KR101803380B1 - Manufacturing method of lithium carbonate from lithium salt - Google Patents

Abstract

An embodiment of the present invention provides a manufacturing method of lithium carbonate from lithium salt, which comprises: a step of adjusting a pH value by adding distilled water and a basic solution to lithium salt (step 1); and a step of adding a carbonate to the pH-adjusted solution to produce solid lithium carbonate (step 2).

Description

TECHNICAL FIELD [0001] The present invention relates to a method for producing a solid lithium carbonate from a lithium salt,

The present invention relates to a process for preparing lithium carbonate in solid phase from a lithium salt, and more particularly, to a process for preparing solid carbonate lithium by controlling pH through a basic solution and adding a carbonate.

Lithium reserves in the world are about 13 million tons, and are concentrated in some parts of South America, so that countries around the world are competing for intense lithium competition. The price of lithium carbonate, which is the main raw material of lithium, has been proven to be economical and scarce enough to trade at about $ 6,000 per tonne.

Currently, Korea relies on import of lithium carbonate, which is the core raw material of rechargeable batteries, and development of lithium related technology is concentrated on recycling due to lack of domestic resources. With the explosion of demand for lithium carbonate, the price of lithium carbonate is expected to surge, so the development of lithium carbonate manufacturing technology is more urgent.

In this connection, Korean Patent Laid-Open No. 10-2012-0070841 discloses a method for producing high purity lithium carbonate using an electrolysis and chemical refining process, but since the prior art requires electrolysis or chemical refining, The manufacturing process of lithium is complicated and the manufacturing cost is high.

Therefore, it is necessary to develop a production method capable of efficiently producing lithium carbonate by efficiently carbonating a lithium salt or the like that can be recovered from a lithium-containing solution.

Korean Patent Publication No. 10-2012-0070841

Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and it is an object of the present invention to provide a method for efficiently producing lithium carbonate that exhibits a high lithium recovery rate by efficiently carbonating a lithium salt or the like.

According to an aspect of the present invention, there is provided a method for preparing a lithium salt, comprising the steps of: (1) adjusting the pH by adding distilled water and a basic solution to a lithium salt; And adding a carbonate to the pH-adjusted solution to produce a solid lithium carbonate (step 2).

In one embodiment, the amount of distilled water added in step 1 may be 2 to 20 times the weight of the lithium salt.

In one embodiment, the basic solution of step 1 is sodium hydroxide (NaOH), potassium hydroxide (KOH), magnesium hydroxide (Mg (OH) _2), calcium hydroxide (Ca (OH) _2), barium hydroxide (Ba (OH ) ₂ ), and a carbonate.

In one embodiment, the pH adjustment in step 1 may be performed by adding the basic solution so that the pH is 9 to 11. [

In one embodiment, the pH adjustment of step 1 may be performed at a temperature of 60 ° C to 90 ° C for 30 minutes to 90 minutes.

In one embodiment, step 1 may be followed by filtration after the pH adjustment.

In one embodiment, the carbonate of the second step is sodium carbonate (Na ₂ CO _3), sodium bicarbonate (NaHCO _3), potassium carbonate (K ₂ CO _3), potassium bicarbonate (KHCO _3), calcium carbonate (CaCO _3), may be at least one member selected from the group consisting of magnesium carbonate (MgCO _3), barium carbonate (BaCO ₃₎ and dolomite _{(CaMg (CO 3) 2)} .

In one embodiment, the step 2 may be followed by filtration after the addition of the carbonate, and the resulting residue may be washed to recover lithium carbonate.

In order to achieve the above object, another aspect of the present invention is a method for preparing a lithium secondary battery, comprising: adding distilled water and a basic solution to solid lithium sulfate to adjust pH and filtering (step i); And a step (ii) of adding solid sodium carbonate to the filtered solution, followed by filtration and washing to produce solid lithium carbonate (step ii).

In order to achieve the above object, another aspect of the present invention is to provide a lithium secondary battery comprising a solid phase lithium carbonate which is prepared by the above method and contains 65 wt% to 85 wt% of lithium relative to the lithium content of the lithium salt as a starting material to provide.

According to an aspect of the present invention, lithium carbonate containing 65 wt% to 85 wt% of lithium relative to the lithium content of the lithium salt as the starting material can be prepared.

It should be understood that the effects of the present invention are not limited to the above effects and include all effects that can be deduced from the detailed description of the present invention or the configuration of the invention described in the claims.

1 is a schematic view showing an example of a method for producing solid lithium carbonate from a lithium salt according to an embodiment of the present invention.
FIG. 2 is a schematic view showing an example of a method for producing solid lithium carbonate from solid lithium sulfate according to an embodiment of the present invention.
3 is a schematic diagram showing another example of a method for producing solid lithium carbonate from solid lithium sulfate according to an embodiment of the present invention.
4 is a graph showing the results of XRD analysis of lithium carbonate prepared in Example 1 of the present invention.
5 is a schematic view showing an example of a production process of a lithium sulfate solid phase of Production Example 1 of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving it will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings.

It should be understood, however, that the present invention is not limited to the disclosed embodiments, but may be embodied in many different forms and should not be construed as limited to the exemplary embodiments set forth herein. To fully inform the inventor of the category of invention. Further, the present invention is only defined by the scope of the claims.

Further, in the following description of the present invention, if it is determined that related arts or the like may obscure the gist of the present invention, detailed description thereof will be omitted.

According to an aspect of the present invention,

Adjusting the pH by adding distilled water and a basic solution to the lithium salt (step 1) (S10); And

And a step (S20) of adding a carbonate to the pH-adjusted solution to produce solid lithium carbonate (step 2).

Hereinafter, a method for producing a solid lithium carbonate from a lithium salt according to one aspect of the present invention will be described in detail for each step.

In the method for producing lithium carbonate in a solid state from a lithium salt according to an aspect of the present invention, the step 1 (S10) adjusts the pH by adding distilled water and a basic solution to the lithium salt. At this time, the main purpose of the pH adjustment is to remove the impurity component remaining in the lithium salt, specifically phosphorus component, and the phosphorus of the lithium salt solution can be precipitated as lithium phosphate through pH control.

The amount of the distilled water added in step 1 may be 2 to 20 times the weight of the lithium salt, and preferably 2 to 10 times the weight of the lithium salt. If the added amount of the distilled water is less than 2 times the weight of the lithium salt, it may not be completely dissolved due to the solubility of the lithium salt. If the added amount of the distilled water is more than 20 times the weight of the lithium salt, And wastewater increase may occur.

A basic solution of step 1 with sodium hydroxide (NaOH), potassium hydroxide (KOH), magnesium hydroxide (Mg (OH) _2), calcium hydroxide (Ca (OH) _2), barium hydroxide (Ba (OH) ₂₎ and carbonate And may include at least one selected from the group consisting of sodium hydroxide, and preferably sodium hydroxide.

The concentration of the basic solution in step 1 may be 10 wt% to 30 wt%, but is not limited thereto.

The pH of the step 1 may be adjusted to a pH of 9 to 11 by adding the basic solution. If the pH is less than 9, there may arise a problem that the impurity component in the lithium salt solution, specifically, phosphorus can not be completely removed. If the pH is more than 11, an increase in cost due to the use of unnecessary basic solution, May lead to loss problems. Of course, the precipitated lithium phosphate can be used, but the unnecessary increase in the process cost is obvious.

The pH adjustment of step 1 may be carried out at a temperature of 60 ° C to 90 ° C for 30 minutes to 90 minutes, preferably at a temperature of 70 ° C to 90 ° C for 45 minutes to 75 minutes.

The step 1 may perform filtration after the pH adjustment, and the residue resulting from the filtration may be recycled. That is, the residue resulting from the filtration may be lithium phosphate, the lithium salt may remain as a residue, and the filtrate may be used in a subsequent process.

In step 2 (S20), carbonate is added to the pH-adjusted solution to prepare lithium carbonate in solid phase in the process for producing lithium carbonate in a solid phase from a lithium salt according to one aspect of the present invention.

Carbonate of the second step is sodium carbonate (Na ₂ CO _3), sodium bicarbonate (NaHCO _3), potassium carbonate (K ₂ CO _3), potassium bicarbonate (KHCO _3), calcium carbonate (CaCO _3), magnesium carbonate (MgCO ₃₎ , it may be a barium carbonate (BaCO ₃₎ and dolomite (CaMg (CO _{3) 2)} be at least one member selected from the group consisting of and, preferably, sodium carbonate.

The carbonate solution of step 2 may be added in a concentration of 5 wt% to 50 wt%, but is not limited thereto.

After the addition of the carbonate in Step 2, the reaction can be carried out at a temperature of 80 ° C to 90 ° C for 1 hour to 2 hours.

In step 2, the filtration may be performed after adding the carbonate, and the filtrate generated in the filtration may contain a small amount of lithium, so that it can be recycled.

The step 2 can perform washing of the lithium carbonate solid phase after the filtration, and the washing liquid generated by the washing may also contain a small amount of lithium and can be recycled.

According to another aspect of the present invention,

Adding distilled water and a basic solution to the solid lithium sulfate to adjust the pH and filtering (step i) (S1); And

(Ii) a step (S2) of adding sodium carbonate to the filtered solution, followed by filtration and washing to produce a solid lithium carbonate; and (S2) a solid phase lithium carbonate.

In the method for producing solid lithium carbonate from solid lithium sulfate according to one aspect of the present invention, the amount of distilled water added in step i may be the same as the amount of distilled water added in step 1 above.

The concentration of the basic solution in step i may be the same as the concentration of the basic solution in step 1 above.

The pH adjustment in step i may be the same as the pH adjustment in step 1 above.

The temperature and the holding time during the pH adjustment of the step i may be the same as the temperature and the holding time of the step 1 above.

The residue resulting from the filtration in step i may be lithium phosphate and the lithium sulfate solid phase in step i, and the filtrate may be used in subsequent processes.

In the method for producing solid lithium carbonate from solid lithium sulfate according to an aspect of the present invention, the sodium carbonate addition in the step ii may be performed by adding a sodium carbonate solution at a concentration of 5 wt% to 50 wt% .

After the addition of the sodium carbonate of the step ii, the reaction can be carried out at a temperature of 80 ° C to 90 ° C for 1 hour to 2 hours.

The filtrate generated in the filtration in step ii may contain a small amount of lithium, so that it can be recycled.

The step ii may perform washing of the lithium carbonate solid phase after the filtration, and the washing liquid generated by the washing may also contain a small amount of lithium and can be recycled.

Lithium carbonate prepared through the above method (Step 1 to Step 2, Step i to Step ii) can produce a lithium carbonate solid containing 65 wt% to 85 wt% of lithium relative to the lithium content of the lithium salt as the starting material have.

In addition, according to one aspect of the present invention, the residue resulting from the filtration of step 1 or i, the filtrate generated in the filtration of step 2 or ii, and the washing liquid generated in washing can be recycled and used, The lithium salt of the lithium salt can be utilized to the maximum extent.

Hereinafter, the present invention will be described in more detail with reference to Production Examples, Examples and Experimental Examples. However, the following Production Examples, Examples and Experimental Examples are intended to illustrate the present invention, but the scope of the present invention is not limited thereto.

< Manufacturing example  1> Lithium sulfate  Solid manufacture

And 63 kg of lithium waste solution (lithium concentration: 3 g / L) of a spent lithium secondary battery. Then, phosphoric acid was added to the waste solution in an amount of 1 molar equivalent relative to lithium. Then, sodium hydroxide (25% concentration) was added to the phosphoric acid-added waste solution to adjust the pH to 11. Then, the pH-adjusted waste solution was heated to a temperature of 80 ° C, reacted for 1 hour and then filtered to collect 1 kg of solid lithium phosphate, which was washed with distilled water.

Next, distilled water 3.5 times (3.5 kg) of distilled water and 1.25 times (1.25 kg) weight of sulfuric acid (95%) were added to the solid lithium phosphate and filtered to prepare 5.75 kg of lithium sulfate solution. Then, the lithium sulfate solution was concentrated by primary evaporation and filtered to separate primary solid lithium sulfate (1.18 kg) and primary filtrate (2.2 kg), and the primary filtrate was subjected to secondary evaporation and filtration to obtain secondary The lithium sulfate solid phase (0.32 kg) and the final filtrate (0.60 kg) were separated and the final filtrate was applied to the phosphoric acid addition process. Then, 20 wt% of distilled water (0.30 kg) was added to the separated lithium sulfate solid phase (1.18 + 0.32 = 1.5 kg), and the washes (0.38 kg) Finally, 1.42 kg of solid lithium sulfate was prepared.

< Example  1> Lithium carbonate  Manufacturing 1

Step 1: To a lithium sulfate solid (1.42 kg) prepared in Preparation Example 1, 2.5 times by weight of distilled water and 25 wt% sodium hydroxide solution were added to adjust the pH to 10 and maintained at 80 DEG C for 1 hour And filtered. The residue (0.01 kg of lithium phosphate, produced) during filtration was recycled, and the filtrate (5 kg) was used as a subsequent process.

Step 2: A sodium carbonate solution (7.13 kg) having a concentration of 15 wt% was added to the filtrate (5 kg), which was then reacted at 80 ° C to 90 ° C for 1 hour to form lithium carbonate, followed by filtration. The filtrate (11.29 kg) produced during the filtration was recycled. The lithium carbonate solid, which was a residue during filtration, was washed by adding distilled water, and then the washing liquid was recycled. Finally, a lithium carbonate solid (0.78 kg) was obtained.

< Example  2> Lithium carbonate  Manufacturing 2

Step 1: The lithium hydroxide solid phase (23.52 kg) was adjusted to a pH of 10 by adding 2.5 times by weight of distilled water and a sodium hydroxide solution of 25 wt%, maintained at 80 DEG C for 1 hour, and then filtered. The filtrate (lithium phosphate, 0.13 kg) was recycled and the filtrate (82.32 kg) was used as a subsequent process.

Step 2: A sodium carbonate solution (117.39 kg) having a concentration of 15 wt% was added to the filtered solution (82.32 kg), and the mixture was reacted at a temperature of 80 ° C to 90 ° C for 1 hour to form lithium carbonate, followed by filtration. The filtrate (176.39 kg) produced during the filtration was recycled. The lithium carbonate solid, which was a residue during filtration, was washed by adding distilled water, then the washing liquid was recycled and finally lithium carbonate solid phase (12.21 kg) was obtained.

< Experimental Example  1> Of lithium carbonate  Measurement of lithium recovery

As a result of the measurement of the lithium recovery rate of lithium carbonate prepared in Examples 1 and 2, it was confirmed that the lithium carbonate produced exhibited lithium recovery rates of 95% and 90%, respectively, relative to the lithium content of the initial lithium sulfate.

The filtrate produced in the filtration of the step 2 and the wash liquid generated in the washing of the step 2 are the same as those of the filtrate of the step It can be used as the lithium-containing waste solution of Production Example 1, confirming that lithium can be utilized to the maximum extent.

< Experimental Example  2> Of lithium carbonate XRD  Measure

The X-ray diffraction analysis of the lithium carbonate prepared in Example 1 was performed, and the results are shown in FIG.

As shown in Fig. 4, it was confirmed that the finally produced lithium carbonate was easily formed.

Although a specific embodiment of a method for producing solid lithium carbonate from a lithium salt according to an aspect of the present invention has been described above, it is apparent that various modifications can be made without departing from the scope of the present invention.

Therefore, the scope of the present invention should not be construed as limited to the embodiments described, but should be determined by the scope of the appended claims, as well as the claims.

It is to be understood that the foregoing embodiments are illustrative and not restrictive in all respects and that the scope of the present invention is indicated by the appended claims rather than the foregoing description, It is intended that all changes and modifications derived from the equivalent concept be included within the scope of the present invention.

Claims (10)

Washing the solid lithium sulfate prepared through the sulfuric acid substitution of lithium phosphate, adjusting the pH by adding distilled water and a basic solution, and performing filtration (step 1); And
Adding a carbonate to the filtered filtrate and filtering to prepare solid carbonate lithium (step 2)
The sulfuric acid substitution is accomplished by adding distilled water and sulfuric acid to the lithium phosphate to prepare a lithium sulfate solution. The lithium sulfate solution is evaporated and filtered to separate the solid lithium sulfate and the filtrate. The filtrate is then concentrated by evaporation and filtration Lt; / RTI &gt;
The washing solution used in washing in step 1 is used for preparing the lithium sulfate solution,
The amount of the distilled water added in step 1 is 2 to 20 times the weight of the lithium sulfate,
The filtration of step 1 above separates lithium phosphate and solid lithium sulfate,
Wherein the lithium phosphate separated from the filtration of step 1 is recycled to the sulfuric acid substitution.
delete The method according to claim 1,
The basic solution of step 1,
Sodium hydroxide (NaOH), potassium hydroxide (KOH), magnesium hydroxide (Mg (OH) _2), calcium hydroxide (Ca (OH) _2), barium hydroxide (Ba (OH) ₂₎ and at least one member selected from the group consisting of carbonate &Lt; / RTI &gt; wherein the solid phase comprises lithium sulphate.
The method according to claim 1,
The pH adjustment of step 1 is carried out,
and the basic solution is added such that the pH is in the range of 9 to 11.
The method according to claim 1,
The pH adjustment of step 1 is carried out,
Wherein the reaction is carried out at a temperature of 60 DEG C to 90 DEG C for 30 minutes to 90 minutes.
delete The method according to claim 1,
The carbonate of step 2 may be,
Sodium carbonate (Na ₂ CO _3), sodium bicarbonate (NaHCO _3), potassium carbonate (K ₂ CO _3), potassium bicarbonate (KHCO _3), calcium carbonate (CaCO _3), magnesium carbonate (MgCO _3), barium carbonate (BaCO ₃ ) And dolomite (CaMg (CO ₃ ) ₂ ). 2. A process for producing a solid lithium carbonate from solid lithium sulphate according to claim 1,
delete delete delete

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