Improvements in or relating to the Treatment or Utilization of Kelp Liquor.
Year: 1895

page_text: Date of Application, 22nd Aug., 1895
Complete Specification Left, 19th May, 1896--Accepted, 4th July, 1896
PROVISIONAL SPECIFICATION.
Improvements in or relating to the Treatment or Utilization of
Kelp Liquor.
I, JOHN WILLIAM STEVENS, of The Oaks, Horley in the County of Surrey,
Manufacturing Chemist do hereby declare the nature of this invention to be as
follows:-
In the treatment of kelp liquors as far as I am aware no attempt or at any rate
no successful attempt has ever been made to make chlorate of potash therefrom by
a direct process.
This invention is designed to effect this. I take the kelp liquors from the
lixiviating vats and treat them electrolytically either before or after the iodine has
been separated, I thus convert the potassium (and sodium) chlorides into chlorates.
If the iodine has not been already separated it is now in the form of an iodate.
The liquor can now be treated in any of the following manners.
The liquor can be partially evaporated and the chlorate of potash separated by
fishing or by slow crystallisation or the liquor can be submitted to an exceedingly
low temperature with or without previous concentration and salts separated in this
way or some or all of the extraneous salts can be precipitated by re-agents prior
to the separation of the chlorate of potash.
Lastly the liquor containing the chlorate of potash with some or all of the mother
liquor or other salts can be used directly in certain manufacturing processes where
oxidising liquor is required.
Deted thin oond d
1005
W. P. THOMPSON & Co.,
31, High Holborn, London, W.C., Patent Agents for the Applicant.
Improvements in or relating to the Treatment or Utilization of
Kelp Liquor.
I, JOHN WILLIAM STEVENS, of The Oaks, Horley, in the County of Surrey,
Manufacturing Chemist, do hereby declare the nature of this invention, and in what
manner the same is to be performed to be particularly described and ascertained in
and by the following statement :-
The invention which forms the subject of my application for Letters Patent
relates to the treatment of lye obtained by the lixiviation of kelp and the
obtaining therefrom of the chlorates of potassium and sodium, by the treatment
hereinafter set forth together with the recovery of iodine and, when advantageous,
also of bromine and incidentally also of other less valuable constituents.
In carrying my process into effect I make use of the kelp preferably broken into
pieces about the size of ordinary road metal. This material is then placed in
lixiviating vats and lixiviated in the ordinary manner. The first liquor from the
lixiviating vats which contains the greater portion of the iodine is then concentrated
Price 8d1

page_text: :
to about 1-3 specific gravity at which strength the sulphate of potash present:
precipitates from the solution in the evaporating vessel. The liquor is then run
into tanks to cool when the greater portion of the potassium chloride crystallises out.
The mother liquor is then further concentrated by boiling and again run into cooling
tanks when the alkaline chlorides which precipitate and crystallize are removed
from the tanks and the liquor again concentrated and salts taken out as before until
the mother liquor is sufficiently strong in iodides and bromides and practically the
whole of the sodium chloride and potassium chloride have been recovered. This
point can be ascertained by working tests in the well known manner. The mother
liquor after the removal of the chlorides is then neutralised with sulphuric acid and
the iodine and bromine is stilled off in the presence of oxide of manganese in the
usual manner. The sodium and potassium chlorides separated out are preferably
used to increase the specific gravity of the second and subsequent liquors from the
lixiviating vats to about 1.3.
The second and subsequent liquors from the lixiviators are carefully neutralised
by means of bydrochloric acid. In this operation a certain amount of free sulphur
is produced by the decomposition of the sulphur compounds in the kelp liquor and
this sulphur must be removed by filtration or settling, the liquor is then concen-
trated until any sulphate of potash present is removed by boiling or crystallizes
'out. The liquor is then treated by electrolysis and the bulk of the alkaline
chlorides is thereby converted into chlorates whilst at the same time the iodides
and bromides are converted into iodates and bromates. When the process is
sufficiently completed the liquor is run into coolers in which the chlorates crystallize
out.
This mother liquor is again concentrated either by steam heat or by
resaturating with the alkaline chlorides obtained as above and again subjected to
treatment. The electrolytic treatment and separation of the chlorates is repeated
until such time as the liquor is sufficiently charged with iodates and bromates
which are then re-converted into iodides and bromides by the use of sulphurous
acid in the well known manner and the iodine and bromine stilled off as in the
process at present in use. The liquor remaining after these operations may then
be taken back to the lixiviating vats or if sufficiently strong may be again treated
in the electrolytic cells.
Various modifications of apparatus and process for electrolysis of salts are
known and I do not confine myself to the use of any one special method, but
reserve the right to make use of any process of electrolysis applicable for the
purpose.
By way of example I may use the cell of ordinary construction having an anode
of a substance not acted upon by the salts under treatment such for instance as
carbon and a cathode consisting of a metal or metallic oxide. The potassium and
sodium chlorates are obtained from the solution by crystallization and purified by
recrystallizing. In the process as above described the greater portion of the
iodine is removed so as to save possible loss of the same by frequent handling, but
I may if desirable take the first liquors from the lixiviators and treat them
according to my process by concentration, neutralising with hydrochloric acid
filtering if necessary and separating the sulphate of potash, and subsequent
electrolysis as described.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what I
claim is
The process for the production of chlorate of sodium and chlorate of potassium
from kelp liquors with recovery of the iodine and bromine or one of them consisting
essentially in
(a) The separation of the first liquor from the tanks containing the greater
portion of the iodine from the subsequent lixiviation with addition of the
recovered chlorides, the treatment of the said first portion by concentration,
precipitation of the sulphate of potash and extraction of the potassium and

page_text: sodium chloride by cooling and cystallization. The neutralization of the
liquor with sulphuric acid and the distillation of the iodine and bromine in
the presence of oxide of manganese.
3) The treatment of the second portion of the liquor from the vats enriched
by the returning of the potassium and sodium chlorides from the first portion
by neutralising with hydrochloric acid, removal of any sulphur produced by
filtration and settling, and of the sulphate of potash by concentration or
crystallization, the treatment of the resulting liquor by electrolysis and
conversion of the bulk of the alkaline chlorides into chlorates and the-
obtaining of the said chlorates by crystallization.
The further treatment of the residual liquor containing iodates and
bromates with sulphurous acid to re-convert the iodates and bromates into.
iodides and bromides, of the extraction of the same with the aid of oxide of
manganese as above set forth.
Dated this 15th dex of Max 1896
W. P. THOMPSON & Co.,
322, High Holborn, London, W.C., Patent Agents for the Applicant..