IMPROVEMENTS IN THE PROCESS FOR MANUFACTURING IODINE
Year: 1854

page_text: LETTERS PATENT to Louis Faure, of Paris, France, and of 4 South
Street, Finsbury, London, for the Invention of "IMPROVEMENTS IN THE
PROCESS FOR MANUFACTURING IODINE."
Sealed the 11th July 1854, and dated the 14th February 1854.
PROVISIONAL SPECIFICATION left by the said Louis Faure at the Office
of the Commissioners of Patents, with his Petition, on the 14th Februar
1854.
I, LOUIS FAURE, of Paris, France, and of 4, South Street, Finsbury, London,
do hereby declare the nature of my Invention for "IMPROVEMENTS IN
PROCESS FOR MANUFACTURING IODINE" to be as follows:-
My Invention consists in applying sulphurous acid to extracting iodine from
native nitrate of soda and from the mother waters employed for the treatment
of that agent. To extract iodic acid in combination with soda, lime, or other
base, I take about two gallons of mother waters holding nitrate of soda in
solution, and at a strength of about 36 to 37 degrees of Beaumes areometer,
and pour into it by drops sulphurous acid held in solution in water, and agitate
the mixture till the iodine is precipitated and the liquid ceases to give a
precipitate on the further addition of sulphurous acid.
This operation is carried on in a vessel made of stone, non-porous brick,
hydraulic cement, or other ceramic product, closed air-tight by a cover provided
with a stirring rod. The supernatant liquid may be drawn off and be sub-
jected to suitable processes for obtaining nitrate and sulphate of soda and other

page_text: products, while the precipitate is carried to a bath, the bottom of which con-
sists of a filter composed of layers of pulverized quartz stone. After a given
time the upper layer of iodine is collected and dried by the absorption of its
moisture in a vessel of plaster of Paris closed air-tight.
The dried iodine is then placed in stone stills for crystallization by the
ordinary processes of sublimation.
To extract iodine contained in mother waters in the state of iodate and
iodide combined, I operate with solutions of chlorine and sulphuric acid, com-
mencing with chlorine if the waters treated contain little iodide and an excess
of iodate, and with sulphuric acid when the waters contain an excess of iodide
and little iodate...
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Louis Faure in the Great Seal Patent Office on the 9th
August 1854.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, LOUIS
FAURE, of Paris, France, and of 4, South Street, Finsbury, London, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fourteenth day of February, in the year of our Lord
One thousand eight hundred and fifty-four, in the seventeenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Louis Faure, Her special license that I, the said Louis Faure, my execu-
tors, administrators, and assigns, or such others as I, the said Louis Faure,
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 PROCESS FOR
MANUFACTURING IODINE," upon the condition (amongst others) that I, the
said Louis Faure, by an instrument in writing under my hand and seal, 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 Louis Faure, do hereby declare the
nature of my said Invention, and in what manner the same is to be performed,

page_text: to be particularly described and ascertained in and by the following statement
thereof, that is to say:--
My Invention consists in the application and mode of applying sulphurous
acid and chlorine to extracting iodine from the mother liquors of nitrate of
soda, and also from native nitrate of soda.
I apply the following process to the treatment of native nitrate of soda and
to the mother liquors therefrom for extracting iodine therein contained in the
state of iodic acid combined with soda, lime, or any other base.
I take about one quart of the mother liquor of nitrate of soda of the
strength of thirty-six degrees to thirty-seven degrees Beaume's areometer, and
pour thereon in small quantities sulphurous acid held in solution in water
from a graduated test glass, continually agitating it until the precipitate of
iodine freely separates from the liquid; and when the liquid, which is slightly
shaded, is filtered, it instantly loses its color, and gives no sign of a further pre-
cipitate of iodine on the addition of one drop of sulphurous acid. This test
should be repeated upon about ten quarts, and if the two results obtained
correspond, five hundred to one thousand quarts of mother liquor can con-
fidently be treated, for which it is merely necessary to employ a suitable
proportion of sulphurous acid, and a vessel capable of containing a little more
than three cubic feet of liquid.
The vessel to be employed should be of a circular form. and made of non-
porous bricks well luted and afterwards lined with hydraulic cement. The
diameter of the upper part of the vessel should be considerably less than that
of the lower part, and should be hermetically closed by means of a wooden lid
well adjusted and lined internally with sheets of glass. I agitate the liquor in
this vessel by means of a vertical shaft or agitator, provided with paddles and
set in motion by a winch and bevil wheels. The paddles are inclined and
made of sand stone, and disposed for agitating violently the mother liquors
when the addition of sulphurous acid is made.
When the globules of gas which maintain part of the iodine precipitate on
the surface of the liquor have been dispelled, I allow the liquor to rest. I then
withdraw the supernatant liquor by means of a sandstone syphon. I after-
wards concentrate the liquor, to extract the nitrate and sulphate of soda and
chlorides of sodium and potassium.
The iodine precipitate is transferred to a sandstone fountain, at the bottom
of which a filter is formed, composed of successive layers of quartz stone finely
powdered, and the grain of which decreases in size from bottom to top. After
the iodine has been sufficiently drained, I draw it off without disturbing the
lower layer of iodine, and convey it into a rectangular box made of plaster of

page_text: Paris, closed by means of a lid of the same composition, sliding friction wise in
two parallel grooves. The lid of the box should be thick enough (but not too
compact) to allow the water of imbibition to filter into the sides & lid of the
box.
When the iodine is sufficiently dried I rapidly charge the sandstone retorts,
in order to crystallize it by sublimation.
To extract iodine from the mother liquor in the state of iodate and iodide, I
treat the liquors successively with a solution of chlorine and sulphurous acid,
previously tested in the following manner :—
When the liquor contains little iodide and much iodate, I first precipitate
the iodine contained in the iodide by means of chlorine, and as soon as the
reaction is terminated I add a sufficient quantity of solution of sulphurous acid
for decomposing the iodates. If the mother liquor contains much iodide and
little iodate, I first employ a solution of sulphurous acid and afterwards an
aqueous solution of previously tested chlorine. Several cubic feet of the
mother liquors may be treated at a time with precision and facility.
The above processes are economical and expeditious, and have the advan-
tage of avoiding the loss of nitrate of potash or soda during the concentration
of the liquors, which result cannot be effected by the employment of sulphuric
acid of commerce by the ordinary method.
And having thus described the nature of my said Invention, and the manner
of carrying the same into effect, I would have it understood that I do not con-
fine myself to the precise details herein laid down, as the same may be varied
or modified according to circumstances. But what I claim as new and intended
to be protected by the herein-before in part recited Letters Patent is, the
application and mode of applying sulphurous acid and chlorine to treating
the mother liquors of nitrate of soda for the extraction of iodine therefrom, as
herein-before described.
In witness whereof, I, the said Louis Faure, have hereunto set my
hand and seal, this Thirty-first day of July, in the year of our Lord
One thousand eight hundred and fifty-four.
LS. FAURE. (L.S.)