IMPROVEMENTS IN OBTAINING SALTS AND PRO- DUCTS FROM THE ASHES OF MARINE PLANTS
Year: 1858

page_text: LETTERS PATENT to Francois Alphonse Theroulde, of 67, Rue Caumartin,
Paris, for the Invention of "IMPROVEMENTS IN OBTAINING SALTS AND PRO-
DUCTS FROM THE ASHES OF MARINE PLANTS."
Sealed the 12th May 1859, and dated the 22nd November 1858.
PROVISIONAL SPECIFICATION left by the said Francois Alphonse The-
roulde at the Office of the Commissioners of Patents, with his Petition,
on the 22nd November 1858.
I, FRANCOIS ALPHONSE THEROULDE, of 67, Rue Caumartin, Paris, do hereby
declare the nature of the Invention for "IMPROVEMENTS IN OBTAINING SALTS
AND PRODUCTS FROM THE ASHES OF MARINE PLANTS," to be as follows:-
This Invention has for its object improvements in obtaining salts and pro-
ducts from the ashes of marine plants. For this purpose a concentrated
solution is prepared from the ashes by causing successive quantities of water
to pass through successive layers of ash, so that each quantity of water passes
first through the layer of ash which is most nearly exhausted, afterwards in
regular order through all the subsequent layers, passing at each step from a
poorer to a richer layer, until lastly it passes through a layer of fresh ash.
A sample drawn from the concentrated solution thus obtained is analysed, to

page_text: ascertain the quantity of potash (in the form of potash salts), which the
solution contains. A sufficient quantity of nitrate of soda is added to the
solution to convert all the potash into nitrate of potash, and it is then evapo-
rated to separate common salt, which is then removed from the liquid. The
liquid is then allowed to cool, and in cooling nitrate of potash is deposited.
Afterwards nitrous acid gas (prepared by acting on a suitable organic sub-
stance with nitric acid) passed through mother liquor, and a precipitate of
iodine is obtained and separated. Lastly, chlorine gas is passed through the
liquid, by which bromine is set free, and it is separated by a process of
distillation. The mother liquor still contains nitrate of potash, a part of
which is separated by evaporation, and the remainder is sent back to the
commencement of the process.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said François Alphonse Theroulde in the Great Seal Patent Office
on the 21st May 1859.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FRANÇOIS
ALPHONSE THEROULDE, of 67, Rue Caumartin, Paris, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-second day of November, in the year of our
Lord One thousand eight hundred and fifty-eight, in the twenty-second year
of Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said François Alphonse Theroulde, Her special licence that I, the said
François Alphonse Theroulde, my executors, administrators, and assigns, or
such others as I, the said François Alphonse Theroulde, my executors, admi-
nistrators, 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 OBTAINING SALTS AND PRODUCTS FROM
THE ASHES OF MARINE PLANTS," upon the condition (amongst others) that I,
the 'said François Alphonse Theroulde, 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.

page_text: NOW KNOW YE, that I, the said François Alphonse Theroulde, 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 thereof, that is to say:―
This Invention has for its object improvements in obtaining salts and pro-
ducts from the ashes of marine plants. For this purpose a concentrated
solution is prepared from the ashes by causing successive quantities of water
to pass through successive layers of ash, so that each quantity of water passes
first through the layer of ash which is most nearly exhausted, afterwards in
regular order through all the subsequent layers, passing at each step from a
poorer to a richer layer, until lastly it passes through a layer of fresh ash.
The following is the manner in which I prefer to conduct the operation :—
I employ ten or other convenient number of rectangular vessels of sheet iron,
arranged side by side, and in two rows; they are each provided with a false
bottom of perforated sheet metal or wood. These vessels are connected
together by pipes passing from the upper part of one vessel to the space under
the false bottom of the next vessel of the series. These vessels are charged
in succession with the ashes to be treated, and they may conveniently be of
such a size as to hold about two tons each. The water to form the solution is
introduced under the false bottom of the vessel containing the ash most nearly
exhausted, and percolates upwards through the contents of the vessel. From
the top of this vessel the liquid passes by a pipe to the space under the false
bottom of the next vessel of the series, and in this manner the liquid passes on
from vessel to vessel until it traverses the ash in the vessel last charged, and
from the top of this vessel the concentrated solution escapes to a large tank,
which by preference is made sufficiently capacious to hold a day's supply of
solution. When the vessel is full, a sample is drawn from it, and is analysed,
to ascertain the quantity of potash (in the form of potash salts) which the
solution contains. A sufficient quantity of nitrate of soda is added to the
solution to convert all the potash into nitrate of potash. In order to facilitate
the solution of the nitrate of soda, a frame is fitted into the upper part of the
tank before mentioned, and the surface of this frame is covered with wire cloth;
the nitrate of soda is spread on the platform thus formed, and the platform being
below the surface of the liquid in the tank, the nitrate of soda quickly dis-
solves. When the whole of the nitrate of soda is dissolved, the liquid is run into
suitable boilers and evaporated, to separate common salt and other soda
salts; the evaporation is carried on in the ordinary manner of evaporating
solutions of salt, the salts being removed by a rake as they fall. When the
liquid is concentrated to from 50° to 55° Beaunić, the evaporation is stopped

page_text: and it is set aside to crystallize; the salts which fall during the evaporation
are placed to drain in a vessel of convenient size, containing a perforated false
bottom on which the salts rest; they consist almost entirely of chloride of
sodium and other soda salts, but still contain small proportions of nitrate of
potash; this is separated by washing, and also at the same time blowing steam
through the salts while they are draining, the steam being introduced under
the false bottom of the draining vessel, this causes the nitrate of potash to
redissolve and filter away, it being very soluble in hot water; the same process
also separates the iodide and the bromide of sodium. The salt which crystal-
lizes out on cooling, when the evaporation is stopped, is drained from the
mother liquor; it consists almost entirely of nitrate of potash, but contains
also small quantities of chloride of sodium, iodide, and bromide of sodium, and
other soda salts, and these I separate by washing in the manner ordinarily
practised. The mother liquor from which the nitrate of potash has crystallized
is again evaporated, together with the liquors resulting from washing the salts,
and the chloride of sodium and other soda salts are separated and treated
as before described. When the liquor is concentrated to the point before
mentioned, nitrate of potash is again crystallized out, which also is treated as
before, and thus the operation is repeated.
Each evaporation and crystallization encreases the proportion of the iodide
and bromide of sodium in the mother liquid, until after three evaporations it
becomes desirable to separate iodine and bromine from it. In order to obtain
iodine from this liquor, I pass through it nitrous acid gas, which I prefer to
obtain in the manufacture of oxalic acid, by acting on a suitable organic
substance with nitric acid in the manner usually practised; this gas is passed
into the liquid until all thé iodine is precipitated, the liquid is then allowed to
stand until the iodine settles to the bottom of the vessel, and the clear liquid
is then drawn off; the iodine is afterwards washed, and either converted into
iodide of potassium or purified by sublimation.
In order to separate bromine I take the clear liquid from which the iodine
lias been separated, and I treat it by the process heretofore ordinarily employed
for separating bromine, viz., by passing chlorine through the liquid, black
oxide of manganese having previously been added thereto; thus the whole of
the bromine salts are decomposed, and the bromine is afterwards separated by
distillation, the distillation being continued as long as any bromine passes
over. The mother liquor still contains nitrate of potash and other salts; 'to
separate these I evaporate the liquor to about 55° Beaunié, withdrawing the
chloride of sodium and other salts which fall during the evaporation as before;
when the evaporation is complete, the liquid is set to crystallize, and the

page_text: resulting nitrate of potash is drained and purified as already explained; the
remaining liquid is taken back to the commencement of the process or the
liquid may be evaporated to dryness, and the salts afterwards separated by
washing.
I would remark that the process above described is, as will be perceived,
based on the conversion of the whole of the potash salts present in the ashes
of marine plants into a single salt of potash, viz. the nitrate of potash, a salt
which is much more soluble in hot water than the salts of soda which the
ashes contain, and also much more soluble than the salts of potash from which
it was formed. By this process I am able to effect the complete separation of
the salts of potash from those of soda, which cannot be done by the processes
heretofore employed.
A further advantage of my process is that I obtain nitrate of potash directly
by adding nitrate of soda to the ashes of marine plants, which has not before
been done. The separation of iodine from the mother liquors by means of
nitrous acid also forms a part of my Invention.
In witness whereof, I, the said François Alphonse Theroulde, have here-
unto set my hand and seal, this Twentieth day of May, in the year
of our Lord One thousand eight hundred and fifty-nine.
FRANÇOIS ALPHONSE THEROULDE.
(L.S.)