JPH0742087B2 - Granulated refined iodine manufacturing method - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing granulated refined iodine.

[0002]

2. Description of the Related Art Solid refined iodine is handled in the form of flakes, granules, spheres, etc., which are obtained by cooling and solidifying molten iodine. However, in the recent era in which high quality is required, refined iodine is not only characterized only by its shape, but also better quality is required.
In the conventional method, in the iodine melting operation in the previous step of producing solid purified iodine, water and other impurities are almost removed, but in the iodine solidification step, air and / or water spray cooling is performed. , The water and other impurities are attached and / or mixed in.
Therefore, they have a great influence on the purity of the purified iodine, and a constant purity cannot be obtained. Furthermore, since iodine dissolves in about 0.3 g in 1 liter of water, if a small amount of water adheres and / or mixes in, a part of iodine is dissolved and converted into hydroiodic acid, and the surface becomes wet. Soil packaging materials and handling equipment. Most of the refined iodine is exported overseas,
The transportation takes about two months, and during that time, caking may occur. This is because when the iodine changes from a liquid to a solid, the volume of the iodine shrinks by about 20%, and a void is formed in the iodine. Depending on the cooling method, a large cavity or a porous cavity may be formed. However, if there are many porous cavities, the surface area increases and the amount of water that adheres and / or mixes with it increases. The fact that they cover the surface of iodine and cause tension between iodine by tension and / or capillarity is the main cause of caking, but the formation of hydroiodic acid is also one of the factors. To be In addition, an apparatus for purifying iodine, which is generally corrosive and sublimable, is complicated in operation and often expensive.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to improve the above-mentioned drawbacks of refined iodine and to economically produce high-quality granular refined iodine that is unlikely to cause caking.

[0004]

In order to advantageously solve the above-mentioned problems, in the method for producing granulated refined iodine of the present invention, molten iodine is injected by an injection nozzle, and this is cooled, dried and cleaned. By bringing the molten iodine into contact with an inert gas and cooling and solidifying the molten iodine, granular refined iodine containing very little water and impurities is produced.

Next, the present invention will be described in detail. Molten iodine is high-purity liquid iodine obtained in the step of refining crude iodine. This is because solid crude iodine is charged into a container which is not corroded by iodine, and after sealing, the container temperature is 115 to 1
It was obtained by melting at 30 ° C., leaving it for a certain period of time, and then separating impurities.

The injection nozzle is a nozzle having a diameter of 0.5 to 3.0 mm.
It is a spray nozzle that requires a certain pressure. When injecting molten iodine, the conduit temperature is adjusted to 115 to 120 ° C., and the injection angle is 55 to 75 ° above the horizontal line.
The injection pressure is set to 1.0 to 3.0 kg / cm ² .

Cooling is an operation of lowering the temperature of the inert gas by water cooling or air cooling, and it is preferably set to 15 ° C. or lower.

Drying is an operation of lowering the humidity of the cooled inert gas with a desiccant or the like, and is preferably set to 20% or less.

The term "cleaning" refers to an operation of removing fine particles in an inert gas which has been cooled and dried by an air cleaner or the like, and it is preferable to remove the particles as much as possible.

The inert gas is a gas that does not react with liquid iodine, and there are various kinds such as nitrogen, helium and air, but air is preferred from the viewpoint of easy handling and economy.

The term "contact" means an operation in which the injected molten iodine is efficiently cooled gradually without coming into contact with an inert gas and being rapidly cooled.

Cooling and solidification refers to an operation in which the injected molten iodine is cooled in an inert gas space and converted into solid particles.

The term "granulation" as used herein refers to particles having a particle size within a certain particle size distribution range regardless of the shape of the solidified iodine, such as round or elongated. In this method, the particles have a particle size distribution range of 0.2 to 2.5 mm.

An example of steps for carrying out the method of the present invention is shown in FIG.
It will be described based on. The crude iodine 13 which is a solid is put in the iodine melting vessel 2 and sealed, and the temperature is raised to melt.
As it is, it is allowed to stand for a certain period of time, and liquid iodine from which impurities and water are separated is prepared and placed. The pressure in the iodine melting vessel 2 is appropriately adjusted according to the particle size. The inert gas 14 is sucked into the granulating tower 1 through the inert gas inlet 5 after passing through the cooler 8, the dryer 7 and the air cleaner 6. The exhaust gas 11 is discharged from the exhaust port 9 in the granulation tower 1 by the exhaust fan 11.
Is passed through the exhaust gas absorption tower 10 and the exhaust fan 11 to be exhausted. Next, the temperature of the molten iodine is adjusted by the temperature controller 3, and the molten iodine is injected from the injection nozzle 4 into the granulating tower. The injection nozzle 4 injects upward into the inert gas space in the granulation tower 1. The refined granular iodine that has been cooled and solidified in the space inside the granulation tower 1 is received by the product receiving port 12 at the bottom of the granulation tower. The product receiving port 12 can be divided according to the particle size.

In the present invention, the following advantages are recognized by adopting the apparatus as described above and carrying out the method for producing granulated refined iodine. Since the granulated purified iodine obtained by this method is in a very dried state, the generation of iodine stains on the device and the occurrence of caking after packaging due to the influence of a trace amount of water are very small. It is presumed that this is because the surface area of the particles becomes smaller than that of the conventional method, and further, it is difficult for water and the like to be mixed in by the operation in an inert gas.

By controlling the temperature and humidity of the inert gas, the purity of the purified iodine is improved and is very stable. In addition, by controlling the cleanliness, the analysis values such as non-volatile residue are also very small and stable, so quality control is easy, and the occurrence of caking is very small, and it can withstand long-term storage. Shipping management is also easy.

Since only the inert gas is used as the cooling medium, the operation and control are easy, and the device can be easily manufactured with a cheap material, and substances other than iodine are not easily mixed.

[0018]

EXAMPLES Next, the method of the present invention will be specifically described by way of examples. Example 1 Granulated purified iodine was produced according to FIG. 1 of the accompanying drawings. The molten iodine was heated from a 15 liter iodine melting vessel 2 adjusted to a pressure of 2.0 kg / cm ² and a temperature of 120 ° C. by a temperature controller 3.
The temperature is adjusted to 115 ° C. with 60 ° C. toward the upper part of the granulation tower 1.
Liquid iodine is sprayed from the spray nozzle 4 at an angle of 50
Jet in kg. The diameter of the injection nozzle 4 is 0.6 mm. The granulating tower 1 is made of a transparent vinyl chloride resin having a height of 2 m, a length of 3 m and a width of 1 m, and the inert gas suction port 5 of the granulating tower 1 sucks air having a temperature of 10 ° C. and a humidity of 20%. . The exhaust gas is exhausted from the exhaust port 9 at a rate of 10 m ³ per minute through the exhaust gas absorption tower 10 and by the exhaust fan 11. The product is received in the product receiving port 12 at the bottom of the granulating tower 1.

As a result of repeating the above operation five times,
The average purity of iodine is 99.85% and the minimum is 99.80.
%, And the maximum value was 99.91%. The non-volatile residue as an impurity was 0.0041% on average, the minimum value was 0.0035%, and the maximum value was 0.0052%. The average particle size is 0.52 mm,
The particle size distribution was 95.5% in the range of 0.2 to 0.8 mm.
As a result of storing in a glass sample bottle at a temperature of 20 ° C., 60
I could not see caking even after a day. Moreover, the inside of the sample bottle was not soiled.

Comparative Example 1 As Comparative Example 1, the following was tested. Air having a temperature of 20 ° C. and a humidity of 70% was taken in through the inert gas inlet port 5, and the same operation as in Example 1 was carried out. As a result of repeating the operation 5 times, the average purity of iodine was 99.75%. , The lowest value is 9
The maximum value was 9.62%, and the maximum was 99.82%. Nonvolatile residue is 0.0053% on average, the lowest value is 0.0035%, and the highest value is
It was 0.0073%. The average particle size was 0.54 mm, and the particle size distribution was 95.2% in the range of 0.2 to 0.8 mm. Temperature 20
Storage in glass sample bottles at 0 ° C. resulted in all caking after 20 days. In addition, light brown stains were found in various places inside the sample bottle. It was found that in this comparative example, the humidity in the air was high, so that the purity of iodine was low and the cake was easily caked.

Comparative Example 2 As Comparative Example 2, the following was tested. An example is shown in which the air cleaner 6 and the dryer 7 shown in FIG. From inert gas inlet 5, temperature 20 ℃, humidity 9
Inhale 0% air. Distilled water 10 minutes per minute in this air
The same operation as in Example 1 was carried out by injecting 0 ml so as to contain a water droplet of 50 microns. As a result of repeating the operation 5 times, the average purity of iodine was 99.30.
%, The lowest value was 99.00%, and the highest value was 99.52%. Nonvolatile residue is 0.0080% on average, and the minimum value is 0.0
The maximum value was 050% and 0.0110%. The average particle size is 0.51 mm, and the particle size distribution is 94.1 in the range of 0.2 to 0.8 mm.
% Was present. After storage in a glass sample bottle at a temperature of 20 ° C., all were caked after 10 days. In addition, the entire inside of the sample bottle became dark brown and droplets were attached.
In this comparative example, the purity and non-volatile residue of iodine were poor, the quality was unstable, and caking was very fast. It is considered that this is because a large number of porous cavities are formed in the particles due to the rapid cooling with water, and the water is adsorbed therein. Moreover, even when this product was dried, the purity did not reach the purity of Comparative Example 1.

[0022]

Industrial Applicability According to the method for producing granular refined iodine of the present invention,
Higher purity and less non-volatile residue than conventional products, stable and high quality can be obtained.Although the particle size is small, the incidence of caking is very low, and even for long-term storage. It is possible to obtain a cake that hardly causes caking. Furthermore, since there is no dirt inside the packaging material, quality control and shipping control are stabilized, improving efficiency.
In use, since the particle size falls within a small range where the particle size distribution is constant, the dissolution rate is fast and a uniform dissolution rate can be obtained. In addition, the device is not complicated,
It can be easily manufactured with an inexpensive material, and since it can be cooled and solidified with a single gas, maintenance and management is easy.

[Brief description of drawings]

FIG. 1 is a flow sheet showing an example of a process for carrying out the method of the present invention.

[Explanation of symbols]

 1 Granulation Tower 2 Iodine Melting Container 3 Temperature Controller 4 Injection Nozzle 5 Inert Gas Intake Port 6 Air Cleaner 7 Dryer 8 Cooler 9 Exhaust Port 10 Exhaust Gas Absorption Tower 11 Exhaust Fan 12 Product Receptor 13 Crude Iodine 14 Inert Gas 15 Exhaust gas

Claims (1)

[Claims] 1. A method for producing granular refined iodine, which comprises injecting molten iodine with an injection nozzle 4, bringing the molten iodine into contact with an inert gas 14 which has been cooled, dried, and cleaned, and then cooled and solidified.