Note: Descriptions are shown in the official language in which they were submitted.
~137~
This application is divided out of our copending application Serial
No. 306,775, filed on July 4, lg78, which relates to an intermediate, non-
crystalline halolithium/lith;um alum:inate complex-containing resin and its
method of preparation.
The present invention relates to a crystalline LiX-2AI(O~l)3-
containing resin, its method of preparation and methods of use.
Various brines exist which contain Li salts. At times, it is desired
to preferentially remove and/or recover the Li ion from the brine. In some
brines, such as geothermal brines or such as Smakover brines, it is often de-
sirable to remove Li values therefrom, either because one wants the Li values
in substantially pure or concentrated form or because one wants the brine to be
substantially free of Li.
There are various published articles and patents dealing with Li
extraction from brines. The most pertinent prior art is believed to be found in
the following patents.
United States Patent No. 2,964,381 teaches to separate lithium values
from an aqueous solution which contains alkaline earth metal salts, by adding
a soluble aluminum salt to precipitate the lithium as a lithium aluminate com-
plex.
United States Patent No. 3~306,700 enlarges on, and improves, the
lithium aluminate complex process of United States Patent No. 2,964,381 above.
United States Patent No. 2,980,497 discloses a method of recovering
the lithium from a lithium aluminate complex formed, e.g., in the process of
United States Patent No. 2,964,381. The method involves heating the complex in
water to at least 75C to decompose it and then using a strongly acidic cation
exchange resin to bind the soluble lithium compound and impurities, subsequentlytreating the resin with a caustic solution to form soluble lithium hydroxide and
- 1 - ~
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~37;~4~
insoluble impurities and recovering the lithium hydroxide.
The invention of our copending application Serial No. 306,775 relates
to a process for preparing a particulate anion exchange resin having halolithium/
lithium alumlnate complex suspended therein which comprises
ta~ impregnating a particulate anion exchange resin with AlCl3,
~b) converting the AlCl3 to Al(OH)3, and
(c) forming said complex on the resin by contacting the so-formed Al(011)3-
containing resin with an aqueous solution containing lithium halide.
Preferably, the process comprises
(a) impregnating a particulate, anion exchange resin with an aqueous AlC13
solution;
(b) contacting the so-formed AlCl3-containing resin with an amount of
NH40H sufficient to convert the AlCl3 to Al(OH)3 and, if the resin is in the
acid form, enough to convert the resin to the base form; and
(c) contacting the so-formed Al(OH)3-containing resin with an aqueous solu-
tion containing lithium halide, thereby forming said halolithium/lithium alumin-
ate complex suspended in said resin.
In another aspect, the invention of our copending application Serial
No. 306,775 provides a halolithium/lithium aluminate complex-containing resin
wherein the resin is a particulate, anion exchange resin having suspended there-
in said halolithium/lithium aluminate complex which has substantially no crys-
tallinity.
According to one aspect of the present invention there is provided a
process for preparing a particulate anion exchange resin having microcrystalline
LiX-2Al(OH)3 suspended therein, where Y equals halogen, said process conmprising
(a) heating an halolithium/lithium complex-containing resin at a tempera-
ture and for a time sufficient to convert the complex to the microcrys~alline
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~37~
structure having the formula LiX-2Al(OH)3, said complex-containing resin being
a particulate, anion exchange resin having suspended therein the halolithium/
lithium aluminate complex, or
(b) prov;ding a particulate anion exchange resin substantially in neutral
or basic orm having s~1spended therein hydrous alumina conforming to the formula
Al(O~1)3; reacting said Al(0~1)3 with aqueous LiO~1 at a temperature and for a
period of time suEficient to form microcrystalline LiOH-2Al(011)3 suspended in
said resin; and reacting the so-formed LiOH-2Al(OH)3 with a halogen acid or
halide salt to convert it to said LiX-2Al~OH)3.
According to another aspect of the present invention there is provided
a composition comprising a particulate, anion exchange resin having suspended
therein a microcrystalline form of I,iX-2Al(OH)3, where X is a halogen.
According to a further aspect o the present invention there is provided
a method for removing lithium values from an aqueous brine which comprises con-
tacting the brine with a particulate, anion exchange resin having suspended there-
in a microcrystalline form of LiX-2Al(OH)3, where X is halogen, and then separat-
ing the lithium values from the resin.
This novel form of resin is useful in preferentially recovering Li
from brines, including brines which contain Mg
The resin of the invention of our copending application Serial No.
306,775 may be used to form a composition comprising a particulate, anion ex-
change resin having suspended therein a microcrystalline form of LiX-2Al(OH)3,
where X is a halogen. Ihis latter resin may be cycled numerous times before
encountering appreciable loss of exchange capacity. As used herein, the term
"microcrystalline" is used to indicate small crystals formed in small pores,
voids, and spaces in the resin which are detectable by X-ray diffraction, if
not by a microscope.
The present invention and that of our a~orementioned copending appli-
-- 3 --
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~37~
cation Serial No. 306,775 will be further described as follows.
Throughout this disclosure, LiX referes to lithium halides, especially
LiCl. The expression "suspended therein" when referring to compounds dispersed
in the resill, means that the compoullds are dispersed within the polymer matrices,
not merely clinging to the external surfaces oE the polymers.
The composition which includes microcrystalline l.iX-2Al~OH)3 may be
used in a process which comprises eluting a portion of the LiX out of the resin
with water containing a small amount of LiX. The resin containing the
LiX-2Al~OH)3, with a portion of the LiX removed, is usable to remove more Li
from brines, including brines which contain Mg
The anion exchange resin with which one starts, may be any particulate
water-insoluble polymeric resin which contains basic amine groups attached to
the polymeric resin. Macroporous anion exchange resins are preferred over the
gel-type resins.
By "macroporous", as the term is commonly used in the resin art, it is
generally meant that the pores, voids, or reticules are substantially within the
range of about 200 to about 2000 A. Another term, meaning the same thing is
"macroreticular."
Of particular interest are macroporous anion exchange resins in the
chloride form of a particulate polystyrene hlghly crosslinked with divinyl-
benzene having
- 3a -
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~37Z~
--4--
~CH2N(CH3)2 groups attached to the benzene rings. These
resins have a particle size, generally, of about 20-50 mesh
(U.S. Standard Sieve size) and about 30-40~ porosity ~based
on total volume~ with an internal surface area of about
30-50 m /gm. Thus, each particle is a reticular solid con-
taining pores of about 200-800 A in si~e, The base
capacity is about 4.2-4.3 meq./gm. of dry resin in its
basic (or free amine) form. The base strength, as measured
by a glass electrode in 26~ NaCl, is p ~ = 4 x 10 7 (mid-
-point in acid-base titration curve is pH - 7.6).
Other resins of particular interest are ~hose
having the amine group -CH~NRR' where R and R' may be,
individually, a hydrogen or alkyl group of 1-4 carbon atoms.
Also, resins containing other amines or amino groups (ter-
tiary, primary, secondary, cyclic) are within the scope ofthe present invention,
Other exchange resins which may be employed are
any anion exchange resins with a base strength greater than
PKb = 1 x 10 7, with macroporous resins being preferred.
2~ The Kirk Othmer Encyclopedia of Chemical Tech-
nology, vol. 11, pp. 871-899 on the subject of "Ion Exchange",
including discussions of commercially available anion exchange
resins, is a helpful reference. Another helpful reerence is
a book titled "Ion Exchange" by Friedrich Helfferich pub-
lished by McGraw Hill, 1962.
Detailed information about pore sizes of "gel-
type", "microreticularl', and "macroreticularl' ion exchange
resins may be ~ound in "Ion Exchanye in The _rocess Indus-
tries" published in 1970 by The Society of Chemical Industry,
14 Belgrave Square, London, S.W.I, England.
18,34OA-F
,
~37~
Among the macroporous anion exchange resins, which may be used are:
strongbase resins containing quaternary ammonium groups fixed to a poly~styrene-
divlnylbenzene); poly(vinyltoluene) which has been side-chain chlorinated and
reacted witl~ a tertiary amine to Eorm a quaternary ammonillm salt; or any of the
water-insoluble, but water-swellable aromatic polymers containing quaternary
ammonium groups.
Also gel-type anion exchange resins which contain primary, secondary,
tertiary amine and quaternary ammonium groups are operable. Such commercial
resins are discussed and described in the literature, such as in the Kirk-Othmer
Encyclopedia of Technology.
In determining the efficacy of an exchange resin, particulate macro-
porous resins which have a porosity of at least about 15%, an internal surface
area of at least about 10 m /gm and a base capacity of at least about 2.0 meq./
gm. ~dry, basic form) are preferred.
Such resins, if obtained in the base form, are preferably converted
to the chloride-fornl prior to being contacted with the aq. AlC13. This is con-
veniently done by treating the amine-form resin under reduced pressure with an
excess of aqueous HCl then filtering, washing and draining off the water. A
pressure differential across the filter may be employed to speed the draining
process, if desired.
The AlC13 which is used in treating the chloride-form of the resin is
conveniently, and preferably, a saturated aqueous solution containing about 31%
to about 32% AlC13 though weaker concentrations are operable, giving less
capacity. Hydrates of AlC13, such as AlCl3 6H2O, are useful in preparing the
aqueous solutions.
-- 5 --
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Outlining the overall preferred steps, generally,
used in preparing the Li~ 2Al(OH)3- containing resin and
employing it to recover Li+ values from brine:
1. Impregnate an anion exchange resin with
aqueous AlC13;
2. Treat the AlC13- impregnated resin with
aqueous NH3 to convert the AlC13 to Al(OH)3;
3. Treat the resulting Al(OH)3- containing
resin with aqueous Li halide to provide halolithium alumi-
nate or lithium aluminate dispersed in the resin;
4. Heat the resin, containing the so-formed
aluminate, at a temperature and for a time sufficient to
form microcrystalline LiX 2Al(OH)3 dispersed in the resin
and adjust the pH, if needed, to within the range of about
6.0 to 7.5 in saturated NaCl brine;
5. Elute a portion of the Li+ values from the
resin by employing a weak solution of LiX;
6. Contact the resin, containing the partially
LiX-depleted micro~rystalline LiX 2Al(OH)3 dispersed
therein, with a Li~-containing brine to selectively remove
the Li+ from the brine;
7. Repeat steps 5 and 6 two or more times.
Ordinarily, a cubic foot (28.3 liters) of resin
prepared by ~he present invention, will contain about 3 to
about 12 pounds (1.36-5.45 kg.) of microcrystalline LiX-2Al(OH)3,
or stated another way, about 50 to about 200 gms./liter of resin~
The above steps are described in greater detail
by the following generalized embodiments:
Ste~ I
The anion exchange resin with which one starts
may be impregnated as is with aqueous AlC13 or may be first
converted to its chloride form by being treated with aqueous
HCl. The anion exchange resin mQy be of the "weak base" or
18,34OA-F
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~372~9
--7--
"strong base" type, normally containing pendant amine, or
quaternary ammonium groups attached to a polymeric structure.
If it is desired to convert the basic form of the resin to
the chloride form, this may be done, e.g., by contacting the
resi.n with a~ueous HCl (of, say, 5-10% concentration).
Ambient temperature may be used for the HCl treatment, though
slightly increased temperature may also be used. In order
to completely "soak" the resin, a reduced pressure is usually
helpful during the HC1 treatment. An aqueous solution of
AlC13 is impregnated into the resin, whethex the resin
is in its basic form or its chloride form. The aqueous
AlC13 is preferably concentrated, with a satura~ed solution
of about 31-3290 AlC13 being most preferred. The amount of
aqueous AlC13 used should be enough to substantially replace
all the liquid which was already in the resin and still have
enough to completely flood the resin. The excess aqueous
AlC13 is then drained, leaving a resin which is moist; the
remaining moisture may be removed, e.g., by blowing hot, dry
inert gas or air through the resin, but this is not neces-
sary. Ambient temperature is operable for this step, though
increased temperature may be used to speed the process.
An alternative method of impregnating the resin
with AlC13 is to add AlC13 to a resin/water mixture, but it
is generally preferred to flow concentrated aqueous AlC13
through a column bed of resin, thereby replacing the liquid
in the resin with the aqueous AlC13.
Step II
The AlC13~containing resin is then treated with
ammonia, preferably aqueous ammonia to convert the AlC13
to Al(OH)3 within the resin particles~ Pmbient temperature
is operable, though increased temperature may be used to
speed the process. Generally, it is best to employ an excess
of NH~O~ to be assured of rapid and complete conversion of
the AlC13 to Al(OH)3. The excess NH~OH may be drained off
18,34OA-F
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~372~9
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and it is generally best to flush with enough H20 or NaCl
brine to substantially remove the NH40H, NH4C1 and any
Al (OH) 3 which may have formed outside the resin particles.
NEI40H is preferred over the us~ o NaOH or KOH or
other strong alkali because the strong alkalis tend to form
water-soluble al]cali aluminates, such as sodium aluminate,
and these soluble aluminates would then be more easily washed
from the resin than the Al(OH)3 precipitated by using NH40H.
The quantity of NH40H to be used is equivalent to the AiC13
according to the equation
3 NHgOH + AlCl3~ Al (OH) 3 ~ 3 NH4Cl
plus the amount required to convert the resin to its basic
form (assuming that all the resin was converted to the
chloride form in Step l.) The preferred amount is a several-
-fold excess of concentrated NH40H over the above minimum
amount. The volume of the NH40H should be as much as is
needed to achieve uniform wetting of the resin particles
throughout. Preferably at least about O.5-l.O part by weight
of concentrated NH40H solution (e.g. about 30% NH3) is used
per part of AlCl3- containing resin. The Al (OH) 3 so-obtained
is an "active" A1 (OH) 3 which will readily absorb LiX from
brine solutions; X-ray diffraction pat-tern analysis indicates
this Al (OH) 3 has little or no crystallinity.
~ ... ... . . .. ..
An alternate, but less desirable, method of conver-
ting the AlC13 to Al (OH) 3 is to treat the thoroughly wett~d
AlC13- containing resin with NH3 gas or NH3 diluted with air
or other inert gas.
Step III
The active Al (OH) 3- containing resin from Step
30 2 is then treated, at pH 6.0 or higher, with an aqueous
solution of lithium halide, es~ecially LiCl. The aqueous
solution may be a Li - containing brine which is Mg++- free.
The Li halide combines with the Al(OH) 3 to give a halolithium
l 8 , 3 4 OA-F
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~372~
aluminate or lithium aluminate which, by X-ray diffraction, is found to have
little or no crystallinity. If the lithium aluminate-resin mixture is employed~
wlthout tile heat treatment described below, to remove l.i from brines, it must
be reconstructed aEter onc cyclc, the residual non-active Al(011)3 removed, re-
impregnlted with AlC13 a1ld then again treated with N~140}1 to regain the active
Al(OH)3 Eorm. It is preferred that the amount of LiX be an amount in excess of
that required to com~lex with the Al(OH)3 to form the structure LiX-2Al(OH~3 in
Step 4.
Step IV
The lithium aluminate-resin, or halolithium aluminate-resin, is heated
at an elevated temperature for a time sufficient to convert the aluminate com-
pound to a microcrystalline form having the formula LiX 2Al(OH)3, where X
equals halide, the crystal structure of which is found to exhibit essentially
the same X-ray diffraction pattern as the aluminates prepared according to
Goodenough and by Lejus et al.
Formation of a crystalline chlorolithium aluminate is reported by
Goodenough and confirmed by X-ray (United States Patent No. 2,964,381~. X-ray
studies of such compounds are reported by Anne Marie Lejus et al in e.g.,
Compt. Rend. vol. 254 (1962) and in Rev. Hautes Temper. et Refract. t. I, 1964,
pp. 53-95.
Preferably the elevated temperature is from at least about 50C up to
the reflux temperature of the mixture, there being enough water present to pro-
vide a refluxing portion while maintaining the resin thoroughly wetted during
the heating. Ordinarily the time of heating for the temperature range of 50-
reflux will be about one hour to about 16 hours. Insufficient heating or in-
sufficient time of heating may result in having some of the aluminate compound
not converted to the microcrystalline form, thereby reducing the cyclable capa-
city of the resin.
_ g _
~37;~
If not enough LiX has been employed in Step 3 to complex with all the
active Al(OH)3 then some crystalline Al(OH)3 may be formed during this Step 4
heating step and not ~o~n the desired LiX 2Al(0~1)3. Such crystalline Al(0~1)3,
e.g. Bayerite, Gibbsite, Norstrandite, or mixtures of these are not effective
in absorbing LiX Erom brine. Thus, it :is preferred that substantially all the
active (freshly prepared) Al~0~1)3 be complexed with excess LiX and then heated
to form microcrystalline LiX-2Al(OH)3 in order to attain or approach the maximum
cyclable capacity. A 26% NaCl brine eontaining at least about 300 - lOOO mg/l
Li is suggested for use in this step.
10 ~
A portion of the Li values are eluted from the resin using an aqueous
wash, preferably containing a small amount of lithium halide, e.g., LiCl. The
concentration of lithium halide in the elution liquor is preferably in the range
of about 300 to about 1500 ppm. An aqueous elution liquor may be employed which
does not contain lithium halide if the elution is done batchwise with only enough
water to remove a portion of the LiX from the resin composition, but is not pre-
ferred since this may reduce the amount of LiX in a given crystal to less than
the amount required to maintain the crystal integrity (crystals may change to
Norstrandite and/or Bayerite). It is best, then, to employ at least a small
amount of lithium halide in ~he eluting liquor especially in column operation,
to assure that not all, preferably not more than half, the lithium halide in the
microcrystalline LiX-2Al(OH)3 is removed. The elution step is best done at
elevated temperatures above about 40C, preferably about 50C to reflux tem-
perature.
Step VI
This step is done, e.g., by contacting the Li -containing brine
with the partially eluted LiX-2Al(OH)3-
- 10 -
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-containing resin from Step V in a column bed by flowing the
brine through until ~he Li+ concentrate in the effluent
approximately equals the Li~ concentrate in the influent.
Loadiny rate is enhanced if ~le temperature of the brine
is above about 40C, preferably ~bout 50C to reflux, most
preferc~bly c~bout 80-108. Higher temperatures, requiring
superatmospheric pressures, require e~uipment capable of
withstanding the pressure.
Ste~ VII
Steps V and VI are repeated, sequentially, a
pluxality of times.
The resin, containing the microcrystalline
LiX 2Al(OH)3 is re-usable numerous times in a cycling pro-
cess where Li ~containinglbrine, even brine containing Mg~+,
is contacted with the resin to recover Li~ from the brine,
then the Li values are eluted from the resin using a weak
concentration of 'aqueous lithium hàlide~
Example l - Pre~arlng the resin~LiCl 2Al(OH)3
The product is prepared in the following way:
2v 40.0 gms of a macroporous anion exchange resin, chloride
- form, of a particulate polystyrene that is highly crosslinked
with divinylbenzene and having --CH2N(CH3)2 groups attached
to the benezere rings ~in dry form) is poured into a solution
of 12.0 yms AlCl3-6H2O in 60 gms H2O. With hand stirring,
using a spatula~ uniformly damp particles result. This
product is dried at room temperature in a stream of dry air
to a weight of 52.67 gms. This free-flowing product is
poured into a solution of 55 m7 ~ NH40H of 8.2% NH3 concen-
trated and mlxed as before to uniformly damp particlesO
Five minutes later it is mixed with 500 ml of 7.0 pH Mg
-free Smackover brine containing 15.8~ NaCl, 9.1% CaC12,
and 305 mg/li~er Li ard warmed to 56C for 45 minutes.
The brine is filtered off and found to contain 55 mg/l Li .
18,340A-F
. .
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~37~
-l2--
Product is mixed with 500 more ml of fresh brine and warmed
to 70C over a period of 45 minutes and filtered, with
filtrate analyzing 215 m~/liter Li . An additional 500 ml
of brine is mixed wi-th the product and refluxed for 16 hours.
5 The Einal filtrate contains 280 mg/liter Li . Thus, the
"sucked" dry product contains 182.5 mg Li~. The bulk or
settled volume of product is 136 ml. The pore volume is
estimated to be 36 ml, which would be filled with final
filtrate containing 10.1 mg Li . Hence, the resin particles
contain 172.4 mg Li+- 0.025 mols Li+. 12.0 gms AlC13 6H20
is equivalent to 0.050 mols Al(OH) 3. Hence, the final
product contains 1 mol Li/2 mol Al. The crystallinity of
the compound, denot~d here as LiCl- 2Al(OH) 3 i5 confirmed
by X-ray diffraction analysis.
Example 2 - Recover Li from brine
The use of the product of Example 1 above is shown
here for recovering Li from brine:
116 ml of product from Example 1 is put in a water
jacketed burette column to produce a resin bed 73 cm in
depth. Product as made is saturated with Li+, so it is
transferred into the column in 7.0 pH Mg-free Smackover
brine (containing 305 m~/liter Li+~. Each cycle then
consists of elution followed by brine resaturation. Eight
cycles are run with downflow of 6.4 ml/min. on water and
brine, and all at 85-90C water jacket temperature. ~hen idle
(e.g., 5 days between Cycle 5 and 6) the column is left in
the brine saturated state and allowed to cool to room tem-
perature. Excessive water washing of earlier products had
resulted in inactivation of 'che LiCl-2Al(OH)3, so a limited
quantity of water is used (250 ml on Cycles 1-5, inclusive
and 200 ml on 6-8, inclusiYe) and a small quantity of LiCl is
added to the water to limit further the reduction in Li~
content of the resin (0.15% LiCl in Cycles 1 and 2, 0.06%
LiCl in Cycles 3-8, inclusive). In each cycle 400 ml of
18,34OA-F
.
: '' . :' ;; ~ `
l3-
brine follows the water elution. This is about 125 ml more
than required for Li saturation. The first five cycles
were Mg -free Smackover brine having 305 mg/liter Li at
pH 7Ø The remaining cycles were with Smackover brine
containing 305 mg/liter Li and 0.31~ Mg at pH 6Ø In
the 6th cycle the effluent is cauyht in a series of 18
receivers: 25 ml in cuts 1-12, inclusive, and 50 ml in
cuts 13-18, inclusive. These cuts are then analyzed or
Li c~ntent by flame photometry. The analyses for Cycle
10 6 are:
Cut No. mg/l Li Cut No. mg/l Li
_ _ _
1 280 10 145
2 287 11 85
3 380 12 0
15 4 1220 13 5
700 14 20
6 345 15 35
7 245 16 210
8 195 17 285
20 9 165 18 305
Integration of the results shows Li removal
and recovery of 57.9 mg, which is 39.5~ of the Li~ on the
resin. Had the brine feed been limited to 275 ml, as required
for Li saturation, the recovery of Li is 69~ from the
brine. The average Li content of the water eluant is 430.7
mg Li/liter = 0.26~ LiC1. The peak Li~ observed in ~he
product (1220 mg/l) is 4 times the brine feed concentration~
The performance shown in Cycle 6 remained substantially the
same through the 8 cycles run: Cycles 1-5, inclusive, using
Mg-free brine and Cycles 6, 7 and 8 using untreated brine
(with Mg present).
Example 3
The base form of the same macroporous anion exchange
resin used in Example 1 is converted to the chloride form
18,340A-F
:; ,
~7~
by treatment with aqueous HCl. The resin is drained, washed
with water, and drained again. The drained resin still
contains about 59.73% water.
Approximately 135 parts of the drained resin is
treated with an excess of 31~ aqueous AlC13 and the excess
liquid is drained of. In effect, the aqueous AlC13 replaces
the water (80.64 parts) in the resin. After draining off
the excess aqueous AlC13, the resin is found to weigh about
159.37 parts and by analysis, is found to contain about
39.66 parts AlC13. Thus, by computation, the resin mixture
contained, at this point about 54.36 parts of resin, about
39.66 parts AlC13 and about 65.35 parts water.
The resin mixture is then treated with about 89.5
parts of 30~ N~40H solution; this constituted about 28~
excess NH3 over that required, theoretically, to convert the
AlC13 to Al~OH)3 and the xesin to the basic form. The resin
is washed and dr~ined.
Example 4
The above resin, containing the Al(0~3, is
~0 treated with an aqueous solution of LiCl in an amount
to flood the resin and to provide more than enough LiCl
to complex with most, if not all, of the Al(OH)3 according
to the formula LiCl 2AltOH)3. The mixture is heated at
- reflux temperature for about 2 hours or more~ After this
time X-ray diffraction patterns indicate the formation of
microcrystalline LiCl 2Al(0~)3 dispersed in the resin
structure.
The resin is then used to preferentially separate
Li from a brine containing about 15.8% NaCl, about 9~1%
CaC12 and about 305 mg/liter ~i+. This is done by passlng
the brine through a column-bed of the resin. After that,
the Li values are eluted from the resin by using a weak
18,340A-F
: ' ,
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~372~
--15--
solution of aqueous LiCl. The cycles of brine flow and
elution are repeated numerous times without encountering a
substantial loss of capacity in the exchange resin.
The time cycles for the brine flow and elution
are establish~d Eor a given resin by determining the resin
capacity, the concentration of Li in the brine, and the
elution factors. Once these have been established for a
given resin and a given brine, the process may be automati~
cally cycled using conventional methods and techniques known
in ion exchange technology.
Exam~le 5
To 350 gms of the same resin used in Example 3
(dry, base form) is added 480 gms AlC13-6H20 dissolved in
410 gms H20. The mixture is prepared, with stirring, and -
then substantially dried by air-blowing at ambient tempera-
ture. The "dried",mixture is found to still contain about
25.9% H20.
To the mixture is added, with stirring, a solution
prepared by diluting 430 ml. of 30% NH3 aqueous solution
20 with 100 ml H20. The resultiny exotherm brings the mixture
to about 67C. After standing for about 1.5 hours during
which time the temperature drops to about 48C, the mixture
is washed with 3 portions of 1000 mlO each of a saturated
NaCl solution to elute excess NH40H and also NH4C1 and
Al(OH)3 formed outside the resin particles. After each
washing step, the NaCl brine is decanted. By analysis, it
is found that 3.9~ of A13+ is removed by the washings.
The resin, still moist with ~aCl brine, is added to
enough NaCl brine to bring the total volume to 3 liters~
Then there is added 85 gms of dry LiCl, which dissolves,
and a small amount of NH3 is added to assure that the mixture
is not too far on the acid side. The pH, as measured by a
18,34OA-F
. ' :
1~L37~
' o
glass electrode with a KCl bridge, is found to be 8.3. This
addition of NH3 is optlonal and is not needed if the pH is
known to be above about 6.5.
The mixture is then heated in a large bea~er for 15
minutes durin~ which time the temperature increases to about
63C and the pH drops to about 7.0O. A small amount of NH3
is added, bringing the pH to 7.5 but NH3 comes out and the
pH quickly drops to about 7.0-7 1.
The mixture is transferred to a round-bottom flask
equipped with a reflux condenser and heated at reflux for
about 2.5 hours. The resin mi~ture is filtered out on a
glass frit using a suction funnel. The still-moist solids
are rinsed twice with 600 ml. distilled water. Analysis
indicates there is about 41.7 gms LiCl in the filtrate, and
about 8.73 gms in the wash water, thus there is a net deposit
in the resin partlcles of about 34.56 gms LiCl.
In an effort to assure high loading, the resin,
after drying to a water content of about 11.2% and a weight
of about 569.3 gms., is treated with a solution prepared by
2~ dissolving 280 gms. AlCl3-6H2O in 240 gms. H2O, stirred well,
then air-dried overnight down to about 804 gms. To this is
added 250 ml. of 30% NH3 with 50 ml. H2O added to it, and
stirred; it exotherms to about 83C. Then mix with 1800
ml. NaCl brine and decant. Analysis shows that 8.04 gms. of
the AlCl3 6H~O does not stay with the resin. 4107 gms of
LiCl in the above filtrate is enriched by adding 8 gms of
LiC1 to it and is then mixed with the drained resin. At
this point the total volume is about 3700 ml. with pH 7.78.
The mixture is heated in a be~Xer to 54C with intermittent
stirring and the pH drops to 7.34.
The mixture is transferred bac~ to the reflux
pot and heated up to re~lux within an hour and refluxed
for about 80 minutes and allowed to stand and cool overnight,
18,340A-F
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.
~1~7Z~
-
-i7-
then filtered. Analysis for Al and Li in the filtrate and
calculations ~ased thereon determines that the resin contains
1.37 moles Li and 3.05 moles A13~. This is .449 Li~ per
A13 which is 89.B~ of theoretical amount of Li:~l in the
formula l,iCl 2~1(OH)3. X-ray diffraction pattern indicates
presence of crystalline LiC1 2Al(OH)3
The resin is transferred to a jacketed, heated
exchange column, and flooded with NaCl brine tactually it is
the filtrate from above and containing a small amount of
Li ). Then alternate cycles of wash water ~containing about
50 ppm Li ) and Smackover brine (pH 5.6) at a pump rate of
13 ml/min. for about 70 mlnutes while h~ating at about 90C.
Of these alternate cycles, the wash cycles are at 13 mls/min.
for 27 minutes and are at ambient temperature but become
heated by the colwnn heated at 90C. The results of the
fourth full wash cycle, taken in 25 ml cuts, is shown below:
Cut Li f Cut Li+
No. mg/liter* Remarks** No. mg/liter~ Remarks**
1400 ~ Start wash 10 500
2430 ~ brine coming out 11 420
3460 ) 12 370
41560 13 333
51540 14 310
61130 15 280start brine
7 880 16 250 ~
8 700 17 65 3wash coming out
9 580 18 80***
* not adjusted for Sr+~ values which interfere with Li+
analysis, but stay in the brine.
**About 75 ml. hold-up in the column.
***This cut is low in lithium content because at this
stage most Gf the lithium remains on the resin.
18,34OA-F
. -
2~
The pre~aration, propert:ies and 1~error1nancc of thc Li.~-2Al(011)3 resin
composition are improved by employing aqucous lit.11ium hydro.Yide to -form micro-
crystalline LiO11-~Al(011)3, a novel, useful compos;tion~ ~hic11 is then reactcd
with a 1ialogen acid or hal;.de salt to obta:i.n the LiX-2Al(011)3.
It has been :fount1, surpr:i.singly and u11e.Ypectcdly, that the micro-
crystalline Li~-'Al(OH)3 formed in an anion e.Ychange resin by the present
method which first forms LiOH-2Al(01-1)3 and then uses a halogen acid or halide
salt to form the LiX'2Al(OH)3, substantially improves the cyclable life of
the LiX-2Al~OH)3 resin when used in recovering Li values from brine. We
have also found, in reviving resins which contain inactive degradation products
of LiX 2Al(OH)3, tha.t aqueous LiOH treatment is effective whereas treatment
with lithium halide is not effective though the aqueous LiOH treatment is
followed by treatment with a halogen acid or halide salt. Alternatively, for
the aqueous LiOH treatment step, an aqueous solution containing both LiOH and
lithium halide may be employed in which case, the need for subsequent treatment
with a halogen acid or halide salt is obviated.
,
'
,
11372~L~
The resin so-~rcpared is usef-1l in rccovcring Li values from
brine, even brine whic1l contains ~1g values, ~nd may be cmployed numerous
timés in such Li val~1e recovery in a tWo-st.1~c cyclic process whic
includes Li elution as one `stage of the cyclc.
The particult1te anion exc11.1n~e resln may be any particulatc,
water-insol~1ble) water-swe]lable, polymcric structure which contains
pendant amine or quaternary ammonium groups, preferably those which are
macroporous. Of particular interest are the particulate macroporous
polymers of styrene cross-linked with divinylbenzene and having pendent
amine or quaternary ammonium groups attached thereto. Anion exchange
resins known in the art as weak-base or strong-base are operable; the
halide salt forms of the anion exchange resins may also be employed.
The hydrous alumina dispersed in the resin may be formed by
impregnating the resin with aqueous AlCl3 and treating with aqueous NH3
to convert the AlCl3 to Al(OH)3, or may be crystalline forms of hydrated
alumina, such as Norstraldite, Bayerite, Gibbsite, or,mixtures of these.
Hydrated alumina may be formed when microcrystalline LiX-2Al(OH)3 dispersed
in the resin is used many times in a cyclic process for removing Li from
brines; the lithium exchange capacity is likely to slowly degenerate as
Norstrandite and/or Bayerite is formed as the degradation product. In either
case, treatment at an1bient or elevated temperature with aqueous LiOH, along
with or followed by treatment with a halogen acid or halide salt, will
rejuvenate the resin by re-forming microcrystalline LiX-2Al(01-1)3 dispersed
therein.
-19-
~;,
.. . . ..... .. ,. _, . .. ...... . . . . . . . .
., . .~ _ . _ . . ... . .. .. _ _. __ _ _ _. , .. .__. .. . _ .,_ _ .. ~ .. _ ,, ... . . __
;. ; .; '-.' ': " ''
,
~137;~9
-20-
When a depleted weak-base resin containing the
degradation product of Ii~ 2Al(OH)3 i5 used it should be
treated with NH~OH to convert the weak-base groups to the
OH orm. ~ strong-base resin may not require treatment
with NH40H, but such treatment is not deleterious, and
in some cases may be bene~icial. The treatment with NH40H
is done prior to treatment with the aqueous LioH.
The amount of aqueous NH3 employed to convert
AlC13 in the resin to Al(OH)3 is generally an excess over
the stoichiometric amount needed plus an amount needed to
neutralize Cl groups which may be still attached to amine
or ammonium groups on the polymer.
The excess NH3 and the NH4C1 is washed out with
water prior to treatment with aqueous LiOH.
The resin, containing Al(OH)3 precipitated therein
or containing Nors~randite and/or Bayerite or other forms of
Al(OH)3, is flooded with enough aqueous LiOH to replace
substantially all the air and/or liquid which may be present
in the resin and to provide enough LiOH in the resin to be
an amount which is rom about 100~ to 110~ of the amount
required stoichiometrically by the formula hiOH 2Al(OH)3.
More than 10% excess may cause solubilization of the alumina
hydrate, whereas less than the stoichiometric amount may
leave some Al~OH)3 unchanged. Even with 10% excess, there
probably is some Al(OH)3 which is not contacted by the
LiOH and therefore remains uncomplexed. Reaction of the
LioH with the Al(OH)3 to form LioH 2Al(OH)3 in the resin can
be done at ambient room temperature, but this may require
extended periods of time of about 24 to 48 hours or more,
especially if the Al(OH)3 is crystalline. Increasing the
temperature speeds the reaction and at reflux temperature
amorphous Al(OH)3 requires only a few minutes whereas crystal-
line Al(OH)3 requires about 0.5 to 1 hour or more. Thus, it
18,340A-F
,
'
,
~37~
,
is preferable, esyecially in the case of crystallinc Al(011)3, to use
increased temperature for tllC reaction with LiO1-1 so as to have the
reaction comp1eted within about 0.25 to about 16 hours.
It has been found by analysis and ~-ray diffraction study that
a more crystallinc form o Li,~-2Al(011) in the resin is yielded by the above
method than when the same compound is formed directly from hydrated alumina
by treatment with lithium halide.
The steps of the process of preparing microcrystalline LiX 2Al(OH)3
dispersed in an anion exc1lange resin, according to the above method7 may be
generalized as follows;
l. Provide an anion exchange resin in neutral or basic form having
dispersed therein an alumina hydrate.
2. React the alumina hydrate with aqueous LlOH at elevated temperature
to form microcrystalline LiOH 2Al(OH)3.
3. Treat the microcrystalline LiOH-2Al(OH)3 with a halogen acid or
halide salt to form microcrystalline LiX-2Al(01~)3, where X is a halogen.
The steps of removing Li values from Li -containing aqueous
solutions, e.g. brines may be generalized as follows;
l. Provide an anion exchange resin having dispersed therein micro-
crystalline LiX 2Al(OH)3.
2. If the LiX-2Al(01-1)3 is loaded wit1l Li -values, reduce the amount
of such Li values by using an aqueous wash, preferably an aqucous wash
containing a small amount of Li values to assure that there remains enough
Li in the resin to preserve thc microcrystalline structure of the aluminate.
If the LiX-2Al(0~1)3 has been previously washed to remove at least an appreciablc
portion of the Li+, t}lcn thc resin is not already loaded and may bc used as
is for thc ne.~t step.
- 21 -
:
t ' ' ` '
:'' : :: . :
:: :, - .
' ''." '' ' : -
~37~
-2,-
3. Contact the Li -containing aqueous solution
or brine wi~ the LiX-2Al(OH)3 resin, thereby loading the
resin with ~i+ and reducing the Li+ content of the solution
or brine.
4. Elute Li values from the resin by employing
an aqueous wash, preferably a wash containing a small amount
o Li~ values. A wash containing about 50 to about 200 mg
per liter of Li is especially suitable.
5. Repeat steps 3 and 4 a plurality of times,
each time using a new batch of Li+-containing aqueous
solution or brine and a new batch of aqueous wash. These
new batches may, of course, include as a portion thereof,
a re cycled portion of a previous batch.
A strong base resin, such as one of the water-
-insoluble, water-swellable aromatic polymers containing
quaternary ammonium groups, is neutral in its chloride form
and may be used in its neutral form or converted to its
basic form.
A weak base resin, such as that used in Example 5,
should not be used in its chloride form but should be con-
verted to its base form for use in the present invention.
Ammonia should be used for converting the resin from its
chloride form to its base form. Alkali metal hydroxides,
e.g. NaOH, may form alkali metal aluminates with the Al
2S compound in the resin which could be easily water-leached
from the resin.
The pH at which the LiXu2Al(OH)3 xesin composition
is used for recovering Li+ values from brines is generally
kept within the range of about 5.5 to 8.0, preferably about
6 to about 7.
The temperature at which the LiX 2Al(OH)3 resin
composition is used ln recoveriny Li values from brines
- 18,340A-F
~L37~
may be elevated, pre~erably above about ~10 C, mos-t prcferably above 50 C.
The elevatcd temper;l~urc cnhallccs thc proccs~. ~lally of thc natural Li~-
containing brine~ are removcd ~rom thc grouncl at elevated temperatures and
may be used wi~llout cooling. Telllpcraturcs hig}l e~nough to causc breakdown or
degradatio~ o tlle polymeric resins should be avoidcd. ~lost of thc anion
exchange resins commercially available would be e~pected to withstand brine
reflu.Y temperatures quite well and most would even withstand operation at
superatmospheric pressures if temperatures slightly above normal reflux tem-
peratures are desired.
The following e~ample illustra*es the above.
Example 6
For this example, a particulate, macroporous anion exchange resin
comprising a styrene-divinylbenzene crosslinked polymer having pendant tertiary
amine groups was used.
The resin is treated by flooding it with aqueous saturated AlCl37
then substantially drying it, then using aqueous N~13 to convert the AlC13 to
Al(OH)3, then reacting it with lithium chloride at elevated temperature to form
crystalline LiX 2Al(0~)3 dispersed in the resin.
The so-prepared resin is subjected to more than 50 cycles of alternate
flo~s of elution water wash and Li -containing brine (Smackover brine) to remove
Li values from the brine. During this time the capacity of the resin is
considerably reduced and it is found by X-ray diffraction that the aluminum
compound dispersed in the resin has been principally converted to an Al(0~1)3
form known as Bayerite, and probably a small amount of ~orstrandite. This form
of Al(011)3 is ineffective and inactive for forming the desired microcrystalline
LiX 2Al (011) 3 and attempts to reactivate it with LiCl at elevated temperàtures
arc unsuccessf~l.
- 2~ -
,'
- 1~372~5~
-2~-
It is found, however, tha-t the resin (containing
the inactive Bayerite and Norstrandite) is reactivated by
treating it with concentrated NE~40H to neutralize any
acidity, then after draining off excess NH40H it is treated
with aqueous LiO~I at elevated temperature. After the LioH
treatment, analysis by X-ray diffraction indicates a well-
-crystallized pa-ttern, LiOH 2Al(OH)3, but no Bayerite or
Norstrandite. Subsequent treatment with a halogen acid
or halide salt, e~g~ LiCl, converts the crystalline LiOH 2Al(OH)3
to crystalline LiX 2Al(OH)3.
The resin i~ found to undergo no significant
decrease of capacity after 140 cycles of alternating flows
of Smackover brine and elution using a wash water containing
about 60 ppm Li .
18,340A-F
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