KR20150124506A - Solvent extraction facilities - Google Patents

Abstract

Provided is a solvent extracting device. According to the present invention, the solvent extracting device, which extracts solvent in multiple stages using aqueous leachate and an organic extractant and using a difference in extraction rates between rare-earth elements, comprises: multiple mixing and settling basins including a mixing part for sucking and mixing the organic phase and the aqueous phase and a settling part for vertically separating the organic phase and the aqueous phase, which have been mixed in the mixing part, using a difference in specific gravity between the organic phase and the aqueous phase, and arranged in multiple stages; and an additional extractant input device for inputting an additional extractant into each of the mixing and settling basins to be able to control the input amount of the organic phase to be inputted into each of the mixing and settling basins in a solvent extracting process.

Description

SOLVENT EXTRACTION FACILITIES

The present invention relates to a solvent extraction apparatus for solvent extraction, and more particularly, to an apparatus and a method for controlling the extraction rate by controlling the amount of organic phase and pH adjusting agent to be controlled in each mixed precipitate among various factors that can be controlled in the solvent extraction process To a solvent extraction apparatus capable of performing the above-described process.

In general, mined rare earth ores are made into concentrated concentrates through the optical circulation process, and after various pretreatment processes, they are converted into the form of the leachate. In order to purify each rare earth element, a solvent extraction process extraction.

The solvent extraction process includes saponification, extraction, scrubbing, and stripping. In the solvent extraction process, a continuous multi-stage mixer- settler facility is used.

This solvent extraction process is a purification process that extracts in multi-stages by using difference of extraction ratio of each rare earth element using an extractant and an extractant suitable for the process.

In the conventional solvent extraction process, the extraction ratio (organic phase) of the extraction section and the injection ratio of the leach solution to be extracted (water phase) are constant, and the extraction is performed by a counter-current method. This method is a reaction in which the rare earth concentration in the organic phase and the rare earth concentration in the water phase reach equilibrium, and the parameters to be controlled in the actual operation are limited to the concentration of the organic phase, the input ratio, the concentration of the water phase, There was no way to control the extraction rate at the stage.

Further, as shown in Fig. 1, the organic phase and the water phase flow countercurrently. One facility in which stirring and separation occur is called a stage. In the stage, the mixing zone for mixing the organic phase and the aqueous phase and the settling zone for separating the organic phase and the aqueous phase are separated. Mixer-Settler). FIGS. 2 and 3 illustrate the principle of mixing and separating an organic phase and an aqueous phase by common mixed sedimentation and discharging the mixture, respectively.

Generally, a high-pore water phase is located below the settling zone, which is discharged using the hydrostatic pressure that the organic phase located above the settling portion presses. The discharged water phase and the organic phase are transported in different directions to the next stage. The power source to be transported is sucked and agitated using the structure of an agitator (impeller) 3).

As described previously, the solvent extraction process is a process based on extracting a rare earth element of an aqueous phase into an organic phase through mixing of an aqueous phase and an organic phase. The extraction rate is greatly influenced by factors such as the concentration of the extractant, the input amount, and pH. 1, the concentration and the amount of the organic phase (extractant) in the organic phase input portion of the extraction portion have already been determined, and the pH of the aqueous phase (leachate) as another factor is determined in the water phase input portion of FIG. 1 , It is necessary to wait until the discharged organic phase and water phase are discharged, and it is not possible to artificially control the process variables in the middle of the process.

Therefore, among various factors that can be controlled in the solvent extraction process, there is a desperate need to control the extraction rate by controlling the amounts of the organic phase and the pH adjusting agent to be controlled by the respective mixed sedimentation accelerators.

The present invention is to provide a solvent extraction apparatus capable of controlling the extraction rate by controlling the amount of the organic phase and the pH adjusting agent to be controlled in the respective mixed sedimentation enhancers among the various factors that can be controlled in the solvent extraction process.

According to an embodiment of the present invention, there is provided a solvent extraction apparatus for extracting in multi-stages using difference in extraction rates of rare earth elements using an extract liquid (water phase) and an extractant (organic phase)

A mixed portion for sucking and mixing the organic phase and water phase, and a sediment portion for vertically separating the organic phase and the water phase mixed in the mixing portion due to the difference in specific gravity between the organic phase and the aqueous phase,

A solvent extraction apparatus may be provided that includes an additional extractor input device for inputting an additional extractant into each mixed sedimentation column so as to control the amount of the organic phase input into each mixed sedimentation column in the solvent extraction process .

Further, according to another embodiment of the present invention, there is provided a solvent extraction apparatus for extracting in multi-stages using difference in extraction rates of rare earth elements using an extract liquid (water phase) and an extracting agent (organic phase)

A mixed portion for sucking and mixing the organic phase and water phase, and a sediment portion for vertically separating the organic phase and the water phase mixed in the mixing portion due to the difference in specific gravity between the organic phase and the aqueous phase,

A solvent extraction apparatus may be provided that includes a pH adjusting agent injecting apparatus for injecting a pH adjusting agent adjusting agent into each mixed sedimentation so that the pH of the water phase of each mixed precipitating emphasis can be controlled in the solvent extraction step.

According to still another embodiment of the present invention, there is provided a solvent extraction apparatus for extracting in multi-stages using difference in extraction rates of rare earth elements using an extract (aqueous phase) and an extractant (organic phase)

A mixing section for sucking and mixing the organic phase and the water phase, and a sedimentation section for separating the organic phase and the water phase mixed up in the mixing section by the difference in specific gravity between the organic phase and the water phase,

An additional extractor feeder for adding additional extractant to each mixed sedimentation so as to control the amount of the organic phase to be added to each mixed sedimentation during the solvent extraction process,

A solvent extraction apparatus may be provided that includes a pH adjuster injector for injecting a pH adjuster into each mixed sedimentation so that the pH of the water phase of each mixed sedimentation enhancement can be controlled in the solvent extraction step.

Said additional extractant dosing device further comprises an additional extractant feed line for feeding additional extractant to said mixed sedimentation concentrate,

A further inlet for introducing the additional extractant is formed at the lower end thereof, an additional extractor inlet for injecting the additional extractant into the mixing portion of the mixed sedimentation stress, and

And a first connector for connecting the additional extractant feed pipe and the additional extractant feeder.

And an additional extraction agent inlet pipe for connecting the first inlet of the additional extraction agent inlet to the mixing section and for introducing the additional extraction agent introduced from the first inlet into the mixing section.

The first connection pipe may be provided with an additional extractant control valve for regulating the flow rate of the additional extractant introduced from the additional extractor feed pipe into the additional extractor feeder.

An impeller for sucking the organic phase and the water phase through an inlet formed at the bottom of the mixing unit and mixing the organic phase introduced into the mixing unit and mixing them uniformly may be provided.

The additional extractant injected from the additional extractant input portion into the additional extractor input pipe may be introduced into the mixing portion by the suction force of the impeller of the mixing portion.

In addition, the PH adjusting agent introducing device may include a PH adjusting agent supplying pipe for supplying the PH adjusting agent to the mixed sedimentation enhancer,

A second inlet for introducing a pH adjusting agent into the lower end thereof, a pH adjusting agent inlet for injecting the pH adjusting agent into the mixed portion of the mixed sedimentation stress,

And a second connection pipe for connecting the PH control agent supply pipe and the PH control agent introduction unit.

And a pH adjusting agent inlet pipe for connecting the second inlet of the PH adjusting agent inlet to the mixing section and for introducing the PH adjusting agent introduced from the second inlet into the mixing section.

The second connection pipe may be provided with a pH adjusting agent control valve for adjusting a flow rate of the pH adjusting agent supplied from the PH adjusting agent supplying pipe to the PH adjusting agent introducing unit.

An impeller for sucking the organic phase and the water phase through an inlet formed at the bottom of the mixing unit and mixing the organic phase introduced into the mixing unit and mixing them uniformly may be provided.

The pH adjusting agent injected into the PH adjusting agent inlet pipe from the PH adjusting agent injecting section may be introduced into the mixing section by the suction force of the impeller of the mixing section.

According to this embodiment, among the various factors that can be controlled in the solvent extraction process, the extraction rate can be controlled by controlling the amount of the organic phase and the pH adjusting agent to be controlled by the respective mixed sedimentation accelerators, It is possible to selectively extract the rare earth element to be extracted by the mixed sedimentation group and to use the small number of mixed sedimentation accelerators so that the stabilization time from the input to the discharge can be greatly shortened.

FIG. 1 is a schematic diagram for explaining a conventional solvent extraction process.
Fig. 2 is a schematic diagram for explaining the structure of a general mixed sedimentation emphasis.
FIG. 3 is a schematic diagram for explaining the principle of separation of a general mixed sedimentation emphasis.
4 is a schematic block diagram of a solvent extraction apparatus according to an embodiment of the present invention.
FIG. 5 is a schematic view illustrating a solvent extraction process according to an embodiment of the present invention. Referring to FIG.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Wherever possible, the same or similar parts are denoted using the same reference numerals in the drawings.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms as used herein include plural forms as long as the phrases do not expressly express the opposite meaning thereto. Means that a particular feature, region, integer, step, operation, element and / or component is specified, and that other specific features, regions, integers, steps, operations, elements, components, and / And the like.

All terms including technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the art to which the present invention belongs. Predefined terms are further interpreted as having a meaning consistent with the relevant technical literature and the present disclosure, and are not to be construed as ideal or very formal meanings unless defined otherwise.

[Principle of Solving the Problems of the Present Invention]

The higher the mixing ratio of the organic phase and the water phase, the higher the extraction characteristics. Therefore, the control of the extraction rate is performed by increasing the mixing ratio by increasing the amount of the extracting agent per mixed precipitate.

In addition, the higher the pH, the higher the extraction rate. The lower the pH, the lower the extraction rate. As a control factor, the control of the extraction rate is proposed.

FIG. 4 is a schematic diagram of a solvent extraction apparatus according to an embodiment of the present invention, and FIG. 5 is a schematic diagram illustrating a solvent extraction process according to an embodiment of the present invention.

4 and 5, the solvent extraction apparatus according to an embodiment of the present invention extracts in multiple stages using difference in extraction rates of rare earth elements using an extractant and an extraction agent suitable for the process.

The solvent extraction apparatus includes a mixing section 110 for sucking and mixing the organic phase and water phase, a sedimenting section 120 for separating the organic phase and water phase mixed in the mixing section 110 by the difference in specific gravity between the organic phase and the water phase, A plurality of mixed precipitated accelerations (100) arranged in multiple stages, and

An additional extractor injector 200 for injecting an additional extractant into each of the mixed precipitating accelerators 100 so as to control the amount of the organic phase injected into each of the mixed precipitating accelerators 100 during the solvent extraction process can do.

The apparatus may further include a pH adjusting agent injecting device 300 for injecting a pH adjusting agent into each of the mixed precipitating accelerators 100 so as to control the pH of the aqueous phase of each mixed sedimentation accelerator 100 in the solvent extraction step.

The mixed sedimentation promoter 100 may include a separator 130 for separating and discharging the organic phase separated from the sedimentation unit 120 and the water phase separated from the sedimentation unit.

The mixing portion 110, the sediment portion 120, and the separation portion 130 may be sequentially disposed in the mixed sedimentation accelerator 100 along the flow direction of the solution.

The separating unit 130 may include an organic phase 131 and an aeration zone 133 through which the organic phase and water phase separated from the settling unit 120 respectively flow.

In the mixing portion 110, the organic phase and the water phase are separated upward and downward due to the difference in specific gravity passing through the settling portion 120. After passing through the settling portion 120, the organic phase is moved to the organic phase 131 connected upward and discharged through the outlet, and the water phase moves to the downwardly connected water zone 133 and is also discharged through the outlet.

An inlet 111 is formed at the bottom of the mixing unit 110. The inlet 111 is connected to a conveyance line 113 through which the water phase and the organic phase separated from the adjacent mixed sedimentation stress (not shown) The organic phase and water phase are introduced into the mixing portion 110 through the inlet 111.

In the transfer line 113, an organic phase feed pipe 115 for feeding an organic phase and a water feed pipe 117 for injecting an aqueous phase can be installed.

An impeller (141) of an agitator (140) for sucking the organic phase and water phase through the inlet (111) and stirring the organic phase introduced into the mixing unit and mixing them uniformly is provided in the mixing unit (110).

The additional extractor dosing device 200 further includes an additional extractor supply piping 210 for supplying the additional extractant to the mixed sedimentation accelerator 100,

A first inlet 221 for introducing the additional extractant is formed at a lower end thereof and an additional extractor input unit 220 for injecting the additional extractant into the mixing unit 110 of the mixed sediment 100,

And a first connection pipe 230 for connecting the additional extraction agent supply pipe 210 and the additional extraction agent injection unit 220.

An additional extraction agent for connecting the first inlet 221 of the additional extraction agent input part 220 and the mixing part 110 and for introducing the additional extraction agent introduced from the first inlet 221 into the mixing part, And an extractive feed pipe 240.

The first connection pipe 230 may further include an additional extractant control valve 250 for controlling the flow rate of the additional extractant injected from the additional extractant feed pipe 210 into the additional extractant feeder 220 Can be installed.

The additional extractant that has passed through the additional extractant control valve 250 is introduced into the additional extractor input unit 220 and is moved to the additional extractor input pipe 240 through the first inlet 221 by its own weight do.

The additional extractant injected from the additional extractor input unit 220 into the additional extractor injection pipe 240 flows into the mixing unit 110 by the suction force of the impeller 141 of the mixing unit 110.

In addition, the PH adjusting agent injecting apparatus 300 may include a PH adjusting agent supplying pipe 310 for supplying the PH adjusting agent to the mixed sediment 100,

A second inlet 321 for introducing a pH adjusting agent into the lower end of the mixing portion 110 and a pH adjusting agent input portion 320 for inputting the pH adjusting agent into the mixing portion 110 of the mixed sediment 100,

And a second connection pipe 330 for connecting the PH adjusting agent supplying pipe 310 and the PH adjusting agent injecting unit 320.

A mixing unit 110 for connecting the second inlet 321 of the PH adjusting agent injecting unit 320 and the PH adjusting agent introduced from the second inlet 321 into the mixing unit 110, And a pH adjusting agent inlet pipe 340.

The second connecting pipe 330 is provided with a pH adjusting agent control valve 350 for controlling the flow rate of the pH adjusting agent supplied from the PH adjusting agent supplying pipe 310 to the PH adjusting agent injecting unit 320 .

The pH adjusting agent passed through the pH adjusting agent control valve 350 is introduced into the pH adjusting agent injecting part 320 and is moved to the pH adjusting agent supplying tube 340 through the second inlet 321 by its own weight.

The PH adjusting agent injected into the PH adjusting agent injecting pipe 340 from the PH adjusting agent injecting unit 320 flows into the mixing unit 110 by the suction force of the impeller 141 of the mixing unit 110.

That is, during operation of the solvent extraction apparatus, the impeller 141 of the stirrer 140 operates to generate a negative pressure at the lower end of the mixing section 110. The added additional extractant and the PH adjusting agent are mixed with the organic phase and the water phase And flows into the mixing portion 110 of the mixed sedimentation accelerator 100.

The solvent extraction apparatus according to an embodiment of the present invention configured as described above is configured to suck an organic phase and a water phase as in the conventional mixed sedimentation emphasis, A further extracting agent introducing device for introducing the extracting agent, and a PH adjusting agent introducing device for inputting the PH adjusting agent are constituted.

The additional extractor injector 200 further includes an additional extractor feed pipe 210 and a further extractor feeder 220 to supply additional extractant, a first connecting pipe 230, (240), and an additional extractant control valve (250) capable of regulating the additional extractant feed flow rate.

Therefore, the additional extraction agent supply pipe 210 and the additional extraction agent injection unit 220, the first connection pipe 230, and the additional extraction agent injection pipe 240 can be further extracted And the additional extractant supply flow rate to be supplied to the mixing section 110 can be controlled by the additional extractant control valve 250. [

The pH adjusting agent injecting apparatus 300 may further include a pH adjusting agent supplying pipe 310, a pH adjusting agent injecting unit 320, a second connecting pipe 330, a pH adjusting agent supplying pipe 340, And a pH adjusting agent control valve 350 capable of adjusting the flow rate of the PH adjusting agent.

Therefore, the PH adjusting agent can be supplied to the mixing unit 110 through the PH adjusting agent supplying pipe 310, the PH adjusting agent injecting unit 320, the second connecting pipe 330, and the pH adjusting agent inlet pipe 340, The flow rate of the PH adjusting agent supplied to the mixing unit 110 can be controlled by the pH adjusting agent control valve 350.

The additional extractant and the pH adjuster injected from the additional extractant control valve 250 and the pH adjuster control valve 350 are introduced into the additional extractor injector 220 and the pH adjuster injector 320, To the additional extractant feed pipe 240 and the pH adjuster feed pipe 340. [

During the solvent extraction process, while the solvent extraction apparatus is operated, the impeller 141 operates to generate a negative pressure at the lower end of the mixing unit 110. The added additional extraction agent and the pH adjusting agent are mixed with the organic phase and water phase, Is mixed and then moved to the settling portion and separated. When one mixed sedimentation enhancement is applied to the solvent extraction process proposed in the present invention, it is configured as shown in FIG.

[Experimental Example]

≪ Embodiment of the present invention &

PC88A, an extracting agent, was mixed with a diluent to adjust the concentration to 1M and saponified 15% by using caustic soda (6.25wt%). (Extractants of PC88A and P507 differ only in their product name. Is a phosphate-based organic extractant called 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester.

The composition of the solvent extraction process was a combination of two sets of mixed sedimentation enhancers. In the first mixed sedimentation tank into which the organic phase was introduced, the mixing ratio of the organic phase and the rare earth leachate was adjusted to be 1: 1. In the second mixed sedimentation enhancement stage, The additional extractant control valve was adjusted so that the mixing ratio was 2: 1.

At this time, the additional additive control agent used was the same extracting agent as that of the originally prepared extracting agent. After the solvent extraction process proposed in the present invention was operated for 2 hours, the rare earth concentration of the water phase and the rare earth concentration of the discharged water phase were analyzed. In the examples of the present invention, a high extraction ratio is shown due to the addition of an additional extractant (see Table 1).

In the embodiment of the present invention, the rare earth raw material is leached into hydrochloric acid and the solvent extraction process using PC88A (or P507) is taken as an example. However, the present invention can be applied to any conventional solvent extraction process using an organic solvent and an aqueous leaching solution.

The solvent extraction process extraction result according to the embodiment of the present invention Rare earth element Incoming award Emitted awards Extraction rate (%) La    33,330.0    28,520.0 14.43% Ce    61,400.0    40,340.0 34.30% Pr      4,583.0      2,185.0 52.32% Nd    16,960.0      5,916.0 65.12% Sm      1,966.0         467.6 76.22% Eu         232.1          13.9 94.02% Unit (mg / L)

<Comparative Example>

The extractant was prepared in the same manner as in the examples of the present invention, and the solvent extraction process was operated by fixing the ratio of organic phase to water phase (1: 1) as in the conventional solvent extraction process. At this time, the composition of the solvent extraction process was composed of 15 sets of mixed sedimentation boosters, and the operation was performed for more than 40 hours for stabilization. After the operation, the extracted water phase and the rare earth element of the discharged water phase were compared with each other, and as a result, the extraction rate was lower than that of the embodiment of the present invention (see Table 2).

Existing solvent extraction process extraction result Rare earth element Incoming award Emitted awards Extraction rate (%) La       33,630.0     30,180.0 10.3% Ce       62,710.0     51,310.0 18.2% Pr        4,082.0      3,131.0 23.3% Nd       17,420.0     10,100.0 42.0% Sm        1,850.0         499.5 73.0% Eu          217.6          17.1 92.2% Unit (mg / L)

&Lt; Comparison of Examples of the Present Invention and Comparative Examples &

Comparing the examples of the invention and the comparative examples, the examples of the present invention were extracted using only two mixed sedimentation accelerators, and in the comparative example, 15 mixed sedimentation accents were used. The embodiment of the present invention shows a higher extraction rate than that of the comparative example even when extracting using a small number of mixed sedimentation accelerators. Also, by using the adjusting agent input method, it is possible to selectively extract the rare earth element to be extracted for each mixed precipitate emphasis. The embodiment of the present invention exhibits a higher extraction ratio than that of the comparative example even when a smaller number of mixed sedimentation accelerations are used than in the comparative example and selective extraction can be performed by a mixed sedimentation group. The time for stabilization can be greatly shortened.

100: mixed sedimentation enhancement 110: mixing part
120: Deposition part 200: Additional extraction agent input device
210: additional extractant feed line 220: additional extractant feeder
230: first connector 240: additional extraction agent input tube
250: Extracting agent regulating valve 300: PH controlling agent injecting device
310: PH adjusting agent input piping 320: PH adjusting agent input section
330: Second connector 340: PH modulator input tube
350: pH adjuster regulating valve

Claims (13)

1. A solvent extraction apparatus for extracting in multi-stages using difference in extraction rates of rare earth elements using an extract (aqueous phase) and an extractant (organic phase)
A mixed portion for sucking and mixing the organic phase and water phase, and a sediment portion for vertically separating the organic phase and the water phase mixed in the mixing portion due to the difference in specific gravity between the organic phase and the aqueous phase,
In order to control the amount of the organic phase to be added to each mixed sedimentation step in the solvent extraction process, an additional extractive additive device
. &Lt; / RTI &gt; 1. A solvent extraction apparatus for extracting in multi-stages using difference in extraction rates of rare earth elements using an extract (aqueous phase) and an extractant (organic phase)
A mixed portion for sucking and mixing the organic phase and water phase, and a sediment portion for vertically separating the organic phase and the water phase mixed in the mixing portion due to the difference in specific gravity between the organic phase and the aqueous phase,
In order to control the pH of the aqueous phase of each mixed precipitate in the solvent extraction step, a pH adjusting agent injecting device
. &Lt; / RTI &gt; 1. A solvent extraction apparatus for extracting in multi-stages using difference in extraction rates of rare earth elements using an extract (aqueous phase) and an extractant (organic phase)
A mixing section for sucking and mixing the organic phase and the water phase, and a sedimentation section for separating the organic phase and the water phase mixed up in the mixing section by the difference in specific gravity between the organic phase and the water phase,
An additional extractor feeder for adding additional extractant to each mixed sedimentation so as to control the amount of the organic phase to be added to each mixed sedimentation during the solvent extraction process,
In order to control the pH of the aqueous phase of each mixed precipitate in the solvent extraction step, a pH adjusting agent injecting device
. &Lt; / RTI &gt; The method according to claim 1 or 3,
Said additional extractant dosing device further comprises an additional extractant feed line for feeding additional extractant to said mixed sedimentation concentrate,
A further inlet for introducing the additional extractant is formed at the lower end thereof, an additional extractor inlet for injecting the additional extractant into the mixing portion of the mixed sedimentation stress, and
And a first connection pipe for connecting the additional extractant feed pipe and the additional extractant feeder. 5. The method of claim 4,
And an additional extraction agent inlet pipe for connecting the first inlet of the additional extractant inlet section to the mixing section and for introducing additional extraction agent introduced from the first inlet into the mixing section. 5. The method of claim 4,
Wherein the first connection pipe is provided with an additional extractant control valve for regulating an input flow rate of the additional extractant introduced from the additional extractant feed pipe into the additional extractant feeder. 6. The method of claim 5,
Wherein the mixing unit is provided with an impeller for sucking the organic phase and the water phase through an inlet formed at the bottom and stirring the organic phase introduced into the mixing unit to mix the organic phase uniformly. 8. The method of claim 7,
Wherein the additional extractant injected from the additional extractant input section into the additional extractant inlet pipe flows into the mixing section by the suction force of the impeller of the mixing section. The method according to claim 2 or 3,
The PH adjusting agent adding device may include a PH adjusting agent supplying pipe for supplying the PH adjusting agent to the mixed sedimentation enhancer,
A second inlet for introducing a pH adjusting agent into the lower end thereof, a pH adjusting agent inlet for injecting the pH adjusting agent into the mixed portion of the mixed sedimentation stress,
And a second connection pipe for connecting the PH control agent supply pipe and the PH control agent introduction unit. 10. The method of claim 9,
And a pH adjusting agent inlet tube for connecting the second inlet of the PH adjusting agent inlet to the mixing section and for introducing the pH adjusting agent introduced from the second inlet into the mixing section. 10. The method of claim 9,
Wherein the second connecting pipe is provided with a pH adjusting agent control valve for adjusting a flow rate of a pH adjusting agent supplied from the PH adjusting agent supplying pipe to the PH adjusting agent introducing unit. 11. The method of claim 10,
Wherein the mixing unit is provided with an impeller for sucking the organic phase and the water phase through an inlet formed at the bottom and stirring the organic phase introduced into the mixing unit to mix the organic phase uniformly. 13. The method of claim 12,
Wherein the PH adjusting agent injected into the PH adjusting agent input tube from the PH adjusting agent input portion flows into the mixing portion by the suction force of the impeller of the mixing portion.

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