LAKE. (L.S.)