IMPROVEMENTS IN THE PURIFICATION OF ALKALINE SOLUTIONS
Year: 1881

page_text: LETTERS PATENT to Eustace Carey, Holbrook Gaskell, the younger, and
Ferdinand Hurter, Ph.D., all of Widnes, in the County of Lancaster, Alkali
Manufacturers, for an Invention of "IMPROVEMENTS IN THE PURIFICATION
OF ALKALINE SOLUTIONS,"
PROVISIONAL SPECIFICATION left by the said Eustace Carey, Holbrook
Gaskell, and Ferdinand Hurter at the Office of the Commissioners of Patents
on the 5th December 1881.
EUSTACE CAREY, HOLBROOK GASKELL, the younger, and FERDINAND HURTER,
Ph.D., all of Widnes, in the County of Lancaster, Alkali Manufacturers.
"IMPROVEMENTS IN THE PURIFICATION OF ALKALINE SOLUTIONS."
Our Invention relates to the purification of the alkaline solutions known in the
alkali trade as "vat" or "tank " liquors, antl as "red liquors," in order to effect the
destruction of the substance known as ferrocyanide of sodium, which may be
contained in such alkaline solutions.
In order to effect this object we subject the liquor containing ferrocyanide to an
elevated temperature, after which the insoluble compounds of iron which have been
formed and precipitated may be separated by settling, filtration, or other convenient
method,
In carrying our Invention into effect we prefer to employ apparatus so constructed
that the raising of the alkaline liquors before referred to to the desired elevated
temperature may be carried on continuously, the solution being constantly caused.
to pass through a heating apparatus.
As a convenient method of accomplishing this result we prefer to force the
liquor through a boiler or an apparatus consisting of a coil or coils, chamber or
chambers, or passage or passages, heated upon the exterior by a furnace or otherwise,
and arranged in such manner that the liquor shall be caused to pass continuously
along in one or more streams, so as to ensure that each and every portion of the
liquor shall be beated to the required temperaturo.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Eustace Carey, Holbrook Gaskell, and Ferdinand Hurter in the
Great Seal Patent Office on the 3rd June 1882.
EUSTACE CAREY, HOLBROOK GASKELL, the younger, and FERDINAND HURTER,
Ph.D, all of Widnes, in the County of Lancaster, Alkali Manufacturers.
"IMPROVEMENTS IN THE PURIFICATION OF ALKALINE SOLUTIONS."
Our Invention relates to the purification of the alkaline solutions known in the
alkali trade as "vat" or tank "liquors," and as "red liquors," in order to effect the
destruction of the substance known as ferrocyanide of sodium, which may be
contained in such alkaline solutions.
In order to effect this object wo subject the liquor containing ferrocyanide to an
elevated temperature, after which the insoluble compounds of iron which have been
formed and precipitated may be separated by settling, filtration, or other convenient
method.
In carrying our Invention into effect we prefer to employ apparatus so constructed
that the raising of the alkaline liquors before referred to to the desired elevated
temperature may be carried on continuously, the solution being constantly caused
to pass through a heating apparatus.
As a convenient method of accomplishing this result we prefer to force the
liquor through a boiler or an apparatus consisting of a coil or coils, chamber or
chambers, or passage or passages, heated upon the exterior by a furnace or otherwise,
and arranged in such manner that the liquor shall be caused to pass continuously
along in one or more streams, so as to ensure that each and every portion of the
liquor shall be heated to the required temperature.
The temperature required for the decomposition of the ferrocyanides is about
380° Fahrenheit.
In order to prevent the boiling of the solution contained in the apparatus, the
solution should be kept under a pressure corresponding at least to the tension of
steam at that temperature, which is about 185 lbs. to the square inch; but in order
to make absolutely certain that no evaporation may take place should the
temperature rise a little above 380 degrees Fahrenheit, we prefer to keep the
solution under very much higher pressure, usually varying from 250 lbs. to
350 lbs. per square inch.
The accompanying Drawings represent one example of the varied forms of
apparatus which may be employed in carrying out our Invention.
Figure 1 represents a longitudinal vertical section of the apparatus; Figure 2 is
a plan of the same with the top arch removed; and Figure 3 is an end view with
the front wall removed.
The apparatus shewn in the Drawing consists as follows:-A triple ram pump A
capable of delivering the necessary quantity of liquid against a pressure or head of,
say, 350 lbs. to the square inch, sends the liquid into the coil B, which is arranged
within a chamber C, so as to be heated by a furnace D, the products of combustion
from which escape to a chimney. We prefer to employ one continuous coil of
pipes presenting sufficient beating surface to allow the liquid to become heated to
380 degrees Fahrenheit in passing once through the entire length of pipes. Between
the pump and the entrance to this coil we place a pressure gauge E.
We prefer
the coil to be arranged so that the liquor enters at the highest point and issues at
the lowest, and we avoid as far as possible any upward movement of the liquid,
all with a view to sweep out solid particles should any enter the tubes along
with the liquid.

page_text: At the outlet end we insert into the pipes a thermometer at G to indicate the
temperature of the liquid, a pet cock F by which to draw samples, and a pressure
gungo H.
The pressure may be conveniently kept up by causing the solution to pass
through a valve I, loaded by a weight or spring to the necessary pressure.
In carrying out this process it is of importance to avoid as far as possible the
entrance of solid substances into the coil, and it is well to filter the solution.
Every attention should be paid to the removal of silica and alumina from the
solution, as these substances cause an incrustation of the pipes. This removal may
be effected by the means described in the Specifications of Patents, No. 2939, in
the year of our Lord One thousand eight hundred and seventy nine, and No. 1161,
in the year of our Lord One thousand eight hundred and eighty one, or by any
other convenient method.
When working with soda solution, care should also be taken not to use the
alkaline solutions in too concentrated a condition; the solubility of carbonate of
soda in water is less at 380 degrees Fahrenheit than at 220 degrees Fahrenheit, and
if too concentrated a solution is introduced into the coil monohydrated carbonate of
soda will be deposited for this purpose. We prefer to use solutions of about
40 degrees Twaddell. Should any deposit in the pipes take place from this cause
it can be removed by passing water through the apparatus.
If the temperature be kept at or above 380 degrees Fahrenheit, the whole of the
ferrocyanides will be decomposed and the iron they contain will be held in
suspension as sulphide or oxide of iron.
The solution should be freed from this precipitate by settling, filtration, or other
convenient method; for this purpose the process!described in the Specification of the
Letters Patent, No. 5312, in the year of our Lord One thousand eight hundred and
eighty one, granted to Henry Wade Deacon and Holbrook Gaskell, junior, may be
advantageously employed.
The solutions are then ready for evaporation or crystallization, and the production
of white alkali or crystals.
Having now described and particularly ascertained the nature of our said
Invention, and the manner in which the same is or may be used or carried into
effect, we would observe in conclusion that what we consider to be novel and
original, and therefore claim as the Invention secured to us by the hereinbefore
in part recited Letters Patent is,-
The system or mode of purifying alkaline solutions by submitting the same to an
elevated temperature in order that the iron they contain may be separated therefrom,
substantially as hereinbefore described.
In witness whereof, we, the said Eustace Carey, Holbrook Gaskell, the younger,
and Ferdinand Hurter, have to this our Specification set our hands and
seals, the Second day of June, One thousand eight hundred and eighty
EUSTACE CAREY.
(L.S.)
HOLBROOK GASKELL, J. (L.S.)
FERDINAND HURTER.
(LS.)