JP5604571B1 - Method for separating zirconium and hafnium and method for producing zirconium from which hafnium has been removed - Google Patents

Abstract

A method for separating zirconium and hafnium and a method for producing zirconium from which hafnium has been removed, which can improve the selective extraction rate of hafnium and can quickly and efficiently obtain zirconium from which hafnium has been removed. .
According to one embodiment of the present invention, a method for separating zirconium and hafnium includes a preparation step of preparing an extraction stock solution containing an aqueous solution containing zirconium, hafnium and sulfuric acid and a catalyst, and the extraction stock solution and the acidic extraction which are aqueous solutions. An organic phase solution containing an agent, and selectively extracting hafnium in the extraction stock solution into the organic phase solution; and a first stirred solution that is an aqueous solution from which hafnium has been removed through the extraction step; A separation step of separating the second extraction liquid, which is an organic phase solution that has passed through the extraction step, and the catalyst is a metal ion that improves the extraction rate of hafnium, and includes nickel ions, copper ions, and combinations thereof. Any one selected from the group consisting of:
[Selection] Figure 1

Description

The present invention relates to D2EHPA (Di- (2-ethylhexyl) phosphoric acid), PC88A (2-Ethylhexyl phosphonic acid mono-2-ethylhexyl ester), M2EHPA (Mono- (2-ethylhexyl) phosphoric acid), Cyanex272 (Bis (2 , 4,4-trimethylpentyl) phosphinic acid) or P-229 (Di (2-ethylhexyl) phosphinic acid) and the like, the present invention relates to a method for separating zirconium and hafnium by a solvent extraction method. In addition, the present invention adds nickel ion or copper ion as a catalyst agent and isoamyl acetate (C ₇ H ₁₄ O ₂ ) to the organic phase in order to improve the extraction rate of unusually slow hafnium. Thus, the present invention relates to a method for improving the selective extraction rate of hafnium and quickly and efficiently obtaining zirconium from which hafnium has been removed.

Zirconium and hafnium, which are metals having similar physicochemical properties, have neutron absorption cross sections of 0.18 barn and 104 barn, respectively, and it is known that the difference in neutron absorption cross section reaches about 600 times. .
Zirconium is a material that must be used in nuclear fuel rods for nuclear power generation because it is a metal with excellent high-temperature corrosion resistance and high-temperature strength, and particularly a very small neutron absorption cross section. In contrast, hafnium is very similar to zirconium in other physical properties, but has a very large neutron absorption cross section. Thus, the metallic zirconium used in nuclear fuel rods is limited to a hafnium content of less than 100 ppm.

Various techniques have been tried to separate zirconium and hafnium from the past, and the solvent extraction method can be said to be a typical conventional method.
Extractants used for the separation and extraction of zirconium and hafnium in aqueous solutions include diethyl ether, methyl isobutyl ketone (MIBK), tributyl phosphate (Tributyl Phosphate, TBP), and trioctylamine (Trioctyl). Various extractants such as Amine, TOA and Trioctyl Methylammonium Chloride have been used.

However, only a part of the extractant has been commercialized and applied to the separation of zirconium and hafnium. This is because there are few extractants with high separation effect of zirconium and hafnium in addition to economic problems such as the price of the extractant.
Conventional solvent extraction processes for zirconium and hafnium include a process using MIBK as an extractant and a process using TBP as an extractant.

However, when MIBK is used as an extractant in the solvent extraction process of zirconium and hafnium, the use of an extractant is used to selectively extract hafnium, which is much less than zirconium, from an aqueous solution, especially at a very low price. Although there is an advantage that the amount is small, since thiocyanate (SCN ⁻¹ ) ions have to be added to the aqueous solution before extraction, there is a drawback in that it causes environmental pollution problems due to cyan (CN) compounds. Moreover, since the solubility of MIBK in water is as high as about 1.8%, there is a disadvantage that the loss of the extractant is large.

  On the other hand, when TBP is used as an extracting agent in the solvent extraction step of zirconium and hafnium, unlike the case where MIBK is used as an extracting agent, there is an advantage that a cyanide compound is not added, but the price of the extracting agent is high. Since zirconium was selectively extracted rather than hafnium, there was a problem that the amount of extractant used was relatively large.

Therefore, in the present invention, a method for selectively extracting hafnium quickly and efficiently and producing zirconium from which hafnium has been removed is presented.
The object of the present invention is to use an extraction agent such as D2EHPA, PC88A, M2EHPA, Cyanex272, P-229, or a combination of these to extract unusually slow hafnium when separating zirconium and hafnium in an aqueous solution by a solvent extraction method. An object of the present invention is to provide a method of effectively performing a separation step by improving the extraction speed of the above.

Another object of the present invention is to selectively add hafnium from an aqueous solution by adding nickel ion or copper ion as a catalyst agent to the aqueous solution and adding isoamyl acetate (C ₇ H ₁₄ O ₂ ) to the organic phase. An object of the present invention is to provide a solvent extraction method that improves the extraction speed and effectively separates zirconium and hafnium.

  In order to achieve the above object, a method for separating zirconium and hafnium according to an embodiment of the present invention includes a preparation step of preparing an extraction stock solution containing an aqueous solution containing zirconium, hafnium and sulfuric acid and a catalyst, and the extraction being an aqueous solution. An extraction step of stirring the stock solution and the organic phase solution containing the acidic extractant to selectively extract hafnium in the extraction stock solution into the organic phase solution, and an aqueous solution from which hafnium has been removed through the extraction step. And a separation step of separating the first agitation liquid and the second extraction liquid that is the organic phase solution that has undergone the extraction stage.

  The catalyst is a metal ion that improves the extraction rate of hafnium, and is any one selected from the group consisting of nickel ions, copper ions, and combinations thereof.

  The organic phase solution may further include isoamyl acetate.

  The acidic extractant is di (2-ethylhexyl) phosphoric acid (D2EHPA), 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (PC88A), mono (2-ethylhexyl) phosphoric acid (M2EHPA), bis (2,4 , 4-trimethylpentyl) phosphinic acid (Cyanex 272), di (2-ethylhexyl) phosphinic acid (P-229), and combinations thereof, may be included.

  The concentration of the sulfuric acid in the extraction stock solution may be 2 to 10 mol / l.

  The concentration of the metal ions in the extraction stock solution may be 0.1 to 2.0 g / l.

  The isoamyl acetate may be contained in the organic phase solution in a range of 0.01 to 0.1 vol%.

  The metal ion may be derived from any one selected from the group consisting of nickel, nickel sulfate, nickel sulfate hydrate, copper, copper sulfate, copper sulfate hydrate, and combinations thereof. Good.

  The method for producing zirconium according to another embodiment of the present invention includes a preparation step of preparing an extraction stock solution containing an aqueous solution containing zirconium, hafnium and sulfuric acid and a catalyst, and an organic phase containing the extraction stock solution and the acidic extractant which are aqueous solutions. The extraction step of stirring the solution and selectively extracting hafnium in the extraction stock solution into the organic phase solution, and the first stirring solution that is an aqueous solution from which hafnium has been removed through the extraction step and the extraction step A separation step of separating the second extract, which is an organic phase solution, and a recovery step of recovering zirconium from which hafnium has been removed from the first stirring solution are included.

  The catalyst is a metal ion that improves the extraction rate of hafnium, and is any one selected from the group consisting of nickel ions, copper ions, and combinations thereof.

  The organic phase solution may further include isoamyl acetate.

  The acidic extractant is di (2-ethylhexyl) phosphoric acid (D2EHPA), 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (PC88A), mono (2-ethylhexyl) phosphoric acid (M2EHPA), bis (2,4 , 4-trimethylpentyl) phosphinic acid (Cyanex 272), di (2-ethylhexyl) phosphinic acid (P-229), and combinations thereof, may be included.

The present invention will be described in detail below.
A method for separating zirconium and hafnium according to an embodiment of the present invention includes a preparation stage, an extraction stage, and a separation stage, and quickly and efficiently separates hafnium, which is a metal having physicochemical properties similar to zirconium.

  The preparation step is a step of preparing an extraction stock solution, wherein zirconium containing hafnium may be dissolved in a sulfuric acid aqueous solution, and a catalyst may be added thereto to prepare an extraction stock solution. A zirconium compound containing a predetermined amount of hafnium. May be dissolved in water, sulfuric acid may be gradually mixed, and a catalyst may be added thereto to prepare an extraction stock solution.

The sulfuric acid is preferably contained in the extraction stock solution at 2 to 10 mol / l. When the concentration of the sulfuric acid in the extraction stock solution is out of the range of 2 to 10 mol / l, the effect of separating zirconium and hafnium is lowered.
It is preferable that the acid component in the aqueous solution substantially contains sulfuric acid. When sulfuric acid is used as the acid component in the aqueous solution rather than hydrochloric acid or nitric acid, the selective recovery rate of zirconium can be improved.

  The catalyst includes any one metal ion selected from the group consisting of nickel ions, copper ions, and combinations thereof. Further, when the catalyst is added to the extraction stock solution and the zirconium and hafnium are separated, the extraction speed is dramatically reduced when zirconium is selectively extracted from the extraction stock solution using an acidic extractant. Get faster.

Any catalyst can be used as long as it can supply the metal ions to the extraction stock solution. In consideration of using an aqueous sulfuric acid solution in the extraction step, the metal ions include nickel, nickel sulfate, It is preferable to apply any one selected from the group consisting of nickel sulfate hydrate, copper, copper sulfate, copper sulfate hydrate, and combinations thereof.
The concentration of the metal ions in the extraction stock solution is preferably 0.1 to 2.0 g / l. When the concentration of the metal ions is less than 0.1 g / l, the effect of improving the extraction rate is reduced. If it exceeds 2.0 g / l, the chemical consumption increases unnecessarily.

  The organic phase solution may further include isoamyl acetate. The isoamyl acetate is contained in the organic phase solution, and further accelerates the hafnium extraction rate by changing the chemical characteristics at the interface where the aqueous solution and the organic phase are in contact.

  That is, changes in interfacial properties (eg, interfacial tension) have a very important effect on the extraction rate because hafnium extraction eventually occurs at the interface. That is, when the organic phase solution further contains isoamyl acetate, in addition to the catalytic action of the metal ions contained in the aqueous solution, the characteristics of the interface between the aqueous solution and the organic phase are changed, and ultimately the extraction of hafnium is performed. Increase speed significantly.

  The isoamyl acetate is preferably added in the range of 0.01 to 0.1 vol% with respect to the entire organic phase solution. If the amount of isoamyl acetate added is less than the above range, the effect of improving the extraction rate of hafnium will be insufficient, and if it is more than the above range, the chemical cost will be very high.

The extraction step is a step of stirring the extraction stock solution that is an aqueous solution and an organic phase solution containing an acidic extractant to selectively extract hafnium in the extraction stock solution into the organic phase solution.
Examples of the acidic extractant include di (2-ethylhexyl) phosphoric acid (D2EHPA), 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (PC88A), mono (2-ethylhexyl) phosphoric acid (M2EHPA), bis ( An acidic extractant comprising any one selected from the group consisting of 2,4,4-trimethylpentyl) phosphinic acid (Cyanex 272), di (2-ethylhexyl) phosphinic acid (P-229), and combinations thereof. May be used.

  The organic phase solution may further include a diluent in the acidic extractant, and the diluent may be an organic solvent. As the diluent, kerosene or the like is used, but is not limited to this, and does not interfere with the extraction reaction, and is well mixed with the acidic extractant and the organic phase solution in the solvent extraction step. Any of those included in the above can be applied. Moreover, the mixing ratio of the diluent and the acidic extractant can be used without limitation as long as it does not inhibit the efficiency of the extraction reaction.

  By the stirring in the extraction step, only a small amount of zirconium in the extraction stock solution is extracted into the organic phase solution, the rest remains in the aqueous solution as it is, and almost all of the hafnium in the extraction stock solution is extracted. Therefore, zirconium and hafnium can be separated very effectively by the method described above.

  The extraction temperature in the extraction stage is not particularly limited, but if necessary, the extraction stage may be performed by increasing the temperature of the reactor.

  In order to improve the separation effect of zirconium and hafnium, an extraction device may be used. For example, the separation method may be applied in multiple stages using an extraction device such as a mixer setra (multi-stage tank type extractor), and an extraction temperature may be used. May be applied at an elevated temperature. However, in the present invention, the above-described separation method of zirconium and hafnium can be applied without being limited to the above-described extraction apparatus and extraction temperature.

FIG. 2 is a graph showing the extraction rate of hafnium according to Comparative Example 1, which will be described later. Referring to FIG. 2, according to Comparative Example 1, the extraction must be continued vigorously until the amount of hafnium extracted reaches equilibrium. It can be confirmed that it takes about 90 minutes or more.
However, in order to obtain a sufficient extraction rate (extraction efficiency) by applying a separation method that requires such a long extraction time, the residence time in the reactor must be increased. A large reactor (for example, a stirrer) must be manufactured, which may eventually increase the cost and reduce the economy.

On the other hand, according to the separation method of the present invention described above, the extraction rate of hafnium is improved in a short time, unlike the case where the amount of treatment per hour that can be treated is small when the method that does not use a catalyst is applied. Such a problem can be solved because the equilibrium value of the extraction is reached.
In other words, the method for separating zirconium and hafnium according to an embodiment of the present invention using a catalyst, when compared with a method not using a catalyst, takes about 10 times the time to reach the equilibrium value of the extraction amount when the experiment is performed under the same conditions. Therefore, even if an extraction time of about 10 minutes is applied, a sufficient hafnium extraction effect can be obtained, which is a feature that is clearly distinguished from a method using no catalyst.

The separation step is a step of separating a first stirring liquid that is an aqueous solution from which hafnium has been removed through the extraction stage and a second extraction liquid that is an organic phase solution that has undergone the extraction stage.
The method for separating the first stirring liquid, which is the aqueous solution, and the second extraction liquid, which is the organic phase solution, is not particularly limited, and a method for separating the aqueous phase and the organic phase by an ordinary solution extraction method. Should be applied.

  In general, zirconium ores distributed in the earth's crust contain about 0.5-2 wt% hafnium, and zirconium and hafnium are very similar in physicochemical properties, and it is very difficult to separate them. difficult. However, by applying the above-described method for separating zirconium and hafnium, it is possible to extract hafnium contained in a trace amount in zirconium by a simple method called solution extraction method, which is excellent in extraction rate and extraction rate and from zirconium. Hafnium can be removed quickly and efficiently.

A method for producing zirconium according to another embodiment of the present invention includes a preparation stage, an extraction stage, a separation stage, and a recovery stage, and can quickly produce zirconium from which hafnium has been removed.
Since the preparation stage, the extraction stage, and the separation stage in other embodiments of the present invention overlap with those of the embodiment of the present invention, they are omitted.

The recovery step is a step of recovering zirconium from which hafnium has been removed from the first stirring liquid, and any method can be used as long as zirconium in the intended form can be obtained from an aqueous solution containing zirconium (first stirring liquid). Applicable. If necessary, a step of removing the metal ions used as the catalyst from the first stirring liquid may be further performed.
In this way, zirconium from which hafnium has been sufficiently removed can be provided in a short time in a relatively simple manner.

  In the method for separating zirconium from hafnium and the method for producing zirconium from which hafnium has been removed according to the present invention, hafnium is selectively used by using acidic extractants such as D2EHPA, PC88A, M2EHPA, Cyanex272, and P-229 alone or in combination. By extracting, the extraction rate of hafnium that is abnormally slow compared to the usual solvent extraction rate of other metals can be dramatically improved.

In Example 1 of this invention, it is a graph which shows the extraction rate (%) by the stirring time in the case of extracting hafnium from zirconium by the system which adds nickel ion to an aqueous phase and adds isoamyl acetate to an organic phase solution. The graph which shows the extraction rate (%) by the stirring time in the case of extracting hafnium from zirconium by the system which does not add nickel ion or copper ion to the aqueous phase and does not add isoamyl acetate to the organic phase solution in Comparative Example 1 of the present invention. It is.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art to which the present invention pertains can easily implement the present invention. However, the present invention is not limited to the embodiments described here, and can be realized in various forms.

Example 1
Nickel sulfate (NiSO ₄ ) was added to 1 liter of an aqueous solution of 2 mol of sulfuric acid containing zirconium 17,500 mg / l and hafnium 148.5 mg / l so that the nickel ion content would be 0.1 g / l, and the extraction stock solution Manufactured.

Then, isoamyl acetate was added to 0.1 vol% to 1 liter of an organic phase solution (first extract) in which 0.1 liter of D2EHPA and 0.9 liter of kerosene (diluent) were mixed. The organic phase solution and 1 liter of the extraction stock solution as an aqueous solution were placed in a reaction vessel, and the aqueous solution (extraction stock solution) and the organic phase solution (first extraction solution) were vigorously stirred with a stirrer at room temperature.
In the stirring process, hafnium in the aqueous solution (extraction stock solution) was selectively extracted into the organic phase solution. After stirring for about 10 minutes, the stirring is stopped, and an organic phase solution containing hafnium extracted from the extraction stock solution (second extraction solution) and an aqueous solution from which hafnium has been selectively removed from the extraction stock solution (first stirring solution) ) And were phase separated.

  Thus, the content of zirconium and hafnium in the aqueous solution (first stirring liquid) obtained by phase separation was analyzed by an ICP spectrophotometer (manufactured by Perkin Elmer, Optima 5300 DV). Further, the extraction time for stirring the aqueous solution (extraction stock solution) and the organic phase solution (first extraction solution) is changed to measure the contents of zirconium and hafnium in the aqueous solution (first stirring solution), and the extraction The ratio (%) of hafnium removed from the stock solution is shown in FIG.

The measurement results of Example 1 stirred for 10 minutes were zirconium 16,300 mg / l and hafnium 0.9 mg / l.
That is, 93.1% (= 16,300 / 17,500) of zirconium contained in the extraction stock solution remains in the aqueous solution (first stirring solution) as it is, and hafnium contained in the extraction stock solution is 99.4% (= (148.5-0.9) /148.5) was extracted into the organic phase solution (second extract).
In other words, despite the simple method of stirring and phase separation with the extractant and the very short extraction time of about 10 minutes of stirring, the zirconium and hafnium separation method is extremely It was confirmed that zirconium having a very low content of hafnium can be produced by selectively removing the hafnium contained in the zirconium in this manner.

(Example 2)
Copper sulfate (CuSO ₄ ) was added to 1 liter of an aqueous solution containing 10 mol of sulfuric acid containing zirconium (17,500 mg / l) and hafnium (148.5 mg / l) so that the copper ion content was 2.0 g / l. Manufactured.

An organic phase solution containing 0.02 liters of D2EHPA, 0.02 liters of PC88A, 0.02 liters of M2EHPA, 0.02 liters of Cyanex272, 0.02 liters of P-229, and 0.9 liters of kerosene (First extract) Isoamyl acetate was added to 1 liter so as to be 0.01 vol%. 1 liter of the organic phase solution and 1 liter of the extraction stock solution as an aqueous solution were placed in a reaction vessel, and the aqueous solution (extraction stock solution) and the organic phase solution (first extraction solution) were vigorously stirred with a stirrer at room temperature.
In the stirring process, hafnium in the aqueous solution (extraction stock solution) was selectively extracted into the organic phase solution. After stirring for about 10 minutes, the stirring is stopped, and an organic phase solution containing hafnium extracted from the extraction stock solution (second extraction solution) and an aqueous solution from which hafnium has been selectively removed from the extraction stock solution (first stirring solution) ) And were phase separated.

Thus, the content of zirconium and hafnium in the aqueous solution (first stirring liquid) obtained by phase separation was analyzed by an ICP spectrophotometer (manufactured by Perkin Elmer, Optima 5300 DV). As a result, the contents of zirconium and hafnium in the aqueous solution (first stirring liquid) were 16,900 mg / l and 1.2 mg / l, respectively.
That is, 96.6% (= 16,900 / 17,500) of zirconium contained in the extraction stock solution remains in the aqueous solution (first stirring solution) as it is, and hafnium contained in the extraction stock solution is 99.2% (= (148.5-1.2) /148.5) was extracted into the organic phase solution (second extract). That is, when the method for separating zirconium and hafnium was used, zirconium and hafnium could be separated very effectively, and zirconium having a very low hafnium content could be produced.

(Comparative Example 1)
One liter of an aqueous solution containing 2500 moles of sulfuric acid containing zirconium 17,500 mg / l and hafnium 148.5 mg / l was prepared without adding nickel ions or copper ions.

Then, 1 liter of organic phase solution (first extract) was prepared by mixing 0.1 liter of D2EHPA and 0.9 liter of kerosene. 1 liter of the produced zirconium aqueous solution (extraction stock solution) and 1 liter of the organic phase solution (first extraction solution) were placed in a reaction vessel, and the aqueous solution (extraction stock solution) and the organic phase solution ( Hafnium was selectively extracted from the aqueous solution into the organic phase solution for 10 minutes while vigorously stirring the first extract).
In the stirring process, hafnium in the aqueous solution (extraction stock solution) is selectively extracted into the organic phase solution, and the contents of zirconium and hafnium in the aqueous solution (first stirring liquid) after the extraction process is completed are determined by ICP. Analysis was performed using a spectrophotometer (manufactured by Perkin Elmer, Optima 5300 DV). Further, the extraction time for stirring the aqueous solution (extraction stock solution) and the organic phase solution (first extraction solution) is changed to measure the contents of zirconium and hafnium in the aqueous solution (first stirring solution), and the extraction The ratio (%) of hafnium removed from the stock solution is shown in FIG.

The measurement results of Comparative Example 1 stirred for 10 minutes were zirconium 16,200 mg / l and hafnium 73.8 mg / l.
That is, 92.6% (= 16,200 / 17,500) of zirconium contained in the extraction stock solution remains in the aqueous solution (first stirring solution) as it is, and shows almost the same result as in Example 1. Only 50.3% (= (148.5-73.8) /148.5) of hafnium contained in the extraction stock solution was extracted into the organic phase solution (second extract), and 99.4% Compared with the result of Example 1 extracted into the organic phase solution (second extract), there was a large difference. That is, it was confirmed that the separation effect of zirconium and hafnium varies greatly depending on whether or not the catalyst is further used.

  The preferred embodiments of the present invention have been described in detail above, but the scope of the present invention is not limited thereto, and various modifications and improvements of the present invention defined in the claims are also included in the present invention. Is included in the scope of rights.

Claims (10)

A preparation stage of preparing an extraction stock solution containing an aqueous solution containing zirconium, hafnium and sulfuric acid and a catalyst;
An extraction step of stirring the extraction stock solution that is an aqueous solution and an organic phase solution containing an acidic extractant to selectively extract hafnium in the extraction stock solution into the organic phase solution;
A separation step of separating a first stirring liquid that is an aqueous solution from which hafnium has been removed through the extraction step and a second extraction liquid that is an organic phase solution that has undergone the extraction step;
The method for separating zirconium and hafnium, wherein the catalyst is a metal ion that improves the extraction rate of hafnium, and is any one selected from the group consisting of nickel ions, copper ions, and combinations thereof.   The method for separating zirconium and hafnium according to claim 1, wherein the organic phase solution further comprises isoamyl acetate.   The acidic extractant is di (2-ethylhexyl) phosphoric acid (D2EHPA), 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (PC88A), mono (2-ethylhexyl) phosphoric acid (M2EHPA), bis (2,4 , 4-trimethylpentyl) phosphinic acid (Cyanex 272), di (2-ethylhexyl) phosphinic acid (P-229), and any one selected from the group consisting of these, Zirconium and hafnium separation method.   2. The method for separating zirconium and hafnium according to claim 1, wherein the concentration of the sulfuric acid in the extraction stock solution is 2 to 10 mol / l.   The method for separating zirconium and hafnium according to claim 1, wherein the concentration of the metal ions in the extraction stock solution is 0.1 to 2.0 g / l.   The method for separating zirconium and hafnium according to claim 2, wherein the isoamyl acetate is contained in the organic phase solution in a range of 0.01 to 0.1 vol%.   The metal ion is derived from any one selected from the group consisting of nickel, nickel sulfate, nickel sulfate hydrate, copper, copper sulfate, copper sulfate hydrate, and combinations thereof, Item 2. The method for separating zirconium and hafnium according to Item 1. A preparation stage of preparing an extraction stock solution containing an aqueous solution containing zirconium, hafnium and sulfuric acid and a catalyst;
An extraction step of stirring the extraction stock solution that is an aqueous solution and an organic phase solution containing an acidic extractant to selectively extract hafnium in the extraction stock solution into the organic phase solution;
A separation step of separating a first stirring liquid that is an aqueous solution from which hafnium has been removed through the extraction step and a second extraction liquid that is an organic phase solution that has undergone the extraction step;
Recovering zirconium from which hafnium has been removed from the first stirring liquid,
The method for producing zirconium, wherein the catalyst is a metal ion that improves the extraction rate of hafnium, and is any one selected from the group consisting of nickel ions, copper ions, and combinations thereof.   The method for producing zirconium according to claim 8, wherein the organic phase solution further contains isoamyl acetate.   The acidic extractant is di (2-ethylhexyl) phosphoric acid (D2EHPA), 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (PC88A), mono (2-ethylhexyl) phosphoric acid (M2EHPA), bis (2,4 , 4-trimethylpentyl) phosphinic acid (Cyanex 272), di (2-ethylhexyl) phosphinic acid (P-229), and any one selected from the group consisting of these, A method for producing zirconium.

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