JPS6351902A - Method and device for extraction - Google Patents

Abstract

PURPOSE:To treat at a high extraction efficiency by adjusting pH of an extraction feed and a back extractant within a good range. CONSTITUTION:An extraction device consists of an extraction means provided with a solid membrane 30 and a crystallization means 2. A pH adjusting agent for acid or alkali is provided to be introduced into a treatment tank 74 by a pump 88 and a piping 86, a pH meter 78 and the pump 88 are linked with, and an adequate quantity of acid or alkali as pH adjusting agent necessary for maintaining an extraction feed within a fixed pH range by using the detected valued of the pH meter 78. By said arrangement, the extraction feed which circulates to an extraction means 1 by a piping 80 is maintained always within an adequate range of pH. As the result, in extraction, back extraction and extraction recovering treatment, the concentration of acid or alkali in the extraction feed and the back extractant can be adjusted easily and accurate ly to continue the operation of the device stabilized for a long time at a high efficiency.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to an extraction method and an extraction device for the same, and in particular, it is possible to achieve high extraction efficiency by adjusting the pH of the extract and the back-extracting agent to a favorable range. The present invention relates to an extraction method and an extraction device for the same.

[Conventional technology and prior art] Extraction is a technology that has been widely used for the separation and purification of various substances for a long time, but recently, a method of extraction via a solid membrane is being considered. . In the extraction method using a solid membrane, extraction is performed by flowing an extraction feed containing the substance to be extracted (extractant) into one side of the solid membrane and an extractant (5olvent) into the other side, and then performing extraction in the same manner. Reverse extraction agent (5trip 5o) on one side
In this method, the target substance, which is the target substance, is recovered by injecting the extracting agent containing the extracted substance into the other side and performing back extraction.

When a certain amount of the substance to be extracted has been extracted into the back-extracting agent, the back-extracting agent is taken out, and if the back-extracting agent is an acid, it is weakened by adding an alkali or diluting it. After making it acidic or neutral, it is sent to an electrolytic cell and subjected to electrolysis to reduce, precipitate, and recover the extracted substance. In some cases, metal hydroxides are obtained by adjusting the pH and recovered by precipitation.

However, the conventional method described above requires an electrolyzer and is not advantageous in terms of equipment costs, maintenance, etc. In addition, the back-extracting agent cannot be reused, resulting in high costs, which is economically disadvantageous. Moreover, when metal hydroxides are precipitated and recovered by pH adjustment, it is difficult to treat the sludge, and there are problems such as high treatment costs.

In order to solve the above-mentioned conventional problems, the present applicant divided the inside of the container into at least two chambers with a solid membrane, filled the first chamber with extraction agent, and removed the remaining extraction agent and back extraction. One of the drugs? ? ! into a second chamber and a remaining liquid (which is substantially immiscible with the extraction agent) into the extraction agent in the first chamber; A patent was previously filed for an extraction device equipped with a crystallization means for back-extracting the substance to be extracted by a means, crystallizing the discharged back-extracting agent, and returning it to the extraction means (Patent application filed in 1983). -66
292, hereinafter referred to as the "prior application". ).

According to the extraction device of the prior application, it is equipped with an extraction means for performing extraction and back-extraction, and a crystallization means for crystallizing and circulating a back-extracting agent that has back-extracted the substance to be extracted from the extraction means. Therefore, it is possible to independently control the back extraction rate and crystallization rate, making it easier to operate the equipment.
Moreover, since the extraction means and the crystallization means are provided separately in this way, each condition (for example, temperature) can be set to the optimum condition for extraction or crystallization, which improves extraction efficiency and crystallization efficiency. can be improved.

[Problems to be Solved by the Invention] Generally, in extraction and back-extraction means, highly concentrated acid or alkali is often used as a back-extracting agent, but if the back-extracting agent is used cyclically, The acid or alkali in the extractant decreases over time.

For example, the extraction and back extraction of Cu contained in the extraction material is performed by SM
Using E-529 (Shell Chemicals) as an extractant, R2SO4
Taking as an example the case where the extraction and back extraction are carried out using .

Belly” Cu 24 (during extraction) + 2HR (during extraction) = CuR2
(In extraction agent) + 28 + (In extraction agent) ... (I) Five Sumai CuR2 (In extraction agent) + H2S04 (In back extraction agent) - = C
uSO+ (in back extractant) + 2HR (in extractant)...(I
I) As shown in the above equation, the extraction material increases in acid concentration, while the back-extraction agent decreases the same equivalent amount of acid.

If the acid concentration or alkali concentration of the extraction material or back-extracting agent changes in this way, the extraction rate and back-extraction rate will decrease, and the extraction and back-extraction efficiency will deteriorate. Further, a reduction in the acid concentration or alkali concentration of the back-extracting agent causes deterioration in the crystallization recovery efficiency of the extracted material in the crystallization means. For example, in the case of the above-mentioned extraction and recovery of Cu, when the acid concentration of the back-extracting agent decreases, the solubility of Cu increases and crystallization may not occur.

Conventionally, the acid or alkali concentration of extraction material or back-extracting agent is controlled by pH. The pH of the extract can be easily adjusted by

However, as mentioned above, since the back-extracting agent is generally a highly concentrated acid or alkali, a slight change in concentration will hardly change the pH, making it difficult to control the concentration by pH. Even in the case of Cu extraction and back extraction, the R2SO4 concentration in the back extractant is about 50 to 200 g/l, making it difficult to adjust the acid concentration by adjusting the pH.

This is a problem not only in the device of the prior application but also in any extraction method in which the back extractant is processed (extractant recovery) and the back extractant is recycled.

[Means for Solving the Problems] The present invention solves the above-mentioned conventional problems, and includes an extraction method in which an extractant is brought into contact with an extraction agent, and the extraction agent and a back-extracting agent are brought into contact with each other. , one of the acid and the alkali is added to the extraction agent and the contacting agent, and the other of the acid and the alkali is back-extracted so that the pH of the extraction agent after contact with the extraction agent is within a predetermined range. and the following means a, b, c, d, e, f, and g, namely: a. Bringing the extract containing the substance to be extracted into contact with the extract. an extraction section having an extraction chamber, a means for introducing the extraction material into the chamber, and a means for discharging the extraction material after contact with the extraction agent; and a chamber for bringing the extraction agent into contact with the back-extracting agent after contact with the extraction agent. , a back-extraction section having a means for introducing a back-extracting agent into the chamber and a means for discharging the back-extracting agent after contact with the extraction agent; b. a substance to be extracted having a liquid introduction means and a liquid discharge means; a means for feeding a liquid from the back-extractant discharge means of the extraction means to the liquid introduction means of the recovery means; a means for feeding the extract; e) a pH adjusting means for supplying acid or alkali to the extractor, which is provided in the circulation path of the extractor; pH measuring means for measuring pH; g; extract pH adjusting means for supplying acid or alkali to the extract, which is provided in the extract introducing means of the extracting means, and adjusting the extract pH. The means is the pH
In addition to supplying the necessary amount of acid or alkali so that the detection value of the measuring means falls within a predetermined range, the pH of the back extractant is
The gist of the adjustment means is an extraction device characterized by supplying the other of acid and alkali.

[Function] As described above, in back extraction, the amount of acid (or alkali) in the back extractant that decreases becomes equivalent to the amount of acid (or alkali) in the extract that increases in extraction.

Therefore, in order to detect the p)l of the extracted material after extraction treatment and bring it into a predetermined range, that is, the pH value of the extracted material suitable for the extraction treatment, one of the acid and alkali necessary for the extraction treatment is applied to the extracted material, and the other is By supplying the extractant to the back-extracting agent, it becomes possible to always maintain the desired acid or alkali concentration in the extraction material and the back-extracting agent.

In this case, the acid or alkali concentration of the extraction material is generally lower than the acid or alkali concentration of the back-extracting agent, so
Even subtle changes in pH can be detected relatively easily.

Therefore, according to the extraction method and extraction apparatus of the great invention, the acid or alkali concentration in the extraction material and the back-extracting agent can be appropriately adjusted, and effective extraction, back-extraction, and extract recovery are possible.

[Example] The present invention will be described in detail below with reference to the drawings showing an example of the extraction apparatus of the present invention suitable for carrying out the method of the present invention.

FIG. 1 is a sectional view showing an extraction device comprising an extraction means 1 equipped with a tubular or holofiber type solid membrane and a crystallization means 2 according to an embodiment of the extraction device of the present invention.

First, the configuration of the extraction means 1 will be explained.

In FIG. 1, reference numeral 10 denotes a cylindrical device casing of the extraction means 1, and a partition plate 1 provided in two stages on the top thereof.
2.14 defines a reverse extraction side introduction chamber 16 and a extraction material introduction chamber 18 on the lower side of the chamber 16. Furthermore, the lower part of the device casing 10 is also provided with two partition plates 20.
22 defines a raffinate discharge chamber 24 and a back extraction side discharge chamber 26 below the raffinate discharge chamber 24 . In addition, the partition plates 14 and 20
A first chamber is provided between the two and serves as an extraction chamber 28 through which the extraction agent flows. A pipe-shaped solid membrane 3 is provided so as to communicate the extraction material introduction chamber 18 and the raffinate discharge chamber 24.
0 is provided, and a second chamber is provided therein. Further, the lower part of the back extraction side introduction chamber 16 is communicated with the upper part of the extraction chamber 28 through a drip pipe 32. Further, the lower part of the extraction chamber 28 is communicated with the back extraction side discharge chamber 26 through a communication pipe 34.

36 and 38 are an inlet and an outlet for the extraction agent, respectively, and are connected by a pipe 42 having a pump 40.

44 and 46 are an inlet and an outlet for the extraction material, respectively, and 48 and 50 are an inlet and an outlet for the back-extracting agent, respectively.

In the extraction device of this embodiment, the outlet 4 of the extraction means 2
The treated extract discharged from P17 is discharged from P17 through piping 76.
4. The treatment tank 74 includes a pH meter 78 for measuring the pH of the treated extracted material, and a pipe 86 for supplying acid or alkali (P) (adjusting agent) to the extracted material.
, a pump 88 is provided, the pump 88 being configured to be coupled by the p)I meter 78. 80
is a pipe for extracting the extract in the processing tank 4 and circulating it again to the extract inlet of the extraction means 1. Moreover, 84 is a piping for supplying extraction material.

Next, the structure of the crystallization means 2 will be explained.

Reference numeral 52 denotes a casing, the bottom of which is provided with a back extraction side inlet 54, and the upper part of which is provided with a back extraction sub-discharge port 56. The back extraction side inlet 54 is connected to the back extraction sub-discharge port 50 of the extraction means 1 and the liquid supply means (in this embodiment, the pump 58
They are connected by a pipe 60) having a Further, the back-extraction sub-discharge port 56 of the crystallization means is connected to the back-extraction side inlet 48 of the extraction means 1 by a liquid supply means (piping 62 in this embodiment).

A discharge port 64 for extracting a portion of the back-extracting agent is provided at a mid-height portion of the casing 52 of the crystallization means 2, and this discharge port 64 is connected to a pipe 6 having a pump 66. This configuration allows the back-extractant to be returned to the bottom of the casing 60. Note that a pipe holder and a pump 82 are connected to the middle of the pipe 60 (downstream of the pump 58) for supplying a pH adjusting agent to the back extractant, and the pump 82 is interlocked with a pH meter 78. It is configured as follows.

In the figure, 72 is a seed crystal placed in the casing 60.

Next, the extraction method of the present invention using the above extraction device will be explained.

In the extraction means 1, the extraction agent is introduced from the introduction port 36 into the extraction chamber 28, which is a first chamber, flows upward therein, reaches the extraction port 38, and is extracted into the device casing 60. The extraction agent extracted from the extraction port 38 is returned to the introduction port 36 through the piping 42 and continuously circulated.

The extracted material is introduced into the extracted material introduction chamber 18 from the extracted material supply port 44 and then into the second chamber inside the solid membrane 30. Then, it flows downward therein and enters the raffinate discharge chamber 24. While passing through the pipe-shaped solid membrane 30, the extraction material contacts the extraction agent in the extraction chamber 28 via the pipe wall surface of the solid membrane 30. As a result, extraction is performed, and the target substance (extract) in the extract is spread in eight lines.

The extracted material (raffinate) is stored in the raffinate discharge chamber 2.
4 and then discharged to the outside of the device casing 10 from the raffinate outlet 46.

The discharged treated extracted material is sent to the treatment tank 74 through a pipe 76, and its pH is measured by a pH meter 78.

Generally, in the extraction process, as mentioned above, the acid or alkali content of the extracted material increases over time, so pH adjustment is necessary. Therefore, as shown in the figure, an acid or alkaline pH adjuster is provided to be supplied to the treatment tank 74 through a pump 88 and piping 86, and the pH meter 78 and pump 88 are linked to
Based on the detected value of the H meter 78, an equivalent amount of acid or alkali necessary to bring the extracted material into a predetermined pH range is supplied as a pH adjuster. As a result, the extract that is circulated through the pipe 80 to the extraction means 1 is always maintained within a suitable pH range. In addition,
In the case where extraction material is not circulated and is processed by a flow-through method, an extraction tank is provided in place of the piping 84, pump 88, and pH adjuster supply piping 86, and the pH adjuster is supplied to this tank. By doing so, p)l of the extracted material can be adjusted to a suitable range, and extraction efficiency can be further improved.

Note that the treatment tank 74 is not necessarily required, and the pH meter 78 may be attached directly to the discharge pipe of the treated extracted material.
By providing the processing tank 74, pH detection can be performed more accurately.

In addition, the pH adjuster supply pipe 86 can be connected to any location on the pipe 80.

The back extraction agent is introduced into the back extraction side introduction chamber 16 from the supply port 48 and then supplied into the extraction chamber 28 from the dripping pipe 32. In this embodiment, the back-extracting agent has a higher specific gravity than the extracting agent and has a property that it does not dissolve in the extracting agent, so when it is sent into the extracting agent from the lower end of the dripping tube 32,
The liquid drops in the form of droplets or liquid columns (droplets in the illustrated example) through the extraction agent in the extraction chamber 28 and comes into direct contact with the extraction agent to effect back extraction. Due to this direct contact, the extract in the extractant is efficiently transferred into the back extractant.

The back extraction agent that has undergone this back extraction is introduced into the back extraction side discharge chamber 26 through the communication pipe 34, and then is introduced into the back extraction side discharge chamber 26.
0 to the crystallization means 2 through a pipe 60 having a pump 58. Note that, as described above, since the specific gravity of the back-extracting agent is greater than that of the extraction agent, the extraction agent in the extraction chamber 28 does not enter the back-extraction side discharge chamber 26.

The back extractant supplied into the casing 52 of the crystallization means 2 via the pipe 60 through the inlet 54 rises inside the casing 52 and brings the seed crystals 72 into a fluid state. Then, the contained substance to be extracted (extract) touches the seed crystal 72 and crystallizes.

On the other hand, the back-extracting agent from which the substance to be extracted has been crystallized and removed is extracted from the extraction port 56 and circulated through the piping 62 to the back-extraction side supply port 48 of the extraction means 1 .

In the crystallization means 2 of this embodiment, a part of the back-extracting agent is extracted from the outlet 64 provided at an intermediate position of the casing 52 and circulated through the piping 68 to the back-extracting agent inlet 54, where it is crystallized again. By controlling the flow state of the seed crystal 72 along with the treatment, it is possible to improve the crystallization rate.

When metals are extracted using a chelate extractant using the apparatus shown in Figure 1, the ratio of the metal concentration in the extractant to the metal concentration in the back-extractant is expressed by the following equation (1). .

For example, when the metal is Cu'', if the pH of the extraction material is 4 and the pH of the back-extracting agent is 1 or less, it can be concentrated more than 1 million times and crystallization becomes possible.

By the way, as mentioned above, the acid or alkali in the back-extracting agent is consumed by back-extraction, and its concentration decreases. Therefore, it is necessary to quantitatively replenish the back extractant with an acid or alkaline pH adjuster to adjust the pH. In the device of this embodiment, the pH adjusting agent necessary for adjusting the pH of the back-extracting agent is supplied to the pipe 7.
0 and the back extractant introduced into the crystallization means by pump 82. At this time, the pump 82 is linked to a pH meter 78 that measures the pH of the treated extraction material, and the pH adjusting agent is used in an amount approximately equivalent to the equivalent of acid or alkali necessary for the detection value of the pH meter to fall within a predetermined range. to the back extractant. That is, as described above, the amount of acid (or alkali) in the back extractant that decreases during back extraction is equivalent to the amount of acid (or alkali) in the extracted material that increases during extraction. Therefore, the pH of the extracted material is detected and a pH adjuster is added in an amount approximately equivalent to the equivalent of the acid or alkali necessary to bring it into a predetermined range, that is, the pH value of the extracted material used for extraction processing. By supplying the back-extracting agent, it is possible to maintain the back-extracting agent at a predetermined acid or alkali concentration at all times.

Note that the pH adjusting agent may be supplied to the back-extracting agent at any point as long as it is in the flow path of the back-extracting agent. can be significantly increased, which is extremely advantageous.

In the apparatus of the present invention, when back-extracting with an acid such as Cu extraction, an alkali is used as a pH adjusting agent for the extract, and an acid is used as a pH adjustment agent for the back-extracting agent. On the other hand, when back-extracting with an alkali, such as when extracting phenol, the pH of the extracted material is adjusted with an acid, and an alkali is injected into the back-extracting agent. In this case, as a matter of course, the pH adjusting agent supplied to the extraction material from the piping 86 and the pH adjusting agent supplied to the back-extracting agent from the piping 70 are in equivalent amounts.

In the apparatus of this embodiment, the extraction efficiency and crystallization efficiency can be further improved by providing a temperature control device in the extraction means 1 or the crystallization means 2 and heating or cooling them. That is, in general, heating the extraction increases the extraction rate and increases the solubility of the substance to be extracted in the back-extracting agent. This tendency is particularly remarkable when the substance to be extracted is a metal salt. On the other hand, crystallization is preferably performed at a low temperature. It is therefore advantageous to carry out heating of the extraction means and/or cooling of the crystallization means. (Of course, depending on the mode of extraction or crystallization, it may be advantageous to cool the extraction means or heat the crystallization means.) By using a method in which the crystals do not overflow, it is possible to prevent extractant from being taken into the crystals and obtain highly pure crystals, but a fixed bed method may also be used.

In the above explanation, a case has been described in which the extraction material is brought into contact with the extraction agent via a solid membrane, and the extraction agent and the back-extracting agent are brought into direct contact. However, in the apparatus of the present invention, the extraction agent and the extraction agent By introducing the back extractant through the supply port 44 and introducing the extraction material through the supply port 48, the back extraction agent and the extraction agent are brought into contact with each other through the solid membrane, and the extraction material and the extraction agent are brought into contact with each other through the solid membrane. They may be brought into direct contact with each other.

That is, one of the extractant and the back-extractant is brought into contact with the extractant through a solid membrane, and the other is brought into contact with the extractant directly. Which of the extractant and the back-extractant is brought into contact with the extractant via the solid membrane is determined by the liquid quality of the three liquids, the extractant, the extraction agent, and the back-extractant. If the extractant and the back-extractant, whichever is more likely to form an emulsion with the extractant, is brought into contact with the extractant through a solid membrane, emulsification can be prevented.

Further, in general, contact without a solid membrane is advantageous in that the extraction rate is faster and there is no possibility of crystals adhering to the solid membrane. Therefore, the extraction rate can be increased by directly contacting the extracting agent with the one having a lower extraction rate. Moreover, by appropriately changing the flow rate of the liquid brought into direct contact with the extraction agent, the extraction rate can be controlled.

Therefore, it is possible to adapt to fluctuations in the amount of water such as extraction material and the like very easily.

In addition, in FIG. 1, the apparatus in which - pipe-shaped solid membranes 30 are installed is shown, but the number of solid membranes may be two or more. Furthermore, a plurality of drip tubes 32 can be provided. By installing a plurality of solid membranes or dropping tubes, the processing capacity can be improved. Furthermore, it is preferable to provide a liquid transfer means 90 as shown in FIG. 1 so that the liquid flowing out from the dripping pipe 32 efficiently goes to the back extraction side discharge chamber 26.

In the embodiment shown in FIG. 1, an example is shown in which a thread-like support is stretched from the upper surface of the casing 10 to the lower part of the communication pipe 34 as the liquid transfer means 90. Any material that can be distributed may be used, and in addition to such thread-like supports, net-like, cross-net-like, teal-like, and rod-like supports can also be used.

The material for the support of the liquid transfer means should be one that has good wettability with the liquid in order to maintain good distribution efficiency of the liquid flowing on its surface, i.e., if the liquid is an aqueous solution, it should be made of a hydrophilic material such as cotton. In the case of an organic solvent, it is preferably a hydrophobic solvent such as polytetrafluoroethylene.

In Fig. 1, an example is shown in which the back-extracting agent is lowered in the form of a droplet or a liquid column into the rising region of the extraction agent, but this can be reversed by
The back extractant may be allowed to rise in the downward flow of the extractant.

In the present invention, various forms of the solid membrane are used, such as a flat membrane type, a tubular type, and a hollow fiber type.

The solid membrane may be porous, and examples thereof include semipermeable membranes made of polytetrafluoroethylene (hereinafter referred to as rPTFEJ), cellulose acetate, polysulfone, polyvinyl chloride, polypropylene, polyamide, etc.
FE is preferred.

Generally, PTFE is commercially available as Teflon (trade name). PTFE has excellent chemical resistance and hydrophobicity, and has an extremely high extraction rate, making it suitable for use as a solid membrane. The thickness, pore diameter, etc. of the porous PTFE membrane are selected depending on the extraction agent used.

The reason why the extraction rate of the PTFE solid membrane is so fast is not clear, but due to its network structure and extreme hydrophobicity (lipophilicity), the contact area between the extraction agent or the back-extraction agent and the extraction agent is not limited to the pores. This is presumed to be because it spreads over the entire membrane surface and the diffusion within the membrane is also fast.

In the apparatus of this embodiment, droplets or liquid columns descending or ascending in the extractant may come into contact with the solid membrane. However, when the extractant and back-extracting agent are aqueous solutions, contact can be more reliably prevented by using PTFE, which has extremely strong hydrophobicity, as the solid membrane. When the extractant and back-extractant are organic solvents and the extractant is an aqueous solution, it is preferable to use a highly hydrophilic solid membrane.

The present invention can be applied to various extraction devices other than those described above without exceeding the gist of the present invention. Therefore, the extraction means is not limited to the three-liquid contact type shown in FIG. 1, but may be of a type in which the extraction part and the back extraction part are independent. In addition to crystallization, the extraction means may be any conventionally used recovery means.

EXPERIMENTAL EXAMPLE An example of an extraction experiment conducted using the extraction apparatus of the present invention will be described below.

Experimental example 1: 15ocrr area as a solid film? Teflon membrane (pore size 0
．． The extraction means 1 of the extraction device as shown in Fig. 1 is equipped with Cu5O+ .5H on one side through a solid membrane.
Extract IJ2 (Cux6.00
0ppm, adjusted by replenishing as appropriate) was circulated at 21/min, and on the other side, an extractant 0.841 consisting of SME-529 (Shell Chemical Exhibition) 10VOf1% and kerosene 90voJ2% was injected. (without circulation), and 1.6 moxibustion of 100g/j2H2SO4 of back extractant was added to it.
．． The liquid was circulated at 21 f/min. Further, the back extractant was circulated through the extraction means 1 and the crystallization means 2 containing seed crystals of copper sulfate.

Therefore, based on the detected value of the pH meter, the extract was
g/It Na OH at pH 4 (actual value 3.8~
4.3), and the same equivalent amount of concH2SO4 as this NaOH was added to the back extractant.

When such extraction and back extraction were continued, crystals began to precipitate when the Cu concentration in the back extractant reached f56000 ppm, and the H2304 concentration (measured by NaOH titration) at that time was i o o g7x.

On the other hand, when H2SO4 was not added to the back-extracting agent, the back-extraction stopped progressing when the Cu concentration in the back-extracting agent was about 60,000 ppm, and the H2SO4 concentration at that time was 6 g/l.

[Effect of the invention] As detailed above, according to the extraction method of the present invention, extraction,
During back extraction and extract recovery processing, the acid or alkali concentration of the extraction material and back extractant can be easily and accurately adjusted, allowing stable and highly efficient equipment operation for long periods of time! It is possible to continue.

Therefore, such an extraction method of the present invention can be carried out extremely easily using the extraction apparatus of the present invention.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of an extraction device according to an embodiment of the present invention. 1...Extraction means, 2...Crystallization means, 10
．． 60... Apparatus casing, 16... Back extractant introduction chamber, 18-... Extractant introduction chamber, 26-... Back extractant discharge chamber, 28... Extraction agent chamber, 3
0--Solid film, 72--Seed crystal, 78-
-pH meter, 90...liquid transfer means.

Claims (6)

[Claims] (1) In an extraction method in which the extraction agent is brought into contact with the extraction agent and the extraction agent is brought into contact with a back-extracting agent, the extraction agent and the extraction agent are brought into contact with each other so that the pH of the extraction agent after contact with the extraction agent is within a predetermined range. An extraction method characterized by injecting one of an acid and an alkali into the extracted material before contact, and injecting the other of the acid and the alkali into a back-extracting agent. (2) Claim 1, characterized in that approximately the same amount of the other acid and alkali is injected into the back-extraction agent as the amount of one of the acid and alkali injected into the extraction material before contact with the extraction agent. Extraction method described in. (3) Each of the following means a, b, c, d, e, f, and g, namely: a. An extraction chamber for bringing the extraction material containing the substance to be extracted into contact with the extraction agent; an extraction section having a means for introducing the extractant and a means for discharging the extractant after contact with the extractant; a chamber for bringing the extractant after contact with the extractant into contact with a back-extracting agent; and a means for introducing the back-extractant into the chamber. and a back-extraction section having a means for discharging the back-extracting agent after contact with the extraction agent; b. An extraction means for recovering the extracted substance having a liquid introduction means and a liquid discharge means; c. A reverse extraction section of the extraction means. means for feeding a liquid from the extractant discharge means to the liquid introduction means of the recovery means; d. means for feeding the liquid from the liquid discharge means of the recovery means to the back extractant introduction means of the extraction means; e. a back extractant. a reverse extractant pH adjustment means for supplying acid or alkali to the reverse extractant, which is provided in the flow path of the extraction means; extract pH adjusting means for supplying acid or alkali to the extract, which is provided in the extract introducing means of the extracting means, and the extract pH adjusting means is provided in the extract introducing means, and the extract pH adjusting means
In addition to supplying the necessary amount of acid or alkali so that the detection value of the measuring means falls within a predetermined range, the pH of the back extractant is
An extraction device characterized in that the adjusting means supplies one of an acid and an alkali. (4) Each of the means a, b, c, d, e, f, and g is the following means a, b, c, d, e, f, and g, respectively. At least two partitioned chambers are provided, the first chamber is an extraction chamber filled with extractant, and the second chamber is provided with means for introducing and discharging either the extractant or the back-extracting agent, an extraction means provided in the first chamber with an introduction means and a discharge means for a liquid substantially immiscible with the extraction agent, either of the extractant or the back-extractant; b. a liquid introduction means and a liquid discharge means; c. Means for feeding the liquid from the back-extractant discharge means of the extraction means to the liquid introduction means of the crystallization means; d. Back-extractant introduction means of the extraction means from the liquid discharge means of the crystallization means. e. Reverse extractant pH adjustment means for supplying acid or alkali to the reverse extractant, which is provided in the flow path of the reverse extractant; f. Measuring the pH of the material
H measuring means; g. extract pH adjusting means for supplying acid or alkali to the extract, which is provided in the extract introducing means of the extracting means; In addition to supplying the necessary amount of one of the acid or the alkali to obtain the desired amount, the back extractant pH adjusting means supplies the other of the acid or the alkali in an amount approximately equivalent to the required amount. The extraction device according to item 3. (5) The extraction device according to claim 3 or 4, further comprising means for feeding the extract discharged from the extraction means to the extract introduction means of the extraction means. (6) Claim 3, characterized in that the back-extractant pH adjustment means is provided in the means for feeding the liquid from the back-extractant discharge means of the extraction means to the introduction means of the crystallization means. 6. The extraction device according to any one of items 5 to 6.