Improvements in the Treatment of Seaweed and the like for the Production of Iodine and other Useful Products.
Year: 1897

page_text: Improvements in the Treatment of Seaweed and the like for the
Production of Iodine and other Useful Products.
I, AUGUSTE JAMES, of l'Hede, Bréhat (Côte du Nord), France, Inventor, do hereby
declare the nature of this invention to be as follows:-
This invention has reference to the production of iodine from seaweed and other
marine plants in the fresh state or simply dried in the air, without destroying the
vegetable portion, and while depriving them of but a very small proportion of the
mineral salts which they contain, thus preserving their value as direct manure.
By my invention I am therefore able to obtain on the one hand the iodine of the
seaweed or the like, and on the other hand a residue capable of immediate employ-
ment in agriculture.
My invention is based upon the following observations.-
(1). If seaweed or marine plants in the fresh state or simply dried in the air, are
treated with sea water or any other saline solution of approximate composition and
density, which has been rendered alkaline and deprived of magnesia by the addi-
tion of a suitable quantity of caustic lime, nearly all the iodine contained in the
vegetable matter passes into the solution.
(2) It is possible by chemical operations conducted at the ordinary temperature
and hereinafter described to recover the whole of the iodine thus brought into
solution.
(3) The seaweed deprived of iodine retains its external appearance and fertiliz-
ing properties; and besides the organic matter which remains unchanged contains
a certain amount of potash which renders it capable of direct employment as
manure.
My invention particularly relates to the treatment of the vegetable matter in its
fresh state but I may also employ somewhat similar treatment to it when in the dry
state.
As the method of treatment is not absolutely the same for fresh and dried
material, I will describe my invention as I apply it in each case, and I will first
take the case of seaweed or the like taken direct from the water.
I take seawater as above described, and for each cubic metre of same I add for
example 8 kg. of quick-lime, this quantity being generally more than sufficient to
effect precipitation of all the magnesia contained and to give a distinct alkaline
reaction the solution is then poured upon the fresh seaweed in the proportion of
say 2 cubic metres to each ton of weed, the latter being kept completely immersed.
In this first operation, which is complete on the average in 12 hours, from 60 to
65 per cent. of the iodine contained in the matter under treatment passes into
solution. The same weed is then treated in the same manner with a fresh quantity
of sea water prepared as above, but in this case only one cubic metre of water
should be added per ton of weed, and this operation should be repeated. The time
occupied for each operation is about 6 hours.

page_text: The second and third treatments deprive the material of the rest of its iodine
with the exception of all but a small quantity which may be extracted by other
washings, but this. quantity is less than 10 per cent of the total amount and con-
sequently too slight for practical extraction. This liquor is not treated directly,
but is enriched by being employed for a first washing. I thus succeed in con-
centrating in 2 cubic metres of the solution the iodine from a ton of fresh sea-weed.
The second part of the process is the extraction of the iodine from dilute solu-
tions thus obtained, and is carried out as follows:-
The solution is first deprived of organic mucilaginous matters which it con-
tains, by the addition of a solution of ordinary ferrous sulphate, in the proportion
of not less that 3 kilogs. per cubic metre of liquor. A voluminous precipitate of
ferrous hydrate is produced which carries down the mucilaginous matters and
permits of ready decantation.
Instead of ferrous sulphate I may employ with advantage a further quantity of
caustic lime; in this case I add say from 3 to 5 kilos of quick lime to cach cubic
metre of liquor, an abundant precipitate being also formed in this case. After
decantation this precipitate or that produced by the ferrous sulphate is again
thrown upon the fresh sea-weed in order to be washed by the first extraction.
The solution obtained after this treatment, which is quite limpid and colorless,
is then brought into wooden vats of a capacity of about two cubic metres pro-
vided with agitators; it is neutralized by the addition of sulphuric acid, say
2 kilogs of acid at 66° to each cubic metre of liquor. I may with advantage for
the rest of the treatment substitute an equivalent quantity of ordinary hydro-
chloric acid for the sulphuric acid.
After this the iodine is liberated by the addition of nitric acid in the proportion
of about 15 kilos per cubic metre of liquor, or by any other appropriate reagent
(persulphate of ammonia, ferric salts &c.). The proportions of acids above indi-
cated may naturally be varied according to the nature and richness in iodine of
the liquors; they are in practice determined each day by test.
The extraction of the iodine thus liberated is effected by treating the solutions
with an appropriate solvent; that which I have found to give the best results is
petroleum oil. It is introduced into the vats with agitators above described in the
proportion of about 30 kilogs. of oil per cubic metre of liquor. The first treatment
removes about 80 per cent of the free iodine and the rest is removed by a second
treatment. The petroleum employed for the second treatment is added to a new
quantity of liquor, so that the iodine furnished by a ton of seaweed becomes dis-
solved in about 30 kilogs. of petroleum.
The iodine dissolved in the petroleum is finally separated by agitation with a
weak potash or soda lye. The whole of the iodine is thus concentrated in the state
of iodide and alkaline hypo-iodite in a small quantity of water.
It is then pre-
cipitated by ordinary means, and it is then only necessary to pass it to the filter
press.
Further, by employing pure potash or soda I may obtain directly the iodides of
potassium and sodium which crystallize out upon evaporation of the solution last
mentioned.
This treatment if well conducted allows of the extraction of from 90 to 95 per
cent of the total amount of iodine contained in the seaweed or the like.

page_text: TREATMENT OF DRY SEAWEED.
The dried weed holds only 25 per cent moisture but when it is thrown into the
lime solution it again takes up the 60 per cent which it has lost; hence it is
necessary to employ for the first washing a larger volume of lime solution.
The treatment differs from that of fresh weed only in the following points;-
1. Volume of sea water employed.
2. Substitution of lime for ferrous sulphate to coagulate the mucilaginous
matters.
3. Employment of hydrochloric acid in place of sulphuric acid for the neutral-
ization &c.
4. Employment of a proportion of 50 kilogs. of petroleum instead of 30 kilogs.
for obtaining the free iodine from the solutions containing it.
These modifications are useful because they admit of a greater degree of con-
centration of the liquors and facilitate the operations of decantation and extraction.
EXAMPLE.
A ton of dry weed was treated with 6 cubic metres limed sea water which had
previously served for second and third washings;
From a ton of dry weed after 12 hours contact there was obtained 4180 cubic
metres of liquor.
The difference represents the water taken up by the weed.
The second treatment is made with three cubic metres of limed sea water.
The same with the third; and the 6 cubic metres of liquor thus obtained serve
in a new operation for use upon a fresh ton of dry weed. A residue of 29 tons to
3 tons of moist weed is thus obtained.
To recapitulate, there is required 6 cubic metres limed sea water for a ton of
dry weed, but as this quantity represents obviously 4 tons of weed taken from the
water, the immediate treatment of which would need 8.cubic metres of limed water,
there is economy of treatment of 2 cubic metres of liquor.
Finally, the weed which has undergone the treatments above described possesses
the following average composition; the organic matter is in no way changed and
the external appearance is the same as when it came out of the water.
The resultant weed contains after desiccation at 100°
Hydrocarbonated organic matter
Nitrogen
Phosphoric acid
Lime
Potash
54.85
3.73
0.57
7:30
10.00
Improvements in the Treatment of Seaweed and the like for the
Production of Iodine and other Useful Products.
I, AUGUSTE JAMES of l'Hede, Bréhat (Côte du Nord), France, Inventor, do hereby
declare the nature of this invention and in what manner the same is to be

page_text: performed, to be particularly, described and ascertained in and by the following
statement:
This invention has reference mainly to the production of iodine from seaweed
and other marine plants in the fresh state or simply dried in the air, without
destroying the vegetable portion, and while depriving them of but a very small
proportion of the mineral salts which they contain, thus preserving their value
as direct manure. By my invention I am therefore able to obtain on the one hand
the iodine of the seaweed or the like, and on the other hand a residue capable of
immediate employment in agriculture.
My invention is based upon the following observations:-
(1) If seaweed or marine plants in the fresh state or simply dried in the air, are
treated with sea water or any other saline solution of approximately similar com-
position and density, which has been rendered alkaline and deprived of magnesia
by the addition of a suitable quantity of caustic lime, nearly all the iodine
contained in the vegetable matter passes into the solution;
(2) It is possible by chemical operations conducted at the ordinary temperature
and hereinafter described to recover the whole of the iodine thus brought into
solution.
(3) The seaweed deprived of iodine retains its external appearance and fertiliz-
ing properties; and, besides the organic matter which remains practically
unchanged, contains a certain amount of potash which renders it capable of direct
employment as manure.
My invention particularly relates to the treatment of the vegetable matter in its
fresh sate but I may also employ somewhat similar treatment to it when in the dry
state.
As the method of treatment is not absolutely the same for fresh and dried
material, I will describe my invention as I apply it in each case, and I will first
take the case of seaweed or the like taken direct from the water.
I take sea-water as above described, and for each cubic metre of same I add for
example 8 kg. of quick-lime this quantity being generally more than sufficient to
effect precipitation of all the magnesia contained and to give a distinct alkaline
reaction; the solution is then poured upon the fresh seaweed in the proportion of
say 2 cubic metres to each ton of weed, the latter being kept completely immersed.
In this first operation, which is complete on the average in 12 hours, from 60 to
65 per cent of the iodine contained in the matter under treatment passes into solu-
tion. The same weed is then treated in the same manner with a fresh quantity of
sea water prepared as above, but in this case only one cubic metre of water should
be added per ton of weed, and this operation should be repeated. The time
occupied for each operation is about hours.
The second and third treatments deprive the material of the rest of its iodine
with the exception of a small quantity which may be extracted by other washings,
but this quantity is less than 10 per cent of the total amount and consequently too
slight for practical extraction. This liquor is not treated directly, but is enriched
by being employed for a first washing. I thus succeed in concentrating in 2 cubic
metres of the solution the iodine from a ton of fresh sea-weed.
The second part of the process is the extraction of the iodine from dilute solu-
tions thus obtained, and is carried out as follows:-
The solution is first deprived of organic mucilaginous matters which it contains,
by the addition of a solution of ordinary ferrous sulphate, in the proportion of not
less than 3 kilos per cubic metre of liquor. A voluminous precipitate of ferrous
hydrate is produced which carries down the mucilaginous matters and permits of
ready decantation.
Instead of ferrous sulphate I may employ with advantage a further quantity of
caustic lime; in this case I add say from 3 to 5 kilos of quick lime to each cubic
metre of liquor, an abundant precipitate being also formed in this case.
decantation this precipitate of that produced by the ferrous sulphate is again
thrown upon the fresh sea-weed in order to be washed by the first extraction.
After

page_text: The solution obtained after this treatment, which is quite limpid and colorless,
is then brought into wooden vats of a capacity of about two cubic metres provided
with agitators; it is neutralized by the addition of sulphuric acid, say 2 kilogs of
acid at 66° to each cubic metre of liquor. I may with advantage for the rest of
the treatment substitute an equivalent quantity of ordinary hydrochloric acid for
the sulphuric acid.
After this the iodine is liberated by the addition of nitrous nitric acid in the pro-
portion of about 15 kilos. per cubic metre of liquor, or by any other appropriate
reagent (persulphate of ammonia, ferric salts &c.). The proportions of acids above
indicated may naturally be varied according to the nature and richness in iodine
of the liquors; they are in practice determined each day by test.
The extraction of the iodine thus liberated is effected by treating the solutions
with an appropriate solvent; that which I have found to give the best results is
petroleum oil. It is introduced into the vats with agitators as above described in
the proportion of about 30 kilogs. of oil per cubic metre of liquor. The first treat-
ment removes about 80 per cent of the free iodine and the rest is removed by a
second treatment. The petroleum employed for the second treatment is added to
a new quantity of liquor, so that the iodine furnished by a ton of seaweed becomes
dissolved in about 30 kilogs. of petroleum.
The iodine dissolved in the petroleum is finally separated by agitation with a
weak potash or soda lye. The whole of the iodine is thus brought into the state
of iodide and alkaline iodate in solution in a small quantity of water. The iodine
is then precipitated from solution by potassium chlorate and hydrochloric acid in
the proportion of about 181 grammes of chlorate for 1 of iodine, and 6 of hydro-
chloric acid for 1 of potassium chlorate, this being the method usually employed.
It is then only necessary to pass it to the filter press.
Further, by employing pure potash or soda I may obtain directly the iodides of
potassium and sodium which crystallize out upon evaporation of the solution last
mentioned.
This treatment if well conducted allows of the extraction of from 90 to 95 per
cent of the total amount of iodine contained in the seaweed or the like.
A ton of sea-weed containing 1040 kilog, of iodine estimated directly, gave-
On the first extraction -
second extraction
""
third extraction
27
Total
The yield is here 916 per cent.
-
663 grammes iodine
-
252
"
"
-
38
"
"
953
"
"
TREATMENT OF DRY SEAWEED.
The dried weed holds only 25 per cent moisture but when it is thrown into the
lime solution it again takes up the 60 per cent which it has lost; hence it is
necessary to employ for the first washing a larger volume of lime solution.
The treatment differs from that of fresh weed only in the following points:-
1. Volume of sea water employed.
2. Substitution of lime for ferrous sulphate to coagulate the mucilaginous
matters.
3. Employment of hydrochloric acid in place of sulphuric acid for the neutraliza-
tion &c.
4. Employment of a proportion of 50 kilogs. of petroleum instead of 30 kilogs.
for obtaining the free iodine from the solutions containing it.
These modifications are useful because they admit of a greater degree of concen-
tration of the liquors and facilitate the operations of decantation and extraction.

page_text: EXAMPLE.
A ton of dry weed was treated with 6 cubic metres limed sea water which had
previously served for second and third washings;
From a ton of dry weed after 12 hours contact there was obtained 4:180 cubic
metres of liquor.
The difference represents the water taken up by the weed.
The second treatment is made with three cubic metres of limed sea water.
The same with the third; and the 6 cubic metres of liquor thus obtained serve
in a new operation for use upon a fresh ton of dry weed. A residue of 2.9 tons
to 3 tons of moist weed is thus obtained.
To recapitulate, there is required 6 cubic metres limed sea water for a ton of dry
weed, but as this quantity represents obviously 4 tons of weed taken from the
water, the immediate treatment of which would need 8 cubic metres of limed water,
there is economy of treatment of 2 cubic metres of liquor.
•
Finally, the weed which has undergone the treatments above described possesses
the following average composition; the organic matter remains practically
unchanged and the external appearance is the same as when it came out of the water.
The resulting weed contains after desiccation at 100°
Hydrocarbonated organic matter
Nitrogen
Phosphoric acid
Lime
Potash
Soda
-
54.85
3.73
0.57
7:30
10'00
12.85.
It forms an excellent manure.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, I declare that what I Claim
is:
1. The treatment of seaweed in the fresh state, substantially as hereinbefore
described, for the purpose of obtaining iodine without materially diminishing the
fertilizing properties possessed by the seaweed before treatment.
2. The treatment of seaweed in the dry state, substantially as hereinbefore
described, for the purpose of obtaining iodine without materially diminishing the
fertilizing properties possessed by the seaweed before treatment."
3. The employment for the purpose specified in Claims 1 and 2 of limed sea-
water or other limed saline solution of approximately the same density and com-
position capable of preventing or diminishing the diffusion of the potash salts
contained in the sea weed, substantially as herein before described.
4. The use in the treatment of sea weed for the purpose set forth of ferrous sul-
phate or of caustic line for coagulating the mucilaginous organic substances in
the diffusion liquors, substantially as herein before described.
5. In the treatment of sea weed for the purpose set forth the extraction or
separation of the iodine from the dilute solutions obtained by diffusion, by
agitating with a suitable solvent such as petroleum oil, substantially as herein-
before described.
Dated this 5th day of October 1897.
J. C. MEWBURN & ELLIS,
55 and 56 Chancery Lane, London, Chartered Patent Agents.