JP6454196B2 - Method for producing dry lithium halide - Google Patents

Description

  The present invention relates to a method for producing dry lithium halide.

  Lithium iodide, which is a lithium halide, is used as an electrolyte and is an indispensable material for a long-life battery such as a heart pacemaker.

  Patent Document 1 discloses a method for removing water from lithium iodide hydrate. Specifically, it is a method of making lithium iodide hydrate anhydrous by azeotropically distilling the moisture of lithium iodide hydrate with alcohol, but since a predetermined alcohol is used, it is unnecessary. There was a drawback that it required equipment and cost.

JP 2013-256416 A

  An object of the present invention is to provide a production method capable of obtaining dry lithium halide with reduced water content without using a solvent such as alcohol.

  As a result of intensive studies by the present inventors, it has been found that even when lithium halide is dried under reduced pressure using a vacuum dryer, drying may be insufficient. It was also found that the amount of water cannot be reduced sufficiently due to aggregation of lithium halide. Accordingly, a new method for drying lithium halide that does not use an organic solvent such as alcohol was found and the present invention was completed.

According to the present invention, the following method for producing dry lithium halide is provided.
1. A method for producing dry lithium halide, wherein the lithium halide is dried while moving.
2. 2. The method for producing dry lithium halide according to 1, wherein the lithium halide is lithium iodide or lithium bromide.
3. 2. The method for producing dry lithium halide according to 1, wherein the lithium halide is lithium iodide.
4). 2. The method for producing dry lithium halide according to 1, wherein the lithium halide is anhydrous lithium iodide.
5. 5. The method for producing dry lithium halide according to 4, wherein the moisture content of the anhydrous lithium iodide is 10,000 ppm or less.
6). 6. The method for producing dry lithium halide according to any one of 1 to 5, wherein the lithium halide is moved by vibration.
7). 7. The method for producing dry lithium halide according to 6, wherein the amplitude of vibration is 0.01 mm or more and 100 mm or less.
8). The method for producing dry lithium halide according to 6 or 7, wherein the vibration frequency is 10 rpm or more and 10,000 rpm or less.
9. The method for producing dry lithium halide according to any one of 1 to 8, wherein the drying temperature is 130 ° C or lower.
10. The method for producing dry lithium halide according to any one of 1 to 8, wherein the drying temperature is 70 ° C or higher and 100 ° C or lower.
11. The manufacturing method of the dry lithium halide in any one of 1-10 which performs the said drying under the pressure of 0.1-50 kPa.
12 The method for producing dry lithium halide according to any one of 1 to 11, wherein the drying time is 1 to 50 hours.
13. The method for producing dry lithium halide according to any one of 1 to 12, wherein the drying atmosphere is an inert gas.
14 The lithium halide is lithium iodide;
The method for producing dry lithium halide according to any one of 1 to 13, wherein the drying is performed at 70 ° C. or higher and 110 ° C. or lower and then further heated at 130 ° C. or higher and 160 ° C. or lower.
15. 15. The method for producing dry lithium halide according to any one of 1 to 14, using a vibration dryer.
16. The method for producing dry lithium halide according to any one of 1 to 15, wherein the water content of the dry lithium halide is 450 ppm or less.

  ADVANTAGE OF THE INVENTION According to this invention, even if it does not use solvents, such as alcohol, the manufacturing method with which the dry lithium halide by which the moisture content was reduced can be obtained can be provided.

In the method for producing dry lithium halide according to the present invention, dry lithium halide with a low water content can be obtained by drying while moving the lithium halide. In addition, the recovered dry lithium halide powder can be prevented from aggregating.
In the production method of the present invention, an organic solvent such as alcohol is usually not used.

  Examples of the lithium halide used as a raw material include lithium iodide, lithium bromide, lithium chloride, and lithium fluoride. Lithium bromide and lithium iodide are preferable, and lithium iodide is more preferable.

The raw material lithium halide may be an anhydride or a hydrate (for example, a dihydrate), but in the production method of the present invention, an anhydride is preferable and anhydrous lithium iodide is more preferable. The moisture content of the anhydride is, for example, 10,000 ppm or less, 8000 ppm or less, 6000 ppm or less, or 5000 ppm or less.
The raw material lithium halide may be an aqueous solution.

The purity of the raw material lithium halide may be selected according to the necessity of the step after the production of dry lithium halide, but is preferably high purity.
The purity of the raw material lithium halide is preferably 90% or more, more preferably 95% or more, and further preferably 98% or more. It may be 99% or more excluding moisture.

  In particular, the purity of the anhydride of lithium halide is preferably 95% or more, more preferably 98% or more, and particularly preferably 99% or more.

  When high purity lithium halide is used as a raw material, it is preferably handled under an inert atmosphere, for example, nitrogen. Aggregation can be further suppressed by handling under nitrogen.

  The particle size of the raw material lithium halide is not particularly limited, but is preferably less than 1000 μm, more preferably 800 μm or less, and more preferably 1 μm or more and 500 μm or less. When coarse particles of 1000 μm or more are present, there is a possibility that the extraction from the apparatus is restricted. In addition, if it is a particle size of 1 micrometer or more, a bulk density will become moderate height and productivity will improve.

  The raw material lithium halide may be used alone or in a mixture of two or more.

  By moving the lithium halide, the lithium halide can be dried while flowing without being fixed in one place.

  Examples of means for moving the lithium halide include vibration, stirring such as blade stirring, and swinging. Of these, vibration is preferable.

  The vibration condition is not particularly limited as long as the vertical flow of the material to be dried is smoothly generated, but the amplitude is preferably 0.01 mm or more and 100 mm or less. For example, it is 0.1 mm or more and 10 mm or less. The frequency is preferably 10 rpm or more and 10,000 rpm or less. For example, it is 100 rpm or more and 5000 rpm or less. By satisfying the above vibration conditions, the fluidity of the powder can be ensured, and the occurrence of aggregation can be further suppressed.

The drying temperature (when performing additional drying, the initial drying temperature) is not particularly limited, but is preferably 130 ° C. or lower. 70 degreeC or more and 130 degrees C or less are more preferable, and 70 degreeC or more and 120 degrees C or less are further more preferable. For example, it is 70 ° C. or higher and 110 ° C. or lower, or 70 ° C. or higher and 100 ° C. or lower. When the drying temperature is 130 ° C. or lower, the adherence of the material to be dried to the apparatus used for drying can be reduced.
When the lithium halide is lithium bromide, even if the drying temperature is 170 ° C. or lower, for example, 150 ° C., the adherence of the material to be dried to the apparatus used for drying is small.

Although drying time is based also on the moisture content of a to-be-dried body, 1 to 50 hours are preferable, 1.5 to 20 hours are more preferable, and 2 to 8 hours are especially preferable. When the drying time is within the above range, the atmosphere in the system during drying can be kept stable.
The dry atmosphere is preferably an inert gas atmosphere. Specific examples include a nitrogen atmosphere and an argon atmosphere.

  Drying may be carried out under reduced pressure, under normal pressure, or under pressure, but preferably under reduced pressure. The pressure condition for drying is preferably 0.1 to 50 kPa, more preferably 0.5 to 20 kPa, and preferably 1 to 10 kPa.

  In the case of pressurization conditions, pressurization may be performed while an inert gas such as nitrogen gas or argon gas is circulated. By circulating an inert gas, exposure to the atmosphere can be prevented.

  After the above drying, it is preferable to perform additional drying by further heating while moving the lithium halide. In the additional drying, the temperature may be raised as it is after the drying, or may be raised after cooling once, but it is preferable to raise the temperature again as it is. By performing additional drying, the moisture content of the lithium halide can be further reduced without causing adhesion of a dried body.

  The additional drying temperature is preferably 130 ° C. or higher, and more preferably 140 ° C. or higher. Although an upper limit is based also on the specification of an apparatus, 200 degrees C or less is preferable, for example, it is good also as 180 degrees C or less and 160 degrees C or less.

Conditions other than the additional drying temperature are the same as the above drying conditions.
For example, after heating at 70 ° C. to 110 ° C. for 2 hours to 8 hours (initial drying), additional drying is performed at 130 ° C. to 160 ° C. for 2 hours to 8 hours.

  In order to dry the lithium halide while moving, it is preferable to use a vibration dryer.

  In the vibration dryer, drying can be performed by indirect heating, and the main body can be vibrated to vibrate lithium halide contained therein, thereby allowing the lithium halide to flow up and down to be uniformly dried.

  A pulverizing medium may be put together with the lithium halide to effectively impart actions such as compression, impact, shear, and friction to the lithium halide. Examples of the grinding media include ceramic balls such as alumina, zirconia, and silicon carbide.

The inner wall of the vibration dryer is preferably made of stainless steel. Moreover, you may coat | cover with ceramics, such as an alumina, a zirconia, and silicon carbide.
The outer wall of the vibration dryer is preferably provided with a function that enables temperature adjustment using a heat medium.

  The vibration dryer can be used in either a batch type or a continuous type.

  The water content of the dry lithium halide produced by the method of the present invention is preferably 450 ppm or less. 400 ppm or less is more preferable, and 350 ppm or less is more preferable. Although a lower limit is not specifically limited, Usually, it is 10 ppm or more.

  The extraction from the apparatus used for drying the lithium halide is preferably performed in a dry room or the like under a nitrogen atmosphere. After extraction, it is preferably stored in a container that can be kept airtight under nitrogen or dry air.

Example 1
Lithium iodide (manufactured by Wako Pure Chemical Industries, Ltd., 101.5 g) was charged into a container provided in a small vibration dryer Mamekan VH type (manufactured by Chuo Kako). After the charging, the internal pressure of the container was reduced to 3.4 kPa with a vacuum pump and the inner wall temperature of the container was raised to 85 ° C. while vibrating (frequency 1500 rpm, amplitude 3 mm), followed by drying for 4 hours. After drying, the dried lithium iodide was recovered.

From the weight of the collected lithium iodide and the weight of the charged lithium iodide, the adhesion rate of lithium iodide that could not be recovered due to adhesion to the inner wall was determined by the following formula.
Adhesion rate = {(input weight) − (recovered weight)} / (input weight) × 100 (%)
The adhesion rate was 0.79%. Since the adhesion rate was extremely low, it was found that there was almost no adhesion to the inner wall.

The moisture content of the dried lithium iodide was 330 ppm.
In addition, the moisture content of the lithium iodide before drying was 3440 ppm. Lithium iodide before drying is “anhydrous”, but “lithium iodide n hydrate” is also present in the reagent for lithium iodide.
As described above, anhydrous lithium iodide before drying removes n-hydrated water, but it is about 1% or less (10000 ppm or less), for example, about 0.1 to 1% (1000 to 10000 ppm). Contains moisture.
The moisture concentration was measured with a Karl Fischer moisture meter.

  The recovered lithium iodide was visually observed to evaluate the presence or absence of aggregation. The recovered lithium iodide was not aggregated.

Example 2
Dry lithium iodide was produced and evaluated in the same manner as in Example 1 except that the inner wall temperature was 145 ° C., the drying time was 6 hours, and the amount of raw materials was as shown in Table 1.
A certain amount adhered to the inner wall of the dryer. The results are shown in Table 1.

Example 3
The amount of the raw material and the internal pressure were as shown in Table 1, and after heating at 85 ° C. for 4 hours, the inner wall temperature was raised to 145 ° C., and additional heating was further performed for 5 hours. Lithium was produced and evaluated. The results are shown in Table 1.
It was found that once it was sufficiently dried, the adhesion rate would be extremely low even with additional heating, that is, there was almost no adhesion to the inner wall.

Examples 4 and 5
Dry lithium iodide was produced and evaluated in the same manner as in Example 1 except that the amount of raw material, internal pressure, inner wall temperature, and drying time were as shown in Table 1. The results are shown in Table 1.

Example 6
2.8 kg of lithium iodide (anhydride) was charged into a vibration dryer VU30 (manufactured by Chuo Kako). After the charging, the internal pressure of the container was reduced to a pressure of 4.4 kPa with a vacuum pump and the inner wall temperature of the container was raised to 90 ° C. while vibrating (frequency 1500 rpm, amplitude 3 mm), followed by drying for 4 hours. After heating at 90 ° C. for 4 hours, the inner wall temperature was raised to 146 ° C. and further heated for 2 hours. After drying, the dried lithium iodide was recovered.

The obtained lithium iodide was evaluated in the same manner as in Example 1.
The adhesion rate of lithium iodide was less than 1%. Since the adhesion rate was extremely low, it was found that there was almost no adhesion to the inner wall.
The moisture content of the dried lithium iodide was 60 ppm. The moisture content of lithium iodide before drying was 1600 ppm.
The recovered lithium iodide was visually observed to evaluate the presence or absence of aggregation. The recovered lithium iodide was not aggregated.

Example 7
5 kg of lithium bromide (manufactured by Honjo Chemical Co., Ltd., anhydrous) was put into a vibration dryer VU30 (manufactured by Chuo Kako). After the charging, the inner pressure of the container was reduced to a pressure of 4.4 kPa with a vacuum pump, and the inner wall temperature of the container was raised to 150 ° C. while vibrating (frequency 1500 rpm, amplitude 3 mm), followed by drying for 6 hours. After drying, the dried lithium bromide was recovered.

The obtained lithium bromide was evaluated in the same manner as in Example 1.
The adhesion rate of lithium bromide was less than 1%. Since the adhesion rate was extremely low, it was found that there was almost no adhesion to the inner wall.
The moisture content of the dried lithium bromide was 40 ppm. The water content of lithium bromide before drying was 3400 ppm.
The recovered lithium bromide was visually observed to evaluate the presence or absence of aggregation. There was no aggregation in the recovered lithium bromide.

Comparative Example 1
Lithium iodide (2.0 g) was put into a 50 ml Schlenk bottle with a branch pipe, heated to 150 ° C. in an oil bath under reduced pressure, and dried for 2 hours.
The dried lithium iodide became a lump and agglomerated. Extracted under nitrogen and ground in a mortar to recover dry lithium iodide. The moisture content of this dry lithium iodide was evaluated in the same manner as in Example 1. The amount of water was 520 ppm.

Comparative Example 2
Dry lithium iodide was produced and evaluated in the same manner as Comparative Example 1 except that the temperature was 100 ° C. and the drying time was 6 hours.
The dried lithium iodide was slightly clumped but could be easily powdered. The water content was 820 ppm.

  The dry lithium halide produced according to the present invention can be used as a long-life battery for medical and battery material raw materials, particularly heart pacemakers.

Claims (15)

A method for producing dry lithium halide, which is dried while moving anhydrous lithium halide. The method for producing dry lithium halide according to claim 1, wherein the anhydrous lithium halide is anhydrous lithium iodide or anhydrous lithium bromide. The method for producing dry lithium halide according to claim 1, wherein the anhydrous lithium halide is anhydrous lithium iodide. The method for producing dry lithium halide according to claim 3 , wherein the moisture content of the anhydrous lithium iodide is 10,000 ppm or less. The method for producing dry lithium halide according to any one of claims 1 to 4 , wherein the anhydrous lithium halide is moved by vibration. The method for producing dry lithium halide according to claim 5 , wherein the vibration amplitude is 0.01 mm or more and 100 mm or less. The method for producing dry lithium halide according to claim 5 or 6, wherein the vibration frequency is 10 rpm or more and 10,000 rpm or less. The method for producing dry lithium halide according to any one of claims 1 to 7 , wherein the drying temperature is 130 ° C or lower. The method for producing dry lithium halide according to any one of claims 1 to 7 , wherein the drying temperature is 70 ° C or higher and 100 ° C or lower. The anhydrous lithium halide is anhydrous lithium iodide;
The method for producing a dry lithium halide according to any one of claims 1 to 7 , wherein the drying is performed at 70 ° C or higher and 110 ° C or lower and then further heated at 130 ° C or higher and 160 ° C or lower.   The method for producing a dry lithium halide according to any one of claims 1 to 10, wherein the drying is performed under a pressure of 0.1 to 50 kPa.   The method for producing dry lithium halide according to any one of claims 1 to 11, wherein the drying time is 1 to 50 hours.   The method for producing dry lithium halide according to any one of claims 1 to 12, wherein the drying atmosphere is an inert gas. Method for producing a dry lithium halide according to any one of claims 1 to 13 using a vibration dryer. The method for producing dry lithium halide according to any one of claims 1 to 14 , wherein the water content of the dry lithium halide is 450 ppm or less.