JPH0323212A - Method for recovering lithium - Google Patents

Abstract

PURPOSE:To extremely efficiently recover Li from an Li-contg. liq. by selectively adsorbing the Li on an inorg. ion exchanger represented by a specified general formula and eluting the adsorbed Li. CONSTITUTION:An inorg. ion exchanger represented by a general formula HxA1-xM2(PO4)2 (where A is Li, Na or K, M is Zr, Ti or Sn and x<1) is prepd. and brought into contact with an Li-contg. liq. to adsorb the Li on the ion exchanger. This ion exchanger is separated and brought into contact with an eluting soln. to elute the adsorbed Li.

Description

Detailed Description of the Invention (a) Purpose of the Invention [Field of Industrial Application] The present invention provides a method for selectively removing lithium from lithium-containing liquids such as seawater and groundwater by using a specific inorganic ion exchanger. This method relates to recovering lithium by adsorbing and eluting ions, and is useful in the liquid treatment industry for natural waters such as seawater and groundwater, or various waste liquids containing lithium ions. [Prior Art] In recent years, lithium metal and its compounds have been used in a wide range of fields, such as ceramics, batteries, refrigerant absorbents, and pharmaceuticals, and in the future, they will also be used in alloy materials, large-capacity 1I1 ponds, nuclear fusion fuels, etc. The demand for lithium is expected to increase significantly. Lithium metal and its compounds are currently produced mainly from lithium-containing minerals such as subodumene, ampligonite, petalite, and lebidolite (lithium content is 2 to 6% by weight), and from salt lakes and groundwater with high lithium concentrations. In Japan, the above-mentioned notium resources are scarce, and most of the demand is currently met by imports, but geothermal water or hot spring water that contains lithium, albeit at a low concentration, is relatively abundant. , a method to efficiently recover lithium from these resources is desired. Generally, lithium in natural resources exists together with large amounts of alkali metals and alkaline earth metals, so in order to efficiently recover lithium that exists as ions in liquids (hereinafter simply referred to as lithium), it is necessary to selectively collect lithium. It is necessary to separate lithium into sodium, etc.
Because its chemical properties are similar to other alkali metals and alkaline earth metals, lithium cannot be recovered depending on the recovery method of adsorbing lithium in liquid using ion exchange resin, a common ion exchanger. Selective separation is extremely difficult. One method of recovering lithium from an aqueous solution is to evaporate seawater or salt lake water by irradiating it with sunlight, precipitate out salt, etc., and then collect lithium salt. The drawbacks are that it requires a large area and is severely restricted by weather conditions, making it difficult to put it into practical use. Other methods of recovering lithium include seawater, hot spring water,
A method is known to recover lithium contained in groundwater etc. by aluminum hydroxide co-precipitation method, but this method has the disadvantage that the adsorption amount and adsorption rate for lithium is small, making it difficult to put it into practical use. There is. On the other hand, as a lithium recovery method using an inorganic ion exchanger, amorphous aluminum hydroxide, metallic aluminum, hydrated tin oxide, porous micro-bolus type manganese oxide, sodium arsenate, antimonic acid, tin antimonate, antimonic acid A method using compounds that exhibit lithium adsorption properties such as titanium, tin phosphate, zirconium phosphate, and titanium phosphate can be considered, but when using any compound, it is difficult to form it into granules due to the ion exchange operation. It is desirable to use aluminum hydroxide, but if the ion exchange properties are significantly deteriorated, there is a problem that the adsorption amount and the There is a problem of low adsorption rate, and when using manganese oxide, there is a problem of low stability in high temperature mature water.
In the case of compounds containing arsenic or antimonic acid, there is a problem of toxicity due to arsenic ions or antimony ions. In addition, recently, NHgZrgP30+z・nHzO (however, n
represents O-0.4. A zirconium hydrogen phosphate compound expressed by the 1M formula HzrzP30+z was proposed by heating and deammonizing the ammonium zirconium phosphate compound expressed by
-96523), this compound exhibits similar adsorption properties for sodium, making it difficult to selectively recover lithium. [The problem that the present invention attempts to solve!] ! ! ] After efficiently adsorbing lithium from liquids containing lithium such as seawater, natural gas brine, geothermal water, hot spring water, etc., salt manufacturing brine, and various factory waste fluids, it is necessary to elute and recover lithium. It has excellent selective adsorption, has a large adsorption rate and absorption IFfi, is stable in liquids, has no toxicity problems, can be used repeatedly for adsorption and elution, and can be used in granular or is required to be able to be formed into a film shape, etc. The object of the present invention is to provide a method for very efficiently recovering lithium from the various lithium-containing liquids using an inorganic ion exchanger that satisfies all of the above requirements. (b) Structure of the invention [Means for solving the problem] As a result of intensive study, the present inventors found that the compound represented by the following general formula is a compound that satisfies all of the above requirements, and uses this compound. The inventors have discovered that lithium can be recovered extremely efficiently from an aqueous solution containing lithium, and have completed the present invention. That is, the present invention provides general 2H-A+-
Mz (P O4) x (In the above formula, X is a positive number less than 1, A is at least 1 selected from Ll, Na, K
#1, M is at least one selected from ZrSTi, Sn
This method of recovering lithium is characterized by contacting the compound represented by (species) with a lithium-containing liquid. Hereinafter, the compounds used in the present invention and the method for using the same will be explained. <Inorganic ion exchanger> The inorganic ion exchanger used in the present invention is a general 2H, A. −
．． M. (p04)s (In the above formula, X is a positive number less than 1, A is at least l types selected from L+, Na, K,
M is at least one selected from Zr, Ti, and Sn. This is hereinafter referred to as compound l. ), and the present invention utilizes ion exchange between the protons of Compound I and lithium. For the manufacturing method of Compound I, please contact Material Research.
Bulletin (Mat, Res. Bull) vojl
2, pl71-182. 1977 or Acta Chemica Scandinavian Power (＾cta.CHEMrC＾.S
cand) voj22, p1822-1832.19
For example, lithium carbonate (Lii
At least one salt selected from salts containing element A in the above general formula, such as COs), sodium carbonate (Na*COs), and potassium carbonate (κICOs), zirconium oxide (ZrOz), titanium oxide (Tilt), and tin oxide ( At least one kind of moth element-containing salts such as
xPO4) and ammonium phosphate ((NHa).
Mix phosphate salts such as POa at a molar ratio of about 4:6 and heat at 100 to 1400°C, preferably 1300°C.
AMx (POa
)s (hereinafter referred to as compound ■) is subjected to acid treatment by immersing it in an inorganic acid such as hydrochloric acid or nitric acid at room temperature to 100°C,
It can be easily obtained by drying. The xO) value of Compound I can be controlled by the acid concentration, temperature, treatment time, etc. when the compound is treated with acid. By such acid treatment, it is actually extremely difficult to replace all of element A in compound (1) with protons;
i Since a trace amount of element A remains, X is a positive number less than 1. In order to increase the ion exchange capacity between protons and lithium, the value of X is preferably set to 0.5 or more, more preferably 0.8 or more. Compound (2) obtained as above is generally in powder form, and its particle size is 0.0
The range is preferably from 1 to 100μ, more preferably from 0.1 to 10μ. Particle size is 0. If it is smaller than Olp■, the powder particles may aggregate, or if a binder is used to shape the particles, the powder particles will be covered with the binder, making it impossible to fully exhibit ion exchange properties. On the other hand, if the particle size is larger than 100μ, there is a risk that when forming with a binder, there will be fewer contact areas between the particles and the binder, making it impossible to obtain a cylindrical body with high mechanical strength. There is. Compound I is extremely stable in an aqueous solution with a pH value of 12 or less, exhibits no solubility, and selectively adsorbs lithium, so it poses no problems even when other ionic species coexist. does not occur. The shape of Compound (I) may be in the powder form obtained as described above, but when Compound I is used in a column packing method, etc., it may be in the form of granules,
It is preferable to use it in an appropriate size and shape, such as a rod or cylinder, and it is preferable that it has sufficient mechanical strength to withstand operations such as backwashing and recycling. Compound! Alternatively, compound (1) can be shaped into a film or granules with or without a binder, and then the formed body obtained by burning can be treated with an acid (only when compound H is used). Various forms of compound (1) can be obtained.
Amazingly, the compound! Unlike conventional lithium adsorbents, the ion-exchange properties of the various rod-shaped bodies do not deteriorate even when they are oversized, and ion exchange can be performed using a column packing method, making them extremely advantageous for industrial use. It is. Kui Kata Method> Kui Kata Method can be broadly divided into methods that use a binder and methods that do not use a binder. i) Method using a binder There are two types of binders: organic ones and inorganic ones.
To take full advantage of the heat resistance of inorganic ion exchangers, it is preferable to use an inorganic binder. Among inorganic binders, clay! ! Is there a method to use metal alkoxide or its hydrolyzate in combination to improve mechanical strength and ion exchange properties after shaping into particles? This is preferable because it tends to have less lower parts. O Clay Minerals Clay minerals include, for example, bentonite, kaolin, diatomaceous earth, Kibushi clay, and Frog's eye clay, and any swellable layered compound based on hydrous silicate may be used. Among these, bentonite is particularly preferred because it is industrially easily available. The preferred amount of clay mineral is 100 parts by weight (hereinafter simply referred to as "parts") of the compound! or 1 to compound ■
It is 70 parts, more preferably 2 to 40 parts. The blending amount is 1
If the amount is less than 70 parts, the mechanical strength of the granular compound (2) will decrease, and even if it is more than 70 parts, the effect of improving the mechanical strength will be small and there is a risk of a decrease in ion exchange ability. ○Metal alkoxide or its hydrolyzate Metal alkoxide is a compound in which the hydrogen of the hydroxyl group of alcohols is replaced with a metal, and specific examples include Si (OR) a , τ
i(OR)a, AI■(OR)x and Zr(OR)
a (R is an alkyl group such as methyl, ethyl, propyl, and butyl), etc. Among these, silicon alkoxides have a lower hydrolysis rate than alkoxides of other metals and can be easily made into a stable sol. This is preferable because it allows you to The metal alkoxide hydrolyzate can be prepared by a conventional method [for example, by Masao Sakuhana, "Sol-gel Science J, 8-241, published by Agne Seifusha (1988)]", using a solvent. Depending on the progress of the hydrolysis and polymerization reaction of the metal alkoxide therein, it becomes a sol or a gel, but it is preferable to use a sol in order to facilitate kneading in the granulation process described below. Either a metal alkoxide or a metal alkoxide hydrolyzate may be used, but in order to shorten the crosstalk time in the granulation process described below, a metal alkoxide hydrolyzate is preferably used. As a solvent for the above metal alkoxide. is methanol,
Examples include alcohols such as ethanol, propanol, butanol, ethylene glycol, ethylene oxide, triethanolamine, xylene, formamide, dimethylformamide, dioxane, and oxalic acid. Alcohols are preferably used. The usual blending and total amount of metal alkoxide or its hydrolyzate varies depending on the type and amount of clay mineral used, but the solid content of metal alkoxide (metal alkoxide It is preferably 1 to 60 parts, preferably 3 to 30 parts, and more preferably 3 to 20 parts in terms of the weight of the metal oxide produced. If the amount is less than 1 part, the compound I
If the amount exceeds 60 parts, the mechanical strength of compound 1 tends to decrease. ○Ogata process Various types of ogata can be formed through the general ogata process consisting of mixing, kneading, granulation, and burning. First, we will explain the mixing and kneading process. In the mixing/kneading step, the components such as compound (1) or compound (2), clay mineral, metal alkoxide or its hydrolyzate, and water are mixed. The mixing order at this time is arbitrary, and it is sufficient to mix each component uniformly. As an example of a mixing/kneading operation, for example, the above clay mineral is added to Compound (1) or Compound (2), and the mixture is homogeneously mixed using a colander or the like, and then the above metal alkoxide or metal alkoxide hydrolyzate and an appropriate amount of water are added. Just add it and mix warmly. The water added at this time is a component added to facilitate mixing and kneading operations, and the amount of water added is a compound! Or, although it varies depending on the type and particle size of compound (1), the type and amount of clay mineral and metal alkoxide or metal alkoxide hydrolyzate, etc., it is usually 1 to 100 parts, preferably 1 to 50 parts, based on 100 parts of solid content in the slurry. Good. The slurry obtained as described above is further kneaded with Niichi Gu or the like for several hours to one day. There are no particular restrictions on the granulation method, but it is preferable to use the extrusion granulation method, which has excellent yield and reproducibility on an industrial scale. It is recommended that the obtained granules be sized into spheres using a conventional centrifugal rotation method. Thereafter, the granules obtained in the above manner are burned to impart sufficient mechanical strength, thereby obtaining Compound I or Compound (2) shaped into granules. The incineration conditions at this time are
Although it varies depending on the type and particle size of Compound I or Compound II, the type and amount of clay mineral and metal alkoxide or metal alkoxide hydrolyzate, etc., the maximum firing temperature during firing is usually 400"C or higher, and Compound I or It is preferable to set the temperature below the melting point of compound (2) and keep the maximum baking temperature for 1 to 8 hours, more preferably 2 to 6 hours.If the baking temperature is less than 400'C, the compound If the II mechanical strength of IFII or compound ① decreases and is higher than the melting point of the inorganic ion exchanger, the particles may fuse to each other, and in some cases, the ion exchange properties may decrease significantly. Temperature rise during calcination There is no particular restriction on the rate, and the usual heating rate, i.e., 1O~800°C/hr, preferably 3
It may be set at 0 to 200°C/hr. ii) Methods that do not use binders, such as pressure molding method, plastic molding method, casting molding method, etc.
Powdered compound 1 or compound
By incinerating at ℃ for 1 to 7 hours, it is possible to easily obtain a cylindrical body with excellent mechanical strength. Liquids containing lithium> Liquids from which lithium can be recovered by contacting with compound ■ are not limited in any way as long as they contain lithium, such as seawater, natural gas brine, and geothermal water. and natural water such as hot spring water, salt-manufactured brine, industrial wastewater, and wastewater containing smelting agents. The temperature of these lithium-containing liquids may be adjusted as long as the target to be ion-exchanged is liquid, but generally speaking, the higher the temperature of the lithium-containing liquid, the higher the rate of adsorption of lithium, so unless there are operational limitations, The temperature of the lithium-containing liquid is preferably high. Further, the pH value of the lithium-containing liquid is preferably 12 or less, but if the pH is 4 or less, the amount of lithium adsorbed tends to decrease, so the more preferable pH value range is 5 to 11. The contact between the compound ■ and the lithium-containing liquid can be carried out either batchwise or continuously, and the operation of separating the compound ■ from the lithium-containing liquid after contact can be carried out using a general solid-liquid separation method. good. <Eluent> By separating Compound I which adsorbed lithium as described above and contacting it with an eluent, lithium is eluted from Compound I and lithium is recovered. Examples of the eluent used at this time include inorganic acids such as hydrochloric acid, boronic acid, nitric acid, and phosphoric acid, and two or more of these may be used as a mixture. In addition, these inorganic acids and ammonium salt aqueous solutions may be used in combination. Regarding elution conditions, the higher the concentration and temperature of the eluent, and the longer the treatment time, the greater the degree of lithium desorption. However, if there are operational limitations, temperatures around room temperature may be sufficient. [Function] Compound ■ is a compound with a three-dimensional skeleton structure having a space group of R2c, in which (PO4) oxygen tetrahedron, (ZrOi) oxygen hexahedron, and (AO&) oxygen hexahedron are bonded to each other while sharing vertices. The space around the A ion in the (aO*) oxygen hexahedron is extremely suitable for the entry and exit of lithium, and this unique structure is maintained even after compound ■ is induced into compound I, so lithium can be selectively transferred. In addition to the property of adsorption, it is thought that the adsorbed lithium and protons are reversibly replaced by contact with the eluent. -1, the ion exchange properties of inorganic ion exchangers are derived from crystallization water, and when heat treated at high temperatures, the crystal water disappears and the ion exchange properties also disappear in many cases, but Compound I used in the present invention Since it does not contain water, its ion exchange properties do not deteriorate at all even after high-temperature heat treatment for molding. [Examples, Reference Examples and Comparative Examples] The present invention will be explained in more detail below using Examples and Comparative Examples. Reference Example 1 1 g of LiZrz(POn)s (compound n) obtained by firing a mixture of lithium carbonate, zirconium oxide, and ammonium phosphate in a predetermined ratio,
Compound 1 was obtained by stirring overnight in 2N salt #100aj of 00"C, filtering and washing with water, and drying at 110°C overnight. As a result of measuring the Li concentration in the filtrate, Compound 1 was obtained.
In the general formula, A is Li, M is Zr, and
The value was 0.9. Example 1 0.1 g of the powdered Compound I obtained in Reference Example 1 was added to 2 L of natural seawater (lithium concentration 0.17 mg/l) and stirred for 24 hours. Thereafter, the powder was filtered, washed, dried, and eluted with 5N hydrochloric acid, and the lithium concentration in the hydrochloric acid was measured to determine the amount of lithium adsorbed and the concentration ratio.
Note that the concentration rate was calculated using the following formula.

Furthermore, the adsorption amount and 'a reduction rate of alkali metals and alkaline earth metals other than lithium in natural seawater were determined for the same camphor tree, and the results are shown in Table 1. From Table I, Hx
LII-wZrz(Pot)z(x=0.9”) has a significantly higher concentration ratio for lithium than alkali metals and alkaline earth metals other than lithium, and using it will greatly improve the recovery of lithium from natural seawater. It can be seen that it can be carried out efficiently. Example 2 The compound obtained in Reference Example I was added to lgt-ike hot water (lithium concentration 5.2 mg/l) 2 1 and stirred for 24 hours. Compound I was separated by filtration, washed with water, and dried.The lithium adsorption amount was determined by measuring the lithium concentration in the filtrate.After drying Compound I, it was soaked in 100 sj of 5N hydrochloric acid and kept at 80°C for 3 hours. Using the same compound 1, repeat the lithium recovery operation by adsorption and elution five times, and measure the lithium concentration in the filtrate and the lithium concentration in hydrochloric acid in each recovery operation. The lithium adsorption amount, lithium adsorption rate, and lithium adsorption rate were determined, and the results are shown in Table 2. From Table 2, }IIILi+-NZr*(POa
)s (xJ.9) shows that the lithium recovery ability does not decrease even if lithium adsorption and elution are repeated. Example 3 1500 g of the compound obtained in Reference Example 1, 55 g of bentonite which is a clay mineral, 120 g of water, and 560 g of silica sol (solid content 15%, solvent: ethanol) prepared from ethyl silicate as a metal alkoxide hydrolyzate were added. and kneaded in a kneader for 2 hours (rotation speed 100 r).
pm) *This kneaded material was granulated using an extrusion granulator with two screws and a 0.5 φ screen set on the side surface of the screw tip (screw rotation speed 20 rpm).
, 0.5 m-φ rod-shaped granules were obtained. The obtained rod-shaped granules were placed in a granulator having a rotary plate at the bottom of a round container and rotated at a rotation speed of 700 rpm for 30 seconds to obtain spherical particles with a diameter of 0.5. was incinerated in an electric furnace at 800°C for 2 hours. 1 g of this calcined spherical material was stirred in 20 ml of seawater for 24 hours, filtered, washed and dried. Thereafter, it was eluted with 5N hydrochloric acid, the lithium concentration in the hydrochloric acid was measured, and the lithium adsorption amount and concentration ratio were determined in the same manner as in Example 1. The results are shown in Table 3. In addition, 1 g of this incinerated spherical material was separated into 100 ml of boiling water at 90'C (250 s L).
When placed in a shaker and shaken at 100 times/min for 30 minutes, no crushing or pulverization was observed and the shape was maintained. From the above, HgLit-lIzrt(POn)s (+1-0.9
) has almost no deterioration in ion-exchange properties and has high mechanical strength, so it can be seen that it can be used in a column packing method. Example 4 To 500 g of Compound 1 obtained in Reference Example 1, 50 g of tetrafluoroethylene resin powder (average particle size 0.1 pm), 5 g of fluorine-based nonionic surfactant, 350 g of water, and 110 g of ethanol were added and mixed. The mixture was kneaded for 15 minutes in a screwdriver (rotational speed 100 rpm). The above kneaded material was granulated using an extrusion granulator with a 21 dl screw and a l--φ screen set on the side surface of one end of the screw (screw rotation speed 20 rpm). ), is11 rod-shaped granules were obtained. The obtained rod-shaped granules were placed in a granulator having a rotating plate at the bottom of a cylindrical container to obtain spherical particles with a diameter of 1 mm. The resulting spherical material was incinerated in an electric furnace at 360'C for IO minutes. Add 1 g of this incinerated spherical material to 201 g of seawater and 24
After stirring for an hour, the mixture was filtered, washed and dried. After that, O. Elution was performed with IN hydrochloric acid, the lithium concentration in the hydrochloric acid was measured, and the lithium adsorption amount and concentration ratio were determined in the same manner as in Example 1. Furthermore, the adsorption amounts and concentration ratios of alkali metals and alkaline earth metals other than lithium were determined in the same manner, and the results are shown in Table 4. Further, when this incinerated spherical material was shaken for 30 minutes in a separatory funnel in the same manner as in Example 1, no crushing or pulverization was observed, and the shape was maintained. From the above, LLi+-lIzrx(POa)s
(x = 0.9) shows that the lithium adsorption properties hardly deteriorate even after shaping into granules using an organic binder, and the mechanical strength of the granules is high, making them practical. Example 5 Commercially available silica sol (average particle size 15μ-150g) was added to 1500g of the compound obtained in Reference Example 1, and the mixture was mixed with a kneader for 2
The mixture was kneaded for hours (rotation speed: 100 rpm), and this kneaded product was granulated using an extrusion granulator with two screws and a 1-φ screen set on the side surface of the screw tip (screw rotation speed: 2 Orpm) to obtain 1 g, φ rod-shaped granules. I got it. The obtained rod-shaped granules were placed in a granulator having a rotary plate at the bottom of a cylindrical container and rotated at a rotational speed of 700 rpm for 30 seconds to obtain 1-11 spherical particles by rotation of the granules. The obtained spherical material was incinerated in an electric furnace at 800"C for 2 hours. 1 g of the incinerated granular material was stirred in seawater 201 for 24 hours, filtered and washed, and then dried.
The lithium adsorption amount and concentration ratio were determined by elution with N-hydrochloric acid and measuring the lithium concentration in the hydrochloric acid. Furthermore, the adsorption amounts and concentration ratios of alkali metals and alkaline earth metals other than lithium were determined in the same manner, and the results are shown in Table 5. Also, when 1 g of the incinerated spherical material was placed in a separator (250 ml) with 100 ml of water at 90°C and subjected to a shaker for 30 minutes at a speed of 100 times/minute, no crushing or powdering was observed. The shape was maintained. From the above, it can be seen that the lithium recovery method of the present invention does not reduce the lithium adsorption ability even after shaping into granules using an inorganic binder, and it is possible to obtain molded products with high mechanical strength. Examples 6 to 8 Compounds used in Examples 3 to 5 were replaced with LiZr (POa>
The spherical objects of Examples 6, 7, and 8 were produced in exactly the same manner as Examples 3, 4, and 5, except for changing to s. 1 g of the obtained spherical material was immersed in 50 hl of 0.5N hydrochloric acid,
After keeping it warm at 80°C for 3 days, it was filtered, washed and dried to obtain a spherical product. 1 g of each of these spherical objects was added to seawater 201, and the lithium adsorption amount and concentration rate were determined in the same manner as in Examples 3 to 5. It is shown in the table. Furthermore, when 1 g of these incinerated spherical objects was subjected to a shaker in the same manner as in Examples 3 to 5, no crushing or pulverization was observed in any case, and no change in shape was observed. There wasn't. Example 9 Compound I obtained in Reference Example 1 was processed using a tablet molding machine} (1
It has an impressive 3-opening φXlowm. A large number of pellets were prepared and heated at 1,000°C for 2 hours to form a beam left for column filling. The thus obtained bereft was packed into a column with a diameter of 4 cm to a height of 40 cm, and 60'C geothermal water was passed through the top of the column at a flow rate of 5 cm/win. In the effluent, the concentration of lithium contained in geothermal water is 1
The concentration is less than 1/000, and the geothermal water at 60°C is
No lithium flow was observed until 0001 was passed. Since the apparent volume of the column is 500 cm',
Lithium concentration is more than 10,000 times higher than that contained in geothermal water - Im
This means that it has been done. The lithium deposited on Ui was recovered with a yield of over 95% by passing 5N hydrochloric acid through the IL. Example 10 LiZrx (P
A pellet was formed using Oa)z, and a pellet for column filling was obtained in the same manner as in Example 9. The pellets were packed into a 4cm diameter column to a height of 40cm, and 5N hydrochloric acid was passed from the top of the column. By measuring the concentration of lithium in the hydrochloric acid flowing out from the column, it was determined that the compound forming the pellet was LiZ.
r*(POa)s to H. iI-wZrzcPOa>
i1 confirmed that it had changed to 3(X・0.9). Geothermal water was passed through this column in the same manner as in Example 9. The lithium concentration in the effluent was 1000 times less than that of the geothermal water, and no quality flow of lithium was observed until the sooot geothermal water was passed through. The adsorbed lithium is dissolved in 5N hydrochloric acid
A yield of more than 95% was recovered by passing through the tube once. In addition, in place of Compound I obtained in Reference N1, Zr was replaced with T3 or Sn, and in these three cases, Lt was replaced with N
Examples 1 to 5 and 9 for those replaced with a or K
Similarly, Examples 6 to 3 were prepared by replacing Zr with Ti or Sn in place of LiZrx(POn)z, and replacing Li with Na or K in these three cases.
As a result of recovering lithium in the same manner as in 8 and 10,
In either case, the same lithium recovery characteristics and mechanical strength as in the example before replacing the metal species were observed.

x8 (c) Effects of the invention The compound used in the invention has excellent properties of selectively adsorbing lithium, has a large adsorption capacity and adsorption rate, and is very stable in an aqueous solution, so there is no problem of toxicity. It has the excellent feature that its ion exchange properties do not change even after being processed into membranes or particles, so by using this compound as an adsorbent, geothermal water, hot spring water,
Lithium can be easily recovered by adsorbing it extremely efficiently from natural water such as natural gas brine, salt production shrubs, and seawater, or from various industrial waste fluids, and then eluting it with an inorganic acid. Therefore, the present invention is extremely useful in the liquid treatment industry for natural water such as fresh water and groundwater, or various waste liquids containing lithium.

Claims (1)

[Claims] 1, General formula H_XA_1_-_XM_2(PO_4)_
3 (In the above formula, X is a positive number less than 1, A is Li, Na
, at least one selected from K, M is Zr, Ti, S
At least one compound selected from n),
A method for recovering lithium, which comprises bringing it into contact with a lithium-containing liquid, separating it, and bringing it into contact with an eluent.