CA1137249A - Recovery of lithium from brines - Google Patents

Abstract

Abstract of the Disclosure The invention relates to a particulate anion exchange resin having microcrystalline LiX-2Al(OH)3 suspended therein, where X equals halogen, and a process for making it. The process comprises (a) heating an halolithium/lithiumcomplex-containing resin at a temperature and for au time sufficient to convert the complex to the microcrystalline structure having the formula LiX-2Al(OH)3, said complex-containing rosin being a particulate, anion exchange resin having suspended therein the halolithium/lithium aluminate complex, or (b) providing a particulate anion exchange rosin substantially in neutral or basic form having suspended therein hydrous alumina conforming to the formula Al(OH)3; reacting said Al(OH)3 with aqueous LiOH at a temperature and for a period of time sufficient to form microcrystalline LiOH-2Al(OH)3 suspended in said resin; and reacting theso-formed LiOH-2Al(OH)3 with a halogen acid or halide salt to convert it to saidLiX-2Al(OH)3. The resin is useful in removing or recovering lithium values fromore or brine containing lithium salts along with salts of other metals, e.g.
ND, Ca, Mg, X, and/or B.

Description

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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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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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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-. - - . ~ , :
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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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~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.

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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.

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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

:: ' ~372~9 "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 -B-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.
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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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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.
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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.
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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-, ~ ,: ;
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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 .

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-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

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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 _ _ _

8 195 17 285 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

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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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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

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' 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 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.

~;, .. . . ..... .. ,. _, . .. ...... . . . . . . . .
., . .~ _ . _ . . ... . .. .. _ _. __ _ _ _. , .. .__. .. . _ .,_ _ .. ~ .. _ ,, ... . . __ ;. ; .; '-.' ': " '' , ~137;~9 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.

:

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

~''" '~ ' "

Claims (4)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:

1. A process for preparing a particulate anion exchange resin having microcrystalline LiX-2Al(OH)3 suspended therein, where X equals halogen, said process comprising (a) heating an halolithium/lithium complex-containing resin at a tempera-ture and for a time sufficient to convert the complex to the microcrystalline 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) providing a particulate anion exchange resin substantially in neutral or basic form having suspended therein hydrous alumina conforming to the formula Al(OH)3; reacting said AL(OH)3 with aqueous LiOH at a temperature and for a period of time sufficient to form microcrystalline LiOH-2Al(OH)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.

2. A process according to claim 1 wherein the particulate, anion exchange resin is macroporous.

3. A process according to claim 1 or 2 wherein the particulate, anion exchange resin is a water-insoluble, water-swellable particle of polystyrene crosslinked with divinylbenzene and having affixed thereto amine or quaternary ammonium groups.

4. A process according to claim 1 a) wherein the heating of the resin containing the aluminate complex to convert it to microcrystalline LiX-2Al(OH)3, where X is halogen, is done at a temperature in the range from 50°C to reflux for a period of time of at least 1 hour.

5. A process according to claim 1 b) wherein the Al(OH)3 is reacted with aqueous LiOH at a temperature at least 40°C.

6. A process according to claim 1 b) or 5 wherein the temperature is in the range of from 50°C to reflux temperature.

7. A process according to claim 1 b) wherein the amount of LiOH is an amount of from 100% to 110% of the stoichiometric amount to complex with the Al(OH)3 to form LiOH-2Al(OH)3.

8. A process according to claim 1 b) wherein the aqueous LiOH contains lithium halide, thereby forming LiX-2Al(OH)3 during the heating step.

9. A composition comprising a particulate, anion exchange resin having suspended therein a microcrystalline form of LiX-2Al(OH)3, where X is a halogen.
10. The composition of claim 9 wherein the resin is a macroporous resin.

11. The composition of claim 10 wherein the macroporous exchange resin is at least one of the group comprising water-insoluble, water-swellable macro-porous particles of polystyrene crosslinked with divinylbenzene and having af-fixed thereto amine or quaternary ammonium groups.

12. The composition of claim 10 wherein the macroporous resin contains -suspended therein, per cubic foot [28.3 liters) of resin, 3 pounds (1.36 kg) to 12 pounds (5.45 kg) of microcrystalline LiX-2Al(OH)3, wherein X equals halogen.

13. A method for removing lithium values from an aqueous brine which com-prises contacting the brine with the LiX-2Al(OH)3 resin of claim 9 and then separating the lithium values from said resin.

14. A method for removing lithium values from an aqueous brine which com prises eluting Li+ values from the LiX-2Al(OH)3 resin of claim 9 by use of an aqueous wash, contacting the treated LiX-2Al(OH)3 resin thus obtained with said aqueous brine to enrich the resin with lithium values from the brine and then separating the resin from the brine.

15. A method for removing lithium values for lithium-containing ores by (a) converting the ore to an aqueous brine solution, (b) treating said solution with said LiX-2Al(OH)3 resin of claim 9, and (c) recovering the lithium values from said resin.

16. A process for removing Li values from aqueous brines, said process comprising, in sequence, the steps of:
(a) contacting a Li+-containing brine with an anion exchange resin having suspended therein a microcrystalline form of LiX-2Al(OH)3, where X is a halogen;
(b) eluting Li+ values from the resin by contacting it with an aqueous wash liquor; and (c) repeating steps (a) and (b), sequentially, a plurality of times by using the resin from step (b) as the resin in step (a).

17. The process of claim 16 wherein the aqueous wash liquor contains a small amount of lithium halide dissolved therein.

18. The process of claim 16 wherein the anion exchange resin is macroporous.

19. The process of claim 17 wherein the amount of lithium halide dissolved in the wash liquor is from 50 to about 200 mg per liter, as Li+.

20. A process for recovering Li+ values from Li+-containing ores, said process comprising: providing the ore in particulate form and leaching water-solubles from the ore using an aqueous brine wash, thereby forming an aqueous brine solution containing Li+ values; contacting the so-formed Li+-containing aqueous brine solution with an anion exchange resin having suspended therein a microcrystalline form of LiX-2Al(OH)3, where X is halogen; eluting Li+ values from said exchange resin, by using an aqueous wash; and recovering Li+ values from said aqueous wash.

21. A process for recovering Li+ values from brine, said process comprising 1. providing a particulate anion exchange resin having suspended therein a microcrystalline LiX-2Al(OH)3 structure, where X is a halogen, which has had a portion of the LiX removed by elution, 2. contacting a Li+-containing brine with said resin, thereby enriching said resin with Li+ values from said brine, and 3. separating said resin, now enriched with Li+ values, from said brine.

22. The process of claim 21 wherein the resin is recycled a plurality of times by taking the resin from step 3 and repeating steps 1, 2 and 3.

23. A process for recovering Li+ values from brine, said process comprising

1. providing in an ion exchange column, a particulate anion exchange resin having dispersed therein a microcrystalline LiX-2Al(OH)3 structure,

2. eluting a portion of the LiX from said resin by passing an aqueous wash through it,

3. flowing a Li+-containing brine through said resin until the resin is enriched to about its full capacity with LiX, and

4. repeating steps 2 and 3, sequentially, a plurality of times.