Water treatment equipment

Abstract

To provide a water treatment apparatus capable of stably giving water solubility to a hardly soluble salt solid at high efficiency with low cost.SOLUTION: The water treatment apparatus which is composed of an ion exchanger for ion exchange of any of constituent ions of a hardly soluble salt-containing aqueous solution, and adsorbs any of the constituent ions to the ion exchanger so as to elute the adsorbed constituent ions from the ion exchanger, includes: accommodation means for accommodating the ion exchanger; supply means for supplying a predetermined aqueous solution to the accommodation means; control means for variably controlling a channel length of an aqueous solution circulating in the accommodation means so that the length in the elution of the constituent ions from the ion exchanger is longer than that in the adsorption of the constituent ions to the ion exchanger; and extraction means for selectively extracting the aqueous solution where any of the constituent ions derived from the hardly soluble salt is dissolved by the control of the control means.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a water treatment apparatus for purifying a water-receiving solution, and more particularly to a water treatment apparatus capable of treating an aqueous solution containing sparingly soluble salts. [Background technology]

[0002] Aqueous solutions containing poorly soluble salts, such as many alkaline earth metal salts, require purification treatment because discharging them directly would place a burden on the environment.

[0003] On the other hand, such aqueous solutions containing sparingly soluble salts often contain useful fertilizer components. Considering the life cycle of fertilizer, a nutrient resource, it is imported from far away overseas using energy, and there is a need for a stable domestic supply. Furthermore, in recent years, there have been concerns about the depletion of buried resources, and there is a growing need for the recycling and efficient use of fertilizer.

[0004] From this point of view, nutrients used in agriculture and daily life can cause environmental degradation through eutrophication if they are discharged or runoff into the environmental waters. Therefore, they are removed into the gas or solid phase, and some of them are recycled and reused as fertilizers such as compost.

[0005] However, nutrients in water systems are recovered as sparingly soluble substances, and the extent of recovery depends on solubility and the balance of supply and demand. Currently, due to their low water solubility, nutrients are circulated as slow-release fertilizers with a slow supply rate.

[0006] For example, gypsum used as a building material such as gypsum board is so unstable that it cannot be reused (Board to Board), and is therefore disposed of, putting pressure on final disposal sites. Calcium, the main component of gypsum, is a semi-essential element for plants and animals, so its use in agriculture has been considered, but its low solubility has raised doubts about its effectiveness, and widespread use has not progressed.

[0007] For example, one method for converting gypsum is to form an aqueous calcium sulfate slurry by adding sulfuric acid or hydrochloric acid, and then react it with a chloride-type anion exchanger at a low pH to obtain water-soluble potassium sulfate or sodium sulfate crystals (Patent Document 1). However, this technique requires a separate step of adding an acid in addition to the gypsum, resulting in high production costs.

[0008] One technique for utilizing nutrient sources in aqueous systems in the agricultural field is phosphate recovery technology using ion exchangers. Known phosphate recovery technology uses an ion exchanger as a separation carrier in liquid chromatography to separate and recover phosphoric acid, nitric acid, and acetic acid from a mixed acid containing phosphoric acid (Patent Document 2). Also known is the production of slow-release fertilizers using an ion exchanger such as zeolite and an organic acid such as citric acid to elute some of the insoluble phosphoric acid from incineration ash containing sparingly soluble phosphoric acid into soil solution using the effect of the organic acid (Patent Document 3).

[0009] However, phosphate forms a sparingly soluble salt in the soil, and its absorption rate by plants is often less than 10% of the administered dose, significantly lower than other essential elements such as potassium and nitrogen, and increasing its absorption rate has been a long-standing challenge.

[0010] In waste-handling industries, nutrients in environmental water are often removed from the water system by forming poorly soluble salts in the solid phase to prevent eutrophication. While poorly soluble salts used as building materials are useful due to their stability, their effectiveness and usefulness are limited when they are used as materials in other industries due to their low solubility and reactivity.

[0011] It is expected that the demand for water-soluble salts will continue to increase in the future as IoT agriculture, which controls the timing of nutrient administration, progresses. The water-solubilizing technology of the present invention for poorly soluble salts will be a key technology in considering the issues of resource circulation, resource conservation, and efficient agriculture.

[0012] As an approach to solving such problems, in order to increase the efficiency of ion exchange treatment, water treatment devices have been developed that control the treatment of aqueous solutions with ion exchange resins by controlling the flow path with an on-off valve.

[0013] For example, a conventional water treatment device is a water softening device that produces neutral water and includes a water softening tank that softens raw water containing hardness components with a weakly acidic cation exchange resin and a neutralization tank that neutralizes the pH of the softened water that has passed through the water softening tank by gradually releasing calcium carbonate. The water softening device also includes an electrolytic tank that produces acidic electrolyzed water for regenerating the weakly acidic cation exchange resin, and a regeneration device that regenerates the weakly acidic cation exchange resin with the acidic electrolyzed water produced by the electrolytic tank. The regeneration device includes a treatment tank that reacts the hardness components discharged from the water softening tank with the alkaline electrolyzed water during regeneration, and a neutralization tank that neutralizes the pH of the softened water that has passed through the water softening tank by gradually releasing calcium carbonate. a recovery flow path that connects the downstream side of the water softening tank to the upstream side of the treatment tank; a supply flow path that connects the downstream side of the treatment tank to the upstream side of the electrolytic tank; a second supply flow path that draws alkaline water from the electrolytic tank and sends it to the treatment tank; and a circulation flow path that circulates water used for regenerating the weakly acidic cation exchange resin, and in the early stage of regeneration of the weakly acidic cation exchange resin, by switching an on / off valve, raw water is passed through the weakly acidic cation exchange resin and stored in the treatment tank (see Patent Document 4).

[0014] Furthermore, for example, a conventional water treatment device is a water purification system that filters raw water to produce purified water, and includes at least one water outlet, a raw water supply flow path that supplies raw water, a first filter, a first purified water supply flow path that supplies filtered water to the first filter, a first purified water flow path that connects the first filter to the water outlet, a second filter with ion separation performance, a second purified water supply flow path that branches off from the first purified water path and supplies filtered water to the second filter, a second purified water flow path that connects the second filter to the water outlet, and a switching means that connects the first purified water flow path and the second purified water flow path to the water outlet, and the switching means can mix the first purified water supplied from the first purified water flow path and the second purified water supplied from the second purified water flow path at any mixing ratio and discharge the mixed water from the water outlet (see Patent Document 5). [Prior art documents] [Patent documents]

[0015] [Patent Document 1] Japanese Patent Application Publication No. 59-83929 [Patent Document 2] Patent Application No. 2014-8411 [Patent Document 3] Patent Application No. 2014-237339 [Patent Document 4] Japanese Patent Publication No. 2021-133268 [Patent Document 5] Japanese Patent Application Laid-Open No. 2015-123389 Summary of the Invention [Problem to be solved by the invention]

[0016] However, in conventional water treatment devices, as in Patent Documents 4 and 5, flow path control is used using on-off valves, which results in complex on-off control using a large number of on-off valves, making the treatment complicated, reducing the maintainability of the water treatment device and increasing costs.

[0017] As described above, it is still difficult for conventional water treatment devices to stably make poorly soluble solid salts water-soluble with a simple configuration, high efficiency, and low cost. Even if the solid salts are reused as slow-release fertilizers made from salts with low water solubility, there is still a problem that the absorption efficiency of the slow-release fertilizer into the plant body cannot be made high.

[0018] SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and to provide a water treatment device capable of stably making a poorly soluble solid salt water soluble with high efficiency and low cost. [Means for solving the problem]

[0019] As a result of extensive research, the inventors have discovered a method for easily converting sparingly soluble salts from industrial waste and other wastes to water-soluble forms without the need for heat treatment or acid / alkali decomposition treatment, and have also developed a water treatment device that enables waste material recycling technology, including the production of water-soluble fertilizer.

[0020] The water treatment device disclosed in the present application is a water treatment device that is composed of an ion exchanger that ion-exchanges any of the constituent ions of an aqueous solution containing a poorly soluble salt, adsorbs any of the constituent ions onto the ion exchanger, and elutes the adsorbed constituent ions from the ion exchanger. The water treatment device comprises: a storage means for storing the ion exchanger; a supply means for supplying a predetermined aqueous solution to the storage means; a control means for variably controlling the flow path length of the aqueous solution flowing through the storage means so that it is longer during the adsorption of the constituent ions onto the ion exchanger than during the elution; and an extraction means for selectively extracting an aqueous solution in which any of the constituent ions derived from the poorly soluble salt have been dissolved under the control of the control means.

[0021] Thus, the water treatment device disclosed in the present application is a water treatment device that is composed of an ion exchanger that exchanges one of the constituent ions of an aqueous solution containing a poorly soluble salt, adsorbs one of the constituent ions onto the ion exchanger, and elutes the adsorbed constituent ions from the ion exchanger. The water treatment device comprises a storage means for storing the ion exchanger, a supply means for supplying a predetermined aqueous solution to the storage means, a control means for variably controlling the flow path length of the aqueous solution flowing through the storage means so that it is longer during the elution of the constituent ions than during the adsorption of the constituent ions onto the ion exchanger, and an extraction means for selectively extracting the aqueous solution in which one of the constituent ions derived from the poorly soluble salt has been dissolved, by the control means. Therefore, by variably controlling the flow path length of the aqueous solution flowing through the storage means so that it is longer during the elution of the constituent ions than during the adsorption of the constituent ions onto the ion exchanger, the adsorption and elution of the constituent ions can be performed optimally and simply within the same device configuration, and the poorly soluble salt can be efficiently dissolved with a simple configuration.

[0022] In the water treatment device disclosed herein, the control means, as necessary, controls the supply means to circulate a predetermined aqueous solution through the storage means after the constituent ions are adsorbed onto the ion exchanger and before the elution, thereby maintaining the ion exchanger in an immersed state. In this way, in the water treatment device disclosed herein, the control means controls the supply means to circulate a predetermined aqueous solution through the storage means after the constituent ions are adsorbed onto the ion exchanger and before the elution, thereby maintaining the ion exchanger in an immersed state. This suppresses the progression of oxidation of the ion exchanger due to the immersion state, thereby enabling the poorly soluble salt to be dissolved with higher quality. Furthermore, simultaneous drainage of the storage container with a short flow path length enables separation of the adsorbed component and the dissolved salt aqueous solution and washing in a short time and with a small volume, thereby easily obtaining a dissolved salt aqueous solution with a higher concentration and an adsorbed component with fewer impurities.

[0023] In addition, in the water treatment device disclosed in the present application, the storage means is composed of a plurality of storage containers, a lower opening / closing valve that connects the lower parts of adjacent storage containers in an openable / closable manner, and an upper opening / closing valve that connects the upper parts of at least one adjacent storage container in an openable / closable manner, and the control means controls the opening / closing state of each of the upper opening / closing valve and the lower opening / closing valve to variably control the flow path length. As described above, in the water treatment device disclosed in the present application, the storage means is composed of a plurality of storage containers, a lower opening / closing valve that connects the lower parts of adjacent storage containers in an openable / closable manner, and an upper opening / closing valve that connects the upper parts of at least one adjacent storage container in an openable / closable manner, and the control means controls the open / close states of the upper opening / closing valve and the lower opening / closing valve to variably control the flow path length. Therefore, the adsorption and elution of the constituent ions can be performed using the same storage container of the storage means simply by switching between the lower opening / closing valve and the upper opening / closing valve, and the adsorption and elution of the constituent ions can be performed optimally and simply using the same storage container, making it possible to efficiently dissolve the poorly soluble salt with an even simpler configuration.

[0024] Furthermore, in the water treatment device disclosed in the present application, the storage container of the storage means is configured as needed to include an ion exchanger storage section in which the ion exchanger placed at an intermediate position of the storage container is stored, a communication section consisting of a spatial region lower than the bottom surface of the ion exchanger storage section, and an overflow section consisting of a spatial region higher than the upper surface of the ion exchanger storage section, and the lower opening / closing valve is disposed in the communication section, and the upper opening / closing valve is disposed in the overflow section. In this way, in the water treatment device disclosed in the present application, the storage container of the storage means is composed of an ion exchanger storage section in which the ion exchanger placed at an intermediate position of the storage container is stored, a communication section consisting of a spatial region lower than the bottom surface of the ion exchanger storage section, and an overflow section consisting of a spatial region higher than the upper surface of the ion exchanger storage section, and the lower on-off valve is disposed in the communication section and the upper on-off valve is disposed in the overflow section. Therefore, by utilizing the naturally occurring water flow from the overflow section to the storage container of the storage means during the elution of the constituent ions, a pressure reducing device is not required and the aqueous solution involved in the elution automatically flows into the adjacent storage container by the action of overflow, making it possible to efficiently dissolve the sparingly soluble salt with an even simpler configuration.

[0025] Furthermore, in the water treatment device disclosed herein, the control means controls the flow path length of the aqueous solution flowing through the storage means, as necessary, based on the pH value and / or EC value of the aqueous solution supplied to the storage means. In this way, in the water treatment device disclosed herein, the control means controls the flow path length of the aqueous solution flowing through the storage means based on the pH value and / or EC value of the aqueous solution supplied to the storage means. As a result, the control means can control the flow path length of the aqueous solution flowing through the storage means using a simple index, the pH value, and it becomes possible to efficiently dissolve the poorly soluble salt with a simpler configuration.

[0026] Furthermore, the liquid fertilizer production apparatus disclosed in the present application is configured from the water treatment device. In this way, since the liquid fertilizer production apparatus disclosed in the present application is configured from the water treatment device, the aqueous solution in which the poorly soluble salt produced in the water treatment device is dissolved is produced as liquid fertilizer, making it possible to efficiently produce liquid fertilizer with a simpler configuration. [Brief explanation of the drawings]

[0027] [Figure 1] 1 shows a configuration diagram of a water treatment device according to a first embodiment of the present invention. [Figure 2] 1 shows a configuration diagram of a storage container of a water treatment device according to a first embodiment of the present invention. [Figure 3] 1 shows a schematic diagram of a water treatment device according to a first embodiment of the present invention. [Figure 4] 1 shows a configuration diagram (state A) of a water treatment device according to a first embodiment of the present invention. [Figure 5] 1 shows a configuration diagram (state B) of a water treatment device according to a first embodiment of the present invention. [Figure 6] FIG. 10 is a diagram showing the configuration of a water treatment device according to a third embodiment of the present invention, which is equipped with a pH detector. [Figure 7] FIG. 10 is a diagram showing the configuration of a water treatment device according to a third embodiment of the present invention, which is equipped with an EC detector. [Figure 8] 1 shows the results of elution of gypsum and phosphate ions in the water treatment devices according to Examples 1 and 2 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0028] (First embodiment) As shown in Figure 1, the water treatment device of the first embodiment is composed of ion exchangers 1a, 1b, 1c, and 1d that exchange one of the constituent ions of an aqueous solution containing a poorly soluble salt, adsorbs one of the constituent ions onto the ion exchangers, and elutes the adsorbed constituent ions from the ion exchangers.The water treatment device comprises: a storage means 1 that stores the ion exchangers; a supply means 2 that supplies a predetermined aqueous solution to the storage means 1; a control means 3 that variably controls the flow path length of the aqueous solution flowing through the storage means 1 so that it is longer during elution than during adsorption of the constituent ions onto the ion exchanger; and an extraction means 4 that selectively extracts the aqueous solution in which one of the constituent ions derived from the poorly soluble salt has been dissolved, under the control of the control means 3.

[0029] The storage means 1 for storing this ion exchanger is not particularly limited, but as shown in Figure 1, it is composed of a plurality of storage containers 11, a lower opening / closing valve 12 that connects the lower parts of adjacent storage containers 11 in an openable / closable manner, and an upper opening / closing valve 13 that connects the upper parts of at least one adjacent storage container 11 in an openable / closable manner, and the control means 3 controls the open / closed state of each of the upper opening / closing valve 13 and the lower opening / closing valve 12 to variably control the flow path length.

[0030] The upper on-off valve 13 and the lower on-off valve 12 are formed as a connecting cock. By connecting a plurality of storage vessels 11 with the connecting cock, the coexistence equilibrium of the hardly soluble solid is promoted.

[0031] Furthermore, as shown in FIG. 2, the storage container 11 of the storage means 1 is not particularly limited, but is composed of an ion exchanger storage section 14a in which an ion exchanger 1a placed at the middle position of the storage container 11 is stored, a communication section 15a consisting of a spatial region lower than the bottom surface of the ion exchanger storage section 14a, and an overflow section 16a consisting of a spatial region higher than the top surface of the ion exchanger storage section 14a, and the lower opening / closing valve 12a is disposed in the communication section 15a, and the upper opening / closing valve 13a is disposed in the overflow section 16a.

[0032] The predetermined aqueous solution is a supply solution 100 supplied to the storage container 11, which is an aqueous solution containing poorly soluble salts containing the constituent ions to be adsorbed when the constituent ions are adsorbed to the ion exchanger, and is stored in the eluate container 21. Elution In this case, the specified aqueous solution is a water-soluble salt aqueous solution capable of generating water-soluble salts from the constituent ions adsorbed on the ion exchanger, which is supplied as a supply solution 100 to the storage container 11. For example, an acetic acid aqueous solution capable of forming water-soluble salts with calcium ions can be used, and the specified aqueous solution is stored in the ion exchange resin regeneration solution container 22.

[0033] A poorly soluble salt refers to a salt that has low solubility in water. A wide range of poorly soluble salt-containing aqueous solutions can be used, including aqueous solutions containing poorly soluble salts, such as alkaline earth metal salts. This method can also be used with incineration ash, such as chicken manure ash, which is a poorly soluble substance. In this case, it is possible to separate water-soluble phosphate from water-soluble metal salts. Furthermore, even when poorly soluble salts coexist with insoluble materials such as paper, plastic, and metal, it is possible to make only the poorly soluble salts water-soluble and then separate and recover the insoluble components using a mesh or the like.

[0034] Ion exchangers 1a, 1b, 1c, and 1d are substances composed of charged functional groups and oppositely charged particles, or counterions, in an organic or inorganic framework. Examples include ion exchange resins and zeolites. Ion exchange refers to a reversible equilibrium in which counterions, charged particles with the opposite sign to the ion exchanger, exchange equivalent amounts with other types of counterions while maintaining electrical neutrality. Counterions refer to particles with a charge of the opposite sign to the ion exchanger's charge, located near the functional groups, in order to keep the overall charge of the ion exchanger neutral.

[0035] As the ion exchanger, for example, a cation exchanger can be used. The type of cation exchanger is not particularly limited, but sodium type, H + It is possible to use a sodium type, a potassium type, an ammonium type, or the like, and for example, a sodium type can be used.

[0036] In addition, the ion exchanger is not limited to a cation exchanger, and an anion exchanger may also be used. When an anion exchanger is used, the order of recovery of the poorly soluble components to be separated and recovered is simply reversed from that in the case of a cation exchanger, and the exchanger can be selected appropriately depending on the desired application.

[0037] The size and number of the storage vessel 11 and suction vessel 42 that contain the ion exchanger can be selected appropriately depending on the desired application, and can be changed depending on the amount of sparingly soluble salt to be treated and the flow path through which the ion exchanger passes.

[0038] The control means 3 variably controls the flow path length of the aqueous solution flowing through the storage means 1 so that it is longer during elution of constituent ions than during adsorption onto the ion exchanger. As shown in Figure 1, the control means 3 controls the open / close states of upper and lower on-off valves 13 and 12, which serve as connecting cocks disposed at the bottom of each storage vessel 11 and the upper end of the ion exchanger interface, thereby switching between a connected liquid-passing state and a blocked state. The upper portion of the storage vessel 11 has an openable structure to facilitate the inflow of a feed solution 100. The control means 3 ensures a long flow path to discharge the solution and promote ion exchange by switching the upper and lower on-off valves 13 and 12, which serve as connecting cocks connecting the storage vessels 11.

[0039] Each storage vessel 11 holds an ion exchanger in an ion exchanger storage section 14, and the bottom of the ion exchanger storage section 14 has a mesh structure to prevent the ion exchanger from leaking out. This mesh structure is not particularly limited, but for example, one with a pore size of 1 mm or less can be used.

[0040] The extraction means 4, under the control of the control means 3, selectively extracts an aqueous solution in which one of the constituent ions derived from the sparingly soluble salt is dissolved, and is configured as a storage container 11 for collecting the solution discharged at the final stage of each of the adsorption and elution steps. During the adsorption of constituent ions into the ion exchanger, the extraction means 4 is configured as an adsorption solution recovery container 43a, which is preferably equipped with a dry vacuum pump 41 and a suction container 42 for the purpose of promoting aeration and drying of the ion exchanger, as shown in Figure 1. During the elution of constituent ions into the ion exchanger, the extraction means 4 is configured as an elution solution recovery container 43b.

[0041] An example of the appearance of a water treatment device with such a configuration is shown in Fig. 3. As shown in Fig. 3, the supply means 2 supplies a predetermined aqueous solution to the storage means 1 and is composed of an eluate container 21 and an ion exchange resin regeneration solution container 22. Furthermore, by providing a lifting platform 200a on which the adsorption solution recovery container 43a is placed and a lifting platform 200b on which the elution solution recovery container 43b is placed, the heights of the lifting platforms 200a and 200b are utilized to facilitate the recovery of solutions into the adsorption solution recovery container 43a and the elution solution recovery container 43b by the action of gravity. Furthermore, by arranging the base 300 around the storage container 11, the ease of maintenance and other operations for the device is improved.

[0042] 3, in order to quickly reach ion exchange equilibrium in each storage vessel 11, it is also possible to apply external energy such as vibration, heat, or overvoltage, and for example, it is also possible to apply vibration using a stirrer 55. In addition, the method for quickly reaching ion exchange equilibrium is not limited to the above, and it is also possible to appropriately apply a continuous multistage extraction method, a fluidized bed method, a column method, etc.

[0043] The operation of the water treatment device according to this embodiment will be described below.

[0044] (First step) First, as shown in Fig. 4, the control means 3 opens only the lower opening / closing valves 12 of each of the connected storage containers 11 (state A). A poorly soluble solid solution formed in solution from the constituent ions of component 1 and component 2 contained in an eluate container 21 is supplied from the supply means 2. For example, in the case of gypsum (main component CaSO4), which is a poorly soluble salt, calcium ions (constituent ions of component 1) and sulfate ions (constituent ions of component 2) are exemplified.

[0045] When a sodium-type ion exchange resin or zeolite with cation exchange capacity is used as the ion exchanger, calcium ions (constituent ions of component 1) are retained on the ion exchanger, and the external solution phase of the ion exchanger becomes an adsorbed solution 100a containing sodium sulfate consisting of sulfate ions (constituent ions of component 2).

[0046] With only the lower on-off valve 12 open by the control means 3, this adsorbed solution 100a is discharged by gravity toward the lower on-off valve 12 and collected in the adsorption solution recovery container 43a. By repeatedly supplying water from the eluate container 21 to each storage container 11 using the supply means 2, the adsorbed solution 100a containing sodium sulfate is repeatedly discharged into the adsorption solution recovery container 43a, and the solution in each storage container 11 is replaced with water.

[0047] By this operation, the gypsum solid, which is a sparingly soluble salt, disappears and the sulfuric acid concentration in the solution phase decreases, and the concentration of sodium sulfate contained in the adsorbed solution 100a in the solution phase becomes almost zero by repeatedly supplying water from the eluate container 21 to each storage container 11 3 to 4 times.

[0048] Following the solution discharge by gravity, the dry vacuum pump 41 is operated to promote forced discharge, and the adsorbed solution 100a is collected as a discharged solution in the suction container 42, and the ion exchanger is dried by aeration. When the suction container 42 is filled, the solution is collected into the adsorption solution recovery container 43a through the lower cock of the suction container 42.

[0049] It is also possible to apply vibration to each storage vessel 11 using, for example, a stirrer 55. This vibration makes it possible for the poorly soluble salt aqueous solution in each storage vessel 11 to reach ion exchange equilibrium quickly.

[0050] Therefore, in this first step, it is preferable that the multiple storage containers 11 constituting the storage means 1 have a wide opening and are provided with an agitator 55 at the top, which allows for more rapid equilibration by introducing the poorly soluble solid salt and stirring it with the ion exchanger.

[0051] (Second step) 5, the control means 3 sets each of the connected storage containers 11 in a state (state B) in which the connecting cocks of the upper on-off valves 13 and the lower on-off valves 12 are alternately opened. In this state, a solution (e.g., an aqueous acetic acid solution) capable of forming a water-soluble salt with the calcium ions (constituent ions of component 1) adsorbed on the ion exchanger is stored in the ion exchange resin regenerating solution container 22 and is supplied from the supply means 2.

[0052] By forming this state B, the aqueous solution is filled up to the overflow part 16 of each storage vessel 11. As shown in FIG. 5, calcium ions (constituent ions of component 1) of the hardly soluble salt held in the ion exchanger and a solution capable of forming a water-soluble salt (e.g., an aqueous solution of acetic acid) are passed through storage vessels 11a, 11b, 11c, and 11d filled with the aqueous solution in this order, and the calcium-type ion exchanger is converted into H + The calcium acetate is converted into an ion exchanger of this type, and an eluted solution 100b containing calcium acetate can be collected in an eluted solution collection container 43b.

[0053] In the above-mentioned state B, the connecting cocks of the upper opening / closing valve 13 and the lower opening / closing valve 12 of each connected storage container 11 are alternately opened, but this is not limited to an alternately opened state, and the above-mentioned state B can also be formed by configuring the upper opening / closing valve 13 so that the upper parts of at least one adjacent storage container 11 are connected to each other so that they can be opened and closed.

[0054] In this way, in this second step, the storage container 11 has a structure that allows the flow path length to be long by switching the cock using the control means 3, so it is possible to achieve complete ion exchange in the second step without refilling the ion exchanger.

[0055] That is, in this water treatment device, ion exchange can be performed in two steps, the first step and the second step, using the same device; an aqueous solution containing constituent ions (e.g., calcium ions) of component 1 contained in a poorly soluble solid (e.g., gypsum) and constituent ions (e.g., sulfate ions) of component 2 contained in the poorly soluble solid (e.g., gypsum) are separated using an ion exchanger; after the aqueous solution containing constituent ions (e.g., calcium ions) of component 1 is discharged, the constituent ions (e.g., sulfate ions) of component 2 are separated and recovered as a water-soluble salt aqueous solution, thereby realizing a compact, low-cost, and highly efficient water treatment device.

[0056] In this way, the sparingly soluble salt introduced as a raw material is treated in two steps: a first step in which the cations (or anions) of the sparingly soluble salt are retained on an ion exchanger and separated from the water-soluble anions (or cations), and a second step in which the cations (or anions) retained on the ion exchanger are eluted into a solution to obtain a water-soluble salt containing the cations (or anions) of the sparingly soluble salt. As a result, the sparingly soluble salt introduced as a raw material is optimally ion-exchanged using the ion exchanger, and efficiently separated into two aqueous solutions: a water-soluble salt containing the cations of the sparingly soluble salt and a water-soluble salt containing the anions.

[0057] In other words, the cations / anions held by the sparingly soluble salt are exchanged with the counterions (cations / anions) of the ion exchanger to produce an aqueous solution composed of the counterions (cations / anions) held by the ion exchanger and the sparingly soluble salt constituent ions (anions / cations) of the sparingly soluble salt. By replacing the solution with water, the sparingly soluble salt components are further solubilized and retained in the ion exchanger. When the aqueous solution coexisting with the ion exchanger is replaced with water, and all of the sparingly soluble salt is dissolved without exceeding the ion exchange capacity, an aqueous solution containing the sparingly soluble salt cations / anions can be obtained by coexisting the cations / anions of the sparingly soluble salt held by the ion exchanger with a solution of a salt containing the anions / cations that form a soluble salt.

[0058] As described above, the water treatment device of this embodiment is composed of an ion exchanger that exchanges one of the constituent ions of an aqueous solution containing a poorly soluble salt, adsorbs one of the constituent ions onto the ion exchanger, and elutes the adsorbed constituent ions from the ion exchanger. The water treatment device comprises a storage means 1 that stores the ion exchanger, a supply means 2 that supplies a predetermined aqueous solution to the storage means 1, a control means 3 that variably controls the flow path length of the aqueous solution flowing through the storage means 1 so that it is longer during elution than during adsorption of the constituent ions onto the ion exchanger, and an extraction means 4 that selectively extracts an aqueous solution in which one of the constituent ions derived from the poorly soluble salt has been dissolved, by controlling the control means 3. Therefore, by variably controlling the flow path length of the aqueous solution flowing through the storage means 1 so that it is longer during elution than during adsorption of the constituent ions onto the ion exchanger, the adsorption and elution of the constituent ions can be performed optimally and simply within the same device configuration, making it possible to efficiently dissolve the poorly soluble salt with a simple configuration.

[0059] Specifically, this system utilizes an equilibrium system in which ion exchangers that exchange either the cations or anions of sparingly soluble salts coexist. The flow path length can be adjusted within the same device to separate the constituent components of sparingly soluble salts in two stages, State A and State B. This two-stage separation of sparingly soluble useful components into soluble salts improves the practicality and convenience of agricultural and industrial applications of sparingly soluble salts. This allows separation through mixing equilibrium without the need for heat treatment or acid-alkali decomposition, converting sparingly soluble industrial waste into soluble salts at low energy cost, reducing waste and producing useful materials.

[0060] Furthermore, as described above, in the water treatment device of this embodiment, the storage means 1 is composed of a plurality of storage containers 11, a lower opening / closing valve 12 that connects the lower parts of adjacent storage containers 11 in an openable / closable manner, and an upper opening / closing valve 13 that connects the upper parts of at least one adjacent storage container 11 in an openable / closable manner, and the control means 3 controls the open / close state of each of the upper opening / closing valve 13 and the lower opening / closing valve 12 to variably control the flow path length.Therefore, the adsorption and elution of the constituent ions can be performed simply by switching between the lower opening / closing valve 12 and the upper opening / closing valve 13, while keeping the same storage container 11 of the storage means 1.This means that the adsorption and elution of the constituent ions can be performed optimally and simply in the same storage container 11, and it becomes possible to efficiently dissolve the sparingly soluble salt with an even simpler configuration.

[0061] Furthermore, as described above, the water treatment device according to this embodiment is configured such that the storage container 11 of the storage means 1 is composed of an ion exchanger storage section 14 in which the ion exchanger placed at the middle position of the storage container 11 is stored, a communication section 15 consisting of a spatial region lower than the bottom surface of the ion exchanger storage section 14, and an overflow section 16 consisting of a spatial region higher than the top surface of the ion exchanger storage section 14. Since the lower opening / closing valve 12 is disposed in the communication section 15 and the upper opening / closing valve 13 is disposed in the overflow section 16, when the constituent ions are eluted, the aqueous solution involved in the elution overflows from the overflow section 16 into the storage container 11 of the storage means 1, making it possible to use a more natural water flow to efficiently dissolve the sparingly soluble salt with a simple configuration.

[0062] (Second embodiment) The water treatment device of the second embodiment, like the first embodiment, comprises the storage means 1, the supply means 2, the control means 3, and the extraction means 4, and further, the control means 3 causes the supply means 2 to circulate a predetermined aqueous solution through the storage means 1 after the constituent ions have been adsorbed onto the ion exchanger and before they are eluted, thereby maintaining the ion exchanger in an immersed state.

[0063] The predetermined aqueous solution is a supply solution 100 supplied to the storage container 11, and includes an aqueous solution of a water-soluble salt that can generate a water-soluble salt from the constituent ions adsorbed on the ion exchanger, such as an aqueous solution of acetic acid that forms a water-soluble salt with calcium, or water.

[0064] "Maintaining the ion exchanger in an immersed state" means that after ions are adsorbed and before they are eluted, the specified aqueous solution is supplied to each storage vessel 11 from the ion exchange resin regeneration solution container 22 containing the specified aqueous solution, and by controlling the opening and closing of the upper opening / closing valve 13 and the lower opening / closing valve 12, each storage vessel 11 is sufficiently filled with the water-soluble salt aqueous solution up to the overflow part 16, thereby maintaining the ion exchanger in an immersed state.

[0065] In this way, in the water treatment device according to the second embodiment, the control means 3 causes the supply means 2 to circulate a predetermined aqueous solution through the storage means 1 after the constituent ions have been adsorbed onto the ion exchanger and before they are eluted, thereby maintaining the ion exchanger in an immersed state. This suppresses the progress of oxidation of the ion exchanger due to the immersion state, thereby enabling the poorly soluble salt to be dissolved with higher quality. Furthermore, the short flow path length of the storage vessel 11 of the storage means 1 allows simultaneous drainage, which enables separation of the adsorbed components from the dissolved salt aqueous solution and washing in a short time and with a small volume, thereby easily obtaining a more concentrated dissolved salt aqueous solution and an adsorbed component with fewer impurities.

[0066] (Third embodiment) In the water treatment device of the third embodiment, the control means 3 controls the flow path length of the aqueous solution flowing through the storage means 1 based on the pH value of the aqueous solution supplied to the storage means 1, and as shown in Figure 6, is equipped with a pH detector 31 that detects the pH value of the adsorbed solution 100a.

[0067] Fluctuations in the pH detector 31 make it possible to detect, for example, the concentration of phosphate ions, making it possible to easily determine the progress of the ion exchange treatment and accurately determine whether to continue or stop the treatment of circulating the aqueous solution. Alternatively, instead of the pH detector 31, as shown in Fig. 7, an EC detector 32 can be provided for this adsorbed solution 100a, making it possible to easily determine the progress of the ion exchange treatment of the gypsum from the EC value and easily determine accurately whether to continue or stop the treatment of circulating the aqueous solution.

[0068] In this way, in the water treatment device of this embodiment, the control means 3 controls the flow path length of the aqueous solution flowing through the storage means 1 based on the pH value of the aqueous solution supplied to the storage means 1. Therefore, the control means 3 can control the flow path length of the aqueous solution flowing through the storage means 1 using a simple indicator, the pH value, making it possible to efficiently dissolve the poorly soluble salt with a simpler configuration.

[0069] Furthermore, a liquid fertilizer production device can be configured from the water treatment devices according to the above embodiments. Since this liquid fertilizer production device is configured from the water treatment device, an aqueous solution in which poorly soluble salts produced by the water treatment device are dissolved is produced as liquid fertilizer, making it possible to efficiently produce liquid fertilizer with a simpler configuration.

[0070] As described above, by converting poorly soluble salts into water-soluble salts using the water treatment device of this embodiment, it is possible to increase the effectiveness and convenience of reuse in agriculture and industry, which in turn contributes to reducing the amount of waste to be disposed of and the amount of imported materials, thereby contributing to the creation of a recycling-oriented society.

[0071] Examples will be given below to illustrate the features of the present invention more specifically, but the present invention is not limited to the following examples.

[0072] Example 1 Salt leaching from gypsum A salt elution treatment from gypsum was performed using the water treatment device according to the first embodiment. Figure 8(a) shows the EC values ​​(S / m) of the eluate when only distilled water was added to the gypsum and when distilled water and an ion exchange resin were added to the gypsum. The results confirmed that, by using the water treatment device, a high concentration of water-soluble salts was eluted from the gypsum, 95% of the eluted ions were Na, and that calcium from the gypsum was adsorbed onto the ion exchanger and dissolved as sodium sulfate.

[0073] Example 2 Phosphate elution from chicken manure ash Using the water treatment device according to the first embodiment described above, 2 g of chicken manure ash was added to a 50 ml centrifuge tube along with ion exchange resin and 15 ml of (A) distilled water, 15 ml of (B) distilled water (pH 4), or 15 ml of (C) distilled water. The tube was shaken for 10 minutes, centrifuged (3000 rpm, 20 minutes) to recover the supernatant, and then filtered through a 0.45 μm filter. The total phosphate concentration in the solution was determined using the heteropolymolybdophosphate method. The amount of phosphate eluted from the resulting chicken manure ash is shown in Figure 8(b). These results confirmed that the poorly soluble phosphate was water-soluble using the water treatment device. [Explanation of symbols]

[0074] 1. Containment means 1a Ion exchanger 1b Ion exchanger 1c Ion exchanger 1d Ion exchanger 11 Containment vessel 12 Lower opening / closing valve 13 Upper opening and closing valve 14 Ion exchanger storage section 15 Communication part 16 Overflow section 2 Supply means 21 Container for eluate 22 Container for ion exchange resin regeneration solution 3. Control measures 31 pH sensor 32 EC detector 4 Extraction means 41 Dry Vacuum Pump 42 Suction container 43a Adsorption solution collection container 43b Elution solution collection container 5. Mixer 100 Feed Solution 100a Adsorbed solution 100b elution solution 200a lift platform 200b Lift platform 300 pedestal

Claims

1. A water treatment device comprising an ion exchanger that exchanges any of the constituent ions of an aqueous solution containing a sparingly soluble salt containing an alkaline earth metal salt, causing any of the constituent ions to be adsorbed onto the ion exchanger, and eluting the adsorbed constituent ions from the ion exchanger, a storage means comprising a plurality of adjacent storage vessels connected in series, each of which comprises an ion exchanger storage section in which the ion exchanger is stored at an intermediate position of the storage vessel, a communication section consisting of a spatial region lower than the bottom surface of the ion exchanger storage section, and an overflow section consisting of a spatial region higher than the upper surface of the ion exchanger storage section; a lower opening / closing valve connecting the communication sections of adjacent storage vessels in an openable / closable manner; and an upper opening / closing valve connecting the overflow sections of adjacent storage vessels in an openable / closable manner in alternate order; a supply means for supplying the poorly soluble salt-containing aqueous solution or water to a container located at an end of the plurality of containers during the adsorption step, and for supplying a water-soluble salt aqueous solution capable of generating a water-soluble salt from the constituent ions adsorbed on the ion exchanger during the elution step; a control means for controlling the open / close states of the upper and lower on-off valves; an extracting means for selectively extracting an aqueous solution in which any of the constituent ions derived from the hardly-soluble salt is dissolved from a storage container located at an end of the plurality of storage containers under the control of the control means, The control means, when adsorbing the constituent ions onto the ion exchanger, closes the upper on-off valves and opens the lower on-off valves to supply the aqueous solution to each storage vessel, and the aqueous solution is supplied to the ion exchanger and discharged toward the lower on-off valves by gravity; when eluting the constituent ions from the ion exchanger, opens the upper on-off valves and closes the corresponding lower on-off valves to supply the aqueous solution to each storage vessel, thereby variably controlling the length of a flow path for the aqueous solution flowing through the storage means. Water treatment equipment.

2. The water treatment device according to claim 1, the control means causes the supply means to circulate an aqueous solution of either water or an aqueous solution of a water-soluble salt capable of producing a water-soluble salt from the constituent ions adsorbed on the ion exchanger through the storage means after the adsorption of the constituent ions on the ion exchanger and before the elution, thereby maintaining the ion exchanger in an immersed state. Water treatment equipment.

3. 3. The water treatment device according to claim 1, The control means controls the flow path length of the aqueous solution flowing through the storage means based on the pH value and / or EC value of the aqueous solution supplied to the storage means. Water treatment equipment.

4. A water treatment device comprising the water treatment device according to any one of claims 1 to 3. Liquid fertilizer production equipment.

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