An iodine granulating device and a method thereof

Abstract

The application discloses an iodine granulating device, which comprises a sublimer, a condensation granulator and an iodine gas pipe, a coarse iodine powder feeding port and an iodine vapor outlet are arranged on the upper part of the sublimer, an air inlet is arranged at the bottom of the sublimer, a heating jacket is arranged on the outer wall of the sublimer, an iodine vapor inlet and a powder and granular iodine feeding port are arranged on the upper part of the condensation granulator, a granular iodine discharging port is arranged at the rear end of the lower part of the condensation granulator, the iodine gas pipe is connected with the iodine vapor outlet and the iodine vapor inlet at two ends respectively, a scraper is arranged on the inner wall of the condensation granulator, a cooling water jacket is arranged on the lower part of the outer wall of the condensation granulator, and a heating companion pipe is arranged on the outer wall of the iodine gas pipe. The iodine granulating device can synchronously realize sublimation refining and condensation granulation of coarse iodine powder, simplifies the production and recovery process of iodine and improves the quality of iodine.

Description

Technical Field

[0001] This invention relates to the refining and granulation of iodine, and more specifically to an iodine granulation apparatus and method thereof. Background Technology

[0002] Iodine is an important resource with wide applications in medicine, electronics, agriculture, dyes, metallurgy, chemicals, food, synthetic rubber, defense, and advanced technologies, possessing high economic value. While iodine is widely distributed globally, its abundance is relatively low, making extraction difficult. Given the large global market demand, the production and recycling of iodine are receiving increasing attention from various countries.

[0003] In the application of iodine, in addition to the intrinsic quality requirements of iodine, some fields also have special requirements for its appearance. Therefore, the crude iodine powder obtained from production and recycling should be refined and granulated to improve the value of iodine and meet market application requirements. However, the existing technology for refining and granulating crude iodine powder has the following shortcomings: First, the process is complex; second, after the iodine granules are cooled and shaped with water, the surface moisture must be dried with air, which consumes a lot of energy; third, the sublimation refining and deposition granulation of crude iodine powder cannot be achieved simultaneously.

[0004] For example, CN101759151A discloses a method for iodine granulation, which includes the following steps: (1) heating iodine to a molten state; (2) using compressed air to extrude the molten iodine into a granulator for granulation; (3) the iodine granules from the granulator are directly cooled in a cooling pool; (4) after the iodine granules have cooled and formed, the surface moisture is dried with air to produce iodine granular products. This invention, through a comprehensive method of heating and melting iodine, air extrusion granulation, cold water cooling and forming, and air drying of surface moisture, produces iodine products with uniform granules diameter of 2-4 mm, smooth and rounded surfaces, and low volatility.

[0005] For example, CN201850136U discloses an iodine granulation device, including a preheater and a pellet dropper. The pellet dropper is a trapezoidal box with an openable top plate and two pipe holes. Several dropping tubes with an inner diameter of 1.5-4 mm are placed at the bottom of the box. The preheater is a rectangular box with a connecting pipe on each side. The top of the box is an openable top plate with two pipe holes. The pipe holes on the top plate of the pellet dropper are connected to the pipe holes on the top plate of the preheater. The pellet dropper is placed inside the preheater box, and the dropping tubes at the bottom of the pellet dropper extend out of the bottom of the preheater. Summary of the Invention

[0006] The purpose of this invention is to provide an iodine granulation device and method. The device of this invention has a simple structure and can simultaneously achieve the sublimation purification and deposition granulation of crude iodine powder through sublimation and deposition granulation, simplifying the iodine production and recovery process and improving the quality of iodine.

[0007] To solve the above problems, the technical solution adopted by the present invention is as follows: an iodine granulation device, comprising a sublimator, a deposition granulator, and an iodine gas pipe. The upper part of the sublimator is provided with a coarse iodine powder feed port and an iodine vapor outlet, the bottom of the sublimator is provided with an air inlet, and the outer wall of the sublimator is provided with a heating jacket. The upper part of the deposition granulator is provided with an iodine vapor inlet and a powder iodine feed port, and the lower rear end of the deposition granulator is provided with a granular iodine outlet. The two ends of the iodine gas pipe are respectively connected to the iodine vapor outlet and the iodine vapor inlet. A scraper is provided on the inner wall of the deposition granulator, a cooling water jacket is provided on the lower part of the outer wall of the deposition granulator, and a heating tracing pipe is provided on the outer wall of the iodine gas pipe.

[0008] In a preferred embodiment of the present invention, a stirrer is provided inside the sublimator.

[0009] In a preferred embodiment of the present invention, a heat preservation device is provided on the upper part of the sublimation granulator.

[0010] In a preferred embodiment of the present invention, the sublimation pelletizer is provided with a non-condensable gas outlet, and the non-condensable gas outlet is connected to a non-condensable gas absorber.

[0011] In a preferred embodiment of the present invention, the sublimation particle generator is inclined, and the angle between the central axis of the sublimation particle generator and the horizontal plane is 1 to 2°.

[0012] The present invention also discloses a method for granulating iodine using the device, comprising the following steps:

[0013] (1) Add crude iodine powder into the sublimator through the crude iodine powder feed port, and introduce heat medium into the heating jacket through the heat medium inlet of the sublimator; introduce heat medium into the heating pipe of the iodine gas pipe through the heat medium inlet to preheat the iodine gas pipe; add pre-set powder iodine into the granulator through the powder iodine feed port, and introduce cooling water into the cooling water jacket through the cooling water inlet; start the scraper.

[0014] (2) When the sublimator is heated to the set temperature, dry air is introduced into the sublimator through the air inlet. The generated iodine vapor enters the condenser from the iodine gas pipe and condenses with the pre-set powder iodine. The non-condensable gas after condensation enters the non-condensable gas absorber and absorbs the uncondensed iodine vapor with sodium sulfite solution. The absorbed tail gas is discharged through the tail gas outlet in compliance with the standard.

[0015] (3) Powdered iodine continuously contacts iodine vapor in the condenser and condenses to grow larger. The coarsened iodine particles gradually move to the rear end. When a certain amount of iodine particles accumulate in the condenser, the supply of dry air to the sublimator is stopped, and the iodine particles are taken out from the iodine particle outlet.

[0016] (4) The granular iodine is screened to obtain the finished product. The fine particles are returned to the condenser to continue to contact with iodine vapor and condense to become coarser granular iodine.

[0017] In a preferred embodiment of the present invention, the temperature of the sublimator is set to 90-110°C.

[0018] In a preferred embodiment of the present invention, the temperature of the iodine gas tube is set to 90-110°C.

[0019] In a preferred embodiment of the present invention, the cooling water outlet temperature of the sublimation pelletizer is set to 25-45°C.

[0020] In a preferred embodiment of the present invention, the amount of iodine powder pre-placed in the sublimation granulator is 10-20% of the volume of the sublimation granulator.

[0021] The sublimator of this invention is equipped with a stirrer to prevent air from short-circuiting during sublimation and improve sublimation efficiency. To prevent iodine vapor from condensing in the iodine gas pipe and affecting the stable operation of the device, this invention uses a heated iodine gas pipe to connect the sublimator and the condensation granulator. The lower part of the outer wall of the condensation granulator is equipped with a cooling water jacket to cool the pre-placed powdered iodine, causing iodine vapor to condense on the surface of the powdered iodine and grow into granules. The upper part of the condensation granulator is equipped with a heat insulator to reduce the direct condensation of iodine vapor on the cylinder wall of the condensation granulator and improve granulation efficiency. The condensation granulator is installed at an angle along the discharge end of the granulated iodine, which allows the coarsened granulated iodine to gradually move towards the rear end, which is beneficial for the discharge of iodine granules.

[0022] In this invention, iodine is sublimated using dry air, which granulates the iodine while further drying and removing moisture to obtain granular dry iodine. To ensure sublimation efficiency, the sublimation temperature should not be too low, but it should not exceed the melting point of iodine. Therefore, the sublimator temperature is preferably set at 90-110℃, and the dry air is preheated to sublimate the iodine, so as to maintain a high sublimation and granulation efficiency.

[0023] In this invention, iodine powder is pre-placed in the sublimation granulator. While cooling in the lower part, it is sprayed onto the sublimation gas flow channel in the middle of the cylinder as the scraper rotates. The hot iodine vapor and the cold iodine powder come into contact and sublimate on the surface of the pre-cooled iodine powder. With continuous sublimation, the iodine powder gradually increases in size and forms granules, which then move towards the lower rear area as the scraper rotates, resulting in enriched iodine particles that are discharged. The pre-placed iodine powder filling amount in the sublimation granulator should ideally be controlled at 10-20%. If it is too low, the contact probability between iodine gas and iodine powder is low, affecting the sublimation efficiency and allowing more iodine vapor to enter the subsequent non-condensable gas absorber, increasing the load on the absorber. If the filling amount is too high, it is difficult to obtain iodine particles with larger particle sizes.

[0024] In this invention, the iodine vapor that has not been completely condensed in the sublimation granulator enters the downstream system with the air. This part of the iodine vapor can be absorbed by the sodium sulfite solution in a cycle. The solution after absorbing the iodine vapor is sent to the iodine recovery system for oxidation and iodine precipitation and filtration into powdered iodine.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The process is simple and efficient. This invention uses a heated iodine gas pipe to connect the sublimator and the granulator. While the iodine vapor is condensing, the powdered iodine grows into granules, realizing the iodine sublimation and refining process while forming granules. This significantly simplifies the iodine production and recycling process and improves production efficiency.

[0027] 2. Low energy consumption: This invention uses dry air to sublimate iodine, which further dries and removes water while sublimating and condensing into granules, thus obtaining dry iodine granules, effectively reducing energy consumption.

[0028] 3. The product quality is good. The iodine particles obtained by this invention have a smooth and round surface and an iodine content of over 99.8%, which expands the application range. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the iodine granulation device of the present invention.

[0030] In the diagram, 1 is the sublimator, 2 is the heating jacket, 3 is the stirrer, 4 is the iodine gas pipe, 5 is the condenser granulator, 6 is the cooling water jacket, 7 is the heat insulator, 8 is the scraper, 9 is the non-condensable gas absorber, 10 is the coarse iodine powder feed port, 11 is the air inlet, 12 is the iodine vapor outlet, 13 is the temperature jacket, 14 is the sublimator heat medium inlet, 15 is the sublimator heat medium outlet, 16 is the iodine gas pipe heat medium inlet, 17 is the iodine gas pipe heat medium outlet, 18 is the iodine vapor inlet, 19 is the powder iodine feed port, 20 is the cooling water outlet, 21 is the cooling water inlet, 22 is the granular iodine discharge port, 23 is the non-condensable gas outlet, 24 is the non-condensable gas inlet, 25 is the tail gas outlet, 26 is the absorbent feed port, and 27 is the drain port. Detailed Implementation

[0031] like Figure 1As shown, the iodine granulation apparatus of the present invention includes a sublimator 1, a condensation granulator 5, and an iodine gas pipe 4. The upper part of the sublimator 1 is provided with a coarse iodine powder feed port 10 and an iodine vapor outlet 12. The bottom of the sublimator 1 is provided with an air inlet 11. A heating jacket 2 is provided on the outer wall of the sublimator 1, and a sublimator heat medium inlet 14 and a sublimator heat medium outlet 15 are provided on the heating jacket 2. The upper part of the condensation granulator 5 is provided with an iodine vapor inlet 18 and a powder iodine feed port 19. The lower rear end of the condensation granulator 5 is provided with a granulated iodine outlet 22. The two ends of the iodine gas pipe 4 are respectively connected to the iodine vapor outlet 12 and the iodine vapor inlet 18. A scraper 8 is provided on the inner wall of the condensation granulator 5. The lower part of the outer wall of the sublimation granulator 5 is provided with a cooling water jacket 6, and the cooling water jacket 6 is provided with a cooling water outlet 20 and a cooling water inlet 21. The outer wall of the iodine gas pipe 4 is provided with a heating tracing pipe, and the heating tracing pipe is provided with an iodine gas pipe heat medium inlet 16 and an iodine gas pipe heat medium outlet 17. The sublimator 1 is also provided with a stirrer 3 and a temperature sleeve 13. The upper part of the sublimation granulator 5 is also provided with a heat preservation device 7. The sublimation granulator 5 is also provided with a non-condensable gas outlet 23, and the non-condensable gas outlet 23 is connected to a non-condensable gas absorber 9. The upper part of the non-condensable gas absorber 9 is provided with a non-condensable gas inlet 24, a tail gas outlet 25 and an absorbent liquid inlet 26, and the lower side is provided with a drain outlet 27.

[0032] The method for granulating iodine using the above-described apparatus includes the following steps:

[0033] (1) Add crude iodine powder into sublimator 1 through crude iodine powder feed port 10, turn on stirrer 3, and introduce heat medium into heating jacket 2 through sublimator heat medium inlet 14; introduce heat medium into heating tracing pipe of iodine gas pipe 4 through iodine gas pipe heat medium inlet 16 to preheat iodine gas pipe 4; add pre-placed powder iodine into granulator 5 through powder iodine feed port 19, and introduce cooling water into cooling water jacket 6 through cooling water inlet 21; start scraper 8.

[0034] (2) When the crude iodine powder in the sublimator 1 is heated to the set temperature, dry air is introduced into the sublimator 1 through the air inlet 11. The generated iodine vapor enters the condenser 5 from the iodine gas pipe 4 and condenses with the pre-set powder iodine. The non-condensable gas after condensation enters the non-condensable gas absorber 9 and absorbs the uncondensed iodine vapor with sodium sulfite solution. The absorbed tail gas is discharged through the tail gas outlet 25 in compliance with the standard.

[0035] (3) Powdered iodine continuously contacts iodine vapor in the condenser 5 and grows. The coarsened iodine particles gradually move to the rear end. When a certain amount of iodine particles accumulate in the condenser 5, the supply of dry air to the sublimator 1 is stopped, and the iodine particles are taken out from the iodine particle outlet 22.

[0036] (4) The granular iodine is screened to obtain the finished product. The fine particles are returned to the granulator 5 to continue to contact with iodine vapor and condense to become coarser granular iodine.

[0037] The present invention will be described in more detail below through embodiments, but the present invention is not limited to these embodiments. Based on the teachings of the present invention, any obvious modifications or substitutions to the present invention by those skilled in the art should also be considered within the scope of protection of the present invention.

[0038] Some of the devices in the embodiments are described below:

[0039] Sublimation unit: Specifications Ф80*200, enamel-lined;

[0040] Sublimation pelletizer: Specifications Ф80*300, enamel-lined;

[0041] Iodine gas tube: a U-shaped tube with a specification of Ф25 and an inner enamel lining.

[0042] Example 1

[0043] The process parameters for iodine granulation using this device are as follows:

[0044] The sublimation granulator is installed at an angle along the iodine discharge port, with the central axis of the sublimation granulator at an angle of 1° to the horizontal plane; the sublimator temperature is set to 90℃; the iodine gas pipe temperature is set to 90℃; the cooling water outlet temperature of the sublimation granulator is 30℃; the flow rate of the dry air is 200L / h; the pre-filled iodine powder with a particle size of less than 1mm in the sublimation granulator accounts for 10% of the volume of the sublimation granulator; the iodine content of the crude iodine powder is 94.32%.

[0045] After 12 hours, the ventilation was stopped, and the granular iodine was taken out from the granular iodine outlet. After sieving, granular iodine with a smooth and round surface, a diameter of 1-3 mm, and an iodine content of 99.87% was obtained. Powdered iodine with a particle size of less than 1 mm was returned to the sublimation granulator.

[0046] Example 2

[0047] The process parameters for iodine granulation using this device are as follows:

[0048] The sublimation granulator is installed at an angle along the iodine discharge port, with the central axis of the sublimation granulator forming an angle of 1.5° with the horizontal plane; the sublimator temperature is set to 100℃; the iodine gas pipe temperature is set to 100℃; the cooling water outlet temperature of the sublimation granulator is 35℃; the flow rate of the dry air is 150L / h; the pre-filled iodine powder with a particle size of less than 1.5mm in the sublimation granulator accounts for 15% of the sublimation granulator volume; the crude iodine powder has an iodine content of 94.32%.

[0049] After 12 hours, the ventilation was stopped, and the granular iodine was taken out from the granular iodine outlet. After sieving, granular iodine with a smooth and round surface, a diameter of 1.5-4 mm, and an iodine content of 99.82% was obtained. Powdered iodine with a particle size of less than 1.5 mm was returned to the granulation condenser.

[0050] Example 3

[0051] The process parameters for iodine granulation using this device are as follows:

[0052] The sublimation granulator is installed at an angle along the iodine discharge port, with the central axis of the sublimation granulator at an angle of 2° to the horizontal plane; the sublimator temperature is set at 110℃; the iodine gas pipe temperature is set at 110℃; the cooling water outlet temperature of the sublimation granulator is 40℃; the flow rate of the dry air is 100L / h; the pre-filled iodine powder with a particle size of less than 2mm in the sublimation granulator accounts for 20% of the volume of the sublimation granulator; the iodine content of the crude iodine powder is 94.32%.

[0053] After 15 hours, the ventilation was stopped, and the granular iodine was taken out from the granular iodine outlet. After screening, granular iodine with a smooth and round surface, a diameter of 2-5 mm, and an iodine content of 99.80% was obtained. Powdered iodine with a particle size of less than 2 mm was returned to the granulation condenser.

Claims

1. An iodine granulation device, characterized in that, The device includes a sublimator, a granulator, and an iodine gas pipe. The upper part of the sublimator is provided with a coarse iodine powder feed port and an iodine vapor outlet. The bottom of the sublimator is provided with an air inlet. The outer wall of the sublimator is provided with a heating jacket. The upper part of the granulator is provided with an iodine vapor inlet, a powder iodine feed port, and a non-condensable gas outlet. The lower rear end of the granulator is provided with a granulated iodine discharge port. The two ends of the iodine gas pipe are connected to the iodine vapor outlet and the iodine vapor inlet, respectively. A scraper is provided on the inner wall of the granulator. A cooling water jacket is provided on the lower part of the outer wall of the granulator. A heat insulator is provided on the upper part of the granulator. A heating tracing pipe is provided on the outer wall of the iodine gas pipe.

2. The iodine granulation apparatus as described in claim 1, characterized in that, The sublimator is equipped with a stirrer.

3. The iodine granulation apparatus as described in claim 1, characterized in that, The non-condensable gas outlet is connected to a non-condensable gas absorber.

4. The iodine granulation apparatus as described in claim 1, characterized in that, The sublimation granulator is inclined, and the angle between the central axis of the sublimation granulator and the horizontal plane is 1 to 2°.

5. The method for granulating iodine using the apparatus of claim 3, characterized in that, Includes the following steps: (1) Add crude iodine powder into the sublimator through the crude iodine powder feed port, and introduce heat medium into the heating jacket through the heat medium inlet of the sublimator; preheat the iodine gas pipe by introducing heat medium into the iodine gas pipe heating pipe through the iodine gas pipe heat medium inlet; add pre-placed powder iodine into the condenser through the powder iodine feed port, wherein the amount of pre-placed powder iodine in the condenser is 10-20% of the volume of the condenser; introduce cooling water into the cooling water jacket through the cooling water inlet; and start the scraper. (2) When the sublimator is heated to the set temperature of 90-110℃, dry air is introduced into the sublimator through the air inlet. The generated iodine vapor enters the condenser from the iodine gas pipe and condenses with the pre-set powder iodine. The non-condensable gas after condensation enters the non-condensable gas absorber and absorbs the uncondensed iodine vapor with sodium sulfite solution. The tail gas after absorption is discharged through the tail gas outlet in compliance with the standard. (3) Powdered iodine continuously contacts iodine vapor in the condenser and condenses to grow larger. The coarsened iodine particles gradually move to the rear end. When a certain amount of iodine particles accumulate in the condenser, the supply of dry air to the sublimator is stopped, and the iodine particles are taken out from the iodine particle outlet. (4) The granular iodine is screened to obtain the finished product. The fine particles are returned to the condenser to continue to contact with iodine vapor and condense to become coarser granular iodine.

6. The method for iodine granulation as described in claim 5, characterized in that, The temperature of the iodine gas tube is set to 90-110℃.

7. The method for iodine granulation as described in claim 5, characterized in that, The cooling water outlet temperature of the sublimation granulator is set to 25-45℃.

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