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Déç. v10,. 1946.
.1.Y cRANsToN
2,412,390
RECOVERY OF BROMINE AND IODINE FROM NÁTURAL BÈINES
Filed May 25, 1943J
2 Sheets-Sheet l
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INVENTOR.
“ Dec. v10,1946.
J. CRANSTON
2,412,390
RECOVERY OF BROMINE AND IODINE FROMl NATURAL BRINEs
l Filed 'May 25, 1945
'2 Sheets-Sheet 2
I I'
A T270:202-117.
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Patented Dec. 10, 1946
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2,412,390
¥UNITED STATES PATENT _oFFlceEK-ï j ~
2,412,390
RECOVERY ’OF BROMINE 4AND IODINE FROM
'
NATURAL BRINES
'
, John Cranston, Ironton, Ohio
`Application May 25„ 1943, Serial No. 488,378
.
2 Claims.
1`
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,
(Cl. 23-217)
2
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mately 98% of the bromine, with simultaneous:
The object of the present invention is to pro
vide an economical and efficient method of re
oxidation of any iodide to the iodate,
covering bromine, and also iodine,v> from natural
brines, such brines being, for example, found in
the Niagara formation in eastern and southern
Ohio, the latter brine containing about three
pounds of bromine per ton, and about one-half
2NaI+2NaBr+7Cl2+6H2O=
Referring to Figure l of lthe drawings, it will.
be .seen that the raw brine may be pumped from
the tank containing the same to the top ofthe
chlorinating tower, the latter receiving chlorine
ounce of iodine per ton, calculated as elemental
halogens. It has been considered impractical to
lattempt recovery of such a small proportion of
iodine, amounting to little more than a trace of
as indicated. It isr well known that by'treating
the brine previous to chlorination with surñcient
acid to give a pI-I value of 2.5-3.0, the required
amount. of chlorine is substantially reduced, this
required amount beingl in excess of the theoreti
cal. In my method I accomplish acidification of
» the material.Y However, if the reco-very can be
accomplished at little or no additionalexpense in
the recovery of larger constituents of the brine,
such as the bromine, the gross value of the iodine
might well, in a commercial plant, amount to a
the brine by . addition of chlorine in amount
'l5-100% in excess of the theoretical. This excess
number of thousands of dollars yearly.
chlorine furnishes its equivalent as hydrochloric
By means of the present invention, I not only
acid, and gives the spent brine a pH of 1.1, which
provide an improved and more economical proc
serves a useful purpose in the liberation of the
20
ess for the recovery of liquid bromine, but also
iodine as toV be hereinafter explained in detail.
make use of certain side products resulting from
After the brine is acidified it is pumped tothe
the bromine operations to recover the iodine con
top ci a packed column I, where it is brought into
tent `at such low cost as to make its recovery com
contact with an upwardly directed current of
mercially practical.
_
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i
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air which is admitted to the bottom of column I..
[The `characteristic of my bromine process is
The brine in its contact with the packing of co1
that it _produces liquid bromine from yvapors
umn I is brought into mechanical disturbance,
thereof distilled at a temperature ofv only 2 or 3°
and this disturbance lowers the surfacetension of
C. above its own boiling point. This low tem- .
the brinewhich brings the bromine out of solue
perature recovery of the bromine effects a num- K
tion so that it is absorbed as vapor by the ups.
ber of economies, both in the amount and char
acter of the equipment required and in cost. and
wardly directed current of air, and `re-establish
ment of equilibrium between the bromine vapor
ease of operation.
and thebrine is prevented.
The characteristic of the
iodine operation is that it proceeds simultane
I
ously with thebromine recovery, making` use of
The air passing kawayat the top of air absorp
tion tower I, heretofore termed the packed col
certain operations and side products of the bro
umn I, carries bromine vapor, some hydrochloric
acid, and also traces of organic gases represented
by the series corresponding to chloroform, bromo
` mine recovery.
My method vwill be described with reference to
the accompanying drawings, in which-
_
form, etc.
Figure l is aL diagrammatic view inA elevation 40
showing the assembled units of a complete bro
mine-iodine recovery plant, employing my proc
' f
I
I
In passing from air absorption tower I, the a'ir,
carrying bromine vapor, etc., enters the first one
Figure 2 is a diagrammatic elevation, partly in
section,` showing the assembled units used in my
of two columns, 2 and 3 respectively, at'the base
of which isa leak-proof tank filled with asolu
tion of ferrous bromide. Immediately above the
level of lferrous bromide in tank 2 vis a horizontal
duct communicatingr with the second column -3
method for the recovery of bromine alone or for
the recovery of the bromine followed by the pas
sage of the bromine removed constituents of the
which has at its base a tank‘area'fñlled with fer'
rous bromide solution. The' solution is continuà
ously circulated from the »baseof each of the
ess, certain tank and column casings being shown
in section.
brine to iodine recovery towers,
„
-I will now describe `my method as used for
simultaneous recovery of both the bromine and
iodineconstituents of natural brine:
'I‘he ñrst step in the DTQcess is to treat the raw
brine with suii'icient chlorine to liberate approxi
50 columns 2 and 3 to the top thereof by mea-nsof
pumps PI and P2 and the pipingindicated in >the
drawings. The columns 2 and 3 are packed or
plate columns, as >indicated in the drawings. As
the current of mixed gases passes through co1:
55 .umn 2..most of the bromine unites withfthefer
‘rous bromide solution, converting it to the ferrie
passesdownwardly through column 4, which isa
condition. The air current, with any traces of
bromine passes through column 3 where such
remaining bromine is absorbed in the ferrous
solution of thatcolumn, while the inert gases
ings, it comes into contact with the current of
air which theretofore has Vcarried the bromine
vapor through towers 2 and 3. This air current
pass on to column 4.
'
packed or plate column as shown in the draw
absorbs the iodine vapor in the same WayV in
which the bromine was earlier absorbed thereby.
At the base of column 4 is a collection chamber
.
When the ferrous solution in column 2 has
been completely brominated to the ferric condi
tion, itis- ready to be treated for the separation
or-tank for receivingA the bromine and iodine- ¿t
of Aits bromine content as liquid bromine. The
finished ferrie solution should be at a speciñc
gravity corresponding to 1%2-2 pounds per gal
free brine and the latter may' be discharged via
Y the pipe shown in the drawings.
»
.
The air current with its content Yof .iodineV
lon, figured as elemental bromine.
vapor is discharged from column 4 into a column
'I'he said strong ferric solution is pumped from
5 near the basev thereof `and through which .
column 2 to the still indicated in the drawings,Y 15 is circulated any desired solution Vfoi-,picking up .
where the temperature ofthe solution is raised
and concentrating the iodineY vapor carried by
to 60° C., or the solution may be pre-heated to
the air current. These solutions may be of
this temperature before its transfer to the still.
sodium hydroxide, sodium carbonate, or the cor
With the solution in the still and the heat con
responding potassium compounds. When the .
trolled to 60° C., chlorine gas is introducedinto
concentration of iodine in the solution has
v,the solution at the rate of approximately 100
reached a desired point, the solution maybe
pounds per hour per 1000 gallons of solution in
drawn off for the Vpreparation of any desired salt
_the still. When the solution becomes saturated
of iodine, and, ofcourse, the iodine salt may
' with bromine, concentrated bromine gas, carry
.be treated for theseparation of elemental iodine.
ing practically no water vapor, passes from the
. It is to be noted that in my process the liber.
still to the condenser, and as long as any com
ation of the iodine >is accomplished by a reduc
bined bromine remains in the solution,_the chem
ing agent; namely, ferrous chloride >obtained
ical equivalent of bromine will be immediately
from the ï ferrie chloride still-liquor. Further
discharged to the condenser with each equivalent
more, the iodide salt present in the raw _brine
of chlorine injected into the solution. 90%' of
at the commencement of the process, is deliber
the bromine will be discharged to the condenser
ately over-oxidized to the iodate for accomplish
without further addition of artincizn heat beyond' ' ing the liberation of the'iodine by use of still- ,
the initial amount used to bring the tempera
Waste from the bromine process. `
¿
tureof the solution to 60° C., the gas passing to
I prefer, in the initial.` step of the bromin
`the condenser at a temperature of only 2 or 3° C. 35 process, to warm the raw brine to about 40-45°
above the boiling point of bromine.
by any convenient means after Which chlorine
When all of the ferrie bromide has been con
is added in suil'ici'ent quantityV to over-oxidize
verted to ferric chloride, the flow of chlorine is
the iodate and to give approximately 98%- liber
stopped, and >the traces of bromine remaining in
ation of bromine. By warming the- brine vwithin
the 'ferric chloride solution may be steamed out 40 the temperature-range stated, the reaction is
by direct injection of low pressure steam.
many times accelerated over a method in which
It Will be understood that when the concentra
:tion of ferric solution in column 3 has reached
av high degree it also may be transferred to the
theV brine'is treated at ordinary temperatures vat
_the initial stage of treatment.
'
».
In my method there is no necessity
y
4for puri-V
ystill for action-as required.
'
. The condensation of concentrated bromine gas
‘,' ñcation of the dilute vapors taken directly olf
at ftheist'ated low temperature eliminates the ne
cessity for condensing quantities of water Vapor,
this permits reduction in construction and oper
` the brine, as is required in other _processesand
ations costs and dispensing with >puriiication
with its high latent heat of evaporation, a con-V
towers, packing,`jpurnps andY pipelines. In'my
dition which prevails through operation of the
method purification of the gas Ais automatickby
reason of ,the fact that the bromine gas >is liber-V
conventional distillation methods 'by high tem
perature steam. "The absence` of> water vapor
permits the use of greatly Vreduced condenser sur
faces With» use _of minimum cooling liquid. The
absence of 'high temperatures throughout opera
tion of the method simplifies construction of
equipment and prolongs its life.-
'
’
. Y
From thevforegoing'it Willgbe seen that brine
at the base lof the air-absorbing column l is
bromine-free. Y For the liberation' of .elemental
iodine from the iodate in said Vbrine,;I ñrst reduce
the `ferric- chloride still-liquor taken from the still
shown inthe drawings, to ferrous chloride. The
still-liquor vis discharged finto a tank, as indi
cated in the drawings, this tank containing iron
particles such as scrap iron. The ferrous chlo
ride thus formedV lspllmped into a tank whichk re
oeives brine discharged from the air-absorbing
column I. Inthe latter tank elemental iodine is
liberated from the' iodatezßinfthe Vbromine-free '
brine byzoxidation of the iron solution> to the fer
ric’iron, so that the brine YWill carry free iodine
in solution; _This solution'is pumped tothe top
ofcolurnnß.l
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ÍAs the `brine,íwith its free-iodine"in'solution,
ated inthe presence of an excess of ferric
bromide.`
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Having described my invention, whatI claim>
-
and desireA to
follows:
'
secure by /_I_lettersV Patent is Vas*
'
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1. A method of recovering bromine and iodine
from"natural brines Which consists in treating
, the raw' brine with excess chlorine _suñicientl‘to
liberate the major bromine Vcontent of the brine
and to" give the spent brine aV pH of approxi
mately 1.1, lowering the .surface> tension ofthe
brine‘by agitating it 'Whilst it is movingy ina
flowing Vstream and simultaneously passing a
currentV of' 'air-V through the flowing stream of - Y
brine under a’gitation,~therebyv absorbing>v the
liberated bromine vapor, removing the bromine
content of the air vby- absorption in a ferrousL -
bromide solutionywhich is brominated tothe
ferrie condition, chlorinating the ferric solution
at a temperaturexof'substantially 60° C.; re
moving the concentrated> bromine,v gas thus -
formed and condensingV it to liquidbrom'ine,l re-`
d_ucing VYthe remaining vferrie chloride ftoj ferrous
chloride, and bringing theï'ferro'usïchlorideY into '
4
2,412,390
Contact with the bromine-spent brine, whereby
ciuding the steps of passing the brine, with its
free iodine in solution into a closed zone, receiv
ing the current of >air from which the bromine
content has been removed by absorption, and
free iodine into a Zone wherein the iodine is 5 passing the brine in a ñow broken up into streams
in Contact with said air current, whereby the
removed therefrom by a stream of air, and then
latter constitutes an absorption medium for
passing said stream through an absorption me-`
iodine vapor liberated from the brine.
dium for the iodine.
JOHN CRANSTON.
2. The method in accordance with claim 1, in
elemental iodine is liberated from the iodate in
the bromine-free brine by oxidation of the iron
solution to ferrie iron passing the brine with its
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