KR102004687B1 - A module for lithium ion recycling of seawater and method for recycling lithium ion thereof - Google Patents

Abstract

The present invention relates to a lithium ion recovery module (100) and a lithium ion recovery method using the same. The lithium ion recovery module 100 includes an anode current collector 10, a first electrode 12, a first porous sheet 14, a flow path plate 30 through which seawater flows and a concentrate of lithium ions flows, A second electrode 22 and a cathode current collector 20 are stacked in this order, and the first porous sheet 14 is formed with a hole 18 having a diameter of 0.01 to 1 탆 .

Description

Field of the Invention [0001] The present invention relates to a lithium ion recovery module in seawater, and a lithium ion recovery method using the same. BACKGROUND OF THE INVENTION 1. Field of the Invention [0001]

The present invention relates to a lithium ion recovery module in seawater and a lithium ion recovery method using the same. More specifically, in a module including a positive electrode collector, a porous sheet, an electrode, a flow path plate, and a negative electrode collector, a voltage is applied between the positive electrode collector and the negative electrode collector to convert cationic lithium ions contained in the seawater into porous A lithium ion recovery module in seawater capable of effectively concentrating and recovering lithium ions present in seawater by adsorption and concentration on an electrode charged through a sheet and charged to a cathode, and a lithium ion recovery method using the same will be.

Lithium has a high energy storage density and light weight and is used as a raw material for various IT related products and electronic devices, battery raw materials for hybrid electric vehicles, light alloy raw materials for aircraft, proliferation materials of tritium, And its importance is continuously increasing, and the world is investing heavily in order to secure lithium. However, currently commercially available lithium is estimated to be 4.1 million tons, which will be depleted in the next 78 years.

Meanwhile, about 230 billion tons of lithium in the seawater is known to be dissolved, giving hope. However, since the concentration of lithium dissolved in seawater is extremely low at about 1.3 ppm (mg / L), there are problems such as an efficient recovery method, a large-capacity water intake facility, and a cost thereof. Therefore, And the technology that can be recalled is getting more attention.

Techniques for extracting useful resources dissolved in existing seawater are generally coprecipitation, adsorption, and solvent extraction methods.

The coprecipitation method is a method in which a precipitant or a coagulant is added to precipitate and collect the metal simultaneously in the seawater. Examples of uranium recovery include ferric chloride, ammonium sulfate, ammonium phosphate, etc., and precipitation of Li (lithium) Zero indicates Al oxide, Ti oxide, and compound. However, the coprecipitation method is difficult to recycle the co-precipitant and the product and repeated use of the co-precipitant, and there is a problem of pretreatment such as the addition of a reagent for adjusting the pH. It is also not suitable for the recovery of a large amount of trace metals because it usually takes a long time to coagulate or precipitate.

The adsorption method is a method in which a solid adsorbent is contacted with seawater to selectively adsorb and extract dissolved metal ions. This method is widely used for collecting useful metals in seawater. However, a method of adsorbing trace metals only depending on the selectivity of adsorbents, The adsorption efficiency is lowered when it is applied to the recovery of the trace metals, and there is a disadvantage that the adsorption takes more than one week and more than one month.

The solvent extraction method is a method in which an organic solvent having no solubility in an aqueous solution is contacted with seawater, and a desired metal is selectively extracted with a solvent and recovered. Since the recovery rate is relatively higher than other methods, But it is not used much in the recovery of useful metals in seawater where large amounts of seawater have to be handled. This is because a part of the expensive organic solvent is dissolved or mixed in seawater and flows out into seawater, which is very disadvantageous in terms of economy and environmental pollution.

An object of the present invention is to provide a lithium ion recovery module for selectively adsorbing and concentrating lithium ions in seawater.

Another object of the present invention is to provide a lithium ion recovery module capable of efficiently and economically recovering lithium ions in seawater.

It is still another object of the present invention to provide a method for recovering lithium ions using the lithium ion recovery module.

One aspect of the present invention relates to a lithium ion recovery module. The lithium ion recovery module includes a negative electrode current collector, a first electrode, a first porous sheet, a cell in which seawater is flowed, a flow path plate for carrying a concentrated solution of lithium ions, a second electrode, And the first porous sheet is characterized in that pores having a diameter of 0.01 to 1 mu m are formed.

And a voltage of 3 V or less is applied between the anode current collector and the cathode current collector.

The channel forming plate is in the form of a plate having a net structure and is 2 mm or less in thickness.

And an anion exchange membrane between the flow path plate and the second electrode.

And a second porous sheet between the flow path plate and the second electrode, wherein the second porous sheet has pores having a diameter of 0.01 to 1 mu m.

The thickness of the first porous sheet and the second porous sheet is 5 to 100 탆, and a plurality of holes having a diameter of 0.01 to 1 탆 are punched.

The first porous sheet and the second porous sheet may be formed of a polyolefin-based polymer, cellulose acetate or polysulfone; metal; And at least one selected from ceramics.

The lithium ion recovery module may be connected in series or in parallel, or may be connected in series and parallel.

The first electrode and the second electrode may include at least one selected from the group consisting of carbon aerogels, carbon nanotubes, activated carbon fiber cloth, activated carbon fiber nonwoven fabric, and activated carbon powder compact.

Wherein the lithium ion recovery module is mounted on a line of concentrated water of a reverse osmosis membrane device or an electrodialysis device.

Another aspect of the present invention relates to a lithium ion recovery method using the lithium ion recovery module. The lithium ion recovery method comprises the steps of: (a) charging lithium-containing raw water into the lithium ion recovery module; (b) applying a voltage of 3 V or less between the anode current collector and the cathode current collector of the lithium ion recovery module to adsorb lithium ions to the first electrode of the module; And (c) recovering lithium ions adsorbed on the first electrode through a flow path plate.

Wherein the lithium ion recovery module is mounted on a line of concentrated water of a reverse osmosis membrane device or an electrodialysis device.

When the lithium ion recovery module according to the present invention is used, the adsorption time of lithium ions is shortened and lithium ions can be recovered with high efficiency, compared with existing modules which depend only on the concentration difference and selectivity of the adsorbent. In addition, the lithium ion recovery module of the present invention can be installed in concentrated water of a conventional seawater desalination apparatus such as a reverse osmosis membrane apparatus, and it is possible to recover lithium ions in seawater without a separate pump and influent piping construction, It is economical to save.

Figure 1 shows a lithium ion recovery module according to one embodiment of the present invention.
2 shows a lithium ion recovery module according to another embodiment of the present invention.
Figure 3 shows a lithium ion recovery module according to another embodiment of the present invention.
4 shows a first porous sheet of a lithium ion recovery module according to the present invention.
FIG. 5 shows a lithium ion recovery module according to the present invention mounted on a concentrated water line of a reverse osmosis membrane device.

One aspect of the present invention relates to a lithium ion recovery module. Hereinafter, a lithium ion recovery module according to the present invention will be described in detail.

Lithium ion  Recovery module

Figure 1 illustrates a lithium ion recovery module 100 in accordance with one embodiment of the present invention. 1, the lithium ion recovery module 100 includes an anode current collector 10, a first electrode 12, a first porous sheet 14, a first porous sheet 14, 1 and 4, the first porous sheet 14 includes at least one cell in which a forming plate 30, a second electrode 22, and a positive electrode collector 20 are stacked in order, A hole 18 having a diameter of 0.01 to 1 mu m may be formed.

The anode current collector 10 may have a plate-like shape that is easy to contact with the first electrode 12 and may have a protrusion 10a to which a voltage is applied. The negative electrode current collector 10 uses an excellent electric conductivity so that an electric field can be uniformly distributed on the surface of the first electrode 12 when a voltage is applied, and may be a commonly used one. For example, aluminum, nickel, copper, titanium, iron, stainless steel, graphite and the like can be used, but are not limited thereto. The thickness of the anode current collector 10 may be 100 to 2000 mu m. Preferably 300 to 1500 mu m. The lamination or the shape deformation at the thickness can be facilitated, and the required area of the lithium ion recovery module 100 can be reduced, so that the object of the present invention can be easily achieved.

The first electrode 12 may be placed in contact with the negative electrode collector 10 and may be formed by molding an activated carbon powder having a specific surface area of 100 m 2 / A carbon nanotube, an activated carbon fiber cloth, an activated carbon fiber nonwoven fabric, or an activated carbon powder compact. When the material is used, it has a high specific surface area and a low electric resistance, and has numerous pores in itself, so that it has excellent adsorption performance and adsorbs an ion component contained in seawater to easily achieve the object of the present invention .

In addition, the first electrode 12 can be manufactured to be processed in a predetermined form using a polymeric binder commonly used with the materials described above. For example, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), carboxymethylcellulose (CMC), polyvinyl alcohol (PVA), and polyvinyl chloride (PVC) no. These may be used alone or in combination of two or more.

The first electrode 12 is manufactured by a conventional method. For example, 1 to 15 parts by weight of polytetrafluoroethylene (PTFE) is mixed with 100 parts by weight of the carbon aerogels to prepare a slurry Rolled using a roller, or directly applied on the negative electrode current collector 10, but the present invention is not limited thereto.

The thickness of the first electrode 12 may be in the range of 50 to 3000 탆, preferably 100 to 900 탆. When the lithium ion secondary battery 100 has the above-described thickness and structure, it can be easily deformed into a plate-like shape, a tubular shape, a roll shape or the like, thereby reducing the required area of the lithium ion recovery module 100 and facilitating fluid contact. The object of the present invention can be easily achieved.

4 shows a first porous sheet 14 of a lithium ion recovery module according to the present invention. Referring to FIG. 4, the first porous sheet 14 may have a plurality of holes 18 having a diameter of 0.01 to 1 μm. Preferably 0.1 to 1 mu m. The lithium ions in the seawater flowing through the flow path plate 30 pass through the holes 18 of the first porous sheet 14 when a voltage is applied to the lithium ion recovery module 100, (Not shown). When the diameter of the hole 18 is less than 0.01 탆, the lithium ion is difficult to pass through. When the diameter of the hole 18 is more than 1 탆, substances other than the lithium ion can be adsorbed, Can not be achieved.

The porosity density of the first porous sheet 14 may be 10 ⁴ to 10 ⁵ / cm 2. In the above range, the lithium ions easily pass through the first porous sheet 14 and are adsorbed in the pores formed in the first electrode 12, thereby easily achieving the object of the present invention.

Also, the thickness of the first porous sheet 14 may be 5 to 100 탆. Preferably 15 to 80 mu m. In this range, it is possible to efficiently utilize the space occupied without hindering the adsorption performance of the lithium ion recovery module 100 of the present invention within the above range, and thus the object of the present invention can be easily achieved can do.

The first porous sheet 14 may be manufactured using a conventional process, and may be a polyolefin-based polymer such as polyethylene, polypropylene, cellulose acetate, polysulfone, or a metal or ceramic having holes 18 of the same diameter Can also be substituted. Preferably, it can be made of a polymer which is relatively light in weight. The object of the present invention can be easily achieved when the first porous sheet 14 is formed of the above material.

In the lithium ion recovery module 100, the first porous sheet 14 may be positioned in contact with the first electrode 12. Alternatively, the first porous sheet 14 may be coated on the first electrode 12. The coating method may be conventional and may be, for example, knife coating or dip coating, but is not limited thereto.

The flow path forming plate 30 is positioned between the first porous sheet 14 and the second porous sheet 24 so that seawater flows into the second porous sheet 24 to form a flow path, And can be easily adsorbed on the second electrode 22. As the flow path plate 30, a polymer that can be formed into a fiber form such as polyethylene or polypropylene can be widely used. The channel forming plate 30 may be a plate-like shape having a mesh structure. Further, the thickness of the flow path plate 30 may be 2 mm or less, preferably 1.5 mm or less. When a mesh structure having the above-described thickness is provided, a flow path of the flow path is formed, and a fluid such as a treatment object water can flow.

When the flow path forming plate 30 is formed, since the seawater continuously flows along the first porous sheet 14, the concentration polarization phenomenon between the first electrode 12 and the second electrode 22 is small, The efficiency is improved and the adsorbed lithium ions can be recovered quickly and easily, so that the object of the present invention can be easily achieved.

The second electrode 22 may be manufactured by the same method as the first electrode 12 described above. The thickness of the second electrode 22 may be in the range of 50 to 3000 탆, preferably 100 to 900 탆. When the lithium ion secondary battery has the above-described thickness and structure, it can be easily deformed into a plate-like shape, a tubular shape, a roll shape, or the like, thereby reducing the required area of the lithium ion recovery module 100 and facilitating fluid contact. The object of the present invention can be easily achieved.

The cathode current collector 20 is in the form of a plate which is easy to contact with the second electrode 22 and may have a protrusion 20a for applying a voltage. The positive electrode current collector 20 uses an excellent electric conductivity so that the electric field can be uniformly distributed on the surface of the second electrode 22 when a voltage is applied, and may be one that is commonly used. For example, aluminum, nickel, copper, titanium, iron, stainless steel, graphite and the like can be used, but are not limited thereto. The thickness of the cathode current collector 20 may be 100 to 2000 μm. Preferably 300 to 1500 mu m. The lamination or the shape deformation at the thickness can be facilitated, and the required area of the lithium ion recovery module 100 can be reduced, so that the object of the present invention can be easily achieved.

In the present invention, a voltage of 3 V or less, preferably 1.5 V or less, can be applied between the anode current collector 10 and the cathode current collector 20. When the voltage of 3 V or more is applied to the lithium ion recovery module 100, the lithium ion recovery module 100 generates oxygen And hydrogen bubbles are covered on the surface of the electrode, the adsorption efficiency is remarkably lowered, and the deterioration of the electrode is promoted.

2 shows a lithium ion recovery module 100 according to another embodiment of the present invention. 2, in another embodiment of the present invention, the lithium ion recovery module 100 may include an anion exchange membrane 40 between the flow path plate 30 and the second electrode 22 . The anion exchange membrane 40 may be a conventional one, for example, an esterification reaction with glutaric acid after polymerization of vinylbenzyltrimethylammonium chloride and 2-hydroxyethylmethacrylate in a polyvinyl alcohol aqueous solution, and The anion exchange membrane 40 may be produced through a cross-linking reaction with glutaraldehyde, but is not limited thereto. When an opposite voltage is applied during the recovery of the adsorbed lithium ions, the anion exchange membrane 40 moves lithium ions of cationic nature adsorbed on the pores formed in the first electrode 12 toward the second electrode 22 Adsorption can be prevented, and the object of the present invention can be achieved.

FIG. 3 illustrates a lithium ion recovery module 100 according to another embodiment of the present invention. 3, the lithium ion recovery module 100 includes a second porous sheet 24 between the flow path plate 30 and the second electrode 22, . ≪ / RTI > The second porous sheet 24 may have a plurality of holes 18 having a diameter of 0.01 to 1 탆. Preferably 0.1 to 1 mu m. In the above range, the anionic inorganic ions can be easily adsorbed to the pores of the second electrode 22, thereby achieving the object of the present invention. The thickness of the second porous sheet 24 may be 5 to 100 탆. Preferably 15 to 80 mu m. Also, the void density of the second porous sheet 24 may be 10 ⁴ to 10 ⁵ / cm 2. In this range, it is possible to efficiently utilize the space occupied without hindering the adsorption performance of the lithium ion recovery module 100 of the present invention within the above range, and thus the object of the present invention can be easily achieved can do.

The lithium ion recovery module 100 may further include an anode collector 10, a first electrode 12, a first porous sheet 14, and a flow path plate (not shown) for improving the adsorption capacity and efficient utilization of space. One or more cells including the lithium secondary battery 30, the second electrode 22, and the positive electrode collector 20 may be stacked, and a plurality of lithium ion recovery modules 100 may be configured in series and in parallel, Can be mixed. With the above arrangement, desired adsorption efficiency can be achieved and the object of the present invention can be achieved.

5 shows a lithium ion exchange module 100 according to an embodiment of the present invention mounted on a concentrated water line 15 of a reverse osmosis membrane device. Referring to FIG. 5, the lithium ion recovery module 100 is installed in the concentrated water line 15 of the reverse osmosis membrane device used for seawater desalination, and can be operated without a separate pump. At this time, since the lithium ion is concentrated in the concentrated water of the reverse osmosis membrane device, the effect of further improving the adsorption efficiency can be obtained. Also, the lithium ion recovery module 100 can obtain the same effect by using the concentrated water line of the evaporation method and electrodialysis device used for seawater desalination, and can also introduce seawater by using a conventional pump.

Another aspect of the present invention relates to a method for recovering lithium ions in seawater by the lithium ion recovery module (100).

In the sea Lithium ion  How to recall

The lithium ion recovery method includes: (a) charging lithium-containing raw water into the lithium ion recovery module 100; (b) a voltage of 3 V or less is applied between the negative electrode current collector 10 and the positive electrode current collector 20 of the lithium ion recovery module 100 to adsorb lithium ions to the first electrode 12 of the module step; And (c) recovering lithium ions adsorbed on the first electrode 12 through the flow path plate 30.

As described above, a voltage of 3 V or less may be applied between the positive electrode current collector 10 and the negative electrode current collector 20 of the lithium ion recovery module 100, and preferably a voltage of 1.5 V or less may be applied . When a voltage is applied, lithium ions having a diameter of 0.01 to 1 mu m out of the cationic ions contained in seawater flowing through the flow path plate 30 act on the first porous sheet 14 due to electrostatic attractive force And may be adsorbed on the first electrode 12. An anionic inorganic ion may be adsorbed on the second electrode 22 due to an electrostatic attracting force.

In the present invention, the current of the lithium ion recovery module 100 varies greatly depending on the area of the first electrode 12 and the second electrode 22 to be adsorbed and the adsorption rate of the ion, As the operating time of the lithium ion recovery module 100 increases, the adsorbed lithium ions are saturated in each pore of the first electrode 12, and the current value gradually decreases to 0 A. When the current value is 0 A, it means that the pores of the first electrode 12 are saturated with the adsorbed lithium ions.

At this time, if the applied voltage is cut off, the electrostatic attraction of the negative electrode current collector 10 and the positive electrode current collector 20 disappears, and the lithium ions adsorbed to the first electrode 12 The lithium ion can be recovered through the first porous sheet 14 and the flow path plate 30.

Alternatively, the voltage may be periodically reversed. The voltage reversal period may be reversed at a cycle of 0.1 to 20 hours, preferably 0.1 to 1 hour. At this time, an electrode regeneration cycle for changing the polarities of the cathode current collector 20 and the anode current collector 10 for 1 to 30 minutes Can be performed. If the periodic reversal is performed as described above, the object of the present invention can be easily achieved by further increasing the desorption rate and desorption efficiency of the lithium ion saturated in the first electrode 12.

5 shows that the lithium ion recovery module 100 according to the present invention is mounted on the concentrated water line 52 of the reverse osmosis membrane device 60. FIG. 5, the lithium ion recovery module 100 may be installed in a concentrated water line 52 of a conventional reverse osmosis membrane device 60 used for seawater desalination to recover lithium ions through a discharge pipe 54 have. At this time, it is possible to operate without a separate pump. At this time, since the lithium ion is concentrated in the concentrated water of the reverse osmosis membrane device 60, the effect of further improving the adsorption efficiency can be obtained. Also, the lithium ion recovery module 100 can obtain the same effect by using the concentrated water line of the evaporation method and electrodialysis device used for seawater desalination, and can also introduce seawater by using a conventional pump.

In addition, extraction of lithium ions from a concentrated lithium ion state, for example, a concentration of several tens of ppm or more can be easily achieved by applying a conventional commercialized process.

Hereinafter, the configuration and operation of the present invention will be described in more detail with reference to preferred embodiments of the present invention. However, the following examples are provided to aid understanding of the present invention, and the scope of the present invention is not limited to the following examples. The contents not described here are sufficiently technically inferior to those skilled in the art, and a description thereof will be omitted.

Example  One

The anode current collector 10 having a thickness of 700 mu m and an area of 10 cm2, the first electrode 12 having a thickness of 300 mu m and the holes 18 having a diameter of 0.1 mu m were punched to have a thickness of 50 mu m, A first porous sheet 14 of 10 ⁵ / cm 2, a channel forming plate 30 of 1.5 mm in thickness having a gap of 200 meshes made of polypropylene, an anion exchange membrane 40, And a positive electrode current collector 20 having a thickness of 700 m and an area of 10 cm2 were sequentially stacked in this order to produce a lithium ion adsorption module 100 of the present invention.

Comparative Example  One

700㎛ thickness and was prepared in H _{1 1 .6 .6} Mn ₄ O 4 heupchakpo area 10㎠.

Experimental Example

20 L of a solution in which the concentration of lithium ions was fixed at 30 ppm was filled in each of two vessels, and Example 1 was immersed in the vessel to apply a voltage of 1.2 V between the anode current collector 10 and the cathode current collector 20, The solution in the container was circulated at a flow rate of 1 L / min.

The adsorbent 4 of Comparative Example 1 was prepared by easily arranging contact with the solution in another container. The mixture was stirred at a speed of 100 rpm using a stirrer to maintain a uniform concentration of each of the containers.

The change in the concentration of lithium ions in the solution in each of the containers immersed in Example 1 and Comparative Example 1 was analyzed using ICP-MS. The results are shown in Table 1 below.

Operating time (hr) 0 One 2 3 Example 1 (Li ppm) 30 20 16 14 Comparative Example 1 (Li ppm) 30 30 30 29

As shown in Table 1, the concentration of lithium ions in the solution immersed in Example 1 of the present invention was continuously lowered for 3 hours after the start of operation, indicating that about 50% of lithium ions were adsorbed on the second electrode. On the other hand, in Comparative Example 1, about 3% of lithium ions were adsorbed on the adsorbent. Therefore, when the lithium ion recovery module 100 according to the present invention and the method using the lithium ion recovery module 100 were used, it was found that the adsorption efficiency was about 14 times higher than the conventional adsorption method.

10: anode current collector 10a:
12: first electrode 14: first porous sheet
18: hole 20: anode current collector
20a: protrusion 22: second electrode
24: second porous sheet 30: flow path plate
40: anion exchange membrane 50: raw milk admission
52: concentrated water line 54: discharge pipe
60: reverse osmosis membrane device 100: lithium ion recovery module

Claims (12)

A lithium ion secondary battery comprising at least one cell in which an anode current collector, a first electrode, a first porous sheet, a flow-channel plate into which seawater flows and a concentrate of lithium ions are transported, a second electrode, Receiving module,
A voltage of 3 V or less is applied between the negative electrode collector and the positive electrode collector,
The lithium ion recovery module is mounted on a line of concentrated water of a reverse osmosis membrane device or an electrodialysis device,
Wherein the flow path plate is made of at least one of polyethylene and polypropylene and has a plate-like shape of a mesh structure, a thickness of 1.5 to 2 mm,
The first porous sheet has a thickness of 15 to 80 탆, a hole having a diameter of 0.1 to 1 탆, a pore density of 10 ⁴ to 10 ⁵ / cm ² ,
Wherein when the voltage is applied to the lithium ion recovery module, lithium passes through the hole of the first porous sheet and is adsorbed in pores formed in the first electrode.
delete delete The method according to claim 1,
And an anion exchange membrane between the flow path plate and the second electrode.
The method according to claim 1,
And a second porous sheet between the flow path plate and the second electrode,
Wherein the second porous sheet is formed with a hole having a diameter of 0.01 to 1 mu m.
6. The method of claim 5,
The thickness of the second porous sheet is 5 to 100 탆,
Wherein the first porous sheet and the second porous sheet each have a plurality of holes each having a diameter of 0.01 to 1 mu m.
6. The method of claim 5,
The first porous sheet and the second porous sheet may be formed of a polyolefin-based polymer, cellulose acetate or polysulfone; metal; And ceramics. ≪ RTI ID = 0.0 > 11. < / RTI >
The method according to claim 1,
Wherein the lithium ion recovery module is connected to at least one of the lithium ion recovery modules in series or in parallel, or in series and parallel.
The method according to claim 1,
Wherein the first electrode and the second electrode include at least one selected from the group consisting of carbon aerogels, carbon nanotubes, activated carbon fiber cloth, activated carbon fiber nonwoven fabric, and activated carbon powder compact.
delete (a) introducing lithium-containing raw water into the lithium ion recovery module of any one of claims 1 to 9;
(b) applying a voltage of 3 V or less between the anode current collector and the cathode current collector of the lithium ion recovery module to adsorb lithium ions to the first electrode of the module; And
(c) recovering lithium ions adsorbed on the first electrode through a flow path plate;
The method of claim 1,
Wherein the lithium ion recovery module is mounted on a line of concentrated water of a reverse osmosis membrane device or an electrodialysis device.

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