Liquid-liquid multi-stage apparatus and method for producing a specific substance using the same

Abstract

To provide a multistage device in which a position of a boundary surface (a liquid-liquid interface) formed by a heavy liquid phase and a light liquid phase does not fluctuate or is suppressed in fluctuation, in a liquid-liquid system formed by two liquid phases that are mutually immiscible, and to provide a method for manufacturing a specific substance using the device.SOLUTION: A device performs multistage extraction using a mechanism in which a heavy liquid phase communicates at a lower part of a container, a mechanism in which a light liquid phase communicates at an upper part of the container, or both mechanisms at two or more stages installed in a connected body of a plurality of adjacent containers or a container having an integral structure with a plurality of partitions arranged therein, so that a position of a boundary surface (a liquid-liquid interface) formed by the heavy liquid phase and the light liquid phase does not fluctuate or is suppressed in fluctuation. Further, a method for manufacturing a specific substance uses the device.SELECTED DRAWING: Figure 6(a)

Description

Technical Field

[0001] The present invention relates to a multi-stage apparatus in a liquid-liquid system composed of two immiscible liquids, in which the position of the liquid-liquid interface does not fluctuate or the fluctuation is suppressed, and a method for producing a specific substance using the same. Here, the multi-stage refers to a mechanism for repeating unit operations. Since the number of times of the unit operation corresponds to the number of stages, a mechanism for repeating the unit operation two or more times is expressed as multi-stage. The multi-stage in a liquid-liquid system means, for example, a mechanism for repeating the unit operation of liquid-liquid extraction (industrially referred to as solvent extraction) a plurality of times, and is widely used in industries such as metal smelting and recycling, separation and purification of organic compounds, and recovery and removal of harmful substances from wastewater.

Background Art

[0002] A liquid-liquid system composed of two immiscible liquids is widely used in the chemical field and the like. For example, liquid-liquid extraction (solvent extraction) that separates, purifies, recovers, or removes substances by utilizing the difference in the distribution of substances between two liquid phases supports core industries such as the metal industry and the chemical industry as a separation and purification method for metal elements and organic compounds, and is also one of the most important technologies as a separation and recovery technology for rare metals indispensable in the high-tech industry.

[0003] On the other hand, in so-called high-tech industries such as electronics and information processing, higher-level separation and purification are required. That is, the requirements for separation and purification are constantly increasing, such as the high purification of metal elements such as four nines (99.99%) and five nines (99.999%), and the mutual separation among element groups with similar chemical properties (for example, rare earths).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

[0005] Separation and purification using liquid-liquid extraction (solvent extraction) can be performed more effectively by repeating the unit operation. However, as the number of repetitions increases, a more complex system consisting of more unit devices is required, and it becomes difficult to operate each unit device simultaneously and efficiently. For example, in solvent extraction apparatus such as mixer-settlers, as the number of stages increases, a lot of effort and time is required to adjust the position of the interface between the heavy liquid phase and the light liquid phase (liquid-liquid interface) and monitor its changes.

[0006] Furthermore, the increased number of stages leads to larger systems, which is a significant economic and spatial obstacle to improving separation and purification performance. Larger systems require larger facilities, equipment, and more components, resulting in higher costs and potentially making implementation difficult due to the large floor space required.

[0007] Furthermore, because the system repeats a unit operation by sequentially moving the liquid phase to be processed to the next stage, the processing time increases in proportion to the number of stages. For example, if the piping connecting each stage for liquid transfer is long, a longer processing time is required. In liquid transfer piping, there is a large pressure loss, so with long liquid transfer piping, the pump load increases, and since a large volume of liquid cannot be transferred, the processing time also increases.

[0008] In particular, in multi-stage systems based on two-phase mixing by droplet ejection from a nozzle, conventional systems require long piping from the bottom to the top of the container for transporting the heavy liquid phase, and long piping from the top to the bottom for transporting the light liquid phase (for example, Patent Documents 1 and 2), resulting in large pressure losses in the transport piping.

[0009] Furthermore, in multi-stage systems utilizing droplet ejection in sealed containers, a single pump may deliver heavy or light liquid phases across multiple stages. For example, by sequentially delivering liquid through the first, second, and third stage nozzles, the cumulative pressure loss at each nozzle gradually reduces the ejection force. This can also cause variations in the position of the liquid-liquid interface at each stage. Additionally, increasing the volumetric velocity increases the effect of pressure loss, thus limiting the ability to deliver large volumes of liquid.

[0010] In mixer-settler systems, the most common industrial apparatus for liquid-liquid extraction (solvent extraction), the processing time is determined by the time required for phase separation. This is because the system waits for phase separation to occur by gravity in the settler section before draining the water. On the other hand, in emulsion flow systems (for example, Patent Documents 3 and 4) where phase mixing and phase separation proceed simultaneously, the processing time depends on the pressure loss during pump delivery.

[0011] This is related to the fact that the principles of liquid transfer differ between mixer-settler systems and emulsion flow systems. Specifically, mixer-settler systems primarily use the suction force of an impeller (agitating blade) to transfer liquid based on overflow, while emulsion flow systems use pressure transfer by a pump or similar device. In overflow transfer systems, pressure loss is often not a major problem, but in pressure transfer systems using pumps, pressure loss significantly affects the processing speed. In multi-stage mixer-settler systems, the stages are usually installed adjacent to each other so that the mixer and settler sections are arranged alternately, and the two sections are connected by a passage. Therefore, liquid transfer piping connecting each stage is unnecessary, and pressure loss is not a problem.

[0012] On the other hand, even when using mechanical impellers, similar to mixer-settler systems, mechanisms based on pressurized liquid delivery by pumps, etc., rather than relying on the suction force of the impellers (patent documents 5 and 6), are significantly affected by pressure loss during liquid delivery, similar to emulsion flow systems.

[0013] As mentioned above, in chemical methods using liquid-liquid systems, such as liquid-liquid extraction (solvent extraction), a multi-stage apparatus that repeats unit operations is necessary to achieve more advanced separation and purification. Conventional multi-stage apparatuses have a structure that repeats unit operations by arranging a number of independently functioning mechanisms in series corresponding to the number of stages. However, such a multi-stage structure has problems such as the interface position at each stage being prone to fluctuations and the inability to deliver large volumes of liquid.

[0014] The object of the present invention is to provide a multi-stage ("internal multi-stage") device that suppresses fluctuations in the interface position by connecting the lower part, upper part, or both of the container, and a method for producing a specific substance using the same. When both the upper and lower parts of the container are connected, adjustment of the interface position becomes virtually unnecessary, and the operability (ease of use) of the device is greatly improved. [Means for solving the problem]

[0015] A key feature of the multi-stage apparatus of the present invention is its structure, which allows each liquid phase to be transported to the next stage without passing through a liquid delivery pipe. In other words, it is possible to avoid large pressure losses in the liquid delivery pipe. Many of the apparatuses shown in the present invention can achieve sufficient phase separation without installing liquid delivery pipes between each stage, thereby significantly reducing the load on liquid delivery and enabling large-capacity liquid delivery. In particular, in conventional multi-stage systems using two-liquid phase mixing by droplet ejection, where the delivery of the heavy liquid phase between stages requires long pipes from the bottom to the top of the container, and the delivery of the light liquid phase also requires long pipes from the top to the bottom, avoiding pressure losses in the liquid delivery pipe is of great significance. Furthermore, the fact that adjustment of the interface position is unnecessary regardless of the amount of liquid delivered is also a factor in enabling large-capacity liquid delivery. The ability to deliver large capacity liquid allows for a significant downsizing of the apparatus.

[0016] In addition, events such as the narrowing or blockage of the liquid supply pipe due to the precipitation of solid components occur daily. Therefore, the absence of pipes connecting each stage improves the ease of handling in terms of reducing the work related to maintenance and management.

[0017] Moreover, the structure shown in the present invention is different from the conventional multi-stage structure in which the liquid is sequentially fed from the first stage to the second stage and then to the third stage through the liquid supply pipe. That is, even in a multi-stage device that uses droplet ejection in a sealed container, no pressure loss occurs due to passing through a large number of nozzles in sequence. This also significantly reduces the pump load and stabilizes the position of the liquid-liquid interface.

Effect of the Invention

[0018] Conventionally, the structure of multi-stage devices used in liquid-liquid systems has problems such as the position of the interface at each stage being likely to fluctuate and the inability to perform liquid feeding in large volumes. The present invention provides a multi-stage device that solves these problems, and by using it, specific substances related to metal materials, chemicals, bioproducts, etc. can be manufactured more efficiently.

Brief Description of the Drawings

[0019] [Figure 1] Example of a connected heavy liquid phase communicating one-sided transverse contact internal multi-stage. [Figure 2] Example of a connected light liquid phase communicating one-sided transverse contact internal multi-stage. [Figure 3(a)] Example of a connected two-phase communicating opposed contact internal multi-stage. [Figure 3(b)] Example of installing a gas phase communication path in a connected two-phase communicating opposed contact internal multi-stage. [Figure 4(a)] Example of installing a direction conversion plate at the center of the stage in a partition plate type heavy liquid phase communicating one-sided transverse contact internal multi-stage. [Figure 4(b)] Example of installing a direction conversion plate on the right side of the stage in a partition plate type heavy liquid phase communicating one-sided transverse contact internal multi-stage. [Figure 4(c)] Example of installing a direction conversion plate on the left side of the stage in a partition plate type heavy liquid phase communicating one-sided transverse contact internal multi-stage. [Figure 5(a)] An example of a partition plate type light liquid phase communication system with one-way transverse contact and multiple internal stages, in which a direction-changing plate is installed in the center of each stage. [Figure 5(b)] An example of a partition plate type light liquid phase communication system with one-way transverse contact and multiple internal stages, in which a direction-changing plate is installed to the right of the stage. [Figure 5(c)] An example of a partition plate type light liquid phase communication system with one-way transverse contact and multiple internal stages, in which a direction-changing plate is installed to the left of the stage. [Figure 6(a)] An example of a partition plate type double-phase communication opposing contact internal multi-stage (communication at the container ceiling) in which the upper and lower direction changing plates are installed in the center of the stage. [Figure 6(b)] An example of a partition-type double-phase communication opposing contact internal multi-stage (communication at the container ceiling) in which the upper direction change plate is installed to the left of the stage and the lower direction change plate is installed to the right of the stage. [Figure 6(c)] An example of a partition-type double-phase communication opposing contact internal multi-stage (communication at the container ceiling) in which the upper direction changing plate is installed towards the right of the stage and the lower direction changing plate is installed towards the left of the stage. [Figure 6(d)] An example of a partition plate type double-phase communication opposing contact internal multi-stage (communication at the container ceiling) in which the upper and lower direction changing plates are installed to the left of the stage. [Figure 6(e)] An example of a partition plate type double-phase communication opposing contact internal multi-stage (communication at the container ceiling) in which the upper and lower direction changing plates are installed to the right of the stage. [Figure 6(f)] An example of a partition-type double-phase communication opposing contact internal multi-stage (communication at the container ceiling) in which the upper direction change plate is installed in the center of the stage and the lower direction change plate is installed to the right of the stage. [Figure 6(g)] An example of a partition-type double-phase communication opposing contact internal multi-stage (communication at the container ceiling) in which the upper direction changing plate is installed slightly to the left of the stage and the lower direction changing plate is installed in the center of the stage. [Figure 6(h)] An example of a partition-type double-phase communication opposing contact internal multi-stage (communication at the container ceiling) in which the upper direction change plate is installed to the right of the stage and the lower direction change plate is installed in the center of the stage. [Figure 7(a)] An example of a partition plate type double-phase communication opposing contact internal multi-stage (communication via upper holes in the stage dividers) with upper and lower direction changing plates installed in the center of the stage. [Figure 7(b)]An example of a partition plate type double-phase communication opposing contact internal multi-stage (communication through upper holes in the stage dividers), where the upper direction changing plate is installed to the left of the stage and the lower direction changing plate is installed to the right of the stage. [Figure 7(c)] An example of a partition plate type double-phase communication opposing contact internal multi-stage (communication through upper holes in the stage dividers), where the upper direction changing plate is installed to the right of the stage and the lower direction changing plate is installed to the left of the stage. [Figure 7(d)] An example of a partition plate type double-phase communication opposing contact internal multi-stage (communication via upper holes in the stage dividers) in which the upper and lower direction changing plates are installed to the left of the stage. [Figure 7(e)] An example of a partition plate type double-phase communication opposing contact internal multi-stage (communication via upper holes in the stage dividers) in which the upper and lower direction changing plates are installed to the right of the stage. [Figure 7(f)] An example of a partition plate type double-phase communication opposing contact internal multi-stage (communication through upper holes in the stage dividers), with the upper direction changing plate installed in the center of the stage and the lower direction changing plate positioned to the right of the stage. [Figure 7(g)] An example of a partition plate type double-phase communication opposing contact internal multi-stage (communication via upper holes in the stage dividers), with the upper direction changing plate positioned to the left of the stage and the lower direction changing plate positioned in the center of the stage. [Figure 7(h)] An example of a partition plate type double-phase communication opposing contact internal multi-stage (communication through upper holes in the stage dividers), with the upper direction changing plate positioned to the right of the stage and the lower direction changing plate positioned in the center of the stage. [Figure 8(a)] An example of a multi-stage, interconnected, double-phase, opposing contact circuit with the upper backflow prevention plate positioned to the left of the stage and the lower backflow prevention plate positioned to the right of the stage. [Figure 8(b)] An example of a multi-stage, interconnected double-phase communication system with a gas-phase communication passage, in which the upper backflow prevention plate is installed to the left of the stage and the lower backflow prevention plate is installed to the right of the stage. [Figure 9(a)] Example 1 of a partition plate type double-phase communication opposing contact internal multi-stage (communication at the container ceiling) in which the upper backflow prevention plate is installed to the left of the stage and the lower backflow prevention plate is installed to the right of the stage. [Figure 9(b)] Example 1 of a partition plate type double-phase communication opposing contact internal multi-stage (communication through upper holes in the stage dividers) in which the upper backflow prevention plate is installed to the left of the stage and the lower backflow prevention plate is installed to the right of the stage. [Figure 9(c)]An example of a partition plate type double-phase communication opposing contact internal multi-stage (communication at the container ceiling) in which the upper backflow prevention plate is installed to the left of the stage and the lower backflow prevention plate is installed to the right of the stage: Part 2. [Figure 9(d)] An example of a partition plate type double-phase communication opposing contact internal multi-stage (communication through upper holes in the stage dividers), where the upper backflow prevention plate is installed to the left of the stage and the lower backflow prevention plate is installed to the right of the stage: Part 2. [Figure 9(e)] Example 3 of a partition plate type double-phase communication opposing contact internal multi-stage (communication at the container ceiling) in which the upper backflow prevention plate is installed to the left of the stage and the lower backflow prevention plate is installed to the right of the stage. [Figure 9(f)] Example 3 of a partition plate type double-phase communication opposing contact internal multi-stage (communication through upper holes in the stage dividers), with the upper backflow prevention plate installed to the left of the stage and the lower backflow prevention plate installed to the right of the stage. [Figure 9(g)] An example of a partition plate type double-phase communication opposing contact internal multi-stage (communication at the container ceiling) in which the lower backflow prevention plate is installed to the right of the stage. [Figure 9(h)] An example of a partition plate type double-phase communication opposing contact internal multi-stage (communication via upper holes in the stage dividers) with the lower backflow prevention plate installed to the right of the stage. [Figure 10(a)] An example of introducing two types of heavy liquid phases in a partition plate type double-phase communication opposing contact internal multi-stage system: Part 1. [Figure 10(b)] An example of introducing two types of heavy liquid phases in a partition plate type double-phase communication opposing contact internal multi-stage system: Part 2. [Figure 10(c)] An example of introducing two types of heavy liquid phases in a partition plate type double-phase communication opposing contact internal multi-stage system: Part 3. [Figure 10(d)] An example of introducing two types of heavy liquid phases in a partition plate type double-phase communication opposing contact internal multi-stage system: Part 4. [Figure 10(e)] An example of introducing two types of heavy liquid phases in a partition plate type double-phase communication opposing contact internal multi-stage system: Part 5. [Figure 10(f)] Example 6 of introducing two types of heavy liquid phases in a partition plate type double-phase communication opposing contact internal multi-stage system: [Figure 11(a)] An example of a multi-stage, interconnected, parallel-contact system with both heavy and light liquid phases having a single inlet. [Figure 11(b)]An example of a multi-stage, interconnected, parallel-contact system with a heavy liquid phase inlet and multiple light liquid phase inlets. [Figure 11(c)] An example of a linked, double-phase parallel contact multi-stage system with one inlet for the light liquid phase and multiple inlets for the heavy liquid phase. [Figure 11(d)] An example of a multi-stage, interconnected, parallel-contact system with a gas-phase connecting passage, where both the heavy liquid phase and the light liquid phase have only one inlet. [Figure 11(e)] An example of a multi-stage, interconnected, parallel-contact system with a gas-phase connecting passage, where there is one inlet for the heavy liquid phase and multiple inlets for the light liquid phase. [Figure 11(f)] An example of a multi-stage, interconnected, parallel-contact system with a gas-phase connecting passage, where there is one inlet for the light liquid phase and multiple inlets for the heavy liquid phase. [Figure 12(a)] An example of a multi-stage internal parallel contact system with partition plates for both phases, where the upper and lower direction-changing plates are installed in the center of the stages, and both the heavy liquid phase and the light liquid phase have a single inlet. [Figure 12(b)] An example of a multi-stage internal parallel contact system with partition plates for both phases, where upper and lower direction-changing plates are installed in the center of the stages, with one inlet for the heavy liquid phase and multiple inlets for the light liquid phase. [Figure 12(c)] An example of a multi-stage internal parallel contact system with partition plates for both phases, where upper and lower direction-changing plates are installed in the center of the stages, with one inlet for the light liquid phase and multiple inlets for the heavy liquid phase. [Figure 12(d)] An example of a multi-stage internal parallel contact system with partition plates for both phases, where the upper direction-changing plate is positioned to the left of the stage and the lower direction-changing plate is positioned to the right of the stage, and both the heavy and light liquid phases have only one inlet. [Figure 12(e)] An example of a multi-stage internal parallel contact system with partition plates for both phases, where the upper direction-changing plate is positioned to the left of the stage and the lower direction-changing plate is positioned to the right of the stage, with one inlet for the heavy liquid phase and multiple inlets for the light liquid phase. [Figure 12(f)] An example of a multi-stage internal multi-stage dual-phase parallel contact system with partition plates, where the upper direction-changing plate is positioned to the left of the stage and the lower direction-changing plate is positioned to the right of the stage, resulting in one inlet for the light liquid phase and multiple inlets for the heavy liquid phase. [Figure 12(g)]An example of a multi-stage internal parallel contact system with partition plates for both phases, where the upper direction-changing plate is positioned to the right of the stage and the lower direction-changing plate is positioned to the left of the stage, and both the heavy and light liquid phases have only one inlet. [Figure 12(h)] An example of a multi-stage internal parallel contact system with partition plates for both phases, where the upper direction-changing plate is positioned to the right of the stage and the lower direction-changing plate is positioned to the left of the stage, with one inlet for the heavy liquid phase and multiple inlets for the light liquid phase. [Figure 12(i)] An example of a multi-stage internal parallel contact system with partition plates for both phases, where the upper direction-changing plate is positioned to the right of the stage and the lower direction-changing plate is positioned to the left of the stage, resulting in one inlet for the light liquid phase and multiple inlets for the heavy liquid phase. [Figure 12(j)] An example of a multi-stage internal parallel contact system with partition plates for both phases, where the upper and lower direction-changing plates are positioned to the left of the stage, and both the heavy and light liquid phases have only one inlet. [Figure 12(k)] An example of a multi-stage internal parallel contact system with partition plates for both phases, where the upper and lower direction-changing plates are positioned to the left of the stage, resulting in one inlet for the heavy liquid phase and multiple inlets for the light liquid phase. [Figure 12(l)] An example of a multi-stage internal parallel contact system with partition plates for both phases, where the upper and lower direction-changing plates are positioned to the left of the stage, resulting in one inlet for the light liquid phase and multiple inlets for the heavy liquid phase. [Figure 12(m)] An example of a multi-stage internal parallel contact system with partition plates for both phases, where the upper and lower direction-changing plates are positioned to the right of the stage, and both the heavy and light liquid phases have a single inlet. [Figure 12(n)] An example of a multi-stage internal parallel contact system with partition plates for both phases, where the upper and lower direction-changing plates are positioned to the right of the stage, resulting in one inlet for the heavy liquid phase and multiple inlets for the light liquid phase. [Figure 12(o)] An example of a multi-stage internal parallel contact system with partition plates for both phases, where the upper and lower direction-changing plates are positioned to the right of the stage, resulting in one inlet for the light liquid phase and multiple inlets for the heavy liquid phase. [Figure 12(p)] An example of a multi-stage internal parallel contact system with partition plates for both phases, where the upper direction-changing plate is positioned in the center of the stage and the lower direction-changing plate is positioned to the right of the stage, with a single inlet for both the heavy and light liquid phases. [Figure 12(q)]An example of a multi-stage internal parallel contact system with partition plates for both phases, where the upper direction-changing plate is positioned in the center of the stage and the lower direction-changing plate is positioned to the right of the stage, with one inlet for the heavy liquid phase and multiple inlets for the light liquid phase. [Figure 12(r)] An example of a multi-stage internal parallel contact system with partition plates for both phases, where the upper direction-changing plate is positioned in the center of the stage and the lower direction-changing plate is positioned to the right of the stage, with one inlet for the light liquid phase and multiple inlets for the heavy liquid phase. [Figure 12(s)] An example of a multi-stage internal parallel contact system with partition plates for both phases, where the upper direction-changing plate is positioned to the left of the stage and the lower direction-changing plate is positioned in the center of the stage, with a single inlet for both the heavy and light liquid phases. [Figure 12(t)] An example of a multi-stage internal parallel contact system with partition plates for both phases, where the upper direction-changing plate is positioned to the left of the stage and the lower direction-changing plate is positioned in the center of the stage, with one inlet for the heavy liquid phase and multiple inlets for the light liquid phase. [Figure 12(u)] An example of a multi-stage internal parallel contact system with partition plates for both phases, where the upper direction-changing plate is positioned to the left of the stage and the lower direction-changing plate is positioned in the center of the stage, with one inlet for the light liquid phase and multiple inlets for the heavy liquid phase. [Figure 13(a)] An example of a multi-stage internal parallel contact system with partition plates for both phases, where a direction-changing plate is installed only at the bottom, in the center of each stage, and both the heavy and light liquid phases have only one inlet. [Figure 13(b)] An example of a multi-stage internal parallel contact system with partition plates for both phases, where a direction-changing plate is installed only at the bottom, in the center of the stage, with one inlet for the heavy liquid phase and multiple inlets for the light liquid phase. [Figure 13(c)] An example of a multi-stage internal multi-stage dual-phase parallel contact system with partition plates, where a direction-changing plate is installed only at the top, in the center of the stage, and both the heavy liquid phase and the light liquid phase have only one inlet. [Figure 13(d)] An example of a multi-stage internal parallel contact system with partition plates for both phases, where a direction-changing plate is installed only at the top, in the center of the stage, with one inlet for the light liquid phase and multiple inlets for the heavy liquid phase. [Figure 13(e)] An example of a multi-stage internal parallel contact system with partition plates for both phases, where a direction-changing plate is installed only at the bottom, slightly to the right of the stage, and both the heavy and light liquid phases have only one inlet. [Figure 13(f)]An example of a multi-stage internal multi-stage dual-phase parallel contact system with partition plates, where a direction-changing plate is installed only at the bottom, slightly to the right of the stage, resulting in one inlet for the heavy liquid phase and multiple inlets for the light liquid phase. [Figure 13(g)] An example of a multi-stage internal multi-stage dual-phase parallel contact system with partition plates, where a direction-changing plate is installed only at the top, slightly to the left of the stage, and both the heavy and light liquid phases have only one inlet. [Figure 13(h)] An example of a multi-stage internal parallel contact system with partition plates for both phases, where a direction-changing plate is installed only at the top, slightly to the left of the stage, resulting in one inlet for the light liquid phase and multiple inlets for the heavy liquid phase. [Figure 13(i)] An example of a multi-stage internal parallel contact system with partition plates for both phases, where a direction-changing plate is installed only at the bottom, slightly to the left of the stage, and both the heavy and light liquid phases have only one inlet. [Figure 13(j)] An example of a multi-stage internal parallel contact system with partition plates for both phases, where a direction-changing plate is installed only at the bottom, slightly to the left of the stage, resulting in one inlet for the heavy liquid phase and multiple inlets for the light liquid phase. [Figure 13(k)] An example of a multi-stage internal multi-stage dual-phase parallel contact system with partition plates, where a direction-changing plate is installed only at the top, slightly to the right of the stage, and both the heavy and light liquid phases have only one inlet. [Figure 13(l)] An example of a multi-stage internal multi-stage dual-phase parallel contact system with partition plates, where a direction-changing plate is installed only at the top, slightly to the right of the stage, resulting in one inlet for the light liquid phase and multiple inlets for the heavy liquid phase. [Figure 13(m)] An example of a multi-stage internal parallel contact system with partition plates for both phases, where a direction-changing plate is installed only at the bottom, either to the left or in the center of the stage, and both the heavy and light liquid phases have only one inlet. [Figure 13(n)] An example of a multi-stage internal parallel contact system with partition plates for both phases, where a direction-changing plate is installed only at the bottom, either to the left or in the center of the stage, with one inlet for the heavy liquid phase and multiple inlets for the light liquid phase. [Figure 13(o)] An example of a multi-stage internal parallel contact system with partition plates for both phases, where a direction-changing plate is installed only at the top, either to the left or right of the stage, and both the heavy and light liquid phases have only one inlet. [Figure 13(p)] An example of a multi-stage internal parallel contact system with partition plates for both phases, where a direction-changing plate is installed only at the top, either to the left or right of the stage, resulting in one inlet for the light liquid phase and multiple inlets for the heavy liquid phase. [Figure 13(q)]An example of a multi-stage internal parallel contact system with partition plates for both phases, where a direction-changing plate is installed only at the bottom, either to the right or in the center of the stage, and both the heavy liquid phase and the light liquid phase have only one inlet. [Figure 13(r)] An example of a multi-stage internal multi-stage dual-phase parallel contact system with partition plates, where a direction-changing plate is installed only at the bottom, either to the right or in the center of the stage, with one inlet for the heavy liquid phase and multiple inlets for the light liquid phase. [Figure 13(s)] An example of a multi-stage internal parallel contact system with partition plates for both phases, where a direction-changing plate is installed only at the top, either to the right or in the center of the stage, and both the heavy liquid phase and the light liquid phase have only one inlet. [Figure 13(t)] An example of a multi-stage internal multi-stage dual-phase parallel contact system with partition plates, where a direction-changing plate is installed only at the top, either to the right or in the center of the stage, with one inlet for the light liquid phase and multiple inlets for the heavy liquid phase. [Figure 14] A conventional multi-stage system with a sealed, droplet-discharge type design connected by liquid supply piping. [Figure 15] The multi-stage air purifier of the present invention is a sealed, droplet-discharge type, as shown in Figure 11(b). [Figure 16] The multi-stage of the present invention, which is a sealed type with a droplet ejection mechanism, has the structure shown in Figure 13(b). [Figure 17] An example of the effect of combining internal multistages and synchronous circulating multistages. [Figure 18] The positive extraction column is a single-stage (one internal stage) system with a synchronous circulating fluid delivery mechanism in multiple stages. [Figure 19] The positive extraction column employs a multi-stage synchronous circulating fluid delivery system with two internal stages. [Figure 20] The positive extraction column employs a multi-stage synchronous circulating fluid delivery system with three internal stages. [Modes for carrying out the invention]

[0020] The present invention relates to an "internal multi-stage" container characterized by the suppression of fluctuations in the interface position by the communication between the lower part, the upper part, or both of the container, and there are two main types of embodiments. One is a form that utilizes a connected body of multiple adjacent containers (referred to as a connected type), and the other is a form that utilizes a container with an integrated structure that has multiple partitions (referred to as a partition plate type).

[0021] Furthermore, for both the connected type and the partition plate type, there are three variations: one in which only the heavy liquid phase is connected at the bottom of the container (referred to as heavy liquid phase connection), one in which only the light liquid phase is connected at the top of the container (referred to as light liquid phase connection), and one in which both the heavy and light liquid phases are connected at the bottom and top of the container (referred to as double-phase connection).

[0022] Furthermore, there are contact methods in which the heavy liquid phase and the light liquid phase traverse each stage while facing each other (referred to as opposing contact), contact methods in which the heavy liquid phase and the light liquid phase traverse each stage while running parallel to each other (referred to as parallel contact), and contact methods in which only one of the liquid phases, either the heavy liquid phase or the light liquid phase, traverses each stage (referred to as one-sided transverse contact). Below, specific examples of embodiments will be shown using the above designations, but the scope of the present invention is not limited to these. Also, for convenience in illustration, an example with four stages will be shown, but the number of stages can be set arbitrarily.

[0023] Figure 1 shows an example of a connected system in which the heavy liquid phases of each stage are connected in multiple adjacent containers. The heavy liquid phases sequentially traverse each stage from the first to the fourth stage. On the other hand, the light liquid phases are not connected between the containers, so they inevitably make contact across one side. In this case, it is preferable that the volume velocity of the light liquid phase supplied to each stage is exactly the same, and under these conditions, the position of the liquid-liquid interface does not fluctuate. The containers forming the connected system may be sealed or open, and droplet nozzles, mechanical impellers, or both can be used for mixing the two liquid phases. Any number of droplet nozzles or mechanical impellers can be installed as appropriate.

[0024] Figure 2 shows an example of a connected system in which the light liquid phase is connected to multiple adjacent containers. The light liquid phase sequentially traverses each stage from the first to the fourth stage. On the other hand, since the heavy liquid phase is not connected between the containers, it inevitably makes contact across one side. In this case, it is preferable that the volume velocity of the heavy liquid phase supplied to each stage is exactly the same, and under these conditions, the position of the liquid-liquid interface does not fluctuate. The containers forming the connected system may be sealed or open, and a droplet nozzle, a mechanical stirring blade, or both can be used for mixing the two liquid phases, and any number of droplet nozzles or mechanical stirring blades can be installed as appropriate.

[0025] Figure 3(a) shows an example of a linked type variation in which both the heavy liquid phase and the light liquid phase are connected in multiple adjacent containers. The heavy liquid phase traverses each stage sequentially from the first to the fourth stage, and conversely, the light liquid phase traverses each stage sequentially from the fourth stage to the first stage, thereby bringing the two phases into opposing contact. Figure 3(b) shows the structure of Figure 3(a) with the addition of a gas phase connection passage. By also connecting the gas phase, the position of the liquid-liquid interface does not change even if gas is mixed into one of the containers forming the linked structure. As with Figures 1 and 2, the linked containers shown in Figures 3(a) and 3(b) may be sealed or unsealed, and droplet nozzles, mechanical stirring blades, or both can be used for mixing the two liquid phases. Any number of droplet nozzles or mechanical stirring blades can be installed as appropriate.

[0026] Figures 4(a) to 4(c) show examples of partition plate variations in a container with a single-piece structure containing multiple partitions, where the heavy liquid phases in each stage are connected. Each stage is separated by a stage divider plate, but they are connected at the bottom of the container, allowing the heavy liquid phase to pass through. This mechanism is characterized by having a partition plate (referred to as a direction-changing partition plate) positioned to change the direction of flow of the emulsion phase, which is a mixture of the heavy and light liquid phases, from bottom to top or top to bottom. In Figure 4(a), the direction-changing partition plate is located in the center of the stage, in Figure 4(b) it is located slightly to the right of the stage, and in Figure 4(c) it is located slightly to the left of the stage. The heavy liquid phase traverses each stage sequentially from the first to the fourth stage, while the light liquid phase side (top of the container) is not connected, resulting in one-sided cross-sectional contact. In this case, it is preferable that the volume velocity of the light liquid phase supplied to each stage is exactly the same, and under these conditions, the position of the liquid-liquid interface does not fluctuate. Furthermore, the container forming the above integrated structure may be sealed or open, and a droplet nozzle, a mechanical stirring blade, or both can be used for mixing the two liquid phases. Any number of droplet nozzles or mechanical stirring blades can be installed as appropriate.

[0027] Figures 5(a) to 5(c) show examples of partition plate variations in a container with a single-piece structure containing multiple partitions, where the light liquid phases in each stage are connected. Each stage is separated by a stage divider plate, but they are connected at the top of the container, allowing the light liquid phase to pass through. Similar to Figures 4(a) to 4(c), a key feature is the presence of a direction-changing partition plate. In Figure 5(a), the direction-changing partition plate is located in the center of the stage, in Figure 5(b) slightly to the right of the stage, and in Figure 5(c) slightly to the left of the stage. The light liquid phase traverses each stage sequentially from the first to the fourth stage, while the heavy liquid phase side (bottom of the container) is not connected, resulting in one-sided transverse contact. In this case, it is preferable that the volume velocity of the light liquid phase supplied to each stage is exactly the same, and under these conditions, the position of the liquid-liquid interface does not fluctuate. Furthermore, the container forming an integrated structure through which the light liquid phases are connected, like the containers shown in Figures 4(a) to 4(c) through which the heavy liquid phases are connected, may be either sealed or open. For mixing the two liquid phases, droplet nozzles, mechanical stirring blades, or both can be used, and any number of droplet nozzles or mechanical stirring blades can be installed as appropriate.

[0028] Figures 6(a) to 6(h) show examples of variations in a container with a single-piece structure featuring multiple partitions, where both the heavy and light liquid phases in each section are connected by partition plates, and the two phases are in direct contact with each other. The heavy liquid phase traverses each section sequentially from the first to the fourth section, and conversely, the light liquid phase traverses each section sequentially from the fourth section to the first section, thus bringing the two phases into direct contact. Each section is separated by a section divider plate, but they are connected at the bottom and top of the container, allowing the heavy and light liquid phases to pass through, respectively. The figures show examples of combinations where the direction-changing partition plates installed at the top and bottom of the container are positioned in the center, left-hand, or right-hand of the section, but this is not limited to these combinations. Note that in these figures, the connection of the light liquid phase is made through a gap between the top of the container and the section divider plate, and the shape and size of this gap are arbitrary. The partition-type container in which the two phases described above are connected may be sealed or unsealed, similar to the containers shown in Figures 4(a) to 4(c) and Figures 5(a) to 5(c). For mixing the two liquid phases, droplet nozzles, mechanical stirring blades, or both can be used, and any number of droplet nozzles or mechanical stirring blades can be installed as appropriate.

[0029] Figures 7(a) to 7(h) are similar to the variations shown in Figures 6(a) to 6(h), but the communication of the light liquid phase is achieved by a hole provided above the stepped divider plate, and the shape and size of this hole are arbitrary. The partition plate type container in which the two phases communicate as described above may be sealed or unsealed, similar to the containers shown in Figures 4(a) to 4(c), Figures 5(a) to 5(c), and Figures 6(a) to 6(h). For mixing the two liquid phases, droplet nozzles, mechanical stirring blades, or both can be used, and any number of droplet nozzles or mechanical stirring blades can be installed as appropriate.

[0030] Figures 8(a) and 8(b) show examples of variations in the installation of backflow prevention plates in a connected container in which both heavy and light liquid phases are connected. A backflow prevention plate is a partition plate positioned to prevent backflow from a later stage to an earlier stage during the process in which the heavy liquid phase, light liquid phase, or emulsion phase moves sequentially through stages installed in the container. By installing a backflow prevention plate, mixing due to backflow is suppressed, enabling more precise multi-stage processing. Backflow prevention plates are more effective when installed near the connecting passage and behind the direction of liquid phase flow in the connecting passage. That is, by making the liquid phase flow pass through a narrow space before reaching the connecting passage, the range of accelerated flow is expanded, making backflow less likely.

[0031] Furthermore, the backflow prevention plate is effective not only in the two-phase communication method described above, but also in the heavy liquid phase communication method and the light liquid phase communication method. Also, although Figures 8(a) and 8(b) show examples of opposing contact, the same applies to parallel contact.

[0032] Figures 9(a) to 9(h) show examples of variations in the installation of backflow prevention plates in partition-type containers where both heavy and light liquid phases are connected. Similar to connected containers, installing backflow prevention plates suppresses mixing due to backflow, enabling more precise multi-stage processing. Backflow prevention plates are more effective when installed behind the direction of liquid phase flow in the gap between the container ceiling and the partition plate or near the upper hole of the partition plate. That is, by passing the liquid phase flow through a narrow space before reaching the gap or hole, the range of accelerated flow is greatly expanded, making backflow less likely. In addition, the direction-changing partition plate may also serve as a backflow prevention plate. Backflow prevention plates are effective not only in the two-phase connection method described above, but also in the heavy liquid phase connection method and the light liquid phase connection method. Also, although Figures 9(a) to 9(h) show examples of opposing contact, the same applies to parallel contact.

[0033] Figures 10(a) to 10(f) show examples of variations in the structure for introducing two types of heavy liquid phases into a container with multiple partitions. For example, by using the aqueous solution to be treated as heavy liquid phase 1 and the aqueous solution for washing the light liquid phase as heavy liquid phase 2 as shown in these figures, more advanced separation and purification can be achieved.

[0034] Figures 11(a) to 11(f) show examples of a connected system in which both heavy and light liquid phases are connected in adjacent containers, with the two phases in parallel contact. Both the heavy and light liquid phases are brought into parallel contact by passing them sequentially through each stage from the first to the fourth stage. In the case of parallel contact, a method of introducing either the heavy or light liquid phase from multiple inlets may be effective. That is, as shown in Figures 11(b), 11(c), 11(e), and 11(f), either the heavy or light liquid phase is introduced from multiple inlets. For example, the same heavy or light liquid phase can be introduced simultaneously via branch pipes, reservoirs, etc.

[0035] Furthermore, in the case of opposing contact, it is formally possible to introduce a heavy liquid phase or a light liquid phase from multiple inlets, following the structural examples shown in Figures 11(b), 11(c), 11(e), and 11(f).

[0036] Similar to the structures shown in Figures 3(a) and 3(b), the structures in Figures 11(a) to 11(c) represent cases where only a light liquid phase communication passage is installed above the container, while the structures in Figures 11(d) to 11(f) represent cases where both a light liquid phase communication passage and a gas phase communication passage are installed above the container.

[0037] Furthermore, similar to the case of opposing contact, the containers used in parallel contact as shown in Figures 11(a) to 11(f) may be either sealed or unsealed, and droplet nozzles, mechanical stirring blades, or both can be used for the phase mixing of the two liquid phases. Any number of droplet nozzles or mechanical stirring blades can be installed as appropriate.

[0038] Figures 12(a) to 12(u) show examples of partition plate type containers where both the heavy and light liquid phases of each stage are connected, and where the direction-changing partition plates are installed above and below the container to bring the two phases into parallel contact. Both the heavy and light liquid phases are brought into parallel contact by passing them across each stage sequentially from the first to the fourth stage.

[0039] Similar to the connected type, in the case of parallel contact with partition plates, a method of introducing either the heavy or light liquid phase from multiple inlets can be effective. That is, as shown in Figures 12(b), 12(c), 12(e), 12(f), 12(h), 12(i), 12(k), 12(l), 12(n), 12(o), 12(q), 12(r), 12(t), and 12(u), either the heavy or light liquid phase is introduced from multiple inlets. For example, the same heavy or light liquid phase can be introduced simultaneously via branch pipes, liquid reservoirs, etc.

[0040] Furthermore, in the case of opposing contact, it is formally possible to introduce a heavy liquid phase or a light liquid phase from multiple inlets, following the structural examples shown in Figures 12(b), 12(c), 12(e), 12(f), 12(h), 12(i), 12(k), 12(l), 12(n), 12(o), 12(q), 12(r), 12(t), and 12(u).

[0041] Furthermore, similar to the case of opposing contact, the containers used in parallel contact as shown in Figures 12(a) to 12(u) may be either sealed or unsealed, and droplet nozzles, mechanical stirring blades, or both can be used for mixing the two liquid phases. Any number of droplet nozzles or mechanical stirring blades can be installed as appropriate.

[0042] Figures 13(a) to 13(t) show examples of partition plate type containers where both the heavy and light liquid phases of each stage are connected, and where the direction-changing partition plate is installed either above or below the container, allowing the two phases to be in parallel contact. Both the heavy and light liquid phases are brought into parallel contact by passing them across each stage sequentially from the first to the fourth stage.

[0043] Even in the case of parallel contact with a direction-changing plate installed either above or below, a method of introducing either the heavy or light liquid phase from multiple inlets may be effective. That is, as shown in Figures 13(b), 13(d), 13(f), 13(h), 13(j), 13(l), 13(n), 13(p), 13(r), and 13(t), either the heavy or light liquid phase is introduced from multiple inlets. For example, the same heavy or light liquid phase can be introduced simultaneously via branch pipes, reservoirs, etc.

[0044] Furthermore, in the case of opposing contact, it is formally possible to introduce a heavy liquid phase or a light liquid phase from multiple inlets, following the structural examples shown in Figures 13(b), 13(d), 13(f), 13(h), 13(j), 13(l), 13(n), 13(p), 13(r), and 13(t).

[0045] Furthermore, similar to the case of opposing contact, the containers used in parallel contact as shown in Figures 13(a) to 13(t) may be either sealed or unsealed, and droplet nozzles, mechanical stirring blades, or both can be used for mixing the two liquid phases. Any number of droplet nozzles or mechanical stirring blades can be installed as appropriate. [Examples]

[0046] Changes in interfacial position in each container structure

[0047] In the structure shown in Figures 1 and 4(a) to 4(c), where only the heavy liquid phase is connected at the bottom of the container, setting the introduction velocity (volume velocity) of the light liquid phase at each stage to be the same resulted in no change in the volume ratio of the heavy liquid phase to the light liquid phase (the so-called O / A ratio), and neither the liquid-liquid interface nor the liquid level of the light liquid phase (the gas-liquid interface between the light liquid phase and the gas phase) fluctuated. Furthermore, the above results were the same regardless of whether the container was sealed or not, whether droplet ejection from a nozzle or mechanical stirring with a stirring blade was performed, or whether the types of solvents in the heavy and light liquid phases were different.

[0048] Furthermore, in the structure shown in Figures 2 and 5(a) to 5(c), where only the light liquid phase is connected at the top of the container, by setting the introduction velocity (volume velocity) of the heavy liquid phase at each stage to be the same, the volume ratio of the heavy liquid phase to the light liquid phase (the so-called O / A ratio) did not change, and neither the liquid-liquid interface nor the liquid level of the light liquid phase (the gas-liquid interface between the light liquid phase and the gas phase) fluctuated. Moreover, the above results were the same regardless of whether the container was sealed or not, whether droplet ejection from a nozzle or mechanical stirring with a stirring blade was used, or whether the types of solvents in the heavy and light liquid phases were different.

[0049] In the structure shown in Figures 3(a) and 3(b), Figures 6(a) to 6(h), Figures 7(a) to 7(h), Figures 8(a) and 8(b), Figures 9(a) to 9(h), Figures 10(a) to 10(f), Figures 11(a) to 11(f), Figures 12(a) to 12(u), and Figures 13(a) to 13(t), where the heavy liquid phase is connected at the bottom of the container and the light liquid phase is connected at the top of the container, the volume ratio of the heavy liquid phase to the light liquid phase (so-called O / A ratio) remained unchanged, regardless of the introduction flow velocity (volume velocity) of the heavy and light liquid phases, the number of inlets, the presence or absence of branch pipes or liquid reservoirs, the difference between sealed and unsealed containers, the difference between droplet ejection from a nozzle and mechanical stirring with agitators, and the difference in the types of solvents in the heavy and light liquid phases. The positions of the liquid-liquid interface and the liquid surface of the light liquid phase remained unchanged. [Examples]

[0050] Comparison of introduction velocity (volume velocity) limits

[0051] As an example, the limits of the introduction flow velocity (volume velocity) of the aqueous solution to be treated were compared between the multi-stage system of the present invention and a conventional multi-stage system (multi-stage systems in which each stage is connected by liquid supply piping) for a closed-type, droplet-discharge multi-stage system. When the same light liquid phase is supplied to each stage (for example, assuming a synchronous circulating liquid supply multi-stage system as shown in [Example 4] below), the conventional multi-stage system consisted of four independent emulsion flow devices connected by liquid supply piping (Figure 14), while the multi-stage system of the present invention consisted of four stages as shown in Figures 11(b) and 13(b) (Figures 15 and 16).

[0052] First, Figure 14 shows a structure in which four independent stages (towers) are connected by heavy liquid phase supply piping. Although not shown, each stage has a pair of nozzles, one for the heavy liquid phase and one for the light liquid phase, installed vertically. The heavy liquid phase passes through the nozzles (four nozzles) installed on each stage, traversing from the first to the fourth stage in order, and is discharged at the fourth stage, while the light liquid phase circulates in each stage. Alternatively, a branch pipe could be placed on the inlet side of the light liquid phase to supply the light liquid phase evenly to each stage, and the light liquid phase could be concentrated and recovered using a branch pipe on the outlet side, and then reintroduced from the inlet side branch pipe to circulate the light liquid phase again. However, with this method, the interface position in each stage tends to fluctuate. Therefore, a structure like the one shown in Figure 14, which circulates the same light liquid phase in each stage and does not cause fluctuations in the interface position due to the supply of the light liquid phase, was selected.

[0053] The mechanism shown in Figure 14 is operated as follows: First, when the circulation and delivery of the light liquid phase is started at each stage, the emulsion phase generated at the liquid-liquid interface at each stage gradually expands vertically. When the emulsion phase reaches the nozzle for the heavy liquid phase, the delivery of the heavy liquid phase is started, and a steady state is reached within a few minutes.

[0054] Figure 15 shows a container structure in which four adjacent stages (towers) are connected by passages for both heavy and light liquid phases. Although not shown, the first stage has a pair of nozzles, one for the heavy liquid phase and one for the light liquid phase, installed vertically. The second, third, and fourth stages each have only one nozzle for the light liquid phase at the bottom. Similar to Figure 14, the heavy liquid phase traverses through the first to fourth stages in order and is discharged at the fourth stage. However, the light liquid phase is supplied to each stage from a branch pipe and returns to the branch pipe again from an outlet installed in the fourth stage. In other words, the light liquid phase circulates throughout all four stages. Figure 15 differs from Figure 14 in that the heavy liquid phase passes through only one nozzle and is not supplied to the next stage through a liquid supply pipe.

[0055] Figure 16 shows a system in which four stages arranged in a partitioned, integrated container are connected to both the heavy and light liquid phases. Although not shown, the first stage has a pair of nozzles, one for the heavy liquid phase and one for the light liquid phase, installed vertically. The second and third stages each have two nozzles for the light liquid phase at the bottom, and the fourth stage has only one nozzle for the light liquid phase at the bottom. Similar to Figure 14, the heavy liquid phase traverses the stages sequentially from the first to the fourth stage before being discharged at the fourth stage. However, the light liquid phase is supplied to each stage from a branch pipe and returns to the branch pipe again from an outlet installed at the fourth stage. In Figure 16, as in Figure 15, there is only one nozzle through which the heavy liquid phase passes, and this heavy liquid phase is not supplied to the next stage through the liquid supply piping, which is different from Figure 14.

[0056] The operation methods in Figures 15 and 16 are the same as those in Figure 14. First, when the circulation of the light liquid phase is started, the emulsion phase generated at the liquid-liquid interface in each stage gradually expands vertically. When the emulsion phase reaches the nozzle for the heavy liquid phase installed in the first stage, the heavy liquid phase is started, and a steady state is reached within a few minutes.

[0057] The limit of the introduction flow velocity (volume velocity) was defined as the point at which either significant turbidity of the wastewater or a clear change in the liquid-liquid interface position occurred. As a result, it was found that the limit of the introduction flow velocity (volume velocity) in the multi-stage system of the present invention (shown in Figures 15 and 16) is at least five times faster than that of the conventional multi-stage system (shown in Figure 14). [Examples]

[0058] Extraction and separation of rare earth elements by multi-stage opposing contact.

[0059] An experiment was conducted to separate erbium (Er) and dysprosium (Dy) from an aqueous nitric acid solution (aqueous phase) using a diluent (product name ShellSol D70) mainly composed of an alkane in which 2-ethylhexyl (2-ethylhexyl)phosphonate (product name PC-88A), a phosphoric acid-based extractant, was dissolved, as the organic phase. As a result, the simulated values ​​(theoretical values) for an ideal multi-stage separation using counter-contact were close to the actual measured values, indicating that a near-ideal multi-stage counter-contact separation was achieved.

[0060] Specifically, experiments were conducted using an open-type apparatus with a container structure as shown in Figure 6(h) and equipped with mechanical stirring blades, where the heavy liquid phase was an aqueous nitric acid solution containing Er and Dy, and the light liquid phase was ShellSol D70 containing PC-88A. As a result, for example, when the theoretical value of the extraction rate of Er reached a steady state in the distribution of Er and Dy, the actual measured value was 97% when the theoretical value of the extraction rate of Dy was 53%, and the actual measured value was 52% when the theoretical value of the extraction rate of Dy was 53%.

[0061] Furthermore, experiments were conducted using an open-type apparatus with a mechanical stirring blade installed in the container structure shown in Figure 10(f), with heavy liquid phase 1 being the nitric acid aqueous solution to be treated and heavy liquid phase 2 being the nitric acid aqueous solution for washing the light liquid phase. As a result, for example, when the theoretical value of the extraction rate of Er reached a steady state in the distribution of Er and Dy was 92%, the actual measured value was 90%, and when the theoretical value of the extraction rate of Dy was 25%, the actual measured value was 27%. [Examples]

[0062] Extraction and separation of rare earth elements in combination with synchronous circulating multi-stage fluid delivery.

[0063] In the extraction and separation of rare earth elements using a multi-stage effect, known as "synchronous circulating multi-stage," which results from integrating forward extraction, washing, and back extraction and synchronously circulating the liquid, experiments were conducted using the "internal multi-stage" of the present invention as the forward extraction column. In "synchronous circulating multi-stage," the number of times the aqueous phase circulates within the forward extraction column corresponds to the number of stages, but it was found that the number of circulations can be significantly reduced by using the "internal multi-stage." Specifically, it was found that, ideally, the number of circulations becomes 1 / n of that in a single-stage system, for a given number of stages n installed in the "internal multi-stage" system.

[0064] Using the same extractant and diluent as in [Example 3], an experiment was conducted to extract and separate the following four rare earth elements from an aqueous nitric acid solution. Figure 17 shows the purity of Ho in the separation of holmium (Ho) and lutetium (Lu), and the purity of Er in the separation of erbium (Er) and ytterbium (Yb). Compared to using a conventional emulsion flow apparatus (1 internal stage) as the positive extraction column, it was found that ideally, the number of cycles can be halved with a 2-stage positive extraction column and halved with a 3-stage positive extraction column. The actual mechanism used is shown in Figures 18, 19, and 20, respectively, for a 1-stage, 2-stage, and 3-stage positive extraction column in a "synchronous circulating multi-stage" system. In the multi-stage (2-stage and 3-stage) systems shown in Figures 19 and 20, a branched pipe was used to introduce the light liquid phase into the positive extraction column, and the same light liquid phase was delivered uniformly. [Examples]

[0065] Stable liquid-liquid extraction in systems containing components with strong surfactant properties

[0066] While it is generally desirable to avoid using substances with strong surfactant activity that cause severe turbidity and gelation in liquid-liquid systems, in practice, such substances can sometimes exhibit extremely high extraction and selective separation capabilities when extracting and separating metal ions. For example, sodium bis(ethylhexyl) sulfosuccinate (trade name Aerosol OT), which forms nano-sized molecular aggregates called reverse micelles in an inert medium, is a useful substance in liquid-liquid extraction, but because it is a surfactant, it tends to cause severe turbidity and gelation.

[0067] However, unlike mechanical stirring using rotating impellers that exert strong shear forces or shaking that involves violent agitation, droplet ejection, which mixes two liquid phases by gently stacking droplets, can sometimes be used for liquid-liquid extraction even with substances that have strong surfactant activity, without causing turbidity or gel formation.

[0068] The container structure provided by the present invention is useful as a mechanism for handling substances with strong surfactant activity, such as Aerosol OT, in multiple stages, as it enables highly efficient multi-stage liquid-liquid extraction based on droplet ejection. In fact, when using the multi-stage droplet ejection device shown in Figure 13(b) with an Aerosol OT-containing system that would otherwise become severely turbid with mechanical stirring, multi-stage liquid-liquid extraction was possible without causing turbidity. [Examples]

[0069] Purification of solid components

[0070] Liquid-liquid extraction can be used to remove fine impurities (solid components) consisting of metals such as iron, carbon, phosphorus, and boron from silicon powder (solid components). The multi-stage internal mechanism provided by this invention is suitable for this purpose and was able to remove impurities from silicon powder with high efficiency.

[0071] Specifically, impurities were removed from silicon powder using the internal multi-stage droplet ejection device shown in Figure 13(b). In the liquid-liquid system of water and hexane, the silicon powder readily distributed into the hexane phase, while the impurities readily distributed into the aqueous phase, allowing for their separation. Furthermore, increasing the number of internal stages improved the recovery rate of impurities from the silicon powder. [Examples]

[0072] Milking of valuable components from algae

[0073] The droplet ejection type multi-stage internal mechanism provided by the present invention can be used for "milking," which recovers valuable components from algae without killing them, similar to milking a cow.

[0074] Algae can produce and store valuable components such as triglycerides, chlorophyll, and β-carotenoids, but attempting to recover these valuable components into a solvent through liquid-liquid extraction results in the death of the algae. Only Botryococcus, which can accumulate valuable components in its intercellular matrix, is said to be an alga whose valuable components can be recovered by milking as they leach out.

[0075] However, it has been found that liquid-liquid extraction using a droplet ejection method, which gently layers droplets to mix the two liquid phases, is capable of milking not only special algae like Botryococcus, but also other types of algae. The container structure provided by the present invention is suitable for algal milking because it can perform liquid-liquid extraction based on droplet ejection in multiple stages with high efficiency.

[0076] Specifically, it was found that β-carotenoids, chlorophyll, and triglycerides could be milked from Dunaliella salina using the internal multi-stage droplet ejection device shown in Figure 13(b). Furthermore, the recovery rate of these valuable components could be increased by increasing the number of internal stages. The viability of Dunaliella salina was confirmed by the preservation of cell shape, the absence of cell saturation leakage, and the increase in cell number through culture. [Examples]

[0077] oil water separation

[0078] The multi-stage internal structure provided by the present invention can also be used as a method for oil-water separation. In particular, the droplet ejection type, which has a high phase separation capability, can achieve advanced oil-water separation.

[0079] As a simulated oil component, ShellSol D70, a solvent mainly composed of alkanes, was selected and emulsified in water using the method described below. An open-system container equipped with a hollow cone nozzle was filled with ion-exchanged distilled water, and ShellSol D70 was ejected into the water from the hollow cone nozzle connected by piping. An emulsion state was reached and maintained for a long period. The emulsion was then collected and observed with an optical microscope, revealing that oil droplets of ShellSol D70 with diameters ranging from a few μm to a maximum of approximately 100 μm were dispersed. Furthermore, the total organic carbon (TOC) of the emulsion was measured to be 239 mg / L.

[0080] When water emulsified with ShellSol D70 oil droplets was treated using an internal multi-stage droplet ejection system, the TOC was significantly reduced. Furthermore, increasing the number of internal stages allowed for an even greater reduction in the TOC value. For example, using an internal four-stage droplet ejection system as shown in Figure 13(b), the TOC was reduced from 239 mg / L to 23 mg / L (approximately 1 / 10). [Industrial applicability]

[0081] This invention relates to a multi-stage mechanism for repeatedly performing unit operations such as liquid-liquid extraction (solvent extraction) using a liquid-liquid system consisting of two liquid phases. It eliminates the difficulty of handling conventional multi-stage devices by eliminating the need to adjust the interface position, and enables large-volume liquid delivery. Improved operability (ease of use) makes it easier to control and automate the device, and the increased liquid delivery volume increases processing speed, allowing for a corresponding downsizing of the device.

[0082] For example, multi-stage liquid-liquid extraction (solvent extraction) can increase the purity of products such as metal materials, chemicals, and bio-based products, and enable difficult elemental separations, such as the separation of elements with similar chemical properties. However, the labor and time required to operate the cumbersome multi-stage equipment, as well as the cost and lack of floor space needed to prepare the required number of stages, often make it unprofitable and unsustainable as a business.

[0083] If the present invention eliminates the low operability, high cost, and lack of compactness associated with conventional multi-stage devices, technologies utilizing two-phase systems, such as liquid-liquid extraction (solvent extraction), will become more accessible. As shown in the examples, it is expected to bring innovation to a wide variety of industrial fields, including metals, chemicals, semiconductors, and biotechnology. [Explanation of symbols]

[0084] 1: Heavy liquid phase communication passage 2: Light liquid phase communication passage 3: Gas-phase connecting passage 4: Step divider 5: Directional turning board 6: Backflow prevention plate

Claims

1. A multi-stage liquid-liquid device having a droplet ejection nozzle that ejects droplets vertically, or a stirring blade that mechanically agitates by rotation, or both, which simultaneously mixes two immiscible liquid phases, a heavy liquid phase and a light liquid phase, until they reach an emulsion phase, while simultaneously promoting phase separation of the two phases, and which does not involve liquid delivery based on overflow, wherein the multi-stage liquid-liquid device further comprises two or more stages partitioned by a plurality of stage partition plates installed in a container of an integral structure, wherein the heavy liquid phase is in communication with an adjacent stage at the lower part of the container, and the light liquid phase is in communication with an adjacent stage at the upper part of the container.

2. A multi-stage liquid-liquid apparatus according to claim 1, characterized in that a direction-changing plate is provided in the stage for changing the direction of flow of the emulsion phase, which is a mixture of the heavy liquid phase and the light liquid phase.

3. A liquid-liquid multi-stage apparatus according to claim 1 or 2, characterized in that, in the process in which the heavy liquid phase, the light liquid phase, or the emulsion phase moves sequentially through the stages installed in the container, a backflow prevention plate is provided to prevent backflow from a later stage to an earlier stage.

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