Separation column for mixed ion exchange resins, and method for separating mixed ion exchange resins using the same.

Abstract

To provide a separation column of a mixed ion exchange resin which can separate the mixed ion exchange resin used in a mixed bed type ion exchanger or the like with accuracy.SOLUTION: In a separation column 1 of a mixed ion exchange resin, a water inflow / outflow port 2 is provided on a bottom of a cylindrical separation column main body 1A and a water supply pipe 3 including a plurality of discharge nozzles 3A is also provided, and a water discharge port 4 is formed on an apex of the same. A water collection plate 5 is arranged on the upper side of the discharge nozzles 3A of the separation column main body 1A. In addition, in the vicinity of center in a vertical direction in the separation column 1, first to third anion exchange resin extraction pipes 6A, 6B, 6C are provided, and a cation exchange resin extraction pipe 27 is provided on the lower side of the anion exchange resin extraction pipe 6C and slightly above the water collection plate 5. On the other hand, an inspection window 8 exists on a side face of the separation column 1.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a separation column for mixed ion exchange resins used in a mixed bed ion exchange device used in a pure water production device or the like, and a method for separating the mixed ion exchange resins extracted from a mixed bed ion exchange device or the like.

Background Art

[0002] In a pure water production device, impurities in raw water are removed to improve the purity of water. However, in order to remove ionic impurities, that is, anionic impurities and cationic impurities, a mixed bed ion exchange device filled with a mixture of an anion exchange resin and a cation exchange resin is widely used. In this mixed bed ion exchange device, when the ion exchange resin exchanges an amount of ions corresponding to the ion exchange capacity, further ionic impurities cannot be removed and breakthrough occurs. Therefore, after treating a certain amount of water, the ion exchange resin is recovered from this mixed bed ion exchange device and separated into each, and is regenerated with sulfuric acid, caustic soda, etc. in a cation exchange resin regeneration tower and an anion exchange resin regeneration tower, respectively, and reused in industrial applications such as CRM and CRM-HX.

[0003] When separating and reusing this mixed ion exchange resin, it is preferable to maintain the regeneration state of the resin at a higher level. For this purpose, it is necessary to minimize the occurrence of reverse regeneration. Reverse regeneration means that when regenerating a cation exchange resin contaminated with an anion exchange resin with an acid solution such as hydrochloric acid or sulfuric acid, the anion exchange resin is regenerated into a Cl form or a SO4 form, etc., and when regenerating an anion exchange resin contaminated with a cation exchange resin with an alkali solution such as sodium hydroxide, the cation exchange resin is regenerated into a Na form, etc. The resin subjected to reverse regeneration leaks Cl or Na into the treated water, leading to deterioration of water quality. Therefore, reducing the mixing rate is an important issue.

[0004] The resin extracted from the mixed bed ion exchange device is introduced into a separation column. After performing bubbling and backwashing, the cation exchange resin and the anion exchange resin are separated using the specific gravity difference, and each is extracted from the separation column.

[0005] An example of a conventional separation tower for mixed ion exchange resins is shown in Figure 6. In Figure 6, the separation tower 21 for mixed ion exchange resins has an inlet / outlet port 22 at the bottom of the cylindrical separation tower body 21A, and a water supply pipe 23 as a discharge section equipped with multiple discharge nozzles 23A, with a drain port 24 formed at the top. A water collection plate 25 is positioned above the discharge nozzles 23A of the separation tower body 21A. An anion exchange resin extraction pipe 26 is provided as an anion exchange resin extraction section near the middle of the vertical direction inside the separation tower 21, and a cation exchange resin extraction pipe 27 is provided below the anion exchange resin extraction pipe 26 and slightly above the water collection plate 25. A viewing window 28 is also provided on the side of the separation tower 21. Note that 29 is an inlet for used mixed ion exchange resins provided on the upper side of the separation tower 21. [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] In the conventional separation tower 21 described above, one anion exchange resin extraction pipe 26 and one cation exchange resin extraction pipe 27 are installed. However, the mixing ratio of anion exchange resin and cation exchange resin in a mixed-bed ion exchange system is often set differently depending on the customer's water supply quality. As a result, the position of the interface between the anion exchange resin and the cation exchange resin differs when separated by specific gravity in a mixed-bed ion exchange system, resulting in an optimal extraction position for the anion exchange resin and an increase in the contamination rate. Conventionally, the amount of resin introduced into the separation tower 21 has been adjusted by visually checking through the viewing window 28 to ensure optimal extraction through the anion exchange resin extraction pipe 26 based on the mixing ratio of anion exchange resin and cation exchange resin. However, this is not only inefficient but also has the problem that it is not possible to sufficiently reduce the contamination rate of other resins when the anion exchange resin or cation exchange resin is extracted.

[0007] The present invention has been made in view of the above problems, and aims to provide a separation column for mixed ion exchange resins that can accurately separate mixed ion exchange resins used in mixed-bed ion exchange apparatuses and the like. The present invention also aims to provide a method for separating mixed ion exchange resins that can accurately separate mixed ion exchange resins used in mixed-bed ion exchange apparatuses and the like. [Means for solving the problem]

[0008] In view of the above objectives, the present invention first provides a separation column for mixed ion exchange resins that separates two types of mixed ion exchange resins having different specific gravities using the difference in specific gravity, wherein a plurality of first ion exchange resin extraction units for extracting the first ion exchange resin with the lower specific gravity are arranged in a series in the vertical direction (Invention 1).

[0009] According to this invention (Invention 1), by selecting a series of first ion exchange resin extraction units from which the first ion exchange resin is extracted, depending on the position of the separation interface between the first ion exchange resin and the second ion exchange resin, the first ion exchange resin can be extracted from an optimal position, thereby enabling the separation of the first ion exchange resin and the second ion exchange resin with reduced contamination by the other ion exchange resin.

[0010] In the above invention (Invention 1), it is preferable to have a viewing window on the side of the separation column for the mixed ion exchange resin (Invention 2).

[0011] According to this invention (Invention 2), by visually observing the separation interface between the first ion exchange resin and the second ion exchange resin through a viewing window, and selecting a series of first ion exchange resin extraction units that extract the first ion exchange resin according to the position of this separation interface, the first ion exchange resin can be extracted at the optimal position.

[0012] In the above invention (Invention 1), it is preferable to include an interface sensor that detects the separation interface between the first ion exchange resin and the second ion exchange resin (Invention 3).

[0013] According to this invention (Invention 3), by determining the separation interface between the first ion exchange resin and the second ion exchange resin using an optical interface sensor such as a chromaticity sensor, and selecting a series of first ion exchange resin extraction units to extract the first ion exchange resin according to the position of this separation interface, the first ion exchange resin can be extracted at the optimal position.

[0014] In the above invention (Invention 3), it is preferable to have a control means for selecting a first ion exchange resin extraction unit from a plurality of series based on the detection result of the separation interface of the interface sensor (Invention 4).

[0015] According to this invention (Invention 4), the separation process of the first ion exchange resin and the second ion exchange resin can be automated by controlling the control means to select a first ion exchange resin extraction unit for extracting the first ion exchange resin based on the determination result of the separation interface of the interface sensor.

[0016] In the above inventions (Inventions 1 to 4), it is preferable that the first ion exchange resin is an anion exchange resin and the second ion exchange resin is a cation exchange resin (Invention 5).

[0017] According to this invention (Invention 5), since anion exchange resin generally has a lower specific gravity than cation exchange resin, when separated by specific gravity, the anion exchange resin settles to the upper side and the cation exchange resin settles to the lower side. Therefore, by then determining the interface between the two, the anion exchange resin can be accurately extracted from the upper anion exchange resin extraction section.

[0018] Secondly, the present invention provides a method for separating mixed ion exchange resins using a mixed ion exchange resin separation column that separates two types of mixed ion exchange resins having different specific gravities by utilizing the difference in specific gravity, wherein the mixed ion exchange resin separation column has a plurality of first ion exchange resin extraction sections arranged vertically for extracting the first ion exchange resin having the lower specific gravity, water is passed through the mixed ion exchange resin separation column in an upward flow to separate the mixed ion exchange resins by utilizing the difference in specific gravity, and one of the plurality of first ion exchange resin extraction sections is selected according to the separation interface between the first ion exchange resin and the second ion exchange resin, and the first ion exchange resin is extracted from the selected first ion exchange resin extraction section (Invention 6).

[0019] According to this invention (Invention 6), by selecting a series of first ion exchange resin extraction units for the first ion exchange resin according to the position of the separation interface between the first ion exchange resin and the second ion exchange resin, the first ion exchange resin can be extracted from an optimal position, thereby enabling the separation of the first ion exchange resin and the second ion exchange resin with reduced contamination by the other ion exchange resin.

[0020] In the above invention (Invention 6), the separation column for the mixed ion exchange resin has a viewing window on its side, and one of the multiple series of first ion exchange resin extraction units can be selected from the viewing window according to the separation interface between the first ion exchange resin and the second ion exchange resin, and the first ion exchange resin can be extracted from the selected first ion exchange resin extraction unit (Invention 7).

[0021] According to this invention (Invention 7), by visualizing the separation interface between the first ion exchange resin and the second ion exchange resin through a viewing window and selecting the series of first ion exchange resin extraction units from which the first ion exchange resin is extracted, the resin can be extracted from the optimal position.

[0022] In the above invention (Invention 6), an interface sensor is provided in the separation column of the mixed ion exchange resin to detect the separation interface between the first ion exchange resin and the second ion exchange resin, and based on the detection result of the separation interface by the interface sensor, one of the plurality of first ion exchange resin extraction units may be selected, and the first ion exchange resin may be extracted from the selected first ion exchange resin extraction unit (Invention 8).

[0023] According to this invention (Invention 8), by determining the separation interface between the first ion exchange resin and the second ion exchange resin using an optical interface sensor such as a chromaticity sensor, and selecting a series of first ion exchange resin extraction units from which the first ion exchange resin is extracted, the resin can be extracted from the optimal position. Furthermore, by providing a separate control means, the separation process of the first ion exchange resin and the second ion exchange resin can be automated by controlling the selection of the first ion exchange resin extraction unit from which the first ion exchange resin is extracted based on the determination result of the separation interface by the interface sensor.

[0024] In the above inventions (Inventions 6-8), it is preferable that the first ion exchange resin is an anion exchange resin and the second ion exchange resin is a cation exchange resin (Invention 9).

[0025] According to this invention (Invention 9), since anion exchange resin generally has a lower specific gravity than cation exchange resin, when separated by specific gravity, the anion exchange resin settles on the upper side and the cation exchange resin settles on the lower side. Therefore, by determining the interface between the two, the anion exchange resin can be accurately extracted from the upper anion exchange resin extraction section. [Effects of the Invention]

[0026] According to the separation tower of the mixed ion exchange resin of the present invention, since a plurality of series of first ion exchange resin extraction parts for extracting the first ion exchange resin with a smaller specific gravity are arranged in the vertical direction, according to the position of the separation interface between the first ion exchange resin and the second ion exchange resin, by selecting the series of the first ion exchange resin extraction parts for extracting the first ion exchange resin, the first ion exchange resin and the second ion exchange resin can be separated with reduced contamination by other ion exchange resins. As a result, there is also an effect that it is not necessary to adjust the input amount of the mixed ion exchange resin input into the separation tower.

Brief Description of the Drawings

[0027] [Figure 1] It is a schematic diagram showing a separation tower of a mixed ion exchange resin according to a first embodiment of the present invention. [Figure 2] It is a schematic diagram showing a backwashing process by a separation tower of a mixed ion exchange resin according to the same embodiment. [Figure 3] It is a schematic diagram showing a separation process by a separation tower of a mixed ion exchange resin according to the same embodiment. [Figure 4] It is a schematic diagram showing a separation tower of a mixed ion exchange resin according to a second embodiment of the present invention. [Figure 5] It is a schematic diagram showing a separation tower of a mixed ion exchange resin according to a third embodiment of the present invention. [Figure 6] It is a schematic diagram showing a separation tower of a conventional mixed ion exchange resin.

Embodiments for Carrying Out the Invention

[0028] Hereinafter, a first embodiment of a separation tower of a mixed ion exchange resin of the present invention will be described in detail with reference to the accompanying drawings.

[0029] First Embodiment 〔Separation Tower of Mixed Ion Exchange Resin〕 Figure 1 shows a separation tower for mixed ion exchange resins according to the first embodiment of the present invention. In Figure 1, the separation tower 1 for mixed ion exchange resins has an inlet / outlet port 2 at the bottom of a cylindrical separation tower body 1A, and a water supply pipe 3 as a water discharge section equipped with multiple discharge nozzles 3A, with a drain port 4 formed at the top. A water collection plate 5 is positioned below the discharge nozzles 3A of the separation tower body 1A. In addition, near the middle of the vertical direction inside the separation tower 1, there are multiple series (3 series in this embodiment) of anion exchange resin extraction sections, namely the first to third anion exchange resin extraction pipes 6A, 6B, and 6C, and a cation exchange resin extraction pipe 7 is provided below these anion exchange resin extraction pipes 6A, 6B, and 6C, above the water collection plate 5. On the other hand, the separation tower 1 has a viewing window 8 on its side. Note that 9 is an inlet for used mixed ion exchange resins provided on the upper side of the separation tower 1.

[0030] In the separation column 1 for mixed ion exchange resin as described above, at the branching points (base ends) of the extraction pipes 6A, 6B, and 6C, on-off valves (not shown) are provided for opening and closing the extraction pipes 6A, 6B, and 6C, and it is possible to manually control the valve of one of the extraction pipes 6A, 6B, or 6C to open and close the others.

[0031] [Method for separating mixed ion exchange resins] Next, a method for separating mixed ion exchange resins using the mixed ion exchange resin separation column 1 of this embodiment, which has the configuration described above, will be explained.

[0032] (Resin introduction) First, as shown in Figure 1, the used mixed ion exchange resin packed in the mixed-bed ion exchange apparatus is removed and filled into the separation column 1 for the mixed ion exchange resin through the inlet 9 for the used mixed ion exchange resin. The introduction of this mixed ion exchange resin R can be done by receiving the mixed ion exchange resin, which has been transported in a flexible container or the like, into a water tank and introducing it into the separation column 1 through the inlet 9 for the used mixed ion exchange resin provided on the side of the separation column 1 using a tube pump, but is not limited to this method.

[0033] At this time, the space above the water collection plate 5 of the separation tower body 1A is filled with used mixed ion exchange resin to an extent that it occupies approximately 40 to 70% by volume. In this embodiment, the mixed ion exchange resin is a mixture of anion exchange resin and cation exchange resin. There are no particular restrictions on the ratio (volume ratio) of anion exchange resin and cation exchange resin in this mixed ion exchange resin, but it is approximately anion exchange resin:cation exchange resin = 30:70 to 70:30. Furthermore, it is preferable that these anion exchange resin and cation exchange resin are porous type ion exchange resins. It is preferable that the height of the upper surface of the introduced mixed ion exchange resin R be above the uppermost first anion exchange resin extraction pipe 6A, particularly about 100 to 700 mm above it.

[0034] (Water filling) As shown below, a predetermined amount of separation water (pure water) is introduced into the separation column 1 from the inlet / outlet port 2 at the bottom. At this time, the water level of the separation water is set to be above the top surface of the ion exchange resin inside the separation column 1, particularly by about 500 mm or less.

[0035] (Air bubbling) Next, air is injected into the separation tower 1 from the inlet / outlet port 2, causing the ion exchange resin R to bubble. This loosens the colloidally entangled resin particles and removes any dirt adhering to the surface of the resin particles.

[0036] (pause) The bubbling is stopped, and the mixed ion exchange resin R is allowed to settle on the water collecting plate 5. During this settling, the cation exchange resin, which has a higher specific gravity, settles first, followed by the anion exchange resin, which has a lower specific gravity.

[0037] (Full of water) In preparation for backwashing, water (separation water) is introduced from the inlet / outlet 2 so that the inside of separation tower 1 is filled with water.

[0038] (backwash / separation) With the container full of water, water W (the same water used for separation) is introduced from the discharge nozzle 3A of the separation tower body 1A and passed through in an upward flow, causing the resin to spread out as shown in Figure 2. After that, by allowing it to stand, the anion exchange resin A separates into the upper layer and the cation exchange resin C separates into the lower layer due to the difference in specific gravity, as shown in Figure 3. Whether or not the separation has occurred can be determined by visual inspection through the viewing window 8, and the time may be extended depending on the situation.

[0039] (Anion exchange resin extraction) After visually confirming the separation of the anion exchange resin and cation exchange resin through the viewing window 8, the anion exchange resin extraction pipe (in this embodiment, the third anion exchange resin extraction pipe 6C) is selected, the lower end of the suction port of the anion exchange resin extraction pipe is closest to the upper surface of the separation interface between anion exchange resin A and cation exchange resin C. The valve of this third anion exchange resin extraction pipe 6C is opened, and the valves of the first and second anion exchange resin extraction pipes 6A and 6B are closed. The anion exchange resin is then extracted by suction from the third anion exchange resin extraction pipe 6C, flowing out as an anion exchange resin-water mixed phase flow. This anion exchange resin-water mixed phase flow can be received in a flexible container or the like. If it is to reliably avoid mixing cation exchange resin C with anion exchange resin A, the resin may be extracted from the second anion exchange resin extraction pipe 6B.

[0040] (Extraction of cation exchange resin) After the anion exchange resin A has been extracted in this manner, the cation exchange resin C can be extracted from the water collection plate 5 to a predetermined height by suction from the cation exchange resin extraction pipe 7. At this time, since there is a high possibility that both resins will be mixed near the separation interface between the anion exchange resin A and the cation exchange resin C, the cation exchange resin C should be extracted from the cation exchange resin extraction pipe 7 so that 5 to 20 volume percent of the resin remains in the separation column 1 relative to the total amount of mixed ion exchange resin. The ion exchange resin remaining in the separation column body 1A can be removed and reused when separating the mixed resin of anion exchange resin and cation exchange resin in the next separation.

[0041] (Regeneration process) The anion exchange resin A and cation exchange resin C separated in this manner can be regenerated using a regeneration tower for each resin as is known.

[0042] Second Embodiment Next, a second embodiment of the separation column for mixed ion exchange resins of the present invention will be described with reference to the attached drawings.

[0043] [Separation column using mixed ion exchange resin] Figure 4 shows a separation column for mixed ion exchange resins according to a second embodiment of the present invention. The separation column for mixed ion exchange resins in this embodiment has basically the same configuration as that of the first embodiment described above, so the same components are denoted by the same reference numerals, and their detailed description is omitted.

[0044] In the separation column 1 for mixed ion exchange resin shown in Figure 4, an interface sensor 8A is provided on the side of the separation column 1 instead of a viewing window 8. This interface sensor 8A can transmit a judgment result to a control means such as a personal computer (not shown), and the control means can open and close the on-off valves provided at the branching points (base ends) of the first to third extraction pipes 6A, 6B, and 6C based on this judgment result.

[0045] In the separation column 1 of the mixed ion exchange resin described above, the interface sensor 8A is preferably one that determines the interface from the difference in color between the anion exchange resin and the cation exchange resin, since the colors of the two resins differ. Specifically, it is preferable to use a sensor that receives reflected light as a two-dimensional received image, such as a CCD camera (especially a color CCD camera) or a two-dimensional image sensor, and measures its chromaticity, but it may also be a light sensor or line sensor that receives light as a point or one-dimensional signal.

[0046] [Method for separating mixed ion exchange resins] The method for separating the mixed ion exchange resin in the mixed ion exchange resin separation tower 1 of this embodiment, having the above configuration, is the same as in the first embodiment described above, except that the lower end of the suction port of the anion exchange resin extraction pipe is selected by visual inspection from the viewing window 8, and the operation of the on / off valves of the first to third anion exchange resin extraction pipes 6A, 6B, and 6C is performed by the interface sensor 8A and the control means.

[0047] As in this embodiment, by performing the operation of the on-off valves of the first to third anion exchange resin extraction pipes 6A, 6B, and 6C using the interface sensor 8A and control means, it becomes possible to automate the high-precision separation of mixed ion exchange resins.

[0048] Third Embodiment Next, a third embodiment of the separation column of the mixed ion exchange resin of the present invention will be described with reference to the attached drawings.

[0049] [Separation column using mixed ion exchange resin] Figure 5 shows a separation column for mixed ion exchange resins according to a third embodiment of the present invention. The separation column for mixed ion exchange resins in this embodiment has basically the same configuration as that of the first embodiment described above, so the same reference numerals are used for the same components, and their detailed descriptions are omitted.

[0050] The separation column 1 for mixed ion exchange resins shown in Figure 5 has an anion exchange resin extraction piping consisting of a main anion exchange resin extraction pipe 61 arranged horizontally in the separation column body 1A, and two extraction pipes of different lengths, a first extraction pipe 61A and a second extraction pipe 61B, branching vertically downward from this main pipe 61. At the branching points (base ends) of the first and second extraction pipes 61A and 61B, on-off valves (not shown) are provided to open and close the extraction pipes 61A and 61B, respectively, and it is possible to control the valves of either the extraction pipes 61A or 61B to open and the other to close.

[0051] [Method for separating mixed ion exchange resins] The method for separating the mixed ion exchange resin in the mixed ion exchange resin separation tower 1 of this embodiment, which has the above configuration, is the same as in the first embodiment described above. By visually observing through the viewing window 8, the anion exchange resin extraction pipe whose lower end of the suction port is closest to the upper surface of the separation interface between the anion exchange resin A and the cation exchange resin C is selected, and the on / off valves of the first or second anion exchange resin extraction pipes 61A and 61B are operated.

[0052] The present invention has been described above with reference to the accompanying drawings and based on the embodiments described above. However, the present invention is not limited to the embodiments described above, and various modifications are possible. For example, although the cation exchange resin extraction piping 7 was a single series in the above embodiments, it may be a series of multiple series. On the other hand, the cation exchange resin C may be regenerated in the separation tower 1 without providing the cation exchange resin extraction piping 7, but it is necessary to note that there is a high possibility that anion exchange resin A will be mixed in. In addition, in the third embodiment, an interface sensor 8A may be provided instead of the viewing window 8. Furthermore, although the above embodiments described the case of two types of resins, anion exchange resin and cation exchange resin, the invention is also applicable when multiple types of anion exchange resin and cation exchange resin of different grades or properties are used. In this specification, ion exchange resin is not limited to anion exchange resin and cation exchange resin, but also includes catalyst resins on which a catalyst metal is supported, and boron selective adsorption resins. [Examples]

[0053] The present invention will be described in more detail by the following specific examples.

[0054] [Example 1] Using the ion exchange resin separation column 1 (diameter 1000 mmΦ, height 6000 mm) shown in Figure 1, a mixed ion exchange resin (anion exchange resin:cation exchange resin = 50:50 (volume ratio)) of porous anion exchange resin and porous cation exchange resin was packed into the column. Backwashing was performed with an upward flow at LV 5 m / h for 1 hour to separate the mixed ion exchange resin using the difference in specific gravity, and the water flow was stopped. The separation interface was visually confirmed through the observation window 8. Then, the third anion exchange resin extraction pipe 6C was selected as the anion exchange resin extraction pipe whose lower end of the suction port was closest to the upper surface of the separation interface between anion exchange resin A and cation exchange resin C, and anion exchange resin A was extracted. Subsequently, cation exchange resin C was extracted from the lower cation exchange resin extraction pipe 7, leaving approximately 10% of the ion exchange resin near the separation interface.

[0055] The percentage of cation exchange resin in the extracted cation exchange resin was found to be 0.004% by volume, which was satisfactory. This result, along with the separation conditions, is shown in Table 1.

[0056] [Example 2] Using the ion exchange resin separation tower 1 (diameter 1000 mmΦ, height 6000 mm) shown in Figure 2, a mixed ion exchange resin (anion exchange resin:cation exchange resin = 50:50 (volume ratio)) of porous anion exchange resin and porous cation exchange resin was packed into the tower. Backwashing was performed with an upward flow at LV 5 m / h for 1 hour to separate the mixed ion exchange resin using the difference in specific gravity, and the water flow was stopped. The separation interface was sensed by interface sensor 8A. Then, the third anion exchange resin extraction pipe 6C was selected as the anion exchange resin extraction pipe whose lower end of the suction port was closest to the upper surface of the separation interface between anion exchange resin A and cation exchange resin C, and anion exchange resin A was extracted. Subsequently, cation exchange resin C was extracted from the lower cation exchange resin extraction pipe 7, leaving approximately 10% of the ion exchange resin near the separation interface. The amount of ion exchange resin remaining at this time was fine-tuned based on the sensing results of interface sensor 8A.

[0057] The percentage of cation exchange resin in the extracted cation exchange resin was found to be 0.002% by volume, which was satisfactory. This result, along with the separation conditions, is shown in Table 1.

[0058] [Example 3] Using the ion exchange resin separation column 1 (diameter 1000 mmΦ, height 6000 mm) shown in Figure 5, a mixed ion exchange resin (anion exchange resin:cation exchange resin = 50:50 (volume ratio)) of porous anion exchange resin and porous cation exchange resin was packed into the column. Backwashing was performed with an upward flow at LV 5 m / h for 1 hour to separate the mixed ion exchange resin using the difference in specific gravity, and the water flow was stopped. The separation interface was visually confirmed through the observation window 8. Then, the second anion exchange resin extraction pipe 61B was selected as the anion exchange resin extraction pipe whose lower end of the suction port was closest to the upper surface of the separation interface between anion exchange resin A and cation exchange resin C, and anion exchange resin A was extracted. Subsequently, cation exchange resin C was extracted from the lower cation exchange resin extraction pipe 7, leaving approximately 10% of the ion exchange resin near the separation interface.

[0059] The percentage of cation exchange resin in the extracted cation exchange resin was found to be 0.005% by volume, which was satisfactory. This result, along with the separation conditions, is shown in Table 1.

[0060] [Example 4] Using the ion exchange resin separation tower 1 (diameter 1000 mmΦ, height 6000 mm) shown in Figure 5, a mixed ion exchange resin (anion exchange resin:cation exchange resin = 50:50 (volume ratio)) of porous anion exchange resin and porous cation exchange resin was packed into the tower. Backwashing was performed with an upward flow at LV 5 m / h for 1 hour to separate the mixed ion exchange resin using the difference in specific gravity, and the water flow was stopped. The separation interface was sensed by interface sensor 8A. Then, the second anion exchange resin extraction pipe 61B was selected as the anion exchange resin extraction pipe whose lower end of the suction port was closest to the upper surface of the separation interface between anion exchange resin A and cation exchange resin C, and anion exchange resin A was extracted. Subsequently, cation exchange resin C was extracted from the lower cation exchange resin extraction pipe 7, leaving approximately 10% of the ion exchange resin near the separation interface. The amount of remaining resin at this time was fine-tuned based on the sensing results of interface sensor 8A.

[0061] The percentage of cation exchange resin in the extracted cation exchange resin was found to be 0.003% by volume, which was satisfactory. This result, along with the separation conditions, is shown in Table 1.

[0062] [Comparative Example 1] Using the ion exchange resin separation column 21 (diameter 1000 mmΦ, height 6000 mm) shown in Figure 6, a mixed ion exchange resin (anion exchange resin:cation exchange resin = 50:50 (volume ratio)) of porous anion exchange resin and porous cation exchange resin was packed into the column. Backwashing was performed with an upward flow at LV 5 m / h for 1 hour, separating the mixed ion exchange resin using the difference in specific gravity, and then the water flow was stopped. The separation interface was visually confirmed through the observation window 8. Then, anion exchange resin A was extracted from the anion exchange resin extraction pipe 26. Subsequently, cation exchange resin C was extracted from the lower cation exchange resin extraction pipe 27, leaving approximately 10% by volume of ion exchange resin near the separation interface without extraction.

[0063] The percentage of cation exchange resin in the extracted cation exchange resin was found to be 0.14% by volume. This result, along with the separation conditions, is shown in Table 1.

[0064] [Comparative Example 2] In the ion exchange resin separation column 21 (diameter 1000 mmΦ, height 6000 mm) shown in Figure 6, an interface sensor 8A was installed instead of a viewing window 8. A mixed ion exchange resin (anion exchange resin:cation exchange resin = 50:50 (volume ratio)) of porous anion exchange resin and porous cation exchange resin was packed into the column, and backwashed with an upward flow at LV 5 m / h for 1 hour. The mixed ion exchange resin was separated using the difference in specific gravity, and the water flow was stopped. The separation interface was sensed by the interface sensor. Anion exchange resin A was then extracted from the anion exchange resin extraction pipe 26. Cation exchange resin C was extracted from the lower cation exchange resin extraction pipe 27, leaving approximately 10% by volume of ion exchange resin near the separation interface.

[0065] The percentage of cation exchange resin in the extracted cation exchange resin was found to be 0.14% by volume. This result, along with the separation conditions, is shown in Table 1.

[0066] [Table 1] [Explanation of Symbols]

[0067] 1. Separation column of mixed ion exchange resins 1A Separation tower body 2 Inlet / outlet 3 Water supply pipe 3A Discharge Nozzle 4 Drain port 5 Water collection plate 6A, 6B, 6C Anion exchange resin extraction piping 7. Cation exchange resin extraction piping 8 Peephole 8A Interface Sensor 9. Inlet for used mixed ion exchange resin R Mixed ion exchange resin A Anion exchange resin C cation exchange resin

Claims

1. A separation column for mixed ion exchange resins that separates two types of mixed ion exchange resins with different specific gravities by utilizing the difference in specific gravity, Multiple series of first ion exchange resin extraction units, which extract the first ion exchange resin with the lower specific gravity, are arranged vertically. An interface sensor for detecting the separation interface between the first ion exchange resin and the second ion exchange resin, A control means for selecting the first ion exchange resin extraction unit from the plurality of series based on the detection result of the separation interface of the interface sensor, Equipped with, A separation column for mixed ion exchange resins, from which the first ion exchange resin is extracted from the selected first ion exchange resin extraction section.

2. The separation column for the mixed ion exchange resin according to claim 1, wherein the separation column for the mixed ion exchange resin has a viewing window on its side.

3. A separation column for a mixed ion exchange resin according to claim 1 or 2, wherein the first ion exchange resin is an anion exchange resin and the second ion exchange resin is a cation exchange resin.

4. A method for separating mixed ion exchange resins using a separation column for mixed ion exchange resins that separates two types of mixed ion exchange resins with different specific gravities by utilizing the difference in specific gravity, The separation column for the mixed ion exchange resins has multiple series of first ion exchange resin extraction units arranged vertically to extract the first ion exchange resin with the lower specific gravity. The mixed ion exchange resin is separated by passing water upward through the separation column of the mixed ion exchange resin using the difference in specific gravity, and one of the multiple series of the first ion exchange resin extraction section is selected according to the separation interface between the first ion exchange resin and the second ion exchange resin, and the first ion exchange resin is extracted from the selected first ion exchange resin extraction section. A method for separating mixed ion exchange resins, comprising: an interface sensor for detecting the separation interface between the first ion exchange resin and the second ion exchange resin is provided in the separation column of the mixed ion exchange resins; and based on the detection result of the separation interface by the interface sensor, one of the multiple series of the first ion exchange resin extraction units is selected, and the first ion exchange resin is extracted from the selected first ion exchange resin extraction unit.

5. The method for separating mixed ion exchange resins according to claim 4, wherein the separation column for the mixed ion exchange resins has a viewing window on its side, and one of the plurality of series of the first ion exchange resin extraction units is selected from the viewing window according to the separation interface between the first ion exchange resin and the second ion exchange resin, and the first ion exchange resin is extracted from the selected first ion exchange resin extraction unit.

6. The method for separating mixed ion exchange resins according to claim 4 or 5, wherein the first ion exchange resin is an anion exchange resin and the second ion exchange resin is a cation exchange resin.

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