KR20080045626A - Ion-exchange type lithium adsorbent using ceramic filter and method for preparing the same - Google Patents

Abstract

An ion-exchange type lithium adsorbent using a ceramic filter and a method for preparing the same easily and simply are provided, wherein the ion-exchange type lithium adsorbent is physically and chemically stable, is easily handled, and is excellent in adsorption performance capable of selectively adsorbing lithium ion only such that the adsorbent adsorbs and recovers lithium efficiently. A method for preparing an ion-exchange type lithium adsorbent using a ceramic filter comprises the steps of: synthesizing a precursor powder that is a lithium manganese oxide with a spinel structure; filling the precursor powder in a ceramic filter; and acid-treating the precursor powder-filled ceramic filter. A method for preparing an ion-exchange type lithium adsorbent using a ceramic filter comprises the steps of: synthesizing a precursor powder of the chemical formula LinMn2-xO4 with a spinel structure, wherein n is ranged from 1 to 1.33, x is ranged from 0 to 0.33, and n is less than or equal to 1+x; filling the precursor powder in a ceramic filter; and acid-treating the precursor powder-filled ceramic filter. An ion-exchange type lithium adsorbent using a ceramic filter comprises an ion exchange type manganese oxide powder with a spinel structure filled in a ceramic filter. An ion-exchange type lithium adsorbent using a ceramic filter comprises an ion exchange type manganese oxide powder of the chemical formula HnMn2-xO4 with a spinel structure filled in a ceramic filter, wherein n is ranged from 1 to 1.33, x is ranged from 0 to 0.33, and n is less than or equal to 1+x.

Description

ION-EXCHANGE TYPE LITHIUM ADSORBENT USING CERAMIC FILTER AND METHOD FOR PREPARING THE SAME}

The present invention relates to an ion exchange lithium adsorbent using a ceramic filter and a method for producing the same. More specifically, the present invention provides a method for preparing an adsorbent capable of selectively adsorbing and recovering only lithium from an aqueous solution containing lithium by filling an acid-exchanged lithium manganese oxide powder in a ceramic filter and acid treatment. The present invention relates to an ion exchange lithium adsorbent using a filter.

Lithium and lithium compounds are currently used in a wide range of fields such as secondary battery materials, refrigerant adsorbents, catalysts, pharmaceuticals, etc., and are one of the important resources attracting attention as fusion energy resources. In addition, the demand for lithium and lithium compounds is expected to further increase in the technical fields such as large-capacity batteries and electric vehicles that are expected to be commercialized.

As such, lithium is an important resource that can be applied to various fields, but its importance is increasing, but the global reserve of lithium land resources is only 2 to 9 million tons. In order to overcome these limitations, research is being conducted to secure lithium resources through various paths, and as part of such research, the present invention effectively recovers a small amount of lithium dissolved in aqueous solutions such as seawater, brine, and lithium battery waste liquid. Research is underway.

Conventional lithium recovery methods are known to reduce lithium ions by electrochemical methods or to reduce lithium oxides with magnesium or aluminum metal, and another method is to use an adsorbent that selectively adsorbs lithium ions. Methods of recovering lithium have been studied. The main interest of these studies using lithium adsorbents is to develop high performance adsorbents with high selectivity for lithium ions and excellent adsorption / desorption performance.

As a result of such studies, a method is known in which a powder which facilitates adsorption / desorption of lithium by a solid phase reaction method or a gel method using manganese oxide as a material is known, and the powder prepared by such a method is a cathode material for a lithium secondary battery, It has been used as a material for lithium adsorbents. However, since the use of powdered lithium adsorbent is inconvenient in handling, it is necessary to mold and use it. For example, as disclosed in Korean Patent Publication No. 10-2003-9509, after mixing a powder with alumina powder, a pore-forming agent such as PVC is used to agglomerate the mixture of the powder and alumina powder to form a bead. It can be molded by applying a method for producing an adsorbent.

However, in the case of preparing the adsorbent in the form of beads using the conventional PVC addition method as described above, while the handling is easy, the adsorption site for the adsorption / desorption of lithium is reported to be reduced by about 30% or more compared to the powder adsorbent As a result, it has been pointed out that the lithium recovery ability is poor when used as a lithium adsorbent.

The present inventors have received a patent registration by inventing an adsorbent using a urethane blowing agent and an adsorbent in the form of a honeycomb (Patent Registration Nos. 10-0557824 and 10-0536957), and accordingly, in a powder state By overcoming the disadvantages of the lithium adsorbent, a lithium adsorbent which is easy to handle and has excellent lithium adsorption performance of selectively adsorbing only lithium ions can be obtained.

However, even though the adsorbent is low, the adsorption efficiency is lowered compared to the powder adsorbent. Therefore, the adsorption efficiency is not lowered compared to the lithium adsorbent in the powder state, and it is possible to selectively adsorb only lithium ions with excellent performance, and also a new type of lithium adsorbent that can be easily desorbed for recovery of lithium after adsorption. There is still a need for.

The present invention provides an ion exchange lithium adsorbent using a ceramic filter that is physically and chemically stable, easy to handle, and has an excellent adsorption performance capable of selectively adsorbing only lithium ions, thereby efficiently adsorbing and recovering lithium. It aims to do it.

In addition, an object of the present invention is to provide a production method capable of easily and simply producing an ion exchange type lithium adsorbent using a ceramic filter having excellent lithium adsorption performance, stability and ease of handling.

The objects of the present invention are not limited to the above-mentioned objects, and other objects and advantages of the present invention which are not mentioned above can be understood by the following description, and will be more clearly understood by the embodiments of the present invention. Also, it will be readily appreciated that the objects and advantages of the present invention may be realized by the means and combinations thereof indicated in the claims.

The present invention for achieving the above object is a step of synthesizing a precursor powder of lithium manganese oxide having a spinel structure; Filling the precursor powder into a ceramic filter; And it provides a method of producing an ion exchange lithium adsorbent using a ceramic filter comprising the step of acid-treating the ceramic filter filled with the precursor powder.

In addition, the present invention has a spinel structure

Li _n Mn _2-x O ₄

(Wherein 1 ≦ n ≦ 1.33, 0 ≦ x ≦ 0.33, n ≦ 1 + x)

Synthesizing a precursor powder of; Filling the precursor powder into a ceramic filter; And it provides a method of producing an ion exchange lithium adsorbent using a ceramic filter comprising the step of acid-treating the ceramic filter filled with the precursor powder.

The present invention also provides an ion exchange lithium adsorbent using a ceramic filter in which an ion exchange manganese oxide having a spinel structure is filled in the ceramic filter.

In addition, the present invention has the following formula 1a having a spinel structure in the ceramic filter

H _n Mn _{2 - x} O ₄

(Wherein 1 ≦ n ≦ 1.33, 0 ≦ x ≦ 0.33, n ≦ 1 + x)

Provided is an ion exchange lithium adsorbent using a ceramic filter filled with ion exchange manganese oxide.

The adsorbent according to the present invention is prepared by filling an ion-exchangeable lithium manganese oxide powder in a ceramic filter having excellent solvent permeability, mechanical strength and chemical resistance, and then acid treatment to form an ionic body. In addition, by providing an excellent adsorption reaction site compared to the conventional molded adsorbent it can selectively adsorb only lithium ions with excellent efficiency, and also has an easy effect of the desorption process for the recovery of the adsorbed lithium ions.

In addition, the ion exchange type lithium adsorbent in the form of a ceramic filter prepared according to the present invention has excellent physical and chemical stability in aqueous solutions of various environments, and exhibits high selectivity for lithium ions. Only lithium can be selectively adsorbed from this dissolved aqueous solution to be used for separation and recovery.

The above objects, features, and advantages will become more apparent from the detailed description given hereinafter with reference to the accompanying drawings, and accordingly, those skilled in the art to which the present invention pertains may share the technical idea of the present invention. It will be easy to implement. In addition, in describing the present invention, when it is determined that the detailed description of the known technology related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description thereof will be omitted. Hereinafter, with reference to the accompanying drawings will be described in detail with respect to the present invention.

In general, lithium adsorbents must maintain physical and chemical stability in aqueous solutions under various conditions and environments, and must be able to provide adsorption sites that can ensure high adsorption efficiency. In addition, it should not adsorb elements other than lithium by maintaining high selectivity to lithium ions, it should also be able to easily be desorption process for recovery of lithium after adsorption.

From this point of view, the result obtained by phase eluting lithium ions in the compound by acid treatment of lithium manganese oxide having a spinel structure as a precursor is known to exhibit excellent selectivity for lithium ions in the target solution.

In the present invention, the spinel structure lithium manganese oxide used as a precursor of the lithium adsorbent is filled into the filter and acid treated, thereby solving the problem of the powder adsorbent and using it as a lithium adsorbent capable of efficiently adsorbing and recovering lithium. It features.

The lithium manganese oxide usable in the present invention can be applied without limitation as long as it has a spinel structure and can be used as a lithium adsorbent by ion exchange. More preferably, in view of the essential properties required for the lithium adsorbent, among the spinel structure lithium manganese oxides known as precursors having selective adsorption performance for lithium ions, the spinel structure as described above is particularly represented by Formula 1 below.

[Formula 1]

Li _n Mn _{2 - x} O ₄

(Wherein 1 ≦ n ≦ 1.33, 0 ≦ x ≦ 0.33, n ≦ 1 + x)

Lithium manganese oxide powder is used as a precursor.

The lithium manganese oxide powder of Formula 1 has a high chemical stability, and when formed as an ionic body can exhibit a selective adsorption performance for lithium ions, it can be suitably used in the present invention as a precursor of the lithium adsorbent.

In the present invention, the lithium manganese oxide of Chemical Formula 1 is not particularly limited, but the following Chemical Formula 2

Li _{1 .33} Mn _{1 .67} O ₄

Lithium manganese oxide is preferably used as an ion exchange precursor powder.

The ion-exchange precursor powder of Chemical Formula 2 can maximize lithium adsorption efficiency when used as a lithium adsorbent, and is easy to handle, and also has an easy desorption process for recovery of lithium ions after adsorption.

The ion exchange precursor powder of Formula 2 is shown in Scheme 1

_{(Li) [Li 0 .33 Mn} (Ⅳ) 1.67] O 4 _{↔ (H) [H 0 .33} Mn (Ⅳ) 1.67] O 4

Where () represents an 8a tetrahedral site in the spinel structure and [] represents a 16d octahedral site in the spinel structure)

As described above, lithium may be adsorbed / desorbed by an ion exchange method, and thus it may be particularly preferably used for an ion exchange lithium adsorbent using a ceramic filter according to the present invention.

In addition, examples of the ion-exchange lithium manganese oxide that can be suitably applied to the present invention is represented by the following formula (3)

Li ₁ Mn _{1 .6 .6} O ₄

Lithium manganese oxide. The lithium manganese oxide of Chemical Formula 3 is known to have excellent selective adsorption efficiency for lithium ions.

Such ion-exchange precursor powders may be prepared according to methods known in the art, for example, by a solid phase reaction method or a gel method. The solid phase reaction method is, for example, a lithium manganese oxide powder is formed by mixing a lithium compound and a manganese compound and then heat treatment at a high temperature, also called a high temperature solid phase reaction method. In the gel process, for example, a lithium compound and a manganese compound are mixed in an appropriate solvent, and then tartaric acid solution or citric acid solution is added and gelled, followed by drying to form lithium manganese oxide powder.

Since the method for producing the ion-exchangeable lithium manganese oxide precursor powder is known, in the present invention, a suitable method can be selected and used according to desired physical properties and production conditions.

In the present invention, the above ion-exchanging precursor powder is filled into the ceramic filter, and the adsorbent is prepared by acid treatment of the ceramic filter filled with the precursor powder to form an ionic body.

Ceramic filters are formed by firing porous ceramic particles at a high temperature, and the pore size is known to have a range of several micrometers and a minimum of about 0.2 μm because the space between the ceramic particles forms pores. Ceramic filters are generally manufactured using porous ceramic materials such as alumina, silica, zirconia and titanium oxide. Since these materials are excellent in characteristics such as heat resistance and chemical resistance, ceramic filters are particularly applied to various applications such as high temperature and high pressure gas dust collection and water purification.

The ceramic filter that can be used in the present invention can be applied without any limitation as long as it is used as a conventional solvent / solute separation filter, and in particular, physical and chemical durability is guaranteed for the target solvent to which the aforementioned precursor powder is applied. It should be noted that the precursor powder filled therein should not be lost to the external solvent, and it is also useful that the solvent can be easily introduced into the filter because of excellent solvent permeability.

In consideration of this aspect, in the present invention, it is particularly preferable to use a cylindrical ceramic filter made of alumina having a pore size of about 1 to 10 μm. Alumina has a high degree of fire resistance, and excellent physical and chemical durability, the ceramic filter using the same can be usefully used in the present invention. In addition, the pore size may be applied without limitation as long as it is a pore size range of a general ceramic filter, but a pore size smaller than that of a precursor powder having a particle size of about 10 μm may be suitably used in the present invention without fear of powder loss. Can be.

In the present invention, the above-mentioned precursor powder is filled into the porous ceramic filter used for the solvent / solute separation. The filling ratio of the precursor powder can be adjusted within the apparent density ratio, the higher the filling ratio is to increase the adsorption efficiency of the adsorbent according to the present invention.

After the ion exchange precursor powder is filled into the ceramic filter, an acid treatment is performed. When acid treatment of the ceramic filter in which the ion exchange precursor powder is filled therein as described above, lithium ions are exchanged into hydrogen ions by the reaction as in Scheme 1, and the target solution is applied on the same principle as the ion sieve. It is possible to produce a lithium adsorbent that can be easily recovered by selectively adsorbing / desorbing only lithium ions dissolved in the water.

That is, the ion-exchangeable lithium manganese oxide precursors of Chemical Formulas 1 to 3 filled in the ceramic filter by acid treatment are each ion-exchanged manganese oxide of Chemical Formula 1a (H _n Mn _2-x O ₄ , wherein 1 ≦ n ≦ 1.33, 0 ≦ x ≦ 0.33, n ≦ 1 + x), ion exchanged manganese oxide of Formula 2a (H _1.33 Mn _1.67 O ₄ ) and ion exchanged manganese oxide of Formula 3a (H _1.6 Mn _1.6 O ₄ ), and acts as an ionic body to adsorb lithium ions by ion exchange.

The acid treatment is preferably performed 3-5 times in 22 ~ 26 hours each time in an acid solution of 0.3 ~ 1.0M. The acidic solution that can be used for the acid treatment is not particularly limited, but hydrochloric acid solution is preferred. In addition, in order to maximize the formation of lithium holes for more effective reversible reaction of lithium ions and hydrogen ions during the aforementioned ion exchange reaction, and to prevent the elution of manganese ions, 0.5 M hydrochloric acid in the acid treatment step It is especially preferable to perform acid treatment four times for 24 hours per time using a solution.

The ion-exchanging lithium adsorbent using the ceramic filter according to the present invention is made by filling an acid-exchanging precursor powder in an inside of a polymer porous ceramic filter having excellent solvent permeability, mechanical strength and chemical resistance, thereby making it physically and chemically stable. It is easy to handle and can exhibit excellent lithium adsorption performance. In addition, the ion exchange type lithium adsorbent using the ceramic filter according to the present invention can eliminate or minimize the deterioration of the adsorption site while overcoming the disadvantages of the powdered adsorbent, thereby increasing the selective adsorption efficiency for lithium ions.

Hereinafter, the present invention will be described in detail with reference to Examples.

However, the following examples are merely to illustrate the invention, but the content of the present invention is not limited to the following examples.

Example  One

LiCO ₃ and MnCO ₃ and the molar ratio 1.33: 1.67, respectively into a stirrer and mixed by stirring sufficiently for 20 minutes, and heat treated for 4 hours at 500 ℃ within an electrically synthesizing a Mn _{1 .67} O ₄ precursor powder by Li _{1 .33} It was.

10 g of the synthesized precursor powder was taken and placed in a ceramic filter having a pore size of 5 μm, an outer diameter of 10 mm, an inner diameter of 7 mm, and a length of 230 mm. Thereafter, as shown in FIG. 1, after fixing several ceramic filters in one frame, 10 stages are mounted in a drawer box made of PVC, and then acid-treated four times for 24 hours in a 0.5 M hydrochloric acid solution. An ion exchange lithium adsorbent using a ceramic filter was prepared.

Example  2

First, a solution was prepared by dissolving CH ₃ COOLi and Mn (CH ₃ COO) ₂ .4H ₂ O in ethanol, respectively. CH ₃ COOLi and Mn (CH ₃ COO) ₂ .4H ₂ O dissolved in this ethanol were respectively taken in a molar ratio of 1.33: 1.67, mixed and vigorously stirred. A 0.1 M tartaric acid solution dissolved in ethanol was slowly added thereto to induce a gelation reaction, thereby obtaining a precipitate condensed to nano size. The obtained precipitate was placed in an oven at 70 ° C. and slowly heated to dryness until the ethanol component was completely removed to obtain a pale pink lithium manganese tartrate precursor. After this, completely removing the water remaining in the re-heating 200 ℃ for 6 hours, nanoscale Li _{1 .33} of the heat-treated at 500 ℃ for 24 hours Mn _{1 .67} O ₄ Precursor powder was synthesized.

1 g of the synthesized precursor powder was taken and placed in a ceramic filter having a pore size of 10 μm, an outer diameter of 10 mm, an inner diameter of 7 mm, and a length of 230 mm. Then, after fixing several ceramic filters in one frame as shown in Figure 1 and then equipped with 10 stages in a PVC drawer box, the present invention by acid treatment four times per 24 hours in 0.5M hydrochloric acid solution An ion exchange lithium adsorbent using a ceramic filter was prepared.

The photograph which observed the ion exchange type lithium adsorbent using the ceramic filter obtained by the said Example 1 and 2 through the electron scanning microscope is shown in FIG. As shown in FIG. 2, the final result obtained in Examples 1 and 2 is an adsorbent in which an ion-exchange manganese oxide is filled in the ceramic filter, and the adsorption reaction site is maximized by maximizing the adsorption reaction site. It can be seen that a very good adsorbent that has not been degraded has been produced.

In order to more clearly evaluate the adsorption efficiency of the adsorbent according to the present invention, the adsorption efficiency of the ion exchange type lithium adsorbent using the ceramic filter obtained in Example 1 and the powdered lithium adsorbent were compared. Artificial seawater samples (Na 1.07x10 ⁴ mg / l, Mg 1.3x10 ³ mg / l, K 0.4x10 ³ mg / l, Ca 0.4x10 ³ mg / l, Cl 1.68x10 ⁴ mg / l and Li 0.2 mg / l) As a result of comparing the equilibrium adsorption amount with respect to Li, the adsorption capacity in the powder state was 28.3 mg of lithium per 1 g of the adsorbent, whereas the adsorption capacity in the case of using a ceramic filter was 28.1 mg of lithium per 1 g of the adsorbent.

As can be clearly seen from the measurement results of the adsorption capacity, the ion-exchange lithium adsorbent using the ceramic filter according to the present invention exhibits high adsorption capacity in the form of powder, while being easy to handle, and also has high physical and chemical stability. Therefore, it can be suitably used as an effective adsorbent for lithium.

The present invention described above can be variously substituted, modified and changed within the scope without departing from the spirit of the present invention for those of ordinary skill in the art to which the present invention belongs, the above-described embodiment and the accompanying drawings It is not limited by.

1 is a photograph of an ion exchange lithium adsorbent using a ceramic filter obtained in Examples 1 and 2 of the present invention.

2 is an electron scanning microscope photograph of an ion exchange type lithium adsorbent using a ceramic filter obtained in Examples 1 and 2 of the present invention.

Claims (18)

Synthesizing a precursor powder that is lithium manganese oxide having a spinel structure; Filling the precursor powder into a ceramic filter; And Acid treating the ceramic filter filled with the precursor powder; Method for producing an ion exchange lithium adsorbent using a ceramic filter comprising a. Formula 1 having a spinel structure [Formula 1] Li _n Mn _{2 - x} O ₄ Synthesizing a precursor powder, wherein 1 ≦ n ≦ 1.33, 0 ≦ x ≦ 0.33, n ≦ 1 + x; Filling the precursor powder into a ceramic filter; And Acid treating the ceramic filter filled with the precursor powder; Method for producing an ion exchange lithium adsorbent using a ceramic filter comprising a. The method of claim 2, The precursor powder of Formula 1 has a spinel structure [Formula 2] Li _{1 .33} Mn _{1 .67} O ₄ Of lithium manganese oxide Method for producing an ion exchange lithium adsorbent using a ceramic filter. The method of claim 1, The precursor powder has a spinel structure [Formula 3] Li ₁ Mn _{1 .6 .6} O ₄ Of lithium manganese oxide Method for producing an ion exchange lithium adsorbent using a ceramic filter. The method according to claim 1 or 2, The acid treatment is carried out in an acid solution of 0.3 ~ 1.0M Method for producing an ion exchange lithium adsorbent using a ceramic filter. The method of claim 5, The acid treatment is performed 3 to 5 times for 22 to 24 hours each time in an acid solution of 0.3 ~ 1.0M Method for producing an ion exchange lithium adsorbent using a ceramic filter. The method of claim 6, The acid treatment is performed four times for 24 hours at a time in 0.5M hydrochloric acid solution Method for producing an ion exchange lithium adsorbent using a ceramic filter. The method according to claim 1 or 2, The ceramic filter is made of alumina Method for producing an ion exchange lithium adsorbent using a ceramic filter. The method of claim 8, The ceramic filter is made of alumina having a pore size of 1 ~ 10㎛ Method for producing an ion exchange lithium adsorbent using a ceramic filter. An ion exchange lithium adsorbent using a ceramic filter, wherein an ion exchange manganese oxide powder having a spinel structure is filled in a ceramic filter. Formula 1a having a spinel structure inside a ceramic filter [Formula 1a] H _n Mn _{2 - x} O ₄ (Wherein 1 ≦ n ≦ 1.33, 0 ≦ x ≦ 0.33, n ≦ 1 + x) Filled with ion-exchangeable manganese oxide powder Ion-exchange lithium adsorbent using ceramic filter. The method of claim 11, The manganese oxide of Chemical Formula 1a may have a spinel structure. [Formula 2a] H _{1 .33} Mn _{1 .67} O ₄ Is an ion-exchangeable manganese oxide Ion-exchange lithium adsorbent using ceramic filter. The method of claim 10, The manganese oxide has the spinel structure of Formula 3a [Formula 3a] H _{1 1 .6 .6} Mn O ₄ Is an ion-exchangeable manganese oxide Ion-exchange lithium adsorbent using ceramic filter. The method according to claim 10 or 11, The ceramic filter is made of alumina Ion-exchange lithium adsorbent using ceramic filter. The method of claim 14, The ceramic filter is made of alumina having a pore size of 1 ~ 10㎛ Ion-exchange lithium adsorbent using ceramic filter. The method of claim 11, The ion exchanged manganese oxide of Chemical Formula 1a may be represented by Chemical Formula 1 below: [Formula 1] Li _n Mn _{2 - x} O ₄ (Wherein 1 ≦ n ≦ 1.33, 0 ≦ x ≦ 0.33, n ≦ 1 + x) Obtained by acid treatment of a lithium manganese oxide precursor Ion-exchange lithium adsorbent using ceramic filter. The method of claim 12, The ion exchanged manganese oxide of Chemical Formula 2a is represented by the following Chemical Formula 2 [Formula 2] Li _{1 .33} Mn _{1 .67} O ₄ Obtained by acid treatment of a lithium manganese oxide precursor Ion-exchange lithium adsorbent using ceramic filter. The method of claim 13, The ion exchanged manganese oxide of Formula 3a is represented by the following Formula 3 [Formula 3] Li ₁ Mn _{1 .6 .6} O ₄ Obtained by acid treatment of a lithium manganese oxide precursor Ion-exchange lithium adsorbent using ceramic filter.

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