JP2021089262A - Reversed micelle evaluation method in organic phase - Google Patents

Abstract

To provide a reversed micelle evaluation method in an organic phase capable of appropriately evaluating dispersibility of an entrainment present in a reversed micelle form in an organic phase.SOLUTION: A reversed micelle evaluation method in an organic phase prepares a first moisture removal organic solution L2 from a fractionated organic solution L1 fractionated from an organic solution L0 used in an organic phase, prepares a water phase dispersion organic solution L3 obtained by dispersing an aqueous solution in the solution and then prepares a second moisture removal organic solution L4 from this solution, determines a moisture rate of the second moisture removal organic solution L4 as Wrm and determines a moisture rate ΔWrm of the second moisture removal organic solution L4 increased from a moisture rate Wb of the first moisture removal organic solution L2, determines a moisture rate W0 from (volume of aqueous solution A)/{(volume of first moisture removal organic solution L2)+(volume of aqueous solution A)}, and calculates a reverse micellisation rate Erm of fine droplet contained in the water phase dispersion organic solution L3 from a ratio of the moisture rate Wrm to the moisture rate W0. Thereby, dispersibility of reversed micelle contained in the organic phase can be appropriately evaluated.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for evaluating inverse micelles in an organic phase. More specifically, the present invention relates to a method for evaluating inverse micelles in an organic phase in a solvent extraction method.

Separation of nickel and cobalt contained in an acidic aqueous solution is the most important technical element in hydrometallurgy of nickel.
Generally, the separation of nickel and cobalt in an acidic aqueous solution is carried out by a solvent extraction method using various organic extractants. As this organic extractant, for example, a phosphoric acid ester-based acidic extractant such as D2EHPA (Di- (2-ethylhexyl) phosphoricacid) or an amine-based extractant such as TNOA (Tri-n-octylamine) is used. In general, when the anion is a sulfate ion, a phosphoric acid ester-based acidic extractant is used, and when the anion is a chloride ion, an amine-based extractant is used, and nickel chloride containing cobalt is used. As a method for industrially separating cobalt from an aqueous solution, a solvent extraction method using an organic solvent containing an amine-based extractant has been adopted.

As an outline of the organic solvent containing this amine-based extractant, in the extraction step, the metal species (cobalt, copper, zinc, iron, etc.) that form the chloro complex ion contained in the nickel chloride aqueous solution are extracted into the organic phase. , Nickel that does not form chloro complex ions is left in the aqueous phase to separate nickel and cobalt. Then, the cobalt supported in the organic phase is distributed to the aqueous phase by the back extraction step of the organic phase to prepare a cobalt chloride aqueous solution, and the obtained cobalt chloride aqueous solution is supplied to the electric sampling step to prepare electric cobalt. To.
On the other hand, the organic phase after the extraction step contains a nickel-containing aqueous phase in the form of fine droplets (also referred to as entrainment or fine droplet emulsion of the aqueous phase). Then, if electric cobalt is produced from the organic phase in which the entrainment is still contained in the electrowinning step, the quality of the electric cobalt may be deteriorated by the nickel contained in the entrainment.
Therefore, usually, the operation of supplying the organic phase after the extraction step to the cleaning step to remove the entrainment from the organic phase is performed.

That is, in the method of preparing a cobalt chloride aqueous solution by solvent-extracting cobalt from a cobalt-containing nickel chloride aqueous solution with an organic solvent containing an amine-based extractant, the nickel concentration in the obtained cobalt chloride aqueous solution is effectively reduced. It has become an important technical issue.

Conventionally, industrially, as a method for cleaning an organic phase, the inside of the mixer tank (stirring tank) is made continuous with the organic phase, and the volume ratio of the organic relative aqueous phase in the mixer tank is set to 3.0 or less. (For example, Patent Document 1).
According to Patent Document 1, by making the inside of the mixer tank continuous with the organic phase, the bonding between water droplets in the organic phase is promoted, the nickel concentration in the entrainment is reduced, and the entrainment itself is reduced. It is described that the cleaning efficiency can be improved because the cleaning efficiency can be improved.

Japanese Unexamined Patent Publication No. 2015-183267

However, in the cleaning method of Patent Document 1, when the oil-water separation efficiency in the settler portion (oil-water separation tank) is lowered, the entrainment in the organic phase is increased and the nickel concentration in the cobalt chloride aqueous solution is reduced. There is a problem that it becomes impossible.

Here, in the industrialized process, in operation, new substances may be generated due to deterioration of the organic solvent, or impurities and the like based on the raw materials may be mixed. Due to such substances, the entrainment in the organic phase tends to have a minute shape, and those having a size of about 1000 nm or less (1 to 1000 nm) tend to exist in the form of inverted micelles.
Since the entrainment existing in the form of such a reverse micelle exists in an extremely stable form in the organic phase, when the reverse micelle is formed, it is easily dispersed by the cleaning method of Patent Document 1. It is thought that the oil-water separability deteriorates even in the settler part with almost no sedimentation.

Therefore, in order to reduce the nickel concentration in the cobalt chloride aqueous solution, the content of the entrainment that exists in the form of reverse micelles is evaluated, and the substances that contribute to the formation of such reverse micelles are identified. At the same time, it is necessary to evaluate the contribution of these substances to reverse micelles.

Conventionally, as a method for evaluating entrainment in an organic phase, for example, a substance to be evaluated is added to the organic phase or the aqueous phase, the organic phase after extraction is taken out, and water slightly contained in the organic phase by centrifugation is performed. There is a method of separating the phases and obtaining from the ratio of the aqueous phase.

However, since the entrainment existing in the form of an inverted micelle has a fine size as described above, it tends to remain in the organic phase even after centrifugation, and there is a problem that it cannot be evaluated accurately by the conventional evaluation method. Is occurring.

In view of the above circumstances, the present invention simply and quantitatively evaluates the dispersibility of the entrainment existing in the form of an inverted micelle among the entrainments to the organic phase (fine emulsion of aqueous phase droplets). It is an object of the present invention to provide a method for evaluating inverse micelles in an organic phase.

The reverse micelle evaluation method in the organic phase of the first invention is a method for evaluating the dispersibility of fine droplets of the aqueous phase contained in the organic phase, and the organic solution used for the organic phase is separated. The separated preparative organic solution is subjected to centrifugation to remove water to prepare a predetermined amount of the first water-removing organic solution, and a predetermined amount of the aqueous solution is added to the first water-removing organic solution to disperse the solution. After preparing the aqueous phase-dispersed organic solution, the aqueous phase-dispersed organic solution was subjected to centrifugation to remove water to prepare a second water-removing organic solution, and the water content of the first water-removing organic solution was determined. W _b , the water content of the second water-removing organic solution is W _{rm, and the water content ΔW rm} increased from the water content _{W b of} the first water-removing organic solution in the second aqueous phase-dispersed organic solution is obtained. the determined from the ratio of the said water content W _rm water content W ₀ moisture content W ₀ from (volume of the solution) / {(the volume of the first water removal organic solution) + (volume of the solution)} and calculating an inverse micelle ratio E _rm of fine droplets contained in the aqueous phase dispersed organic solution.
The method for evaluating an inverse micelle in an organic phase according to a second aspect of the present invention is the inverse micelle in the organic phase according to claim 1, wherein the inverse micelle conversion rate _Erm is calculated by the following formula in the first invention. Evaluation method.
E _rm = ΔW _rm / W ₀
The method for evaluating inverse micelles in the organic phase of the third invention is based on the first invention or the second invention, for any one of the organic solution, the preparative organic solution, or the aqueous solution, or two or more solutions. It is characterized by adding a substance to be evaluated.
The reverse micelle evaluation method in the organic phase of the fourth invention is characterized in that, in any one of the first invention, the second invention, or the third invention, the organic solution contains an organic extractant.
In the method for evaluating the reverse micelle in the organic phase of the fifth invention, in any one of the first invention, the second invention, the third invention or the fourth invention, the organic extractant is a phosphoric acid ester-based acidic extractant or an amine. It is characterized by being a system extractant.

According to the first invention, it is possible to calculate the inverse micelle ratio E _rm of fine droplets contained in the second aqueous dispersion an organic solution by a simple operation. Then, based on the inverse micelle formation rate _Erm , the dispersibility of the inverse micelles contained in the organic phase can be appropriately evaluated.
According to the second invention, evaluation can be performed based on a uniformly dispersed ideal state.
According to the third invention, the influence of the substance to be evaluated can be easily investigated.
According to the fourth and fifth inventions, the dispersibility of inverse micelles in the organic phase in the solvent extraction method can be appropriately evaluated.

It is a schematic flow chart of the reverse micelle evaluation method in the organic phase of this embodiment. It is a figure which showed the experimental result, and is an example of the relationship between the dispersion time (stirring time) in the dispersion treatment S2 of the evaluation method of this invention, and the moisture content in an organic phase. It is a figure which showed the experimental result, and is the graph which shows the relationship between the substance M (concentration of hepanoic acid) to be evaluated in an organic phase, and the inverse micelle formation rate _Erm. It is a figure which showed the experimental result, and is the graph which shows the relationship between the substance M (concentration of octanoic acid) to be evaluated in an organic phase, and the inverse micelle formation rate _Erm. It is a figure which showed the experimental result, and is the graph which shows the relationship between the substance M (concentration of heptanic acid) to be evaluated in the organic phase and the inverse micelle formation rate _{Erm when an aqueous phase different from FIG. 3 is added.} is there. Experimental results are views showing a graph showing the relationship between the evaluated material M in the organic phase (MNOA (concentration of Mono-n-octylamine)) and reversed micelle ratio _{E rm.} It is a figure which showed the experimental result, and is the graph which shows the relationship between the substance M (concentration of methanesulfonic acid) to be evaluated in the aqueous phase, and the inverse micelle formation rate _Erm. A view showing the experimental results, is a graph showing the relationship between the TNOA concentration and reversed micelle ratio E _rm in the organic phase. It is a figure which showed the experimental result, and is the graph which shows the relationship between the substance M (concentration of methaneic acid) to be evaluated in an organic phase, and the inverse micelle formation rate _Erm. It is a figure which showed the experimental result, and is the graph which shows the relationship between the substance M (concentration of propanoic acid) to be evaluated in an organic phase, and the inverse micelle formation rate _Erm. It is a figure which showed the experimental result, and is the graph which shows the relationship between the substance M (concentration of butanoic acid) to be evaluated in an organic phase, and the inverse micelle formation rate _Erm. It is a figure which showed the experimental result, and is the graph which shows the relationship between the substance M (concentration of pentanoic acid) to be evaluated in an organic phase, and the inverse micelle formation rate _Erm. It is a figure which showed the experimental result, and is the graph which shows the relationship between the substance M (concentration of caproic acid) to be evaluated in an organic phase, and the inverse micelle formation rate _Erm.

The method for evaluating the reverse micelles in the organic phase of the present embodiment is a method for evaluating the dispersibility of the droplets of the fine aqueous phase contained in the organic phase, and is the reverse micelles of the entrainment in the organic phase. It is characterized by making it possible to easily evaluate the dispersibility of the product.

The organic phase to be evaluated in the inverse micelle evaluation method in the organic phase of the present embodiment is not particularly limited as long as it is the organic phase used in the solvent extraction method. For example, an organic phase in a solvent extraction method used for wet smelting of non-ferrous metals, an organic phase used for solvent extraction in a general chemical treatment step, and an organic phase in an industrial or experimental solvent extraction method. Can be the target solution for evaluation.

In the following, the solution to be evaluated by the inverse micelle evaluation method in the organic phase of the present embodiment is the solvent extraction method adopted in the hydrometallurgy method for non-ferrous metals such as nickel, that is, the organic phase in the industrial solvent extraction method. The case of is described as a representative.

The term "entration" in the organic phase as used herein refers to an aqueous solution (aqueous phase) contained in the organic phase in the form of fine droplets. Hereinafter, this entrainment may be referred to as a water drop emulsion.

The reverse micelle is a molecular assembly in which the hydrophilic base of the surfactant molecule is directed to the inside and the hydrophobic base is directed to the outside in a non-polar solvent. This molecular assembly is thermodynamically stable and has the ability to solubilize a large amount of aqueous phase inside. In the present specification, the ratio of the aqueous phase (a part of the aqueous solution A) incorporated into the reverse micelles out of the aqueous solution A added to the organic solution L is defined as the _{reverse micelleization rate Erm.}
The aqueous phase (a part of the aqueous solution A) inside the reverse micelle can also be regarded as being extracted into the organic phase when the organic solution L and the aqueous solution A are mixed. In this case, the inverse micelle conversion rate _Erm can be considered as the inverse micelle extraction rate.

The size of the reverse micelle as described above is not particularly limited as long as it exists in the organic solution L in a stable form. For example, if the size is about 1000 nm or less (1 to 1000 nm), even if the centrifugation treatments S1 and S3 are performed, the state remains dispersed in the organic phase.

<Summary of the method for evaluating inverse micelles in the organic phase of the present embodiment>
First, before explaining in detail the method for evaluating inverse micelles in the organic phase of the present embodiment, the outline thereof will be briefly described.

Summary of the reverse micelle method of evaluating organic phase of this embodiment is that evaluated by reversed micelle rate E _rm calculated based on the water content W in the organic solution L (see FIG. 1).

First, a sample for measuring the water content W is prepared.
A sample is sampled from a predetermined organic solution L0 (the organic solution used for the organic phase to be evaluated), and the separated organic solution L1 is subjected to centrifugation S1 to remove water and the first water content. Prepare the removed organic solution L2. Then, a predetermined amount of the aqueous solution A is added to the first water-removing organic solution L2, and the aqueous phase-dispersed organic solution L3 in which the aqueous solution A is dispersed S2 by stirring or the like is prepared. The aqueous phase-dispersed organic solution L3 is again subjected to the centrifugation treatment S3 to remove water to prepare a second water-removing organic solution L4.

Then, the water content W of each prepared sample is measured.
From the prepared first water-removing organic solution L2 and second water-removing organic solution L4, the respective water content W (moisture rate W _b , water content W _rm ) is measured.
In the second aqueous phase dispersed organic solution L4, _{the water content ΔW rm} increased from the water content _{W b of} the first water-removing organic solution L2 is calculated from the formula 3) or the formula 4) described later.
Then, from (the volume of solution A) / Formula 5) or Formula 6 below the water content W ₀ of the theoretical obtained from {(the volume of the first water removal organic solution L2) + (volume of the aqueous solution A)}) calculate.
Then, by substituting the calculated water content W ₀ and the water content ΔW _rm into the formula 7) described later, among the fine droplets (that is, the entrainment) contained in the aqueous phase-dispersed organic solution L3, the reverse micelle calculating the inverse micelle ratio E _rm of entrainment present in the form.

The larger the calculated inverse micelleization rate _Erm , the more minute entrainments contained in the organic solution L (that is, the entrainments existing in the form of inverse micelles), and vice versa. means that small entrainment micelles rate E _rm is included if in organic solution L smaller is reduced.

<Detailed explanation of the inverse micelle evaluation method in the organic phase of the present embodiment>
Next, each operation of the inverse micelle evaluation method in the organic phase of the present embodiment will be specifically described below.

<Adjustment of organic solution L0>
The organic solution L0 used in the reverse micelle evaluation method in the organic phase of the present embodiment preferably corresponds to the organic solution used for the organic phase to be evaluated as described above. For example, as described above, a solution corresponding to the organic solution used as the organic phase in the solvent extraction method of the nickel hydrometallurgical method may be prepared and used, or the one used in the operation may be used.

As described above, the organic solution L0 is not particularly limited as long as it is an organic solution used for the organic phase to be evaluated. For example, in addition to hydrocarbon-based solvents such as hexane, isooctane, and dodecane, which are generally used as organic solvents, aromatic hydrocarbons such as benzene, toluene, and xylene, and halogen-based solvents such as chloroform and diclomethane, they are valuable. Examples thereof include amine-based extracts used for extracting metals and the like, phosphoric acid ester-based acidic extracts, carboxylic acid-based extracts, and organic extracts such as phosphorus-based neutral extracts. Further, the organic solution L0 may be prepared by using the organic solvent or the organic extractant as described above alone or by mixing two or more kinds. For example, as the organic solution used as the organic phase in the solvent extraction method of the nickel wet smelting method described above, an organic solution L0 can be prepared by mixing an organic extractant and an organic solvent that functions as a diluent.
Further, the organic solution L0 may contain a modifier such as methanol or decanol in addition to the above organic solvent or organic extractant.

Examples of the above-mentioned organic extractant include, but are not limited to, the above-mentioned amine-based extractant and phosphoric acid ester-based acidic extractant, as well as a carboxylic acid-based extractant and a phosphorus-based neutral extractant.
For example, in the solvent extraction method used for separating nickel and cobalt in an acidic aqueous solution in a nickel hydrometallurgy method, an amine-based extractant is used when the anion of the extraction starting solution is chloride ion. A tertiary amine is used as the amine-based extractant, and examples of the tertiary amine include TNOA (Tri-n-octylamine) and TIOA (Tri-i-octylamine).
When the anion is sulfate ion, a phosphate ester-based acidic extractant is used. Examples of the phosphoric acid ester-based acidic extractant include trade name PC-88A (main component: 2-ethylhexyl 2-ethylhexyl phosphonate) and D2EHPA (Di- (2-ethylhexyl) phosphoricacid).
Here, it is known that the amine-based extractant has a higher separation coefficient between cobalt and nickel than the phosphoric acid ester-based acidic extractant.
Therefore, in the separation and purification of nickel and cobalt in the nickel hydrometallurgical method, an amine-based extractant is generally used in many cases. In particular, tertiary amine-based extractants are often used from the viewpoints of high reactivity and low solubility in water, and among them, TNOA or TIOA is often used in terms of handleability and price. There is. Therefore, when the organic phase in the above-mentioned industrial solvent extraction method is to be evaluated, the organic solution used for this organic phase contains TNOA or TIOA, which is an amine-based extractant. It is preferable to use it.

(Organic solvent)
As described above, the organic solution L0 may use only the organic solvent or the organic extractant alone, but both can be mixed and used, and when both are mixed and used, the organic solvent can be used. Can be used to function as a diluent for organic extracts.
Specifically, the organic solution L0 can be prepared by diluting the above-mentioned organic extractant with an organic solvent (diluent). The organic solvent that functions as such a diluent is not particularly limited, and the above-mentioned solvent or the like can be adopted. In particular, from the viewpoint of low solubility in water and good oil-water separability, it is preferable to use aromatic hydrocarbons, naphthenic hydrocarbons, and the like.
Further, it is preferable that the concentration of the organic extractant in the mixture of the organic extractant and the organic solvent (diluent) is appropriately adjusted according to the desired viscosity range of the organic solution L0. For example, it can be adjusted to be within the range of 10 to 40% by volume of the total organic solution used.

(Substance to be evaluated M)
In particular, when verifying a substance that contributes to an increase in entrainment (hereinafter, also simply referred to as reverse micelle) existing in the form of reverse micelle in the organic phase in the solvent extraction method, the organic solution L is evaluated. It is desirable to add substance M (hereinafter referred to as evaluation target substance M) to evaluate the relationship between the evaluation target substance M and the inverse micelle.

The evaluation target substance M may be added to, for example, the prepared organic solution L0, the preparative organic solution L1 or the aqueous solution A, or to two or more of the organic solution L0, the preparative organic solution L1 and the aqueous solution A. It may be added. That is, the substance M to be evaluated may be added to any one of the above three solutions, may be added to two solutions, or may be added to all three solutions. Further, when a plurality of substances are adopted as the evaluation target substance M as described later, they may be added to the same solution or may be added to different solutions.
The addition concentration is not particularly limited as long as it can evaluate the relationship with the reverse micelle, and may be appropriately adjusted so as to be within a range expected to be industrially mixed, for example.

As the substance M to be evaluated, various substances expected in operation can be adopted. For example, substances obtained by lowering the amine-based extractant, carboxylic acids such as methanoic acid, enanthic acid, propionic acid, butanoic acid, pentanic acid, hexanic acid, hepanoic acid, and octanoic acid, and amide compounds can be mentioned. , Not limited to such substances. Further, for example, in addition to MNOA (Mono-n-octylamine) and methanesulfonic acid, TNOA used as an amine-based extractant can also be adopted as the substance to be evaluated M.
Further, the substance M to be evaluated is not limited to one kind, and two or more kinds of substances may be adopted. For example, different substances may be used as the evaluation target substance M1 and the evaluation target substance M2. In this case, for example, the evaluation target substances M1 and M2 are added to different solutions (for example, the evaluation target substance M1 is added to the preparative organic solution L1 and the evaluation target substance M2 is added to the aqueous solution A). It may be added to the same solution. Further, the evaluation target substance M may be prepared so as to contain two or more kinds of evaluation target substances M1, M2, and so on.

(Centrifugal treatment S1, S3)
The first water-removing organic solution L2 is prepared by separating a predetermined amount from the organic solution L0, subjecting the separated preparative organic solution L1 to a centrifuge, and then removing the aqueous phase.
Further, the second water-removing organic solution L4 is prepared by subjecting the aqueous phase-dispersed organic solution L3 in which the aqueous solution A is dispersed to a centrifuge and then removing the aqueous phase.
Centrifugation treatment S1 is an operation of removing water that can be separated by centrifugation from the organic solution L1 because water that cannot be seen by appearance may be dissolved.
Centrifugation treatment S3 is an operation of removing centrifugable water in the separable aqueous phase and the organic phase. That is, this centrifugation treatment S3 is an operation of removing the entrainment having a size larger than 1000 nm dispersed in the organic phase by the dispersion treatment S2 from the aqueous phase dispersed organic solution L3. In other words, from the centrifugation treatment S3, the aqueous phase-dispersed organic solution L3 contains only the entrainments that are extremely stable in the form of inverted micelles having a size of 1000 nm or less. It is an operation to make.
The device or the like used for the centrifugation treatments S1 and S3 is not particularly limited as long as it is a device or device capable of exerting the above-mentioned functions, and for example, a commercially available centrifuge or the like may be adopted. Can be done.

(Distributed processing S2)
_{The aqueous phase-dispersed organic solution L3 is prepared by separating a predetermined amount (volume Vorg1} ) from the first water-removing organic solution L2 from which the aqueous phase has been removed by separating the water separable by the method described above by centrifugation. to moisture removal organic solution L2 predetermined amount (volume _{V org1),} was added an aqueous solution a of a predetermined amount (volume _{V aq1),} prepared by dispersing S2 by stirring or the like.

_{The amount (volume Vorg1} ) of the first water-removing organic solution L2 is not particularly limited. For example, from the viewpoint of operability, it can be prepared to be 10 ml to 100 ml.

The amount of the aqueous solution A to be added is preferably adjusted so that the first water-removing organic solution L2 has a continuous phase. For example, it is preferable that the addition amount of the aqueous solution A (volume _{V aq1)} is 10% by volume or less with respect to water removal organic solution L2 (volume _{V org1).}
If the amount of the aqueous solution A added is too small, it becomes difficult to measure the water content. Therefore, it is preferable to set the measurement within a range in which the measurement can be appropriately performed in consideration of the total amount of the liquid, the amount of sampling, and the like. The dispersion treatment S2 is preferably performed at a temperature near room temperature, but if the organic solution (moisture-removing organic solution L2) has a high viscosity, the temperature may be raised. However, when raising the temperature, it is necessary to consider the decrease due to the evaporation of water.

In the dispersion treatment S2, as long as the aqueous solution A can be dispersed in the first water-removing organic solution L2, the instruments and devices used are not particularly limited, and a commercially available stirring device or the like can be adopted. For example, when a commercially available magnetic stirrer is used, the aqueous phase dispersed organic solution L3 can be prepared if the treatment conditions are a rotation speed of 500 rpm to 2000 rpm and a stirring time of 1 minute or more.

(Dispersion time)
In particular, the dispersion time (stirring time) in the dispersion treatment S2 is not particularly limited as long as the added aqueous solution A is in a stable state, and may be appropriately adjusted depending on the treatment conditions and the like.
For example, when the treatment conditions for a predetermined amount of the aqueous solution A are room temperature (temperature around 25 ° C.) and a rotation speed of 500 to 1500 rpm, 1 minute or more is preferable, 3 minutes or more is more preferable, and 5 minutes or more is further preferable. Stir so that

The state in which the added aqueous solution A is appropriately dispersed can be grasped from the relationship between the dispersion time (stirring time) and the increased water content ΔW in the aqueous phase-dispersed organic solution L3.
For example, FIG. 2 shows the dispersion time (stirring time) in the dispersion treatment S2 and the increased water content ΔW in the aqueous phase-dispersed organic solution L3 when the aqueous solution A corresponding to 3000 volume ppm was added to the water-removing organic solution L2. It is a figure which showed the relationship of.

It increased moisture content ΔW of the aqueous phase dispersed organic solution L3 are sampled organic phase (i.e. aqueous phase dispersed organic solution L3) of water content W _a background to be described later of the water content W _{b (i.e.} the moisture removal organic solution L2 It can be calculated from the difference in water content W).
Specifically, the increased water content ΔW in the aqueous phase dispersed organic solution L3 can be calculated from the following formula 1) or the following formula 2).

ΔW = {W _a × (V _org + V _aq ) −W _b × V _org } / (V _org + V _aq ) ・ ・ ・ Equation 1)

In _the case of V org _{»V aq,}

ΔW ≒ W _a −W _b・ ・ ・ Equation 2)

Can be approximated.

As shown in FIG. 2, at the initial stage of stirring, the water content ΔW increased by the addition of the aqueous phase increases with the increase of the stirring time, and it is considered that it takes about 5 minutes to stabilize. Therefore, when a predetermined amount of the aqueous solution A is added under the above conditions, it is preferable to perform sampling after stirring for 5 minutes or more.

Further, the sampling location is preferably at least one-third the height from the bottom of the water-removing organic solution L2 in the container containing the water-removing organic solution L2. The reason is that when the aqueous solution A is difficult to disperse in the water-removing organic solution L2, the specific gravity of the aqueous solution A may be larger than that of the organic solution. In this case, the aqueous solution A tends to be unevenly distributed toward the bottom. Because.

(Measurement of moisture content W)
The first water removal organic solution L2 prepared, the aqueous phase dispersed organic solution L3, moisture content _W of the second moisture removal organic solution L4 _{(W b,} W _{a, W rm)} is the Karl Fischer method (conforming to JIS K0113) Can be measured.

In particular, even if the dissolved water that can be centrifuged is removed by the centrifugation treatment S1, the water cannot be completely removed, and a certain amount of water molecules are present in the first water-removing organic solution L2. Therefore, the moisture content W in the first moisture-removing organic solution L2 is measured using a Karl Fischer titer, and the background existing in the first moisture-removing organic solution L2 that cannot be completely removed by the centrifugation treatment S1. It is desirable to know the water content Wb of.

Also, increase in water content [Delta] W _rm from water content W _b of the first water removal organic solution L2 in the second water removal organic solution L4 can be calculated from Equation 3) or Formula 4 below) below ..
Incidentally, V _aq1 in the formula is the added volume of the added aqueous solution A, V _org1 is the volume of the first water removal organic solution L2 prepared, V _org2, the second water removal organic prepared It is the volume of the solution L4.

ΔW _rm = (W _rm × V _org2 −W _b × V _org1 ) / _Vorg2 ... Equation 3)

In _the case of the _{V org1 »V aq1, V org1 ≒} V org2 next,

ΔW _rm ≈ W _rm −W _b・ ・ ・ Equation 4)

Can be approximated.

(Calculation of inverse micelle conversion rate _Erm)
First, (the added volume of the aqueous solution A) / {(the volume of the first water removal organic solution L2) + (volume of added aqueous A)} Equation 5 below the water content W ₀ obtained from) or Equation 6) Calculate from.
If the added solution A is uniformly dispersed ideal state, the water content W ₀ everywhere the sampling.

_{W 0 = V aq1 / (V} org1 + V aq1) ··· Formula 5)

In _the case of the V org1 <sub>»V aq1,

W 0 ≒ V aq1 / V org1</sub> ··· formula 6)

Can be approximated.
_Also, it is used in place of _{V aq1} to _{(ΔW rm × V org2 + V} aq2) it is possible to obtain the same results.

Using the above water content W _{0 and the water content ΔW rm} increased from the _{water content W b} of the first water removal organic solution L2 in the second water removal organic solution L4, the inverse micelleization rate E _rm is calculated by the following formula. Obtained by 7).

E _rm = ΔW _rm / W ₀ ... Equation 7)

Since the dispersed state of the aqueous solution A may not always be uniform, it is preferable to perform sampling a plurality of times and obtain an average value for evaluation. Further, in order to improve the accuracy of the measured value of the Karl Fischer titer, it is desirable to use the average value measured a plurality of times.

As described above, if the reverse micelle evaluation method in the organic phase of the present embodiment is used, the aqueous solution A dispersed in the organic solution L used for the organic phase to be evaluated is in the form of fine droplet reverse micelles. in can be determined reverse micelles rate E _rm present a simple operation.
The aqueous solution A dispersed in the organic solution L is contained in the form of fine droplets, and corresponds to the entrainment in the organic phase in the solvent extraction method. The entrainment present in the form corresponds to a finer droplet that is difficult to separate from the organic phase in general centrifugations S1 and S3. That is, by using the inverse micelle evaluation method in the organic phase of the present embodiment, it becomes possible to easily grasp the inverted micelle-ized entrance, which was difficult to grasp by the conventional method.

Moreover, if grasp reverse micelle ratio E _rm of the aqueous solution A was dispersed in an organic solution L, entrainment in the organic phase in the solvent extraction method (droplet fine aqueous phase suspended in the organic phase) Of these, it is possible to appropriately predict the increase or decrease of the entrainment existing in the form of finer inverted micelles.
Then, if it is possible to grasp the inverse micelle-ized entrainment existing in the organic solution L, fine impurities in industrial products (small particles existing in the form of reverse micelles), which have been difficult to grasp in the past, can be grasped. Since it becomes possible to properly grasp the various impurities, it becomes possible to properly manage high-quality industrial products.

For example, when cobalt is separated and recovered from a cobalt-containing nickel chloride aqueous solution by solvent-extracting cobalt with an organic solution containing an amine-based extractant to produce a cobalt chloride aqueous solution, an organic phase containing an amine-based extractant is used. If the organic solution used is the organic solution L0 and the nickel chloride solution containing cobalt, which is the extraction starting solution in the solvent extraction step, is the aqueous solution A, the minute entley existing in the form of inverse micelles in the cobalt chloride aqueous solution. The amount of nickel contained in the ment can be easily grasped.
Therefore, by using the inverse micelle evaluation method in the organic phase of the present embodiment, it is possible to predict the trace amount of nickel concentration in the cobalt chloride aqueous solution during operation, so that the quality of the cobalt chloride aqueous solution can be improved. Will be able to manage properly.

Further, by using the method for evaluating inverse micelles in the organic phase of the present embodiment, the substance M to be evaluated, which is considered to contribute to the increase of minute entrainment existing in the form of inverse micelles in the organic solution L in advance, is determined. Can be identified. In other words, since the substance that affects minute entrainment can be easily grasped from the relationship with the _{inverse micelle formation rate Erm, the evaluation as the evaluation target substance M becomes easy.} Then, if the concentration of the substance M to be evaluated is controlled by monitoring or the like during the operation, it is possible to suppress an increase in minute entrainment existing in the form of reverse micelle formation in the organic phase. That is, by using the inverse micelle evaluation method in the organic phase of the present embodiment, it is possible to easily investigate the influence of various evaluation target substances M.

Then, if the substance M to be evaluated due to the increase in entrainment in the organic phase can be identified, the quality of the electric cobalt produced in the electrowinning process can be improved by monitoring the concentration of the substance M in the operation. It will be possible to maintain the state. In other words, by identifying the substances that cause the formation of reverse micelles and controlling them to a concentration below the appropriate level, the quality of the cobalt chloride aqueous solution can be maintained appropriately. It is possible to manage the state with less contamination caused by nickel.
The appropriate concentration of the substance M to be evaluated can be appropriately adjusted according to the quality of the product such as the cobalt chloride aqueous solution and the electric cobalt. For example, it is preferable to control the concentration of the substance M to be evaluated so that the reverse micelleization rate Erm is 20% or less, more preferably the reverse micelleization rate Erm is 10% or less, and further preferably reverse micelle formation. Manage so that the rate Erm is 5% or less.

Hereinafter, examples of the present invention will be shown and more specifically described. The present invention is not limited to the following examples.

(Experiment 1)
A predetermined amount is separated from an organic solvent (trade name Swazole 1800 manufactured by Maruzen Petrochemical Co., Ltd.) (corresponding to the organic solution L0 of the present embodiment) containing an amine-based extractant TNOA (Farmin T-08 manufactured by Kao Corporation). An organic solution (corresponding to the preparative organic solution L1 of the present embodiment) was prepared by adding enanthic acid (corresponding to the evaluation target substance M of the present embodiment) to the preparative organic solvent.
The prepared organic solution was centrifuged using a centrifuge (5220 manufactured by Kubota Shoji Co., Ltd.) (corresponding to the centrifugation treatment S1 of the present embodiment). The aqueous phase separated by centrifugation was removed to prepare a 25 mL organic phase (corresponding to the first water-removing organic solution L2 of the present embodiment).
Centrifugation conditions: Rotation speed 3000 rpm, rotation time 10 minutes 10 μL was collected from the prepared organic phase (corresponding to the first water-removing organic solution L2 of the present embodiment) using a macrosyringer, and a Karl Fischer titer (Kyoto). _{Moisture content W b} was measured with MKH-710M) manufactured by Denshi Kogyo Co., Ltd.

Subsequently, this organic phase (corresponding to the first water-removing organic solution L2 of the present embodiment) is a nickel chloride solution containing cobalt as the extraction starting solution of the solvent extraction step corresponding to 3000 volume ppm of the organic phase as the aqueous phase. After adding (corresponding to the aqueous solution A of the present embodiment), the mixture was stirred at room temperature (about 25 ° C.) at a rotation speed of 800 rpm for 10 minutes (corresponding to the dispersion treatment S2 of the present embodiment) to disperse the nickel chloride solution. An organic phase (aqueous phase dispersed organic solution L3 of the present embodiment) was prepared.
It was collected organic phase 10μL using macro syringe from the produced organic phase (aqueous phase dispersed organic solution L3 in this embodiment) to measure the moisture content W _a by the Karl Fischer moisture meter.

Next, this organic phase (aqueous phase-dispersed organic solution L3 of the present embodiment) is centrifuged again (corresponding to the centrifugation treatment S3 of the present embodiment) to separate the aqueous phase from the organic phase, and then centrifuged again. Separation was performed to prepare an organic phase (second water-removing organic solution L4 of the present embodiment).
From this prepared organic phase (second water-removing organic solution L4 of the present embodiment), 10 μL of the organic phase was collected with a macrosyringe.
For the water content W of the collected organic phase, the water content W _rm was measured with a Karl Fischer titer.

Then, with respect to the organic phase in which the nickel chloride solution was dispersed (the aqueous phase dispersed organic solution L3 of the present embodiment), the inverse micelle conversion rate _Erm was calculated by the above formula 7).

(Experimental result)
The result of the experiment (1) is shown in FIG.
FIG. 3 shows the relationship between the concentration of heptane added to the organic phase (mmol / l) and the inverse micelle formation rate (%) of minute emulsions in the organic phase. The result was that the reverse micelle formation rate (%) increased as the concentration of enanthic acid increased.

(Experiment 2)
An organic solution obtained by adding octanoic acid instead of enanthic acid to an organic solvent obtained by separating a predetermined amount from an organic solvent containing an amine-based extractant TNOA (Farmin T-08 manufactured by Kao Co., Ltd.) (preparative organic solution of the present embodiment). The inverse micelle formation rate (%) was calculated by the same method as in the experiment (1) except that (corresponding to the solution L1) was prepared.

(Experimental result)
The result of the experiment (2) is shown in FIG.
FIG. 4 shows the relationship between the concentration of octanoic acid added to the organic phase (mmol / l) and the inverse micelle formation rate (%) of minute emulsions in the organic phase. The result was that the inverse micelle formation rate (%) increased as the concentration of octanoic acid increased.

(Experiment 3)
As the aqueous phase to be added to the organic phase (corresponding to the first water-removing organic solution L2 of the present embodiment), instead of the nickel chloride solution, nickel chloride 440 g / L and cobalt chloride 22 g / L corresponding to 3000 volume ppm of the organic phase The inverse micelle formation rate (%) was calculated in the same manner as in Experiment (1) except that the aqueous phase (nickel chloride / cobalt chloride solution) containing the above was added.

(Experimental result)
The result of the experiment (3) is shown in FIG.
FIG. 5 shows the relationship between the concentration of enanthic acid added to the organic phase (mmol / l) and the inverse micelle formation rate (%) of minute emulsions in the organic phase. Under all conditions, the inverse micelle formation rate (%) was almost zero.

(Experiment 4)
An organic solution (Mono-n-octylamine) is added to an organic solvent containing a predetermined amount of an amine-based extractant TNOA (Farmin T-08 manufactured by Kao Corporation) instead of heptanic acid. The inverse micelle formation rate (%) was calculated by the same method as in the experiment (1) except that the preparative organic solution L1 of the embodiment was prepared.

(Experimental result)
The result of the experiment (4) is shown in FIG.
FIG. 6 shows the relationship between the concentration of MNAO added to the organic phase (mmol / l) and the inverse micelle formation rate (%) of minute entrainments in the organic phase. Under all conditions, the inverse micelle formation rate (%) was almost zero.

(Experiment 5)
Add 3.5 mmol / L of enanthic acid so that the amount of enanthic acid to be added to the organic solvent prepared by separating a predetermined amount from the organic solvent containing the amine-based extractant TNOA (Farmin T-08 manufactured by Kao Corporation) is constant. An organic solution (corresponding to the preparative organic solution L1 of the present embodiment) was prepared. An aqueous phase containing 440 g / L of nickel chloride and 22 g / L of cobalt chloride, which corresponds to 3000 volume ppm of the organic phase, as an aqueous phase to be added to the organic phase (corresponding to the first water-removing organic solution L2 of the present embodiment) (nickel chloride). -Cobalt chloride solution) was added. Methanesulfonic acid was added to this aqueous phase. Except for these, the inverse micelle formation rate (%) was calculated by the same method as in the experiment (1).

(Experimental result)
The result of the experiment (5) is shown in FIG.
FIG. 7 shows the relationship between the concentration of methanesulfonic acid added to the aqueous phase (mmol / l) and the inverse micelle formation rate (%) of minute entrainments in the organic phase. As the concentration of methanesulfonic acid increased, the inverse micelle formation rate (%) increased.

(Experiment 6)
The TNOA concentration (vol%) in an organic solvent containing the amine-based extractant TNOA (Farmin T-08 manufactured by Kao Co., Ltd.) is varied, and a predetermined amount of heptanic acid is added to the organic solvent separated from this preparative organic solvent. In the same manner as in Experiment (1), the reverse was made in the same manner as in Experiment (1), except that an organic solution (corresponding to the preparative organic solution L1 of the present embodiment) was prepared by adding 3.5 mmol / L of heptanic acid so that The micelle formation rate (%) was calculated.

(Experimental result)
The result of the experiment (6) is shown in FIG.
FIG. 8 shows the relationship between the TNOA concentration (vol%) added to the organic phase and the inverse micelle formation rate (%) of minute emulsions in the organic phase. The result was that the inverse micelle formation rate (%) increased as the TNOA concentration increased.

(Experiment 7)
An organic solution obtained by adding formic acid instead of enanthic acid to an organic solvent obtained by separating a predetermined amount from an organic solvent containing an amine-based extractant TNOA (Farmin T-08 manufactured by Kao Co., Ltd.) (the preparative organic solution of the present embodiment). The inverse micelle formation rate (%) was calculated by the same method as in the experiment (1) except that (corresponding to the solution L1) was prepared.

(Experimental result)
The result of the experiment (7) is shown in FIG.
FIG. 9 shows the relationship between the concentration of formic acid added to the organic phase (mmol / l) and the inverse micelle formation rate (%) of minute entrainments in the organic phase. Under all conditions, the inverse micelle formation rate (%) was almost zero.

(Experiment 8)
An organic solution obtained by adding propionic acid instead of enanthic acid to an organic solvent obtained by separating a predetermined amount from an organic solvent containing an amine-based extractant TNOA (Farmin T-08 manufactured by Kao Co., Ltd.) (preparative organic solution of the present embodiment). The inverse micelle formation rate (%) was calculated by the same method as in the experiment (1) except that (corresponding to the solution L1) was prepared.

(Experimental result)
The result of the experiment (8) is shown in FIG.
FIG. 10 shows the relationship between the concentration of propanoic acid added to the organic phase (mmol / l) and the inverse micelle formation rate (%) of minute emulsions in the organic phase. Under all conditions, the inverse micelle formation rate (%) was almost zero.

(Experiment 9)
An organic solution (prepared organic of the present embodiment) is prepared by adding butyric acid instead of enanthic acid to an organic solvent obtained by separating a predetermined amount from an organic solvent containing an amine-based extractant TNOA (Farmin T-08 manufactured by Kao Co., Ltd.). The inverse micelle formation rate (%) was calculated by the same method as in the experiment (1) except that (corresponding to the solution L1) was prepared.

(Experimental result)
The result of the experiment (9) is shown in FIG.
FIG. 11 shows the relationship between the concentration of butanoic acid added to the organic phase (mmol / l) and the inverse micelle formation rate (%) of minute entrainments in the organic phase. Under all conditions, the inverse micelle formation rate (%) was almost zero.

(Experiment 10)
An organic solution obtained by adding pentanic acid instead of enanthic acid to an organic solvent obtained by separating a predetermined amount from an organic solvent containing an amine-based extractant TNOA (Farmin T-08 manufactured by Kao Co., Ltd.) (the preparative organic solution of the present embodiment). The inverse micelle formation rate (%) was calculated by the same method as in the experiment (1) except that (corresponding to the solution L1) was prepared.

(Experimental result)
The results of the experiment (10) are shown in FIG.
FIG. 12 shows the relationship between the concentration of pentanoic acid added to the organic phase (mmol / l) and the inverse micelle formation rate (%) of minute emulsions in the organic phase. The result was that the reverse micelle formation rate (%) increased as the concentration of pentanoic acid increased.

(Experiment 11)
An organic solution obtained by adding caproic acid instead of enanthic acid to an organic solvent obtained by separating a predetermined amount from an organic solvent containing an amine-based extractant TNOA (Farmin T-08 manufactured by Kao Co., Ltd.) (the preparative organic solution of the present embodiment). The inverse micelle formation rate (%) was calculated by the same method as in the experiment (1) except that (corresponding to the solution L1) was prepared.

(Experimental result)
The result of the experiment (11) is shown in FIG.
FIG. 13 shows the relationship between the concentration of hexanoic acid added to the organic phase (mmol / l) and the inverse micelle formation rate (%) of minute emulsions in the organic phase. The result was that the reverse micelle formation rate (%) increased as the concentration of caproic acid increased.

The method for evaluating reverse micelles in an organic phase of the present invention is suitable for a method for evaluating the dispersibility of entrainments existing in the form of reverse micelles in an organic phase in solvent extraction used in hydrometallurgy of non-ferrous metals. ing.

A aqueous solution L1 preparative organic solution L2 first water removal organic solution L3 aqueous phase dispersion organic solution L4 second water removal organic solution S1 centrifuge treatment S2 water solution dispersion treatment S3 second centrifugation treatment W moisture content _Erm reverse micelle Conversion rate

Claims (5)

A method for evaluating the dispersibility of fine aqueous phase droplets contained in an organic phase.
The organic solution used for the organic phase is separated, and the separated organic solution is subjected to centrifugation to remove water to prepare a predetermined amount of the first water-removing organic solution, and the first water-removing organic solution is prepared. After preparing an aqueous phase-dispersed organic solution in which a predetermined amount of an aqueous solution is added to the solution and dispersed, the aqueous phase-dispersed organic solution is subjected to centrifugation to remove water to prepare a second water-removing organic solution. ,
The water content of the first water-removing organic solution is W _b, and the water content of the second water-removing organic solution is W _rm .
_{The water content ΔW rm} increased from the water content _{W b of} the first water-removing organic solution in the second aqueous phase dispersed organic solution was determined.
_{Obtain the water content W 0} from (volume of the aqueous solution) / {(volume of the first water-removing organic solution) + (volume of the aqueous solution)}.
Reverse micelles of Organic phase, characterized by calculating the moisture content W _rm a reversed micelle ratio E _rm of fine droplets contained from the ratio of the water content W ₀ in the aqueous phase dispersed in the organic solution Method. The method for evaluating inverse micelles in an organic phase according to claim 1, wherein the inverse micelle conversion rate _{Erm is calculated by the following formula.}
E _rm = ΔW _rm / W ₀ The reverse of the organic phase according to claim 1 or 2, wherein the substance to be evaluated is added to the organic solution, the preparative organic solution, the solution of any one of the aqueous solutions, or two or more solutions. Micelle evaluation method. The method for evaluating reverse micelles in an organic phase according to claim 1, 2 or 3, wherein the organic solution contains an organic extractant. The reverse micelle evaluation method in an organic phase according to claim 4, wherein the organic extractant is a phosphoric acid ester-based acidic extractant or an amine-based extractant.

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