KR101645431B1

KR101645431B1 - Method for Recover Tantalum or Tantalum/Niobium

Info

Publication number: KR101645431B1
Application number: KR1020150113540A
Authority: KR
Inventors: 김태엽; 구본우
Original assignee: (주)에코리사이클링
Priority date: 2015-08-12
Filing date: 2015-08-12
Publication date: 2016-08-04

Abstract

The present disclosure relates to a method for separating and recovering tantalum or tantalum / niobium from a raw material containing tantalum or tantalum / niobium with high efficiency, and is capable of effectively separating and recovering tantalum or tantalum / niobium without using hydrofluoric acid, , It is possible to suppress the problems arising from the use of the conventional MIBK extraction solvent and to perform stable operation.

Description

Method for Recovering Tantalum or Tantalum / Niobium (Method for Recovering Tantalum or Tantalum / Niobium)

The present invention relates to a method for recovering tantalum or tantalum / niobium. More specifically, the present invention relates to a method for efficiently separating and recovering tantalum or tantalum / niobium from a raw material containing tantalum or tantalum / niobium.

Tantalum is a transition metal having a melting point of 2996 캜 and a boiling point of 5425 캜, and is excellent in corrosion resistance and has good thermal and electric conductive properties. Therefore, various industrial devices such as distillation towers, autoclaves, heat exchangers, Is known to be used in.

In general, the tantalum oxide film generally has a property called a valve action (when the electrode is an anode, it works on the dielectric, and conversely, when the electrode is a cathode, it does not work as a dielectric, Is used as a transport device, an electronic device, an electronic control device, and the like. In addition, tantalum oxide is applied as electronic ceramics and LN (LiNbO ₃ ). Furthermore, the demand for tantalum carbide as a material for hard cutting tools and tantalum oxide as an additive for optical lenses is increasing widely. Particularly, in order to use a tantalum powder as a capacitor grade, a powder having a purity of 99.5% or more is required.

On the other hand, niobium is used as a steel additive (in the form of Fe-Nb) because it stabilizes carbon components in steel to prevent corrosion. Niobium oxide is also utilized in the fields of optics and electronic ceramics. In particular, a niobium alloy has been put to practical use as a conductive tube attached to a lamp light emitting portion of a high-pressure sodium lamp, and is also used as an additive element of superconducting material or superalloy.

Tantalum and niobium are generally contained in raw materials such as ores, and therefore, separation and purification processes are required. In Korea, waste scrap such as waste condenser, tantalum target, etc. is discharged, and it is necessary to separate and recover the tantalum component from it, but now it is exported to all over the world. In fact, as of 2011, about 74% of the tantalum supply is derived from minerals, while about 18% is known to be reclaimed from scrap recycling and about 8% from tin slag.

Conventionally, the following method has been used as a method for separating tantalum from a raw material or removing impurities in a tantalum compound.

(i) a solvent extraction method using extraction selectivity,

(ii) fractional crystallization method using the difference in solubility of the metal compound,

(iii) ion exchange separation using adsorption selectivity of ion exchange resins, and

(iv) A volatilization method in which anions are volatilized and removed by high-temperature firing.

Among the above methods, the solvent extraction method has been widely used. Typically, a raw material such as a tantalum-containing ore such as tantalite or a scrap of a tantalum capacitor is first pulverized and a fluoride (for example, hydrofluoric acid (HF ), A mixed acid of hydrofluoric acid and inorganic acid), and then the concentration of the solution is adjusted by adding sulfuric acid. In this connection, the reaction with HF can be illustrated in the following reaction scheme 1.

[Reaction Scheme 1]

Ta ₂ O ₅ + 14HF (aq) -> 2H ₂ TaF ₇ (aq) + 5H ₂ O

At this time, it is known that when tantalum or tantalum and niobium-containing raw materials are dissolved in fluoride, two types of complexes are formed: TaF ₇ ^2- / TaF ₆ ^- and NbOF ₅ ^2- / NbF ₆ ^- . The equilibrium between the complexes depends on the acidity of the aqueous acid solution, and for each of tantalum and niobium, the following Equation 2 can be given.

[Reaction Scheme 2]

Thereafter, the solution is filtered using a filter press, and then tantalum and niobium are separated as an extract by performing extraction using a solvent (for example, methyl isobutyl ketone (MIBK)). At this time, the impurities contained in the raw material, such as iron, manganese, silicon, etc., remain in the extraction raffinate.

As an example of the solvent extraction method, an aqueous solution obtained by dissolving a raw material such as tantalite in HF alone or a mixed acid of HF and H ₂ SO ₄ ) is extracted with a solvent, and the separated organic phase is washed with water or NH ₄ F Containing solution to remove Nb ₂ O ₅ , Fe, Mn, Ti, and the like. When the solvent containing tantalum and niobium is back-extracted, the niobium migrates into the aqueous phase, and the high-purity tantalum remains in the solvent. The tantalum in the solvent is purified, back-extracted with water, and transferred to an aqueous solution to recover the solvent For example, Japanese Patent Laid-Open No. 64-45325). On the other hand, the niobium in the aqueous solution is extracted again using a solvent to extract a small amount of tantalum to purify the niobium in the aqueous solution. Ammonia water is added to each purified aqueous solution of tantalum and niobium to precipitate hydroxides, which are then filtered and dried to be finally calcined to prepare tantalum oxide and niobium oxide (see, for example, JP-A-3-502116 number).

In the solvent extraction method as described above, methyl isobutyl ketone (MIBK) is typically used as a solvent for extracting tantalum and niobium (for example, U.S. Patent No. 5,209,910). However, in the case of the solvent extraction method using MIBK, since the solubility of MIBK in water is high, there is a tendency that MIBK is lost during operation, so it is necessary to supplement a large amount of MIBK. In addition, since it is difficult to drain water, the cost of operation and drainage are increased, and the separation performance of tantalum and niobium is not large. Therefore, there is a problem that many extraction stages are required. Furthermore, MIBK is highly volatile and generates a large amount of gas, generates harmful odors, and has a high risk of fire.

On the other hand, in the case of the above-described conventional techniques, a mixed acid of HF or HF and a mineral acid (for example, nitric acid) is usually used to dissolve tantalum (or tantalum and niobium) in a raw material Patent Publication Nos. 2010-0107897, 2002-316822, etc.). However, HF is not only a difficult and dangerous material to handle, but it also needs to be disposed of because it is inevitably contaminated with HF.

Also, according to the prior art, tantalum and / or niobium powder is obtained by reduction with an alkali metal, especially sodium, in order to produce elemental tantalum and / or niobium powder. However, in the case of using sodium as a reducing agent, the time required for the reduction reaction is long, so that the mass productivity can be lowered, and the excess tantalum is used because of the excessive amount of the reducing agent. Particularly, since sodium metal which is most widely used reacts with moisture in the atmosphere and generates heat by self-extinguishing, the handling property is deteriorated, and in particular, it is exposed to the risk of explosion even in a high temperature reaction.

As described above, the prior art for separating (purifying) tantalum or tantalum and niobium from raw materials containing tantalum (or tantalum / niobium) with high purity and high efficiency is inevitable in at least one of the process elements constituting the whole process In addition, the domestic tantalum manufacturing process has not been commercialized, and at most, it is limited to the unit process of the laboratory scale at most.

Accordingly, the present disclosure intends to provide a novel tantalum (or tantalum / niobium) separation and purification process capable of solving the problems of the prior art at once.

According to a first aspect of the present invention,

a) a first leaching step of treating a tantalum (Ta) -containing raw material using hydrochloric acid and nitric acid separately or in the form of a mixed acid;

b) leaching a tantalum-containing raw material through said first leaching step using a combination of (i) sulfuric acid, hydrochloric acid, nitric acid or a mixture thereof, and (ii) a fluoride of an alkali metal or an alkaline earth metal;

c) separating the leach from the second leaching step from the solid residue;

d) separating the leach solution obtained from the second leaching step into a tantalum-rich first organic phase and a tantalum-lean first aqueous liquid phase by extraction using a phosphoric acid ester compound represented by the following general formula 1 as an extractant; And

e) separating the tantalum compound from the first organic phase;

A method of recovering tantalum comprising:

[Formula 1]

Wherein R is hydrogen, an alkyl group having 1 to 10 carbon atoms or an aryl group having 6 to 10 carbon atoms, and the three R's are the same or different.

According to a second aspect of the present invention,

a ') a first leaching step of treating the tantalum / niobium (Ta / Nb) -containing feedstock using hydrochloric acid and nitric acid separately or in mixed acid form;

b ') that leaches the tantalum / niobium-containing feedstock through the first leaching step using a combination of (i) sulfuric acid, hydrochloric acid, nitric acid or a mixture thereof, and (ii) a fluoride of an alkali metal or an alkaline earth metal. Leaching step;

c ') separating the leach obtained from said second leaching step from the solid residue;

d ') extracting the leach solution obtained from the second leaching step using a phosphoric acid ester compound represented by the following general formula (1) as an extractant to obtain a first tantalum / niobium-rich organic phase and a first tantalum / niobium- ; And

e ') separating the tantalum compound and the niobium compound from the first organic phase, respectively;

A method of recovering tantalum and niobium comprising:

[Formula 1]

According to an exemplary embodiment, the phosphoric acid ester compound may be represented by the following general formula 2:

[Formula 2]

.

The method provided in accordance with embodiments of the present invention may be used in place of the hydrofluoric acid (HF), which adversely affects the environment in the leaching (elution) step to obtain the target component tantalum or tantalum / niobium from the tantalum-containing or tantalum / (Sulfuric acid, hydrochloric acid, nitric acid, etc.), which are less toxic to tantalum or tantalum / niobium, are environmentally friendly. In addition, when MIBK is used as an extraction solvent for separating tantalum (or tantalum / niobium), stable operation can be performed by suppressing explosion and fire risk. Furthermore, the process provided in a further embodiment can significantly reduce the risk of explosion in the atmosphere caused by Na which has been conventionally used in the reduction step for producing tantalum or tantalum / niobium in the element (metal) form, It is also excellent in safety and operational safety. Therefore, it is expected to be widely applied in the future.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a process diagram schematically showing a process for recovering tantalum (Ta) or tantalum / niobium (Ta / Nb) provided in an exemplary embodiment of the present invention,
FIGS. 2A and 2B show XRD pattern analysis results for each of the Ta ₂ O ₅ powder and Nb ₂ O ₅ powder produced by the calcination treatment in the examples, and FIGS.
FIG. 2C shows the XRD pattern analysis results for the tantalum (Ta) powder prepared by the thermal reduction reaction of Ta ₂ O ₅ using Ca in the examples.

The present invention can be all accomplished by the following description. The following description should be understood to describe preferred embodiments of the present invention, but the present invention is not necessarily limited thereto.

FIG. 1 schematically shows an example of a process for recovering tantalum (Ta) or tantalum / niobium (Ta / Nb) provided according to an embodiment.

The tantalum-containing raw material or the tantalum / niobium-containing raw material

According to one embodiment, a tantalum-containing raw material or a tantalum / niobium-containing raw material is used as a starting material. According to one embodiment, ores (minerals) such as tantalite, columbite, pyrochlore, or combinations thereof are used as sources of tantalum-containing raw materials or tantalum / niobium-containing raw materials . Double tantalite is typically represented by the formula (Fe, Mn) Ta ₂ O ₆ , while in the case of columbite, it is represented by (Fe, Mn) Nb ₂ O ₆ . In addition, pyrochlore is represented by (Na, Ca) Nb ₂ O ₆ (OH, F), and contains niobium as main component and tantalum as subcomponent.

Exemplary compositions of such tantalum-containing minerals are shown in Table 1 below (composition ranges can be varied depending on the mountain area, even for the same ore).

In this regard, in an exemplary embodiment, the content of tantalum (based on oxide) in the feedstock may range from at least about 1 wt%, specifically from about 30 to 90 wt%, more specifically from about 40 to 85 wt% The sum of the niobium content may be, for example, in the range of about 3 to 90% by weight, specifically about 10 to 99% by weight, but the present invention is not necessarily limited thereto.

According to an alternative embodiment, the waste of various components (e.g., electrolytic capacitors, specifically electrodes of electrolytic capacitors) that utilize the properties of the valve metal as the tantalum-containing raw material, the residue or deposition waste of the tantalum- - Composite scrap such as Ta oxide, Co-Ta or In-Ta, Machined waste scrap of hardened tool material, Ferro alloy, etc., and can be used to produce tantalum (or tantalum and niobium) In some cases, tantalum / niobium products and liquid raw materials (for example, flux washing water in the preparation of tantalum and / or niobium powder) may be used. In this case, it is preferable that the raw material contains tantalum as a main component.

In this regard, in the case of electrolytic capacitor scrap, copper and nickel are present as major impurities in the shell, and the amount of tantalum contained may vary depending on the type of scrap. In addition, the tantalum-containing target material also has a constant tantalum content, but it may be advantageous for the materialization because it does not contain various kinds of impurities.

According to an exemplary embodiment, the tantalum (on an elemental basis) is present in the waste material in the range of, for example, about 10 to 90 wt%, specifically about 40 to 80 wt%, and more specifically about 50 to 70 wt% But the present invention is not necessarily limited thereto.

Grinding of tantalum-containing raw materials (optional)

In one embodiment, the tantalum-containing feedstock can be provided in the form of a particle (or powder), which can be pulverized to a suitable size so that the tantalum and / or niobium component can be easily eluted during the subsequent leaching process have. In particular, when a tantalum-containing electrolytic capacitor (or capacitor) or the like is used as a raw material, the resin component and the like can be separated through a pulverizing process.

In this regard, the size of the raw material can be determined by suitably taking into account the leaching rate in the subsequent leaching step and the content of tantalum and / or niobium in the leach solution, for example, about 50 to 1000 mesh, specifically about 100 To about 500 mesh, and more specifically from about 150 to about 300 mesh. The preferred particle size of the raw material may vary depending on the kind of the raw material, the content of tantalum and / or niobium in the raw material, the kind of the acid component used in the leaching process, and the like. However, since the particle size influences the leaching rate during the subsequent leaching process (the smaller the particle size, the larger the interfacial area between the solid and the liquid, and the more difficult it is to circulate the liquid and to separate the particles from the liquid) .

Also, the pre-leached tantalum-containing feedstock (or ground feedstock) may have a purity of at least about 0.001 m ² / g, specifically about 0.013 to 0.072 m ² / g, more specifically about 0.018 to 0.036 m ² / g It may have a specific surface area, but is not necessarily limited to the above-described numerical range.

For the grinding step, any grinding means known in the art such as, for example, a vibrating mill, a ball mill, a hammer mill, a rod mill or the like can be used without particular limitation.

In an exemplary embodiment, the above-described pulverizing step can be carried out by two or more steps (in particular, when the raw material is present in a bulk rather than in a particulate form), in this example of multi- Jaw crusher, hammer mill or the like, and then pulverized in a ball mill, rod mill or the like in two or more steps, and it is preferable to have a homogeneous particle size distribution as much as possible Lt; / RTI > In some cases, the classification or classification process may be accompanied by the use of vibration bars.

Leaching (leaching) step

As shown in FIG. 1, according to an exemplary embodiment of the present invention, the tantalum-containing raw material particles (or the pulverized material thereof) are contacted with an acid component and subjected to a leaching step. The niobium component is contained in the leach solution while other impurity-containing solids (solid residue) are obtained.

It should be noted that, in the above specific example, HF (or a mixed acid of HF and another inorganic acid) is not used unlike the prior art. To this end, the leaching step may be configured in a multi-stage (e.g., a two stage leaching stage) and the leaching (leaching) effect at least equivalent to the leaching component based on HF by using a particular leaching component for each leaching stage And thus can alleviate the complexity resulting from the additional processing associated with the use of HF.

In an exemplary embodiment, tantalum and / or niobium can be effectively contained in the leachate through a two stage leaching step as follows. The reason for performing the multi-stage leaching step is as follows. First, the impurities in the raw material are effectively removed to increase the relative content of the tantalum (or tantalum / niobium) component in the raw material. Subsequently, For the purpose of eluting tantalum (tantalum / niobium).

- the first leaching (leaching) step

In one embodiment, impurities dissolved in the water in the water are pre-leached out by the pretreatment concept using the characteristic that tantalum (tantalum / niobium) is not dissolved (eluted) in inorganic acids other than HF to remove tantalum (tantalum / niobium ) Is present in a relatively high content. At this time, an acid component which can dissolve other impurities in the raw material even though tantalum and / or niobium can not be dissolved can be used as a component used for leaching.

In this connection, since the ore source of tantalum (or tantalum / niobium) contains impurities such as copper, nickel, iron, tin and zinc, Other inorganic acids) are used to primarily remove impurities in the ore.

Also, in the case of a waste-type source, tantalum and / or niobium are mostly used in the form of metal (element), so that the waste generated therefrom also exists mainly in the form of metal, but may exist in oxide form in some waste. For example, in the case of condenser scrap, the main component of the shell is copper, nickel, etc., and tantalum exists in the form of a metal powder. Because of this, when the shell is melted and filtered in aqua regia beforehand, only the clean tantalum (or tantalum / niobium) will be present as a residue, as the shell has a tendency to dissolve mainly in hydrochloric acid and / or nitric acid. Thus, a large amount of impurities can be relatively easily separated from tantalum (tantalum / niobium) in a subsequent step. In this connection, waste such as Co-Ta target or In-Ta, which is a composite scrap, is discharged as metal-type waste similarly to a capacitor scrap. Therefore, most of the impurity elements such as Co, In, Li, Can be removed.

According to an exemplary embodiment, for example, hydrochloric acid, nitric acid and / or a mixture thereof may be used as the acid component used in the first leaching (leaching) step. However, when hydrochloric acid or nitric acid is used alone, the components leached into hydrochloric acid and the components leached into nitric acid in the raw materials are different from each other, and it may be difficult to obtain a desired level of impurity removal effect.

Thus, in a preferred embodiment, it may be advantageous to use a mixture of hydrochloric acid and nitric acid, specifically water. The water is called a nitro-hydrochloric acid and is a solution of concentrated nitric acid and hydrochloric acid mixed at a ratio of, for example, about 1: 3 to 1: 4 (by volume), typically about 1: 3, It is possible to dissolve precious metals such as platinum. The concentration of the usable water (aqueous solution) may be, for example, about 15 to 40% by volume, specifically about 20 to 35% by volume, more specifically about 25 to 32% by volume, Can be adjusted appropriately.

In an exemplary embodiment, the amount of water used varies depending on the impurity level in the raw material and the like, but is typically on a raw material basis, for example, about 10 to 50 wt%, specifically about 20 to 40 wt% About 25 to 35% by weight. However, when an excessively large amount of the water is added to the raw material, it may be advantageous to use an appropriate amount since it may be unnecessary to process the water afterward.

On the other hand, the first leaching (leaching) step can be optionally carried out under stirring, for example at about 40 to 80 캜, specifically about 45 to 70 캜, more specifically about 50 to 65 캜. At this time, the leaching time can be adjusted, for example, in the range of about 3 to 8 hours, specifically about 4 to 7 hours, more specifically about 5 to 6 hours, but this can be changed depending on the raw material properties and the like.

According to an alternative embodiment, the first leaching step may be a two-step process (e.g., treatment with hydrochloric acid followed by treatment with nitric acid) using hydrochloric acid and nitric acid separately. In this case, the process may be complicated as compared with the case where the mixture of hydrochloric acid and nitric acid is used in one step as described above, but this disclosure does not exclude this two-step process. However, even if hydrochloric acid and nitric acid are respectively used in multi-stages, the concentration of each of hydrochloric acid and nitric acid, the treatment conditions and the like can be controlled within a range similar to that in the case of using aqua regia.

- Second leaching (leaching) step

According to one embodiment, after the first leaching step, a second leaching step is performed with different acid components. At this time, the leaching solution may be separated from the tantalum (or tantalum / niobium) -containing raw material (first leaching step treatment product) obtained from the first leaching step, and then the second leaching step may be performed. Alternatively, Step, but it may be advantageous to perform a second leaching step for the post-separation treatment, given the reason for going through the first leaching step. As described above, the second leaching step is carried out for the purpose of eluting tantalum (or tantalum / niobium) using less harmful components instead of HF.

According to an exemplary embodiment, a combination of (i) an inorganic acid other than hydrofluoric acid (HF) and (ii) a fluoride of an alkali metal or alkaline earth metal is charged (used) in a second leaching step. In this case, the chemical reaction between the components (i) and (ii) leads to a reaction similar to the chemical reaction of the use of HF, so that tantalum and / or niobium can be safely leached.

With respect to component (i), sulfuric acid, hydrochloric acid, nitric acid or mixtures thereof can be used. However, when hydrochloric acid is used, it generates a lot of hydrochloric acid gas in itself when it is exposed to the atmosphere, and nitric acid may cause gas generation as well as difficulty in nitrogen treatment in the subsequent wastewater treatment. On the other hand, sulfuric acid may be advantageous to use only sulfuric acid since not only the gas is rarely generated before the reaction but also the amount of hydrogen ion is present in the amount of 2 equivalents, so that the use amount can be lowered. In this embodiment, the acid concentration of component (i) may be in the range of, for example, about 35 to 70 vol%, specifically about 40 to 65 vol%, more specifically about 45 to 55 vol%.

In the case of the component (ii), lithium, sodium, potassium and combinations thereof may be used as the alkali metal in the fluoride of the alkali metal, and magnesium, calcium and combinations thereof may be selected as the alkali earth metal. However, in case of KF, the tantalum fluoride salt can be precipitated depending on the condition when tantalum is leached. In the case of CaF, the precipitate such as CaSO ₄ is formed by reaction with sulfuric acid, There is room for action. Thus, in a preferred embodiment sodium fluoride (NaF) can be used.

The reaction between the components (i) and (ii) of tantalum (when tantalum exists in the form of oxide such as ore) among the first leached raw materials as described above can be exemplified as shown in the following reaction formula (3).

[Reaction Scheme 3]

Ta ₂ O ₅ + 2H ₂ SO ₄ + 14 NaF → 2H ₂ TaF ₇ + 2NaSO ₄ + 10Na ⁺ + 5O ^2-

The tantalum (tantalum / niobium) component contained in the raw material subjected to the first leaching step according to the reaction scheme 3 is reacted with the conventional HF directly in the second leaching step (Ta ₂ O ₅ + 14H ₂ F → 2H ₂ TaF ₇ + 10 H ₂ O), which is one of the main advantages of the present disclosure.

In an exemplary embodiment, the amount of each of the components (i) and (ii) may be determined according to the characteristics of the raw material subjected to the first leaching treatment, but may be determined, for example, on the basis of the first leached raw material , For example about 100 to 800 wt% (specifically about 300 to 650 wt%, more specifically about 350 to 500 wt%) and about 100 to 600 wt% (specifically about 300 to 500 wt% About 320 to 400% by weight).

The second leaching step may optionally be carried out under agitation, for example at at least about 50 캜, specifically about 55 to 90 캜, more specifically about 60 to 80 캜. In addition, the second leaching step may be carried out, for example, in the range of about 6 to 18 hours, specifically about 7 to 15 hours, more specifically about 8 to 12 hours. However, it is advantageous to perform the stirring under the stirring condition so that the raw material does not remain on the bottom, and the stirring speed can be flexibly adjusted according to the specific gravity of the raw material and the amount of the raw material.

(I.e., a solid / liquid mixture) after the above-described two-stage leaching step, when the total amount of tantalum and the impurities is 100 wt%, a considerable amount (for example, (Or tantalum / niobium) tantalum (or tantalum / niobium) of about 90 wt.% Or more, specifically about 98 wt. , W, etc.) may be contained in an amount of about 10% by weight or less (specifically about 2% by weight or less). At this time, tantalum and niobium may be present in a fluoride form such as H ₂ Ta (Nb) F ₇ , Ta (Nb) F ₅ .2HF or H ₂ NbOF ₅ , respectively.

In the leaching solution, nitric acid, hydrochloric acid, sulfuric acid, a mixture thereof and the like used in the second stage leaching step described above as an acid component may be contained. Other impurities and the like are present mainly in the residue of the solid phase but are still contained in a certain amount in the leaching solution. Especially when the leaching step does not involve separation after the first leaching step, impurities other than tantalum or tantalum / Lt; / RTI >

Thus, in one embodiment, the extraction step is subsequently carried out for the purpose of selectively separating only tantalum or tantalum / niobium in the leachate.

According to an illustrative embodiment, the leaching step first sets the treated material to a standstill, since the specific gravity of the solid residue is large, for example, after about 10 to 50 minutes (specifically about 20 to 40 minutes) Residue sinks to the bottom. Liquid / liquid separation can be carried out after the above-mentioned or after the abovementioned step, using filtration techniques which are typically known in the art, such as belt filtration, rotary filtration, centrifugal filtration, drum filtration and countercurrent decantation decantation, pressure filtration, vacuum filtration, and the like.

Solvent extraction step

According to one embodiment, solvent extraction is performed on the leach solution (tantalum or tantalum / niobium-containing aqueous solution) to selectively shift tantalum (or tantalum / niobium) in the extraction phase (extract) (Raffinate) is left in the extracted after-image (raffinate). That is, it is separated into a tantalum-rich (or tantalum / niobium-rich) first organic phase and a tantalum-lean (or tantalum / niobium-lean) first aqueous liquid phase by solvent extraction.

In this embodiment, instead of MIBK, which is conventionally widely used as an extraction solvent, a phosphoric acid ester compound represented by the following general formula 1 is used:

[Formula 1]

Here, R is hydrogen, an alkyl group having 2 to 7 carbon atoms (specifically, an alkyl group having about 3 to 5 carbon atoms), or an aryl group having 6 to 10 carbon atoms (specifically, an aryl group having 7 to 9 carbon atoms) Or different.

According to a preferred embodiment, the phosphate ester compound can be represented by the following general formula 2:

[Formula 2]

.

As shown in the following Table 2, the compound of the general formula (2) has a lower solubility in aqueous solution than that of MIBK, so that it is possible to lower the loss during extraction. In addition to being comparatively inexpensive, The separation and purification ability is equal to or more than that.

compound Density (20 ℃) Solubility in water Boiling point MIBK 0.802 g / cc 1.91% (20 < 0 > C) 116.5 DEG C The compound of the general formula 3 0.973 g / cc 0.4% (20 캜) 289 ° C

According to another embodiment, in order to further increase the extraction efficiency, a phosphinic acid ester compound may be mixed with the phosphoric acid ester compound of the general formula 2 as an extractant. In this connection, a representative example of the phosphinic acid ester compound can be represented by the following general formula (3).

[Formula 3]

In this embodiment, the compound of the general formula 2 and the compound of the general formula 3 can be mixed at a ratio of, for example, about 1: 0.5 to 1: 3, specifically about 1: 1 to 1: 2. However, since the compound of the general formula (3) is expensive, it is advantageous to use the compound of the general formula (2) alone but to use a multi-stage extraction method for the purpose of increasing the extraction efficiency as required.

In an exemplary embodiment, the phosphate ester compound is introduced using a diluent to form an organic phase (extract phase or extract). The reason for using the diluent is that when the phosphoric acid ester compound, which is an extracting agent, is used alone, the difference in specific gravity between the phosphoric acid ester and the aqueous solution phase may decrease, and phase separation may not be easy. Examples of the diluent include organic solvents or petroleum hydrocarbons, specifically aliphatic hydrocarbons C9 to C15 paraffins, more specifically, benzene, toluene, and kerosene. From these, one or more kinds of diluents can be selected and used have. In this case, the content of the phosphoric acid ester compound as the extracting agent may be in the range of, for example, about 10 to 50% by weight, specifically about 20 to 40% by weight, more specifically about 25 to 35% by weight.

In this embodiment, the ratio of the extraction solvent (organic phase) to the leachate (in aqueous solution) is in the range of, for example, about 0.5 to 2, specifically about 0.7 to 1.5, more specifically about 0.9 to 1.2 If the O / A ratio is excessively small, the extraction ability of the target metal (tantalum and / or niobium) is lowered and the separation from the aqueous phase is lowered. On the other hand, when the O / A ratio is excessively large, And thus it may be preferable to appropriately control the temperature within the above-mentioned range.

For extracting the solvent, a liquid-liquid extraction technique known in the art can be utilized. For example, a mixer-settler method and a column method can be used, and a higher extraction efficiency and processing Speed (co-current or counter current) operation. In the case of a mixer-settler, a mixer and a settler are provided. In a mixer, a solvent and an aqueous solution of an organic acid are brought into contact with each other. In the settler, a harder image moves to the upper side of the settler, and a heavier image sinks to the bottom of the settler. However, when the mixer-settler is used, crystals may form and adhere to the apparatus to cause a phenomenon that may interfere with the flow of the liquid. However, the phosphate ester used in the embodiment, particularly the compound represented by the general formula 2, It does not cause problems.

Further, the pH range of the leaching solution introduced into the extraction step is a factor affecting the extraction efficiency with respect to tantalum (or tantalum / niobium), for example, from about strong acidity (-) to 1, specifically about strong acidity 0 < / RTI > In addition, the extraction step may be carried out at a temperature of, for example, about 10 to 40 DEG C, specifically about 15 to 30 DEG C, more specifically about 20 to 25 DEG C, especially at room temperature.

According to exemplary embodiments, it may be advantageous to involve stirring in the liquid-liquid extraction, wherein the agitation time is adjusted to a range of about 10 to 60 minutes, specifically about 15 to 40 minutes, more specifically about 20 to 30 minutes But it should be understood that this is illustrative.

In addition, tantalum and / or niobium may be contained in the extracted after-image (raffinate) generated during the solvent extraction step, and the extraction step may be further performed using an extraction solvent which is the same as or similar to the solvent used previously The recovery rate of the target metal may be increased.

Separation of tantalum compounds and niobium compounds (optional)

The extracted phase (first organic phase) separated through the solvent extraction step is tantalum (or tantalum / niobium) rich oil. Illustratively, the content of tantalum (or tantalum / niobium) in the metal component, excluding the solvent in the extracted phase, can be in the range of, for example, about 80 to 99 wt%, specifically about 90 to 98 wt% . However, in the case of using ore as a raw material, since it contains both tantalum and niobium in the extraction phase, it may be required to separate it into individual components in order to use it for a specific use. However, the separation process of tantalum and niobium may not be required unless the niobium component is substantially present in the raw material (when the Ta waste is used as the raw material).

Therefore, according to the exemplary embodiment, in order to separate the tantalum compound and the niobium compound, a tantalum component (ion) is selectively back-extracted using a separate solvent to form a second tantalum-rich aqueous solution phase, Impurities remain in the organic solvent to form a niobium-rich second organic phase. That is, after extraction of tantalum and niobium with an extraction agent according to the general formula (1) into an organic phase (first organic phase), only the tantalum in the first organic phase in the first back extraction step is back extracted Niobium remaining in the organic phase (niobium-rich second organic phase) in the first back extraction step in the second back extraction step and niobium in the minor amount of the impurities in the aqueous phase solution 3 aqueous phase) to separate tantalum and niobium from each other.

An acid component (specifically, nitric acid, hydrochloric acid, etc.) may be used as a solvent for back extraction, and it may be advantageous to use nitric acid to selectively back-extract tantalum.

According to a particular embodiment, the concentration of the acid component (especially nitric acid) used in the first back extraction step is, for example, about 10 to 30% by volume, specifically about 15 to 25% by volume, 22% by volume. During back extraction in the acid concentration range during the first back extraction step, tantalum present in the organic phase preferentially or selectively migrates into the aqueous solution while niobium remains in the organic phase. Thereafter, the niobium and trace impurities remaining in the organic phase (second organic phase) in the second back extraction step are removed at a high concentration, for example, about 30% by volume or more (specifically about 35% (In the third aqueous solution) in the case of back-extraction again with an acid component (nitric acid, hydrochloric acid, a mixture thereof, etc.) of from 50 to 50% by volume.

According to an alternative embodiment, water may be used in place of the acid component for the back extraction of niobium during the second back extraction step, but in this case a plurality of back extraction steps are required, resulting in an increase in the volume of the subsequent treatment solution It may be advantageous to use an acid component of a specific concentration as described above.

In this embodiment, the input amount of the acid component in the first back extraction step may vary depending on the characteristics of the tantalum component in the first organic phase and the like. Typically, the amount of tantalum (element) extracted in the first organic phase From about 10 to 50% by weight, and more typically from about 25 to 35% by weight. Also, the amount of acid component input during the second back extraction step may range from about 30 to 50 wt%, more typically from about 35 to 45 wt%, based on the weight of niobium (element) in the second organic phase. It should be understood, however, that the above-described ranges of the amounts of the acid components are illustrative, and the present invention is not necessarily limited to these ranges.

On the other hand, according to an exemplary embodiment, tantalum present in a small amount (e.g., about 10 wt.% Or less based on the elements contained in the second organic phase) in the second organic phase in the first back extraction step is reused (Specifically, sodium hydroxide, potassium hydroxide, etc.) solution to be converted to hydroxide through a saponification process. At this time, when the pH of the solvent is changed from a neutral region to a weakly alkaline region (specifically, pH 7 to 9) by reacting with an alkali solution, it can be recycled.

In the tantalum compound-containing aqueous solution (or the tantalum-rich second aqueous solution) and the niobium compound aqueous solution (or the niobium-rich third aqueous solution) separated as described above, tantalum and niobium are represented by the chemical formulas of H ₂ TaF ₇ and H ₂ NbF ₇ And most of them are present in a dissolved state. Therefore, for recovery, it may be required to convert tantalum and niobium into a precipitate form in a subsequent process. To this end, a base component such as ammonia (for example, gaseous phase Ammonia, ammonia water, etc.), an alkali solution such as sodium hydroxide and / or potassium hydroxide may be added. At this time, tantalum and niobium are converted to Ta (OH) ₅ and Nb (OH) ₅ and precipitated as shown in the following reaction formula (4).

[Reaction Scheme 4]

H ₂ TaF ₇ + 5NH ₄ OH → Ta (OH) ₅ ↓ + 2HF + 5NH ₄ F

H ₂ NbF ₇ + 5NH ₄ OH → Nb (OH) ₅ ↓ + 2HF + 5NH ₄ F

On the other hand, the amount of the base component added can be controlled depending on the amount of tantalum and niobium in the liquid. In addition, the pH of each aqueous solution during the precipitation process can be adjusted within the range of, for example, about 5 to 9, specifically about 6 to 8, more specifically about 6.5 to 7.5.

Thereafter, the precipitate of each of the separated tantalum hydroxide and niobium hydroxide is separated and washed with water as an optional step to remove the residual ions contained in the precipitate. In some cases, they may be further treated using filtration means and / or drying means known in the art.

Calcination step (when obtaining tantalum and / or niobium oxide)

In one embodiment, a calcination step may be performed to convert the precipitate of tantalum hydroxide obtained in the above step or the precipitate of each of tantalum hydroxide and niobium hydroxide into an oxide form. At this time, the calcination step can be carried out under an oxygen-containing atmosphere (for example, air) and temperature conditions of about 650 to 1000 ° C, specifically about 700 to 900 ° C, more specifically about 750 to 850 ° C. The calcining step may also be carried out at a heating rate of, for example, about 7 to 15 占 폚 / min, specifically about 9 to 12 占 폚 / min for about 40 to 150 minutes, specifically about 50 to 130 minutes, 120 minutes. As a result, titanium oxide (Ta ₂ O ₅ ) and niobium oxide (Nb ₂ O ₅ ) are obtained, respectively.

According to an exemplary embodiment, the purity of the tantalum oxide may be at least about 99%, more specifically at least about 99.9%, and the niobium oxide may have a purity of at least about 98%, more specifically at least about 98.5%.

Reduction step (when obtaining elemental tantalum and / or niobium)

In one embodiment, in order to obtain powders in the form of element (metal), respectively, from the tantalum oxide and niobium oxide produced from the calcination step described above, additionally (optionally) a reduction step, in particular an alkaline earth metal (Concretely, Mg, Ca, etc.).

[Reaction Scheme 5]

_{Ta 2 O 5 + 5Ca → 2Ta} + 5CaO

In this connection, in consideration of the reactivity and the loss according to the above reaction formula, for example, about 4 to 7 mol, specifically about 5 to 6 mol, of an alkaline earth metal may be used for each metal oxide.

At this time, the alkaline earth metal as the reducing agent can be used in a bulk type (for example, about 1 to 5 mm in size), and in some cases, it can also be introduced into a molten state or a gas phase. It may also be required to block the air with an inert gas (e. G., Helium, argon, nitrogen, etc.) during the reduction reaction. According to an illustrative embodiment, the reduction temperature is in the range of about 800 to 1100 ° C, specifically about 900 to 1000 ° C, more specifically about 950 to 980 ° C, and the reduction time is, for example, about 1 to 5 hours Can range from about 2 to 3 hours.

The tantalum (or tantalum / niobium) powder obtained through the above-described reduction reaction may have an average particle size in the range of, for example, about 1000 to 5000 mu m, specifically about 1500 to 2500 mu m. In addition, depending on the application, the particle size may be increased through heat treatment or the like.

On the other hand, according to one embodiment, if necessary, the purification process described above may be repeated to increase the purity of tantalum or tantalum / niobium. In this case, tantalum, for example, can increase the purity to about 99.99% and niobium to about 99%.

The present invention can be more clearly understood by the following examples, and the following examples are merely illustrative of the present invention and are not intended to limit the scope of the invention.

Example 1

In this embodiment, Russian ore (tantalite) having a tantalum (Ta) content of 38.65% by weight and a niobium (Nb) content of 9.78% is used as a raw material. The content of the ingredients and their contents were analyzed using ICP-OES 5300DV from Perkin Elmer, and the results are shown in Table 3 below.

Ingredients in raw materials (element) Raw ore (wt%) Na 0.63 Mg 0.012 K 1.02 Ca 0.06 Fe 3.48 Al 2.56 P 0.01 Ti 0.37 Zr 0.3 Zn 0.008 Ba 0.009 Pb 0.03 Mn 4.65 Si 2.86 Sn 10.08 Hf 0.1 Nb 9.78 Ta 38.65

Crushing of raw materials

The ore was first pulverized with a jaw crusher, secondarily pulverized using a ball mill, and then sieved to obtain a powder having a particle size of 2 mm or less.

Leaching of raw materials (first leaching and second leaching)

500 g of the raw material powder thus prepared was charged into a circular container made of PP. Separately, 500 ml of aqua regia prepared by mixing hydrochloric acid and nitric acid at a ratio of 3: 1 was mixed with 500 ml of distilled water to prepare 1 liter of the first leaching solution. The leach solution was added to the round vessel and incubated at 50 ° C for 5 hours (First leaching step).

The first leaching step treatment was filtered, and 1 L of a second leaching solution prepared by mixing 306.2 g of sulfuric acid, 262.5 g of NaF and 500 g of distilled water was added to the remaining residue (second leaching step). After the addition of the second leachate, the mixture was treated at a temperature of 60 ° C and a stirring speed of 120 rpm for 7 hours, and then the concentration and leach rate of each of tantalum and niobium in the leachate (filtrate) were analyzed. Table 3 shows the results.

Separately, the concentration and leach rate of each of tantalum and niobium in the leach solution containing HF (concentration: 50%) as the second leach solution for comparison purposes are shown in Table 4 together.

ingredient The second leach (g / L) Leaching Rate (%) HF Leachate (g / L) Leaching Rate (%) Na 0.3 - 3.1 - Mg 0.02 - 0.0055 - K 0.4 - 0.5 - Ca 0.001 - 0.3 - Fe 1.3 - 15.5 - Al 0.9 - 11.9 - P ND - 0.04 - Ti 0.1 - 1.81 - Zr 0.9 - 1.34 - Zn ND - 0.03 - Ba ND - 0.04 - Pb 0.12 - 0.05 - Mn 1.1 - 22.93 - Si 8.5 - 12.6 - Sn 1.0 - 48.8 - Hf 0.3 - 0.39 - Nb 48.4 99 48.5 99 Ta 189.1 98 189.1 98

As can be seen from the above table, as compared with the case of leaching using HF (Comparative Example), the leaching rate in this example is 98% of Ta and 99% of Nb and the leaching rate is equivalent to that in the case of using HF Respectively. Therefore, it was confirmed that the problems caused by the use of the conventional HF or the mixed acid thereof can be prevented, and at the same time, the leaching effect equivalent to or more than that can be obtained.

Solvent extraction

An extraction solvent prepared by mixing 300 ml of the compound of the formula 2 (Duksan Co., Ltd.) and 700 ml of kerosene (Ducksan) was added to the filtrate obtained by filtering the leached solution obtained according to the procedure described above, and the mixture was stirred at room temperature (350 rpm) Lt; / RTI > for about 10 minutes. At this time, the extraction process was performed twice (two-step extraction) in order to move the tantalum component in the leaching solution (filtrate) as far as possible to the solvent phase or the organic phase (first organic phase).

In the first step extraction, about 90% of the tantalum and about 60% of the niobium were extracted. In the second step extraction, about 99% of tantalum and about 80% of niobium were extracted Respectively. As such, it was determined that the after-rut (first aqueous solution) of the aqueous system contained about 20% by weight of niobium.

Mutual separation of tantalum and niobium

(1000 ml) obtained from the solvent extraction described above was subjected to back extraction using dilute nitric acid (1000 ml) of 20% (volume), whereby tantalum was selectively transferred to the aqueous phase (water phase) First reverse extraction) to obtain a water-based tantalum-rich reverse extract 1 (on the second aqueous solution). Then, the organic phase (1000 ml) was back-extracted with a relatively high concentration of nitric acid (1000 ml) of 35% (volume) (second reverse extraction), and the aqueous niobium-rich reverse extract 2 ).

The results of solvent extraction and two-stage back extraction (first and second back extraction) are shown in Table 5 below.

ingredient Undiluted solution
(g / L) Extraction Balance 1
(g / L) Extraction Balance 2
(g / L) Reverse extract 1
(g / L) Reverse extract 2
(g / L) Extraction rate
(%) Na 0.3 0.3 0.3 0.1 <0.001 - Mg 0.02 0.02 0.02 0.002 <0.001 - K 0.4 0.4 0.4 0.001 <0.001 - Ca 0.001 0.001 0.001 0.002 <0.001 - Fe 1.3 1.2 1.1 0.05 0.03 - Al 0.9 0.9 0.9 0.001 <0.001 - P ND ND ND ND ND - Ti 0.1 0.1 0.1 ND ND - Zr 0.9 0.8 0.8 0.005 <0.001 - Zn ND ND ND ND ND - Ba ND ND ND ND ND - Pb 0.12 0.12 0.12 ND ND - Mn 1.1 1.1 1.1 ND ND - Si 8.5 8.5 8.4 0.05 0.02 - Sn 1.0 1.0 0.99 0.001 <0.001 - Hf 0.3 0.3 0.3 ND ND - Nb 48.4 19.3 7.5 0.002 38.8 80.3 Ta 189.1 18.9 1.88 186.1 0.9 98.9

From the above table, solvent extraction using the dilute solution of the general formula 2 was performed. As a result, it is considered that good separation effect on tantalum / niobium can be achieved without using the conventional MIBK extraction solvent. In addition, it can be seen that the organic phase obtained from the extraction process can be effectively separated into a tantalum-rich aqueous solution and a niobium-rich aqueous solution through two stages of back extraction with different concentrations of nitric acid.

Sediment recovery for each of tantalum and niobium

Rich solution and a niobium-tantalum obtained from the two-stage stripping process as described above, ammonia water (concentration: 25%) for each rich aqueous solution by adjusting within the pH 7.5 to 8 range and the addition of Ta (OH) ₅ and Nb ( OH) ₅ . Each of the precipitates was subjected to solid / liquid separation using a vacuum filter (TC-501 v, product name of Ding Hwa Co., Ltd.). Further, each of the precipitates recovered as solids was treated with fresh water to wash away remaining ion components, followed by further solid / liquid separation.

Preparation of Tantalum Oxide and Niobium Oxide by Calcination

For each of the hydroxide-type solids obtained from the solid / liquid separation, primary drying was carried out at about 90 ° C for 12 hours in order to remove moisture, and calcination was carried out for about 2 hours under an atmospheric condition and at a temperature of 750 ° C, ₂ O ₅ powder and Nb ₂ O ₅ powder were obtained. The XRD pattern was analyzed for each of the Ta ₂ O ₅ powder and Nb ₂ O ₅ powder thus prepared (DMAX 2500 by Rigaku Corporation), and the results are shown in FIGS. 2A and 2B, respectively.

The purity analysis results of the recovered Ta ₂ O ₅ powder and Nb ₂ O ₅ powder are shown in Table 6 below.

ingredient Ta ₂ O ₅ Nb ₂ O ₅ Na 4 5 Mg 0 2 K One 2 Ca 3 5 Fe 101 1690 Al 5 7 P 0 0 Ti 0 One Zr One 3 Zn 49 63 Ba 0 0 Pb 0 0 Mn 59 72 Si 12 63 Sn 48 79 Hf 0 0 Nb 5 69.8 (%) Ta 81.6 (%) 1720 water(%) 99.9712 99.6288

Thus, it was confirmed that high purity Ta ₂ O ₅ powder and Nb ₂ O ₅ powder were produced through the calcination process according to the present embodiment.

Manufacture of tantalum powder and niobium powder

The Ta ₂ O ₅ powder prepared above was subjected to a thermal reduction reaction with tantalum powder using Ca as a reducing agent. At this time, the Ca addition amount was adjusted to 100%, 120%, 150%, and 200% of the reaction equivalence ratios in consideration of the theoretical chemical reaction formula (Ta ₂ O ₅ + ₅ Ca 2Ta ⁰ + ₅ CaO).

The thermal reduction reaction was carried out at a temperature of 950 ° C. for 3 hours. In order to prevent re-oxidation, argon gas was introduced and the reaction was carried out in an inert atmosphere. The recovery rates of tantalum powder were 100%, 120%, 150% and 200%, respectively. The recoveries of tantalum powder were 85%, 94%, and 97%, respectively, And 97%, respectively. Considering the above results, it is necessary to add a reducing agent of at least 150% of the equivalence ratio to obtain an appropriate tantalum recovery rate.

The tantalum powder recovered as described above was subjected to purity evaluation and XRD analysis according to the procedure described above, and the results are shown in Tables 7 and 2C below.

ingredient Ta Na 7 Mg 0 K 3 Ca 5 Fe 121 Al 6 P 0 Ti 0 Zr One Zn 51 Ba 0 Pb 0 Mn 63 Si 24 Sn 61 Hf 0 Nb 9 Ta 98 water(%) 99.9649

According to the above table, the tantalum powder recovered through the thermal reduction reaction of Ta ₂ O ₅ using Ca as a reducing agent has a purity of 99.96%. The purity of tantalum thus obtained was equivalent to the purity of tantalum recovered by the conventional method using sodium heat reduction. Further, according to FIG. 2C, a characteristic peak of a definite tantalum element (metal) was formed.

Thus, it has been confirmed through this example that tantalum in high purity can be effectively recovered from the tantalum-containing ores.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the appended claims.

Claims

a) a first leaching step of treating the tantalum-containing raw material using hydrochloric acid and nitric acid separately or in the form of a mixed acid;
b) leaching a tantalum-containing raw material through said first leaching step using a combination of (i) sulfuric acid, hydrochloric acid, nitric acid or a mixture thereof, and (ii) a fluoride of an alkali metal or an alkaline earth metal;
c) separating the leach from the second leaching step from the solid residue;
d) extracting the leachate separated from the solid residue in step c) with the phosphoric acid ester compound represented by the following general formula (1) as an extractant to obtain a tantalum-rich first organic phase and a tantalum-lean first aqueous solution ; And
e) separating the tantalum compound from the first organic phase;
A method for recovering tantalum comprising:
[Formula 1]

Here, R is hydrogen, an alkyl group having 2 to 7 carbon atoms, or an aryl group having 6 to 10 carbon atoms, and the three R's are the same or different.

a ') a first leaching step of treating the tantalum / niobium-containing feedstock using hydrochloric acid and nitric acid separately or in mixed acid form;
b ') that leaches the tantalum / niobium-containing feedstock through the first leaching step using a combination of (i) sulfuric acid, hydrochloric acid, nitric acid or a mixture thereof, and (ii) a fluoride of an alkali metal or an alkaline earth metal. Leaching step;
c ') separating the leach obtained from said second leaching step from the solid residue;
d ') The tantalum / niobium-rich first organic phase and the tantalum / niobium-rich organic phase are extracted by extraction with the phosphoric acid ester compound represented by the following general formula (1) as an extractant, Separating into a lean first aqueous phase; And
e ') separating the tantalum compound and the niobium compound from the first organic phase, respectively;
Recovering tantalum and niobium comprising:
[Formula 1]

The method of claim 1 or 2, wherein the tantalum-containing raw material or the tantalum / niobium-containing raw material is a mineral containing 30 to 90 wt% tantalum (based on oxide).

The method of claim 1 or 2, wherein the tantalum-containing raw material or the tantalum / niobium-containing raw material is a waste or residue containing 10 to 90% by weight of tantalum (on an element basis).

The method of claim 1 or 2, wherein the tantalum-containing raw material or the tantalum / niobium-containing raw material has a particle size of 150 to 300 mesh.

The recovery method according to claim 1 or 2, wherein the first leaching step is performed in one step using aqua regia.

The method of claim 1 or 2, wherein the second leaching step is performed using a combination of (i) sulfuric acid and (ii) sodium fluoride.

3. The recovery method according to claim 1 or 2, wherein the phosphoric acid ester compound is represented by the following general formula (2)
[Formula 2]

.

The recovery method according to claim 1 or 2, wherein the phosphoric acid ester compound is used in a diluted state in one or more kinds of diluents selected from paraffins C9 to C15 and kerosene.

3. The method of claim 2, wherein step e ') is performed through a two-stage back extraction process using two acids having different concentration ranges.

11. The method of claim 10, wherein step e '
The first organic phase is first back-extracted with an acid component at a concentration of 10-30 volume% selected from nitric acid, hydrochloric acid or a combination thereof to form a second tantalum-rich aqueous phase and a second niobium- ; And
Subjecting the second organic phase to a second back extraction using an acid component at a concentration of 30 to 50 volume% selected from nitric acid, hydrochloric acid or a combination thereof to form a niobium-rich third aqueous solution phase;
Wherein the recovery step comprises:

2. The recovery method according to claim 1, wherein a base component selected from ammonia, sodium hydroxide, potassium hydroxide or a combination thereof is added to an aqueous solution of the tantalum compound separated from the first organic phase to convert it to tantalum hydroxide.

3. The method according to claim 2, wherein a base component selected from ammonia, sodium hydroxide, potassium hydroxide or a combination thereof is added to each of the aqueous solution of the tantalum compound separated from the first organic phase and the aqueous solution of the niobium compound to form tantalum hydroxide and niobium hydroxide Wherein the recovery step is carried out.

14. The method of claim 12 or 13, further comprising the step of calcining each of the converted tantalum hydroxide, or tantalum hydroxide and niobium hydroxide, respectively, into tantalum oxide, or tantalum oxide and niobium oxide, respectively Way.

15. The method of claim 14, further comprising reducing the tantalum oxide, tantalum oxide, and niobium oxide to tantalum or tantalum and niobium, respectively, using an alkaline earth metal as a reducing agent.