KR20200023884A - Lithium ion adsorbent and a method for recovering lithium ion using the same - Google Patents

Abstract

The present invention relates to a lithium ion adsorbent and a method for recovering lithium ions using the same. The lithium ion adsorbent according to the present invention exhibits excellent adsorption selectivity for lithium ions, and can be obtained through recycling of residual minerals generated after extracting lithium from raw minerals, thereby providing advantages in terms of economy.

Description

Lithium ion adsorbent and recovery method for lithium ions using the same {LITHIUM ION ADSORBENT AND A METHOD FOR RECOVERING LITHIUM ION USING THE SAME}

The present invention relates to a lithium ion adsorbent and a method for recovering lithium ions using the same.

As demand for lithium increases rapidly and prices rise, development of methods for extracting lithium from lithium-containing sources and the materials used therein is being actively conducted.

For example, Patent Document 1 (Korean Patent Publication No. 10-0727576, 2007.06.05) discloses an ion exchange filter for lithium adsorption in which a lithium adsorbent is deposited on an ion exchange fiber having a crosslinked structure with an ion exchange group. do.

In said patent document 1, a manganese peroxide is used as a lithium adsorption agent. However, manganese peroxide has a low adsorption selectivity to lithium.

Patent Document 2 (Korean Patent Publication No. 10-2009-056009, 2009.06.30) discloses a lithium manganese oxide represented by the chemical formula of Li _{1 + x} Mn _1-xy M _y O _{2 + z} and a lithium ion using the same. The adsorption method is disclosed.

It is known that the lithium manganese oxide of the said patent document 2 is excellent in the adsorption performance with respect to lithium. However, the lithium manganese oxide is not only complicated in its manufacturing method but also requires a high cost for its production.

In addition, the lithium manganese oxide has a limitation in that its structure is deformed and its performance is deteriorated by an acid treatment process that is essential and repeatedly performed in the adsorption and extraction process of lithium.

Republic of Korea Patent Publication No. 10-0727576 (2007.06.05) Republic of Korea Patent Publication No. 10-2009-056009 (2009.06.30)

The present invention is to provide a lithium ion adsorbent exhibiting excellent adsorption selectivity with respect to lithium ions.

The present invention also provides a method for recovering lithium ions from an aqueous solution containing lithium ions using the lithium ion adsorbent.

According to the invention,

There is provided a lithium ion adsorbent comprising a compound represented by the formula:

[Formula 1]

H _x Li _(1-x) Al _y Si _z O _a N _b

In Chemical Formula 1,

N is at least one element selected from the group consisting of Na, K, Mg, Ca, S, and Fe,

0 <x ≦ 1.0, 0 <y ≦ 2.0, 0 <z ≦ 4.0, 0 <a ≦ 9.0, and 0 <b ≦ 1.0.

And, according to the present invention,

Adding the lithium ion adsorbent according to claim 1 to an aqueous solution containing lithium ions at a temperature of 20 to 30 ° C. and a hydrogen ion concentration of pH 7.0 to pH 12.0,

Stirring the aqueous solution to which the lithium ion adsorbent is added,

Adsorbing lithium ions in the aqueous solution to the lithium ion adsorbent by an ion exchange reaction, and

Recovering the lithium ion adsorbent to which the lithium ions are adsorbed from the aqueous solution

Provided is a method for recovering lithium ions comprising a.

Hereinafter, a lithium ion adsorbent and a method for recovering lithium ions using the same according to embodiments of the present invention will be described.

Unless expressly stated herein, the terminology is merely for reference to particular embodiments and is not intended to limit the invention.

As used herein, the singular forms “a,” “an,” and “the” include plural forms as well, unless the phrases clearly indicate the opposite.

As used herein, the meaning of “includes” embodies a particular characteristic, region, integer, step, operation, element, or component, and excludes the addition of other specific characteristics, region, integer, step, operation, element, or component. It is not.

I. Lithium ion adsorbent

According to one embodiment of the invention, there is provided a lithium ion adsorbent comprising a compound represented by the following formula (1):

[Formula 1]

H _x Li _(1-x) Al _y Si _z O _a N _b

In Chemical Formula 1,

N is at least one element selected from the group consisting of Na, K, Mg, Ca, S, Mn, Ti, and Fe,

0 <x ≦ 1.0, 0 <y ≦ 2.0, 0 <z ≦ 4.0, 0 <a ≦ 9.0, and 0 <b ≦ 1.0.

The compound represented by Chemical Formula 1 shows excellent adsorption selectivity for lithium ions. The compound represented by Chemical Formula 1 may be used as a lithium ion adsorbent capable of effectively recovering lithium ions contained in an aqueous source such as seawater and brine.

The compound represented by Chemical Formula 1 may be obtained through recycling of residual minerals generated after lithium is extracted from a raw mineral containing lithium such as spodumene.

When the compound represented by Chemical Formula 1 is added to an aqueous solution containing lithium ions, an ion exchange reaction between hydrogen contained in the compound represented by Chemical Formula 1 and lithium included in the aqueous solution proceeds. Lithium ions are adsorbed onto the compound represented by Chemical Formula 1 through the ion exchange reaction of hydrogen and lithium.

In Formula 1, N is at least one element selected from the group consisting of Na, K, Mg, Ca, S, Mn, Ti, and Fe.

In Formula 1, x is greater than 0 and less than or equal to 1.0, preferably x = 1.0.

In Formula 1, y is greater than 0 and less than or equal to 2.0, preferably 0.8 ≦ y ≦ 1.2, more preferably y = 1.0.

In Chemical Formula 1, z is greater than 0 and less than or equal to 4.0, preferably 1.5 ≦ z ≦ 2.5, and more preferably z = 2.0.

In Formula 1, a is greater than 0 and 9.0 or less, preferably 4.5 ≦ a ≦ 7.5, and more preferably 5.5 ≦ a ≦ 6.5.

In Formula 1, b is greater than 0 and less than or equal to 1.0, preferably 0 ≦ b ≦ 0.5, and more preferably 0 ≦ b ≦ 0.1.

Specifically, the compound represented by Formula 1 is 5 to 20% by weight of aluminum (Al), 20 to 40% by weight of silicon (Si), 40 to 60% by weight of oxygen (O), 0.5 to 2% by weight of Hydrogen (H), 0-1 wt% sodium (Na), 0-1 wt% potassium (K), 0-1 wt% magnesium (Mg), 0-5 wt% calcium (Ca), 0 It may have a chemical composition comprising from 1% by weight of iron (Fe), 0-1% by weight manganese (Mn), 0-0.5% by weight titanium (Ti), and 0-1% by weight of lithium (Li). have.

Preferably, the compound represented by Formula 1 is 8 to 13% by weight of aluminum (Al), 25 to 35% by weight of silicon (Si), 50 to 65% by weight of oxygen (O), 0.1 to 1% by weight Of hydrogen (H), 0.01 to 0.5 wt% sodium (Na), 0.01 to 0.5 wt% potassium (K), 0.01 to 0.1 wt% magnesium (Mg), 2 to 5 wt% calcium (Ca), Have a chemical composition comprising 0.01 to 0.5 wt% iron (Fe), 0.01 to 0.5 wt% manganese (Mn), 0.001 to 0.1 wt% titanium (Ti), and 0.1 to 0.5 wt% lithium (Li) Can be.

For example, the compound represented by Chemical Formula 1 may have a chemical composition including silicon dioxide and aluminum oxide as main components.

The compound represented by Chemical Formula 1 has a crystal system of tetragonal crystal system.

In the compound represented by Formula 1, deintercalation and intercalation are performed through an ion exchange reaction between hydrogen ions forming a tetragonal system and lithium ions included in an aqueous source such as seawater and brine.

On the other hand, the compound represented by Formula 1 is a particle having a 50% volume cumulative particle diameter (D ₅₀ ) of 0.01 ㎛ to 50 ㎛.

Specifically, the 50% volume cumulative particle diameter (D ₅₀ ) of the particles is at least 0.01 μm, or at least 0.1 μm, or at least 0.5 μm, or at least 1.0 μm; 50 μm or less, or 40 μm or less, or 35 μm or less, or 30 μm or less.

Preferably, the 50% volume cumulative particle diameter (D ₅₀ ) of the particles may be 0.01 μm to 50 μm, or 0.1 μm to 40 μm, or 0.1 μm to 30 μm.

When the particle size of the particles is too large, the surface area per unit weight is small, so that the adsorption performance of the lithium ion adsorbent may be deteriorated. When the particle size of the particles is too small, the grinding process is complicated and the cost is high, and the particles are easily aggregated in the adsorption process, so that the adsorption performance of the lithium ion adsorbent may be deteriorated. Therefore, it is advantageous for the expression of the effect according to the invention that the particles have a 50% volume cumulative particle diameter (D ₅₀ ) selected within this range.

The 50% volume cumulative particle diameter (D ₅₀ ) of the particles can be obtained according to the corresponding standard measurement method using a conventional particle size analyzer. As a non-limiting example, the particle diameter can be measured using a particle size analyzer (PSA, LA-960, Horiba co.) According to the relevant standard test method.

The compound represented by Chemical Formula 1 is a particle having a Brunner-Emmett-Teller specific surface area (S _BET ) of 3 m ² / g to 50 m ² / g by nitrogen adsorption / desorption analysis.

Specifically, the S _BET of the particles is at least 3.0 m ² / g, or at least 5.0 m ² / g, or at least 5.5 m ² / g, or at least 6.0 m ² / g, or at least 6.5 m ² / g, or 7.0 m ² / g or more; 50.0 m ² / g or less, or 45.0 m ² / g or less, or 40.0 m ² / g or less, or 35.0 m ² / g or less, or 30.0 m ² / g or less.

Preferably, the S _BET of the particles may be 5.0 m ² / g to 50.0 m ² / g, or 5.0 m ² / g to 45.0 m ² / g, or 7.0 m ² / g to 30.0 m ² / g .

If the specific surface area of the particles is too small, the adsorption performance of the lithium ion adsorbent may be poor. If the specific surface area of the particles is too large, the particles may easily collapse in the course of using the lithium ion adsorbent, so that it is difficult to obtain a target adsorption performance. Therefore, it is advantageous for the expression of the effect according to the invention that the particles have a specific surface area selected within this range.

The specific surface area (S _BET ) of the particles can be obtained according to the corresponding standard measurement method using a conventional specific surface area analyzer. As a non-limiting example, the specific surface area can be measured according to the relevant standard test method using a specific surface area analyzer (BEL Japan Inc., BELSORP-max).

The compound represented by Chemical Formula 1 may be obtained through recycling of residual minerals generated after lithium is extracted from a raw mineral containing lithium such as spodumene.

Specifically, according to another embodiment of the invention, (1) calcining α-spodumene concentrate at a temperature of 1000 to 1200 ℃ to obtain β-spodumene; (2) mixing the product of step (1) with sulfuric acid to extract lithium sulfate at a temperature of 100 to 250 ℃; (3) adding calcium hydroxide (Ca (OH) ₂ ) to the product of step (2) and heating it; (4) separating the precipitate precipitated from the product of step (3); And (5) there is provided a method for producing a lithium ion adsorbent comprising the step of obtaining the compound represented by the formula (1) by drying the precipitate of step (4).

Here, step (3) may be omitted as necessary.

II. Lithium ion recovery  Way

According to another embodiment of the invention,

Adding a lithium ion adsorbent including the compound represented by Chemical Formula 1 to an aqueous solution containing lithium ions at a temperature of 20 to 30 ° C. and a hydrogen ion concentration of pH 7.0 to pH 12.0,

Stirring the aqueous solution to which the lithium ion adsorbent is added,

Adsorbing lithium ions in the aqueous solution to the lithium ion adsorbent by an ion exchange reaction, and

Recovering the lithium ion adsorbent to which the lithium ions are adsorbed from the aqueous solution

Provided is a method for recovering lithium ions comprising a.

The method of recovering lithium ions using the lithium ion adsorbent may be performed under normal temperature and weak base conditions.

That is, the lithium ion adsorbent may exhibit excellent adsorption selectivity for lithium ions even at room temperature of less than 20 to 30 ℃, preferably less than 30 ℃.

In order to improve the adsorption efficiency of lithium ions, the aqueous solution containing lithium ions is preferably prepared at a hydrogen ion concentration of pH 7.0 to pH 12.0 or pH 9.0 to pH 11.0.

The aqueous solution containing the lithium ion is not particularly limited in kind, and may be preferably seawater or brine.

Under the above conditions, the lithium ion adsorbent is added to the aqueous solution containing lithium ions, followed by stirring.

The holding time of the said stirring is not specifically limited. However, in order to allow sufficient adsorption of lithium ions, the stirring may be maintained for 24 hours or more, or for 24 to 720 hours.

The stirring causes an ion exchange reaction between hydrogen of the lithium ion adsorbent and lithium ions of the aqueous solution. Lithium ions are adsorbed onto the lithium ion adsorbent through the ion exchange reaction.

Subsequently, the lithium ion adsorbent to which the lithium ions are adsorbed is recovered from the aqueous solution.

In addition, the recovered lithium ion adsorbent may be transferred to a separate process, and deintercalation of lithium ions from the lithium ion adsorbent may be performed to regenerate the compound represented by Chemical Formula 1.

Although the lithium ion adsorbent according to the present invention exhibits excellent adsorption selectivity for lithium ions, it can be obtained through recycling of the remaining minerals generated after extracting lithium from the raw minerals, thereby providing an economical advantage.

1 is a scanning electron microscopy (SEM) image [(a) 500 times magnification of a compound particle according to Preparation Example 1; (b) 2000 times magnification].
2 is an SEM image of the compound particles according to Preparation Example 2 ((a) 2000 times magnification; (b) 5000 times magnification] image.
3 is (a) X-ray diffraction (XRD) pattern for the compound particles according to Preparation Example 1.
4 is a graph showing a change in concentration of lithium ions in the lithium ion adsorption test according to Test Example 6.

Hereinafter, preferred embodiments will be presented to aid in understanding the present invention. However, the following examples are only for illustrating the present invention, and the present invention is not limited thereto.

Production Example  One

(1) calcining α-spodumene concentrate at a temperature of 1000 to 1200 ° C. to obtain β-spodumene; (2) mixing the product of step (1) with sulfuric acid to extract lithium sulfate at a temperature of 100 to 250 ℃; (3) heating by adding calcium hydroxide (Ca (OH) ₂ ) to the product of step (2); (4) separating the precipitate precipitated from the product of step (3); And (5) drying the precipitate of step (4).

1.0 kg of the compound particles having a composition of Table 1 (D ₅₀ = 50.0 μm) was prepared by the above method.

Production Example  2

50 g of the compound particles (D ₅₀ = 50 μm) according to Preparation Example 1 were ball milled for 3 hours with ZrO ₂ balls (particle diameter of 5 mm) to obtain compound particles having a D ₅₀ = 3.6 μm.

Test Example  One

ICP-OES Spectrometers (Optima 7300DV) was used to confirm the chemical composition of the compound particles according to the preparation examples. The XRF was utilized to Rh target, and was measured by mounting the particle powder in a holder of 30mm diameter.

weight% Preparation Example 1 Preparation Example 2 Al 10.97 10.97 Si 27.47 27.47 Ca 2.94 2.94 Fe 0.06 0.06 K 0.39 0.39 Li 0.39 0.39 Mg 0.01 0.01 Mn 0.11 0.11 Na 0.13 0.13 Ti <0.01 <0.01 H 1.00 1.00 O 56.52 56.52

Test Example  2

A specific surface area analyzer (BEL Japan Inc., BELSORP-max) was used to measure nitrogen adsorption / desorption Brunner-Emit-Teller specific surface area (S _BET ) for compound particles according to the above preparations. In the measurement of the above characteristics, the target particles were pretreated by heating at 250 ° C. for 4 hours, and the temperature of the air oven mounted to the analyzer was maintained at 40 ° C.

Preparation Example 1 Preparation Example 2 S _BET (m ² / g) 5.24 7.32

Test Example  3

50% volume cumulative particle diameter (D ₅₀ ) of the compound particles according to the above production examples was measured using a particle size analyzer (PSA, LA-960, Horiba co.).

Preparation Example 1 Preparation Example 2 D ₅₀ (㎛) 50.0 3.6

Test Example  4

Scanning electron microscopy (SEM) images of the compound particles according to Preparation Examples 1 and 2 were taken.

1 is a scanning electron microscopy (SEM) image [(a) 500 times magnification of a compound particle according to Preparation Example 1; (b) 2000 times magnification].

2 is an SEM image of the compound particles according to Preparation Example 2 ((a) 2000 times magnification; (b) 5000 times magnification] image.

Test Example  5

Using an X-ray diffractometer (Bruker AXS D4-Endeavor XRD), an X-ray diffraction analysis was performed on the compound particles according to Preparation Examples 1 and 3 under an applied voltage of 40 kV and an applied current of 40 mA. .

The measured 2θ ranged from 10 ° to 90 ° and was scanned at 0.05 ° intervals. In this case, a slit was used as a variable divergence slit 6 mm, and a large PMMA holder (diameter = 20 mm) was used to eliminate background noise caused by the PMMA holder.

3 is (a) X-ray diffraction (XRD) pattern for the compound particles according to Preparation Example 1.

As a result of the XRD analysis, it was confirmed that the compound particles according to Preparation Example 1 had a tetragonal crystal system.

Test Example  6

An aqueous solution containing 100 ppm of lithium ions was prepared. 500 ml of the aqueous solution was added to a 1 L reactor, and ammonium hydroxide (NH ₄ OH) was added to adjust the pH to pH 9.5. 5.0 g of compound particles according to Preparation Example 1 or 2 was added to the reactor. This was stirred for 28 days in total using a stirrer under 25 ° C.

In the course of performing the stirring, the compound particles were recovered at 3 days (72 hours), 7 days (168 hours), 14 days (336 hours), and 28 days (672 hours) after the start point. The lithium ion concentration adsorbed on the compound particles was measured. The results are shown in Table 4 below and FIG. 4.

The lithium ion concentration adsorbed on the compound particles was measured using ICP-OES Spectrometers (Optima 7300DV).

Li ion (ppm) Preparation Example 1 Preparation Example 2 initial 200 - 3 days 1760 2210 7 days 2630 3430 14 days 3020 3960 28 days 3100 4550

Referring to Table 4 and FIG. 4, when the compound particles having a small average particle diameter and a large specific surface area were used through the ball mill grinding, the adsorption amount of lithium ions was increased rapidly and the total adsorption amount of lithium ions was also large.

Test Example  7

An aqueous solution containing 100 ppm of lithium (Li), 100 ppm of magnesium (Mg), and 100 ppm of sodium (Na) ions was prepared. 500 ml of the aqueous solution was added to a 1 L reactor, and ammonium hydroxide (NH ₄ OH) was added to adjust the pH to pH 9.5. 5.0 g of the compound particles of Preparation Example 1 was added to the reactor. It was stirred for 3 days (72 hours) using a stirrer under 25 ° C.

After the stirring, the compound particles were recovered, and the lithium, magnesium and sodium ions concentrations adsorbed on the compound particles were measured, and the results are shown in Table 5 below. The ion concentration was measured using ICP-OES Spectrometers (Optima 7300DV).

Ion concentration (ppm) initial 3 days later Lithium (Li) 230 1620 Magnesium (Mg) 90 190 Sodium (Na) 1080 1290

Referring to Table 5, the compound particles of Preparation Example 1 was excellent in the adsorption efficiency for lithium ions compared to the magnesium ions and sodium ions contained in the aqueous solution. That is, the compound particles were confirmed to have excellent selective adsorption effect on lithium ions.

Claims (7)

Lithium ion adsorbent containing a compound represented by the following formula (1):
[Formula 1]
H _x Li _(1-x) Al _y Si _z O _a N _b
In Chemical Formula 1,
N is at least one element selected from the group consisting of Na, K, Mg, Ca, S, Mn, Ti, and Fe,
0 <x ≦ 1.0, 0 <y ≦ 2.0, 0 <z ≦ 4.0, 0 <a ≦ 9.0, and 0 <b ≦ 1.0.
The method of claim 1,
Compound represented by the formula (1) is 5 to 20% by weight of aluminum (Al), 20 to 40% by weight of silicon (Si), 40 to 60% by weight of oxygen (O), 0.5 to 2% by weight of hydrogen (H ), 0 to 1 weight percent sodium (Na), 0 to 1 weight percent potassium (K), 0 to 1 weight percent magnesium (Mg), 0 to 5 weight percent calcium (Ca), 0 to 1 weight Lithium ion adsorbent having a chemical composition comprising% iron (Fe), 0-1 wt% manganese (Mn), 0-0.5 wt% titanium (Ti), and 0-1 wt% lithium (Li) .
The method of claim 1,
The compound represented by the formula (1) has a tetragonal crystal system, lithium ion adsorbent.
The method of claim 1,
Compound represented by the formula (1) is a particle having a 50% volume cumulative particle diameter (D ₅₀ ) of 0.01 ㎛ to 50 ㎛, lithium ion adsorbent.
The method of claim 1,
Compound represented by the formula (1) is a particle having a Brunner-Emmett-Teller specific surface area (S _BET ) of 3 m ² / g to 50 m ² / g by nitrogen adsorption / desorption analysis, lithium ion adsorbent.
Adding the lithium ion adsorbent according to claim 1 to an aqueous solution containing lithium ions at a temperature of 20 to 30 ° C. and a hydrogen ion concentration of pH 7.0 to pH 12.0,
Stirring the aqueous solution to which the lithium ion adsorbent is added,
Adsorbing lithium ions in the aqueous solution to the lithium ion adsorbent by an ion exchange reaction, and
Recovering the lithium ion adsorbent having the lithium ions adsorbed from the aqueous solution
Method for recovering lithium ions comprising a.
The method of claim 6,
The aqueous solution containing lithium ions is seawater (brine), brine (brine), a method of recovering lithium ions.

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