IMPROVEMENTS IN THE MANUFACTURE OF CAUSTIC SODA
Year: 1862

page_text: LETTERS PATENT to Henry Deacon, of Appleton House, Appleton,
in the County of Lancaster, Alkali Manufacturer, for the Invention of
"IMPROVEMENTS IN THE MANUFACTURE OF CAUSTIC SODA."
Sealed the 3rd October 1862, and dated the 10th April 1862.
PROVISIONAL SPECIFICATION left by the said Henry Deacon at the
Office of the Commissioners of Patents, with his Petition, on the
10th April 1862. ..
I, HENRY DEACON, of Appleton House, Appleton, in the County of
Lancaster, Alkali Manufacturer, do hereby declare the nature of the said
Invention of IMPROVEMENTS IN THE MANUFACTURE OF CAUSTIC SODA," to be
as follows:-
In the ordinary manufacture of caustic soda the caustic liquors are
evaporated, and during evaporation the salts precipitated are removed, and
evaporation is continued until the residual liquors become so concentrated
as to solidify on cooling or until as much of the water is driven off as is
required.
My improvements consist in stopping this evaporation at an earlier stage,
removing the salts precipitated during evaporation as usual, and continuing
the evaporation or concentration, until the caustic alkaline liquor will deposit
crystals of hydrated caustic soda on cooling to the ordinary atmospherio
temperature. These crystals of bydrated caustic soda, after the mother
liquors have been separated therefrom, are nearly pure or sufficiently so for
commercial purposes. The mother liquors separated from these crystals
may be used for subsequent operations or are finished alone. The crystals
of hydrated caustic soda thus obtained may be employed for most of the

page_text: purposes for which ordinary caustic soda is used, it being borne in mind
that they contain water of crystallization, and are therefore proportionately
weaker in soda or "real alkali," than the ordinary fused or solid caustic soda.
The crystals may be melted and concentrated by the application of heat
should it be desired to obtain fused or a more concentrated form of caustic
soda..
My improvements further consist in effecting the separation of the mother
liquors from the crystals of the hydrate of soda. This I prefer effecting by
the application of a small amount of heat in any convenient manner, and in
any convenient vessel. The application of heat effects a more speedy, and
more thorough drainage or separation of the mother liquor from the crystals of
hydrated caustic soda; of course care must be taken that the temperature of
the mother liquors be not increased to such an extent as to redissolve the
crystals formed or as to melt the crystals of hydrated 'caustic soda in, their
water of crystallization.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Henry Deacon in the Great Seal Patent Office on the
10th October 1862.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, HENRY
DON, of Appleton House, Appleton, in the County of Lancaster, Alkali
Manufacturer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Tenth day of April, in the year of our Lord
One thousand eight hundred, and sixty-two, in the twenty-fifth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Henry Deacon, Her special license that I, the said Henry
Deacon, my executors, administrators, and assigns, or such others as I, the
said Henry Deacon, my executors, administrators, or 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 "IM-
.PROVEMENTS IN THE MANUFACTURE OF CAUSTIC SODA," upon the condition
(amongst others) that I, the said Henry Deacon, my executors or adminis-
trators, by an instrument in writing under my hand and seal or under the
band and seal of one of them, should particularly describe and ascertain the
nature of the said Invention, and in what manner the same was to be

page_text: 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 Henry Deacon, 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, that is to say :-
In the ordinary manufacture of caustic soda, the caustic liquors are
evaporated, and during evaporation the salts precipitated are removed, and
evaporation is continued until the residual liquors become so concentrated
as to solidify on cooling or until as much of the water is driven off as 'is
required.
My improvements consist in stopping this evaporation at an earlier stage,
removing the salts precipitated during evaporation as usual, and continuing
the evaporation or concentration until the caustic 'alkaline liquor will deposit
crystals of hydrated caustic soda, on cooling to the ordinary atmospheric
temperature. These crystals of hydrated caustic soda, after the mother
liquors have been separated therefrom are nearly pure or sufficiently so for
commercial purposes. The mother liquors separated from these crystals
may be used for subsequent operations, or are finished alone. The crystals
of hydrated caustic soda thus obtained may be employed for most of the
'purposes for which ordinary caustic soda is used, it being borne in mind
that they contain water of crystallization, and are therefore proportionately
weaker in soda or "real alkali," than the ordinary fused or solid caustic soda.
The crystals may be melted and concentrated by the application of heat
should it be desired to obtain fused or a more concentrated form of caustic
soda.
:
My improvements further consist in effecting the separation of the mother
liquors from the crystals of the hydrate of soda, this I prefer effecting by the
application of a small amount of heat in any convenient manner, and in any
convenient vessel.
:
The application of. heat effects a more speedy, and more thorough drainage
or separation of the mother liquor from the crystals of hydrated caustic soda;
of course care must be taken that the temperature of the mother liquors be
not increased to such an extent as to redissolve the crystals formed, or as to
melt the crystals of hydrated caustic soda in their water of crystallization.
I prefer stopping the evaporation of the caustic liquors when their boiling
point is about 350°. They are then cooled to about 160°, and the clear
liquors transferred to the crystallizing vessels. which I prefer leaving open at

page_text: the top during the crystallization. The salts deposited during this cooling
of the liquors are treated in the ordinary way. A thin hemisphere of cast
iron about six feet diameter, and three feet deep forms a convenient crystal-
lizing vessel. A hole may be made at the bottom and provided with a long
hollow plug or tube taper its whole length, fitting the hole at bottom closely,
and rising above the surface of the liquor. In this or other convenient vessels
the liquors crystallize, and when the temperature of the mother liquor has
fallen to about one hundred and twenty degrees, it is removed. In the vessel
described this is effected by withdrawing the hollow taper plug or tube, first
inserting a hot iron into it or passing a jet of steam into or through it to melt.
crystals formed in contact with and adhering to it. The crystallizing vessel
is closely covered, as and when the mother liquors are removed, and it is also
provided with a steam casing or other means of applying heat so that its
contents may be heated to complete the drainage of the mother liquors from
the crystals, and with this object. I prefer increasing the temperature of the
.crystals to about one hundred and forty degrees. When the crystals are well
drained the heat may be increased until they are melted and they can then
be run into suitable packages for sale, or be concentrated by the application of
stronger heat. The mother liquors are added to other caustic liquors, and are
reworked.
Having now described and particularly ascertained the nature of my said
Invention, & the manner in which the same is or may be used, or carried
into effect, I would observe in conclusion, that what I consider to be novel
and original, and therefore claim as the Invention secured to me by the
herein-before in part recited Letters Patent, is,
First, the process of obtaining crystals of caustic soda containing more
than one atom of water by cooling caustic soda liquors as herein-before
described.
'
2nd, the removing the last portions of mother liquors from caustic soda
..crystals by means of an elevated temperature below but approaching to their
melting point.
In witness whereof, I, the said Henry Deacón, have hereunto set my
hand and seal, the Seventh day of October, One thousand. eight
hundred and sixty-two..
HENRY DEACON. (L.S.)