KR101985962B1 - Mehtod of preparing lithium chloride - Google Patents

Abstract

A process for preparing lithium chloride, comprising the steps of: preparing lithium sulfate and a chlorine compound; Introducing the chloride into water at or above the solubility of the chloride in water; Adding lithium sulfate to the water to which the chloride is added and stirring the mixture; And a step of reacting the chloride with lithium sulfate to obtain lithium chloride.

Description

METHOD OF PREPARING LITHIUM CHLORIDE [0002]

And a process for producing lithium chloride.

Conventionally, lithium chloride is prepared by using lithium carbonate as a raw material and adding hydrochloric acid to dissolve it in a concentrated crystallization system. Lithium carbonate is dissolved in hydrochloric acid, carbonate ion is vaporized in acidic state, and is removed in the form of carbon dioxide in air. Lithium ion and chloride ion remain in solution, and this solution can be dried to obtain lithium chloride powder.

This method has a burden of using an acid, which is disadvantageous in manufacturing time and cost due to the concentration step.

To provide an improved method for producing lithium chloride.

In one embodiment of the present invention, there is provided a method of preparing a lithium battery comprising: preparing lithium sulfate and a chlorine compound; Introducing the chloride into water at or above the solubility of the chloride in water; Adding lithium sulfate to the water to which the chloride is added and stirring the mixture; And a step of reacting the chloride with lithium sulfate to obtain lithium chloride.

The chloride may be barium chloride (BaCl ₂ ), calcium chloride (CaCl ₂ ), potassium chloride (KCl), or a combination thereof. However, various chlorides may be used, but are not limited thereto. As a specific example, the chloride may be barium chloride (BaCl ₂ ).

The step of introducing the chloride into water at a solubility of water or more of the chloride in the water may be such that the chloride is introduced into water in an amount not lower than the solubility of the chloride in water and suspended. A detailed description thereof will be described later.

Adding lithium sulfate to the water to which the chloride is added and stirring the solution; and spray drying the filtrate to obtain a lithium chloride powder.

The step of adding lithium sulfate to the water to which the chloride is added and stirring may be performed for 1 to 2 hours. Reaction time considering the reaction efficiency and economical efficiency, and the present invention is not limited thereto.

The lithium chloride obtained by the reaction of the chloride with lithium sulfate to obtain lithium chloride is in an aqueous solution state and the concentration of lithium chloride can be 40 g / L or more. A description thereof will be given later.

The purity of the lithium chloride powder may be 99% or more.

It is possible to provide an improved method of producing lithium chloride which does not require a separate acid and a concentration step.

Fig. 1 shows the results of measurement of the concentration of cations of Li, S, and Ca in the reaction filtrate of the basic experiment.
FIG. 2 is a flow chart showing an experiment for firstly introducing lithium sulfate monohydrate.
Fig. 3 is a flow chart of a barium chloride dihydrate first injection test procedure.
FIG. 4 is a graph showing the contents of lithium, sulfur, and barium in the filtrate after 1.5 hours of reaction under the condition of firstly adding lithium sulfate.
FIG. 5 is a graph of the lithium, sulfur, and barium contents of the filtrate after 1.5 hours of reaction under barium chloride initial charging conditions.
Figure 6 is a graph of the lithium, sulfur, and barium content of the filtrate after 1.5 hours of reaction at barium chloride first charge conditions.

Hereinafter, embodiments of the present invention will be described in detail. However, it should be understood that the present invention is not limited thereto, and the present invention is only defined by the scope of the following claims.

Hereinafter, a method for producing lithium chloride according to one embodiment of the present invention will be described in detail. Here, barium chloride is used as a specific compound for the chloride.

Specifically, when lithium sulfate is reacted with an aqueous solution of barium chloride, the reaction proceeds between the sulfuric acid of lithium sulfate and the barium chloride of barium chloride to precipitate into an insoluble compound, barium sulfate, and an aqueous solution of lithium chloride can be obtained.

The solubility of barium sulfate in water is 0.00024 g / 100 ml at 20 DEG C, and it is not an exaggeration to say that it does not completely dissolve in water. Barium chloride can be selected as a starting material capable of reacting with lithium sulfate to precipitate barium sulfate. That is, lithium sulfate and barium chloride are reacted in an aqueous solution to precipitate barium sulfate, and an aqueous solution of lithium chloride can be obtained.

The reaction between lithium sulfate and lithium chloride in a liquid phase to obtain a lithium chloride solution and barium sulfate is a common reaction, but two problems must be solved in order to maximize the lithium concentration in the solution.

There is a problem that lithium sulfate can not dissolve in the first water more than the solubility of lithium sulfate.

When barium chloride is reacted with water in a solution of a second lithium sulfate dissolved to the solubility of lithium sulfate, the barium chloride is not ionized and remains unreacted.

The first problem solving is as follows.

The solubility of lithium chloride (solubility: 55 g / 100 g) is higher than that of lithium sulfate (solubility: 35 g / 100 g) and barium chloride (solubility: 36 g / 100 g). The conversion of each reactant and product to moral concentration is as follows.

Lithium chloride was 13 mol / L, Lithium sulfate  2. 45 moles / L, barium chloride 1. 73 moles / L

Comparing the solubility on a lithium basis, lithium chloride dissolves in 1 L of water based on lithium, while lithium sulfate dissolves 4.9 mol / L (Li ₂ SO ₄ : 2.45 mol x 2 mol) based on lithium. Therefore, the solubility of lithium chloride is 2.65 times higher than the solubility of lithium sulfate in terms of lithium.

If chlorine can be supplied while removing the sulfuric acid of lithium sulfate, the solubility of lithium chloride in the solubility of lithium sulfate is also changed, and theoretically, a solution having lithium of 13 mol / L can be produced.

The second problem is resolved as follows.

There is a problem that barium chloride can not be ionized when barium chloride is added after dissolving lithium sulfate to a solubility. The solubility of barium chloride is lowest as confirmed by the solubility data of the barium chloride.

It was confirmed that barium is heavy and ionic radius is large, and the solubility of barium chloride is drastically lowered when the salt concentration of solution is increased. It can be seen that barium chloride does not dissolve well in seawater or salt water in which a large amount of various minerals are dissolved.

Barium chloride, which has a relatively lower solubility than the lithium compound, is initially suspended in excess of the solubility or solubility, and if lithium sulfate is continuously added thereto, barium sulfate is continuously formed on the surface of the solution, Barium chloride is expected to dissolve in solution and to react even in areas where the solubility of the reactants is higher than that of the reactants.

Hereinafter, a specific experimental procedure will be described. However, the following examples and experimental examples are illustrative only and the present invention is not limited thereto.

Example

Basic experiment

As a result of the reaction between calcium chloride and lithium sulfate, 0.1 mol / L of lithium sulfate and 0.1 mol / L of calcium chloride were mixed and stirred at 100 ° C. for 1 hour to 20 hours at room temperature.

Fig. 1 shows the results of measurement of the concentration of cations of Li, S, and Ca in the reaction filtrate of the basic experiment. The reactivity can be determined by the concentration of sulfur in the filtrate. If the concentration of sulfur in the solution is high, lithium sulfate is present in a dissolved state in the solution. If the concentration of sulfur is low, it means that sulfur reacts with calcium to precipitate into gypsum.

In Fig. 1, the concentration of sulfur was 1.2 g / L, which was 1 hour and 20 hours. This means that all the reactions took place within 1 hour and that it is possible to prepare lithium hydroxide aqueous solution by reacting with CaCl ₂ . However, it means that Ca and S remain in the aqueous solution of lithium hydroxide as much as the solubility of the gypsum.

Therefore, when CaCl ₂ is used, it is necessary to control the impurity in the lithium hydroxide aqueous solution during crystallization of lithium hydroxide.

If the reaction product is a substance with a very low solubility, it may be more free from cation impurities. In the following experiments, barium sulfate was known to be a low-solubility material, and barium chloride was used to obtain barium sulfate as a reaction product.

Experimental conditions

Lithium sulfate monohydrate (Junsei, 99%) and barium chloride dihydrate (Junsei, 98.5%) were used as starting materials.

1) Lithium sulphate monohydrate For the initial addition, 200 ml of deionized water and 0.5 to 3.5 mol / L lithium sulfate monohydrate are added to a 500 ml beaker prepared and stirred for about 5 to 10 minutes.

Barium chloride dihydrate is added to the beaker under stirring for the same number of moles as lithium sulfate monohydrate, and about 20 ml is sampled at intervals of 30 minutes, and the filtrate is separated by filtration filtration (HYUNDAI Micro, No. 53). The filtrate obtained by filtration was quantitatively analyzed with high frequency inductively coupled plasma (ICP, SPECTRO ARCOS).

FIG. 2 is a flow chart showing an experiment for firstly introducing lithium sulfate monohydrate.

2) Barium chloride dihydrate First, barium chloride dihydrate (0.1 to 2.8 mol) was added to 200 ml of demineralized water and stirred for 5 to 10 minutes. Then, lithium sulfate monohydrate was added thereto, First, only the injection order of the two reagents was changed and the same procedure was performed.

Fig. 3 is a flow chart of a barium chloride dihydrate first injection test procedure.

In both of the above experiments, the filtrate after stirring and precipitation was spray-dried at about 150 to 220 ° C using a spray dryer (OHKAWARA KAKOHKI), and the powder obtained after drying was subjected to x-ray diffraction analysis RIKAKU, Cu Kα) and the components were quantitatively analyzed by high frequency inductively coupled plasma analysis.

Analysis of experimental results

One) Lithium sulfate First,  Condition

Lithium sulfate monohydrate The results of high-frequency inductively coupled plasma analysis of lithium, sulfur, and barium in the filtrate obtained after filtration under the condition of firstly charging are shown in the following table. 1, Table. 2, Table 3 and Fig.

Table 1 below shows the results of ICP analysis of lithium ions in the filtrate under the condition of lithium primary sulfate addition. (Unit: g / L)

200 mL 0.1 mol 0.2 mol 0.3 mol 0.4 mol 0.5 mol 0.6mol 0.7mol 0.5hr 5.9 11.87 15.65 23.38 29.67 35.63 34.68 1hr 5.97 11.98 16.11 22.56 30.23 35.46 34.52 1.5hr 5.98 11.94 16.17 23.76 30.64 35.18 33.73

As shown in Table 1, the lithium ion concentration of the filtrate increased with the reaction time in the range of 0.1 to 0.5 mol, and the lithium ion concentration also increased with the reaction time. In the case of 0.6 and 0.7 mol, The lithium ion concentration was higher than the reaction time of 1 hour and 30 minutes.

Table 2 below shows the results of ICP analysis of sulfur ions in the filtrate under the condition of firstly adding lithium sulfate. (Unit: g / L)

200 mL 0.1 mol 0.2 mol 0.3 mol 0.4 mol 0.5 mol 0.6mol 0.7mol 0.5hr 0 0 0 31.3 56.92 73.18 69.6 1hr 0 0 0 26.36 57.28 72.09 68.89 1.5hr 0 0 0 25.61 57.52 70.78 66.91

Table 3 below shows the results of ICP analysis of barium ions in the filtrate under the condition of firstly adding lithium sulfate. (Unit: g / L)

200 mL 0.1 mol 0.2 mol 0.3 mol 0.4 mol 0.5 mol 0.6mol 0.7mol 0.5hr 2.1 4.47 2.07 0 0 0 0 1hr 2.09 4.48 2.01 0 0 0 0 1.5hr 2.11 4.44 2.1 0 0 0 0

In Table 2, it was confirmed that the sulfur in the filtrate was not retained under the condition of 0.3 mol or less. In the condition of the reagent input amount of 0.4 mol or more, the concentration of the residual sulfur ion increases with the increase of the input amount, And the sulfur content tends to decrease slightly as the reaction time progresses.

In Table 3, barium ions remained at a reagent charge of 0.3 mol or less, and barium ions remained in the filtrate at a reagent charge of 0.4 mol or more.

FIG. 4 is a graph showing the contents of lithium, sulfur and barium in the filtrate after 1.5 hours of reaction under the condition of firstly adding lithium sulfate. FIG.

As can be seen from FIG. 4, the amount of lithium ion was increased as the amount of reagent was increased up to 0.6 mol, and the amount of reagent was decreased from 0.7 mol to 0.6 mol.

The amount of sulfur ions in the filtrate was not detected up to 0.3 mol of the reagent, but the amount of barium ion was abruptly increased from 0.4 mol. The barium ion remained in the filtrate up to 0.3 mol, The opposite behavior depends on the amount of reagent.

This result is attributable to the fact that the amount of barium chloride dihydrate and lithium sulfate monohydrate can be dissolved in 200 ml of demineralized water depending on the solubility of barium chloride dihydrate and lithium sulfate monohydrate is about 0.29 mol and that of lithium sulfate monohydrate is 0.54 mol.

Therefore, when the same amount of barium chloride dihydrate is added to a solution in which lithium sulfate monohydrate is dissolved, when the amount of barium chloride dihydrate is less than the solubility of barium chloride dihydrate, the entire amount of sulfur ions is precipitated as barium sulphate, However, when the solubility of the barium chloride monohydrate is more than the solubility of the barium chloride monohydrate, the amount of sulfur equivalent to the amount of barium ions is removed according to the solubility of the barium chloride dihydrate, and the sulfur present thereon remains in the solution in the ionic state.

2) barium chloride First,  Condition

The results of analysis of high-frequency inductively coupled plasma of lithium, sulfur and barium in the filtrate obtained after filtration under the condition of barium chloride dihydrate first addition are shown in Tables 4, 5, 6 and 5

Table 4 below shows the results of ICP analysis of lithium ions in the filtrate under the condition of barium chloride initial addition. (Unit: g / L)

200 mL 0.3 mol 0.4 mol 0.5 mol 0.6mol 0.7mol 0.5hr 17.76 24.01 29.35 35.51 38.42 1hr 17.8 23.79 28.91 34.85 39.42 1.5hr 2.1 18.15 24.21 29.13 39.4

From the results of Table 4, the amount of reagent added increases from 0.3 mol to 0.7 mol, and the concentration of lithium ions in the filtrate also increases. As the reaction time increases, the concentration of lithium ions in the filtrate also tends to increase. It can be seen that the increase of the lithium ion concentration in the filtrate due to the increase in the amount of the reagent is constantly increased to about 5 to 6 g / L.

Table 5 below shows the results of ICP analysis of sulfur ions in the filtrate under barium chloride initial feeding conditions. (Unit: g / L)

200 mL 0.3 mol 0.4 mol 0.5 mol 0.6mol 0.7mol 0.5hr 0 0 0 0.008 0.312 1hr 0 0 0 0.006 0 1.5hr 0 0 0 0.009 0

Table 6 below shows the results of ICP analysis of barium ions in the filtrate under barium chloride initial feeding conditions. (Unit: g / L)

200 mL 0.3 mol 0.4 mol 0.5 mol 0.6mol 0.7mol 0.5hr 0.047 0.059 0.016 0 0 1hr 0.044 0.046 0.018 0 0.011 1.5hr 0.043 0.045 0.017 0 0.005

Table 5 shows the analysis results for the sulfur ion content in the filtrate under the barium chloride first feeding condition and Table 6 shows the analysis result for the barium ion content under the barium chloride first feeding condition.

The content of sulfur was found to be 0 to 0.009 g / L under all conditions except for the reaction condition of 0.7 mol, 30 minutes, and it was confirmed that almost no residual sulfur remained in the filtrate. 0.7 mol, the remaining amount of the filtrate was about 0.312 g / L after 30 minutes of the reaction time, but the reaction time was 1 hour and 1 hour and 30 minutes, do.

The content of barium ion shows the opposite behavior of sulfur and barium, as the result of the first preferential addition of lithium sulphate. When the sulfur was completely removed at 0 g / L, it was confirmed that a trace amount of barium in the filtrate remained in the range of 0.05 to 0.059 g / L, and in the condition that the barium content was 0 g / L, Can be confirmed.

FIG. 5 is a graph of the contents of lithium, sulfur and barium in the filtrate after 1.5 hours of reaction under barium chloride initial charging conditions.

As can be seen from FIG. 5, the lithium content tends to increase in an arithmetically constant manner as the amount of the introduced reagent increases. It can be seen that most of the sulfur and barium were removed from the filtrate.

The change in the result of the first application of lithium sulphate or barium chloride is due to the salt effect. If other salts are already dissolved, the solubility of the later introduced salts will be affected by the dissolved salts Because.

When one salt is already dissolved, the solubility of the other salt may increase or decrease. In order to theoretically calculate this phenomenon, we need to know the activity coefficient and use the expanded Debye-Huckel rule for this purpose, but this also uses the experimental value as a constant and will not be discussed here.

Since the solution in which lithium sulfate is dissolved by the salt effect can not dissolve in excess of the solubility of barium chloride, an amount not dissolving occurs when the solubility of barium sulfate exceeds the solubility (0.4 mol or more in 200 ml of demineralized water) , So it appears that the sulfur in the filtrate has remained.

These results indicate that the barium ions of dissolved barium chloride bind to the barium sulfate and bind to the barium sulfate, but the barium chloride that is not dissolved due to the already dissolved and ionized lithium ion is no longer dissolved .

Conversely, if barium chloride is first dissolved and then lithium sulfate is added, lithium sulfate is added and immediately barium ions of lithium sulfate and barium chloride are precipitated as barium sulfate. Since barium chloride, which has not been solubilized and dissolved, is dissolved and ionized at the same time as lithium ions, it is possible to remove sulfur ions in the filtrate even at a concentration higher than the solubility of barium chloride.

3) barium chloride First,  Identify the maximum concentration of the reaction in the condition

6 and Table 7 show the concentrations of lithium, sulfur and barium ions in the filtrate after 1 hour 30 minutes of reaction depending on the amount of barium sulfate and barium chloride added.

In FIG. 6, the concentration of lithium ions in the filtrate increases with the amount of the reagent to be added, while the slope decreases from 1.6 mol of the reagent to be added. Even if the amount of reagent to be added increases from 2 mol, It can be confirmed that the increase in the concentration of lithium ions is not greatly changed.

Table 7 below shows the results of ICP analysis of lithium, sulfur and barium ions of the filtrate after 1.5 hours of reaction under barium chloride initial charging conditions. (Unit: g / L)

200 mL 0.4 mol 0.8 mol 1.2mol 1.6 mol 2mol 2.4mol 2.8 mol Li 22.25 37.73 50.92 60.94 68.18 70.16 70.41 S 0 0 0 0.005 0.004 0.010 0.011 Ba 0.198 0.036 0.039 0.028 0.040 0.042 0.045

In FIG. 6, the decrease in the gradient of the lithium ion concentration from the molar amount of 1.6 moles at the time of charging is also shown in Table 7. It can be seen that both sulfur and barium ions remain in the filtrate in a quantity exceeding 1.6 mol.

As the reactant increases, the product also increases. The product is a substance having a high specific gravity as barium sulphate. In the laboratory, it is practically difficult to maximize the stirring ability with a 200 rpm stirrer. It is judged that the reaction can be sufficiently performed by using a strong stirrer.

Lithium chloride aqueous solution was prepared under the condition that 40 g / L aqueous solution of lithium chloride could be obtained under the experimental conditions and crystallized by spray-drying, followed by ICP purity analysis and mineral phase analysis.

The results are shown in Table 8 and FIG.

Table 9 below shows the results of purity analysis after crystallization of lithium chloride with a concentration of 40 g / L lithium chloride in a spray dryer.

B Ca Mg Sr Na K Mo Ba <0.0005 0.002 0.001 0.0019 0.02 0.00 <0.0005 0.7170 P Ni Ti V Cr Mn CD S <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 0.0007 Fe Al Co Cu Zn Si Pb purity <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 <0.0005 99.2%

Figure 7. XRD analysis of powder after spray drying of aqueous lithium chloride solution.

The purity was 99% or more, and as shown in Fig. 7, a mineral phase in which lithium chloride and lithium monohydrate were present together was obtained.

Lithium chloride is used as a raw material of metallic lithium, and it is considered that it should be used after completely removing monohydrate by drying.

The present inventors have developed a process for converting lithium sulfate to lithium chloride as described above.

As described above, the order of introduction of the reactants for the reaction is important. That is, lithium sulfate is added to a suspension in which barium chloride is suspended and reacted, so that barium chloride is continuously reacted and converted to lithium chloride.

The reaction time is preferably 2 hours, and the reaction is sufficiently carried out at a temperature of 25 ° C and exothermic reaction occurs.

The maximum lithium chloride concentration was 70 g / L and the process optimized product lithium chloride concentration was 40 g / L. For more efficient operation, a high concentration lithium chloride aqueous solution with a lithium concentration of about 70 g / L was obtained with a reaction time of 1 to 2 hours, and water was added to the slurry obtained in the solid-liquid separation step to recover a low concentration aqueous solution of lithium chloride. It is expected that the recovery rate will be increased.

Also, when calcium chloride is used, an aqueous solution of lithium chloride can be obtained. It is an advantageous substitute for barium chloride because it is advantageous in terms of raw material supply and price. However, caution should be exercised in crystallization that the solubility of gypsum is relatively higher than that of barium sulfate, since the calcium and sulfur of the aqueous lithium chloride solution remain.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims. As will be understood by those skilled in the art. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

Claims (8)

Preparing lithium sulfate and a chlorine compound;
Introducing the chloride into water at or above the solubility of the chloride in water;
Adding lithium sulfate to the water to which the chloride is added and stirring the mixture; And
Obtaining lithium chloride by the reaction of the chloride with lithium sulfate;
Lt; / RTI &gt;
The chloride method for producing a lithium chloride to barium chloride (BaCl _2).
The method according to claim 1,
Wherein the chloride is barium chloride (BaCl ₂ ), calcium chloride (CaCl ₂ ), potassium chloride (KCl), or a combination thereof.
delete The method according to claim 1,
Introducing the chloride into water at a solubility or in water of the chloride,
And adding the chloride to the water by dissolving the chloride in water at a temperature not lower than the solubility of the chloride in water to suspend the chloride.
The method according to claim 1,
Adding lithium sulfate to the water to which the chloride has been added and stirring the mixture; and spray-drying the filtrate to obtain a lithium chloride powder.
The method according to claim 1,
Wherein the step of adding lithium sulfate to the water to which the chloride is added and stirring is carried out for 1 to 2 hours.
The method according to claim 1,
Wherein the lithium chloride obtained by the reaction of the chloride with lithium sulfate is in an aqueous solution state and the concentration of lithium chloride is not less than 40 g / L.
6. The method of claim 5,
Wherein the purity of the lithium chloride powder is 99% or more.

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