IMPROVEMENTS IN THE MANU- FACTURE OF CITRIC AND TARTARIC ACIDS, AND IN THE MANUFACTURE AND TREATMENT OF CITRATE AND TARTRATE OF LINE AND ANALOGOUS BASIC COMPOUNDS, AND IN APPARATUS EMPLOYED THEREFOR
Year: 1865

page_text: LETTERS PATENT to Frederic Row, of Colchester, in the County of Essex,
Practical Chemist, for the Invention of "IMPROVEMENTS IN THE MANU-
FACTURE OF CITRIC AND TARTARIC ACIDS, AND IN THE MANUFACTURE AND
TREATMENT OF CITRATE AND TARTRATE OF LINE AND ANALOGOUS BASIC
COMPOUNDS, AND IN APPARATUS EMPLOYED THEREFOR."
Scaled the 28th July 1865, and dated the 4th February 1865.
PROVISIONAL SPECIFICATION left by the said Frederic Row at the
Office of the Commissioners of Patents, with his Petition, on the 4th
February 1865.
I, FREDERIC ROW, of Colchester, in the County of Essex, Practical Chemist,
do hereby declare the nature of the said Invention for "IMPROVEMENTS IN THE
MANUFACTURE OF CITRIC AND TARTARIC ACIDS. AND IN THE MANUFACTURE AND
TREATMENT OF CITRATE AND TARTRATE OF LIME AND ANALOGOUS BASIC COMPOUNDS,
AND IN APPARATUS EMPLOYED THEREFOR," to be as follows:-
This Invention consists in submitting crude argol or tartar, lemon juice, or
the insoluble citrate or tartrate of lime or other base to such preparation as
shall tend to purify them in a more effectual manner than usual, and also to
render the solutions of these acids more concentrated when first produced
(thus saving much cost of evaporation), certain improved apparatus being
used for effecting the objects before mentioned. In order to render lemon
juice more fit for the production of citric acid, it is first diluted in a convenient
Price 8d.]

page_text: vessel with such quantities of water as may be required to precipitate as much
as possible of the colouring matter, the clear solution being afterwards drawn
off from the sediment. As much whiting, lime, or other suitable base is then
to be added to the clear solution as may be necessary to neutralize all the free
citric acid, precipitating it as citrate of lime or other base, the mixture being
kept constantly agitated and warm during the process. The treatment of
crude argol or tartar, when tartrate of lime or other base is to be produced, is
similar to that last described with reference to lemon juice. The whole
contents of the "generator." as the vessel in which the said operations are
conducted is termed, are then run into a vessel or cistern constructed as
follows: This cistern is formed of wood and of any convenient size, and lined
with lead, the bottom thereof being partly rounded instead of flat in order to
facilitate the action of stirrers, which are arranged so as to revolve in the
cistern for the purpose of agitating the contents thereof. The said stirrers
consist of splints of wood rabbeted into a square spindle of which they occupy
one-third more or less of the whole length. the spindle being mounted in
suitable bearings in the sides of the cistern, and actuated by means of any
suitable motive power.
The cistern is furnished with a false bottom made of
wood covered with flannel or other similar material, or made of any other
filtering substance applicable to the purpose. An air pipe is provided to
allow the air to escape from the bottom of the cistern, in which is also fixed
an outlet pipe for the escape of the liquid, a vessel constructed of lead being
placed so as to receive such liquid when required. The citrate or tartrate of
lime or other base, prepared as before mentioned, together with such liquid or
solution as may have remained with it in the generator, are run into the
before-described vessel or cistern, which is termed the "decomposing back,"
and the liquid thus becomes separated by filtration and is conducted away
when required by the outlet pipe. Clean water, either warm or cold, is then
introduced and allowed to percolate through the substance under treatment
until it has removed from it all impurities or salts soluble in water, when the
outlet pipe is stopped by a plug or other convenient means
To the partly
dry mass is added a quantity of the weak liquors resulting from a previous
operation with such a quantity of sulphuric acid as is necessary to complete
the decomposition and liberate the citric or tartaric acid. When the sulphuric
acid is being added, the stirrers before-described are kept in motion, a
complete admixture of the contents of the back being thus effected. When
the decomposition is completed the solution is drawn off, and the remaining
sulphate of lime or other base is washed in the ordinary way, the weaker
solution being kept for the next decomposition. When the citrate or tartrate
25

page_text: of lime or other base produced as herein-before described is required to be
kept for any length of time or prepared for exportation, it must be freed as
much as possible from moisture by hydraulic or other pressure, and packed in
vessels from which the air is carefully excluded.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Frederic Row in the Great Seal Patent Office on the
4th August 1865.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FREDERIC
Row, of Colchester, in the County of Essex, Practical Chemist; send greeting.
WHEREAS Iler most Excellent Majesty Queen Victoria. by Her Letters
Patent, bearing date the Fourth day of February, in the year of our Lord
One thousand eight hundred and sixty-five, in the twenty-eighth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Frederick Row, Her special licence that 1, the said Frederic Row, my
executors, administrators, and assigns, or such others as I, the said Frederick
Row, 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 MANUFAC
TURE OF CITRIC AND TARTARIC ACIDS, AND IN THE MANUFACTURE AND TREATMENT
OF CITRATE AND TARTRATE OF LINE AND ANALOGOUS BASIC COMPOUNDS, AND IN
APPARATUS EMPLOYED THEREFOг," upon the condition (amongst others) that I,
the said Frederic Row, 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 Frederic Row, 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, reference being had to the Drawings hereunto annexed and to the
figures and letters marked thereon, that is to say;-
My said Invention consists in submitting lemon juice, crude argol or tartar,
and the insoluble citrate or tartrate of lime or other base to such preparations

page_text: as shall tend to purify them in a more effectual manner than usual. At the
same time I use less water in washing, thus saving loss by solution, and
rendering the tartaric and citric acid liquors produced so pure and of such
strength or degree of concentration that great cost of evaporation and also of
repeated recrystallization may be avoided. To render lemon juice more fit for
the preparation of citric acid, I first dilute it in a convenient vessel with such
quantities of water as may be necessary to precipitate as much as possible of
the colouring matter. In order to separate the iron existing in the juice and
to precipitate it as ferro-cyanide of iron, I add to the diluted lemon juice
under treatment as much ferro-cyanide of potassium (known as prussiate of
potash) as is necessary for that operation, the proportions usually required
for the treatment of one pipe of lemon juice as imported being about three
parts of water and four pounds of the ferro-cyanide of potassium, but I do not
confine or restrict myself to those precise proportions. The mixture thus
formed is allowed to stand in the vessel in which the last-mentioned operations
are conducted until the precipitate has fully subsided, and the clear solution is
then drawn off into a vessel such as is usually employed for the purpose, called
a "generator," and mixed with as much whiting or carbonate of lime or other
base as may be required to neutralize all the pure citric acid contained in it,
precipitating it as a citrate of such base, the mixture in the meanwhile being
kept warm and constantly agitated during the process as in the usual manner.
In treating crude argol or tartar in the preparation of tartrate of lime or other
base for the manufacture of tartaric acid, I add to the mixture of. whiting or
such base as is used to neutralise the free acid existing in the argol or tartar
as much ferro-cyanide of potassium as is found necessary to precipitate all the
iron existing therein as prussian blue, the tartrate of potash being 'decomposed
with a salt of lime, either sulphate, nitrate, or muriate (according to the
current value of the potash salt) formed in the usual manner, and with the
usual apparatus for mingling and treating the mixture. The ferro-cyanide of
potassium may be used to precipitate the iron from the solutions of citric and
tartaric acids at any stage or stages of the process, and whether such
solutions be strong or weak. The next portion of the process is precisely the
same whether a citrate or tartrate compound be under treatment. The citrate
or tartrate compound being so formed as before mentioned, I first allow the
precipitate to subside and draw off into suitable reservoirs as much as possible
of the clear liquid, and then, after well mixing up the precipitate that remains
with or without the addition of cold water as may be necessary, I run out
the whole contents of the "generator" into a vessel, which I will now proceed
to describe.

page_text: The accompanying Drawings shew the apparatus in longitudinal and
sectional elevation. A is a wooden cistern lined with lead (and which I call
the "decomposing back "), of any convenient size, the bottom of which is
slightly rounded so as to facilitate the action of the stirrers B. as shewn in the
section. The stirrers consist of splines of wood fixed into a square spindle
occupying one-third more or less of the whole length (although I do not
confine myself to any special size), the spindle when in action being turned by
a band on a pulley at the end of it, and actuated by any suitable motive
power; C is a false bottom- made of wood covered with flannel or any other
filtering material, or the patent siliceous stone may be used: D is an outlet
pipe for the filtered liquor, and E is an outlet pipe for the air contained in the
chamber. F is a lead pump to produce a partial vacuum when necessary.
Gis a cover to prevent splashing from the stirrers.
I will now proceed to describe the mode of using the apparatus. The citrate
or tartrate compound being run into the decomposing back, the liquid becomes
entirely separated by virtue of the filtering medium. to be treated as circum-
stances may require. Cold water is then allowed to percolate through the mass
until it has removed from it all impurities, when it is fit for decomposition by
means of sulphuric acid, for which purpose I add to the partly dry mass (the outlet
being closed) as much washing from a previous operation as is necessary to
make it into a semi-fluid mass when mixed, and also some mother liquor of a
previous working in order to extract from it the excess of sulphuric acid
which it has gained from frequent concentration, and then as much more
sulphuric acid as may be required to complete the decomposition and liberate
the citric and tartaric acid, and shew a slight reaction with a soluble salt of
lime, the stirrers being meanwhile kept in motion. A complete admixture
of the contents of the back being thus effected, the outlet pipe is then again
opened and the liquor run into a suitable reservoir, the remaining sulphate of
lime or other base being washed clean with water in the ordinary way, the
weaker washings being kept for future operations.
The results of my said Invention are that the coloring matter and the iron
contained in the lemon juice and tartar under treatment are effectually
removed, and the citrate and tartrate of lime or other base are washed more
completely, and thereby rendered less liable to fermentation than when washed
by the ordinary means, while the solutions of citric and tartaric acids respec-
tively are produced in a much purer and more concentrated state, thus
effecting a great saving in the expence of evaporation and recrystalization
Having thus fully declared and ascertained the nature of my said Invention,
and the manner in which it is to be performed. I would observe in conclusion,

page_text: that what I consider novel and original, and therefore claim as constituting my
said Invention, are-
First, the separation of the coloring matter from the concentrated lemon
juice by dilution with water as herein-before described and set forth.
Secondly, the removal of the iron held in solution in lemon juice and
solutions of tartar by means of ferro-cyanide of potassium as herein-before set
forth.
And, thirdly, the construction. combination, and arrangement of the
apparatus for washing citrate and tartrate of lime or other base as herein-before
described and set forth.
In witness whereof, 1, the said Frederick Row, have hereunto set my
hand and seal, this Third day of August, in the year of our Lord
One thousand eight hundred and sixty-five.
Witness,
JNO. STEPHENS,
Carter.
FREDERIC ROW. (L.S.)