JPS63235435A - Manufacture of metallic tantalum - Google Patents

Abstract

PURPOSE:To obtain good-quality metallic Ta in high yield, by extracting Ta with a organic solvent from a hydrofluoric-acid solution containing Ta and Nb, back- extracting Ta into a water system, adding NH3, etc., to the above water, dissolving the resulting precipitate with acid, bringing the above into contact with an organic solvent and then by bringing metallic Na into contact with the resulting Ta halide. CONSTITUTION:Hydrofluoric acid in which Ta, Nb, and metallic-impurity ions coexist or a mixed solution of hydrofluoric acid is brought into contact with an organic solvent A diluted with petroleum hydrocarbon, and Ta is selectively extracted. The organic solvent A is brought into contact with water, etc., so as to back-extract Ta into a water system and also to regenerate the organic solvent A. NH3, etc., are added to the water into which Ta is back-extracted to form a precipitate. H2SO4, etc., are added to the precipitate for dissolution so as to regulate H<+>-ion concentration, and then an organic solvent B selected from an ester group, etc., is brought into contact with the above so as to extract Ta ions in the form of a metal-halide complex. The organic solvent B is regenerated by means of heating, evaporation, etc. The resulting Ta halide is brought into contact with a simple substance (alloy) of metallic Na, Mg, Ca, Zn, and Pb so as to manufacture metallic Ta.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for manufacturing tantalum metal.

[Conventional technology/problems] Conventionally, tantalum metal often coexists with niobium, and Fe, Mn, and T are extracted using solvent extraction technology.
Crystals of 2TaFγ are created by separating impurities such as i, Sn, Sb, W, Si and/or AI into niobium, and contacting an aqueous solution containing KOH and KCI with an organic solvent from which tantalum ions are extracted. , this KiT・aFy
There is a method of reducing tantalum in a molten salt electrolytic bath to obtain tantalum metal.

In addition, the crystals of K and TaFt are converted into metal Na as shown in the following formula.
, A method of obtaining metallic tantalum by contacting with Mg has also been adopted.

KzTaFv+5Na47a+2KF+5NaFThese methods had the disadvantage that the reduction was costly. Furthermore, the molten salt electrolysis method has the disadvantage that it is not possible to obtain fine metallic tantalum, and it is not possible to produce tantalum with properties suitable for use in tantalum capacitors.

In addition, a widely adopted method for producing tantalum halides is to first produce tantalum metal and then contact it with halogen gas to obtain tantalum fluoride or chloride as shown in the following formula. There is.

T a+ 2,5 Cb” T aCbTa+ 2.
5 F 2 → TaF sIn this conventional method, a metal is first produced and then reacted with halogen gas to produce a halide, which is expensive because it uses expensive tantalum metal as the starting material. Moreover, it had the disadvantage of low yield. Also, to improve purity,
It was an energy-intensive manufacturing method, requiring the use of electron beams.

[Means for Solving the Problems] The method for producing tantalum metal of the present invention uses tantalum halide as a raw material, and involves producing tantalum halide using expensive metal tantalum as a starting material.
This method is different from previous methods and generally includes naturally occurring mineral resources such as tankulite, columbite, struberite virochlore, and tin slag, TaNbF.
A method for producing tantalum halide of high purity from tantalum-containing raw materials such as e-alloys or from industrial waste, such as scraps of tantalum capacitors and carbide rolls, /knops, etc., and using this as a raw material to produce tantalum metal. In addition to the conventional method, which uses solvent extraction technology to separate impurities and produce TaFt crystals, this is then used to create tantalum metal using metallic Na. This method consists of a step of producing tantalum halide by reacting tantalum metal as a raw material with halogen gas at high temperatures, which overcomes the disadvantages of a long process and a decrease in yield.

Therefore, the present invention provides a method for producing tantalum metal from hydrofluoric acid or a mixture of hydrofluoric acid and sulfuric acid mainly containing tantalum and niobium and in which one or more metal impurity ions coexist. One or more organic solvents selected from the group of ketones, neutral phosphoric acid esters, alkyl amines, and amides in an acid or a mixture of hydrofluoric acid and sulfuric acid, and petroleum-based carbonization. Contacting an organic solvent (A) diluted with hydrogen to preferentially extract tantalum in the hydrofluoric acid or a mixture of hydrofluoric acid and sulfuric acid,
Next, the tantalum extracted into the organic solvent (A) is back-extracted to the water or aqueous solution side by bringing the organic solvent (A) into contact with water or an aqueous solution containing NH, and HF or NH and HF. The first step of regenerating the organic solvent (A) with: (b) an aqueous solution containing the back-extracted tantalum ions, NH3 and NH,OH or KOH and K;
A second step of adding F to produce a precipitate containing tantalum, fluorine and NH4+ or tantalum, fluorine and NH4+; (c) tantalum-containing extract obtained in the first step or produced in the second step To the precipitate, H2SO,, HCI, H
After adding one or more acids selected from the group of I, HBr and HF, dissolving the precipitate into a solution and adjusting the H+ ion concentration, the ester group, the ether group,
By contacting one or more organic solvents (B) selected from the group consisting of ketones and alcohols, tantalum ions in the solution are converted into a metal halide complex and converted into an organic solvent (B). a third step of regenerating the organic solvent (B) and producing tantalum halide by extracting and then heating/evaporating or heating/distilling the organic solvent (B) under normal pressure or reduced pressure; and (d) The tantalum halide obtained in the third step,
To provide a method for producing tantalum metal, which comprises a fourth step of producing tantalum metal by contacting it with elemental metals Na, My, Ca, Zn, and Pb and/or an alloy mainly composed of these metals. .

[Function] Tantalum-containing raw materials such as columbite, struberite, pyrochlore, tin slag, TaNbFc alloy, or tantalum-containing industrial waste recovered by removing W from tantalum capacitor scrap and carbide roll scrap, etc. of solid matter in HF and HF+H2S
Mainly containing tantalum and niobium obtained by dissolving in O4 mixed acid and containing one or more metal impurity ions (e.g. Fe, Mn, i'i, Sn, Sb,
W, Ni, Co, Cu, K, Na, N H4
, Zn, Mo, Si, Af, Ca, V, Li, Th, etc.)
Hydrofluoric acid or a mixture of hydrofluoric acid and sulfuric acid in which
selected organic solvents from the group of ketones, the group of neutral phosphate esters, the group of alkylamines and the group of amides,
Next, tantalum in the hydrofluoric acid or a mixture of hydrofluoric acid and sulfuric acid is preferentially extracted by contacting with an organic solvent (A) diluted with petroleum-based hydrocarbon and separated from other metal ions;
If the concentration of Nb and other metal impurities extracted in the organic solvent (A) is unacceptable, the organic solvent (A) is brought into contact with water or an aqueous solution containing NH, and HF. Next, the organic solvent (
By bringing A) into contact with water or an aqueous solution containing NH, HF or K", and HF, the tantalum contained in the organic solvent (A) is back-extracted to the aqueous solution side and the organic solvent (A) is regenerated. The above steps constitute the first step of the present invention.

The second step of the present invention is to add NH and NH40H or KOH and KF to the aqueous solution containing back-extracted tantalum ions to form F− ions and NH, +
ion or F- ion and the formation of a precipitate containing ions: Reaction in the low pH region HTaFs + 3NtlJ-(Ni14)zTall
Fs↓Reaction in high pH region HTaFi + H3O+ 3NII3→(NII+)
iTaOFs L + Nl14F The third step of the method of the present invention is to add H2S O4, HCl and HF to the precipitate produced in the second step, an example of which is shown above, or to the tantalum ion-containing strip extract obtained in the first step. Add one or more acids selected from the group of esters, ethers, ketones and alcohols after dissolving the precipitate and adjusting the H+ ion concentration. One or more organic solvents selected from the group consisting of
) to extract the tantalum ions in the solvent as a metal halide complex into the organic solvent (B),
Next, the organic solvent (B) is heated and evaporated or heated and distilled under normal pressure or reduced pressure.
) and producing tantalum halide. Here, when tantalum ions are extracted into the organic solvent (B), if the concentration of Nb and other metal impurities in the organic solvent (B) is unacceptable, use the same method as the organic solvent (A) described above. A step in which Nb and other metal impurities are transferred to the aqueous phase by operation can be incorporated as appropriate.

In the fourth step of the present invention, the tantalum halide obtained in the third step is mixed with metals Na, Mg, Ca, Zn and Pb.
Tantalum metal is produced by contacting it with a simple substance and/or an alloy mainly composed of these.

HF or H containing tantalum and niobium and in which one or more metal impurity ions as mentioned above coexist
The mixed solution of F+H2SO4 is diluted with petroleum hydrocarbon and one or more organic solvents selected from the group of ketones, neutral phosphoric acid esters, alkyl amines and amides. When brought into contact with the organic solvent (A), the organic solvent (A) preferentially extracts tantalum ions in the HF or the mixture as shown in the following formula.

TiF4−+H”+ nOrg−+HTaFs −nO
The rg extraction/distribution ratio is T a > N b, and the extraction/distribution ratio of other metal ions is even smaller, being 10'''3 compared to the extraction/distribution ratio of Nb.

Since the extraction and distribution ratio of Nb approaches the extraction and distribution ratio of Ta as the H2SO4 concentration increases, it is important to adjust the H2SO and concentration when extracting Ta.

Next, by contacting the organic solvent (A) containing Ta with water or NH3) (F), Nb and other metals co-extracted with the organic solvent are Trace amounts of impurity metal ions can be selectively transferred from the organic phase to the aqueous phase.
This step is necessary when the concentration of Nb and other metal impurities therein is unacceptable, but it is usually necessary when using raw materials such as those mentioned above.

Unlike Ta, Nb and other metal impurities such as those mentioned above are extracted from the organic solvent (A) after removing the co-extractable substances from the organic phase, taking advantage of the property that the extraction distribution ratio changes greatly depending on the H and SO4 concentrations. The tantalum ions are back-extracted into the aqueous phase by contacting again with water or an aqueous solution containing NH3 and HF or NH3 and HF.

Even though the same aqueous solution is used in the co-extract washing operation and the Ta ion back-extraction operation, the free HF concentration on the aqueous phase side changes by increasing the flow rate ratio during contact or the mixing ratio of NH3. As a result, the extraction and distribution ratio of tantalum changes greatly.

tlTaF1norg+ 3NHJ-+ (NHn)z
TaFt+NtlnHF2+nOrgThe tantalum ions back-extracted into the aqueous phase produce a precipitate containing hydroxide-like N2)I4+ and F- as shown in the following equation by adding NH.

(Nun)zTaFt + 2NH3+ H20→side H
,), Ta0F5↓+2Nl (, If a large amount of water is added to dilute the HF concentration in the aqueous solution before adding FNH3, tantalum ions can be precipitated as hydroxide.

(Nf14)a aF7+5NH3+5Hzo-Ta(
OH)s↓+78H,F Next, add HF, HI, HBr, H2 to the tantalum strip extract and the tantalum-containing precipitate.
One or more acids selected from SO4 and HCl are added to dissolve the precipitate and adjust the H+ ion concentration.

(NH4) 2TaF 7 + Lso4-+ TaF
i-” (NH4) 2SO4〇F + II〇(N
! 14) zTaOFs 11F + 112SO<-T
aFs-+(N11.)2S04+l+20+8” Ta(Oll)s+611C1-TaC1g-+5
11zO+I+" One or more organic solvents selected from the group consisting of esters, ethers, ketones, and alcohols (B ) by contacting tantalum with halogen gunmetal EI as shown in the following formula.
It can be extracted as O-form.

TaF5−+ H”+ nOrg−>HTaFs ・n
orgTaCl, −+ H”+ norg−*HTa
In the Cli HnOrg formula, ○rg represents an oxygen-containing organic solvent selected from the groups of esters, ethers, ketones, and alcohols.

Next, if necessary, the organic solvent (B) is washed, and then
Extract the tantalum metal halide complex and recover the organic solvent (B) as shown in the following formula by heating and evaporating or heating and distilling the organic solvent (B) containing it under normal pressure or reduced pressure. Tantalum halides can be made.

Heating HTaF6- norg ---+TaF5+ IIF
↑+nOrg↑ Also, before heating/evaporating or heating/distilling, remove physically mixed water,
By drying and removing the extracted H2O, T
The amount of oxygen contained in a F s and TaCl5 can be reduced to an extremely small amount.

Depending on the heating/evaporation and heating/distillation temperatures, the inside of the apparatus can be filled with an inert gas for the purpose of preventing oxidation of the oxygen-containing organic solvent (B) and preventing oxidation of the generated halide. .

The tantalum halide produced as described above is converted into metal Na, My, Ca, Zn and pb as shown in the following formula.
Tantalum metal can be produced by bringing it into contact with a single element selected from the group consisting of: and/or an alloy mainly composed of these elements.

TaC5+5Nm-+Ta+5NaF TaC1s+2.5MfI-Ta+2.5MgCj! z
TaFs+2.5Ca-+Ta+2.5CaF.

TaCl5+ 2.5 Zn-Ta+ 2.5 ZnC
1zTaFs+2.5Pb-+Ta+2.5PbFzThe above-mentioned metals alone or alloys used as reducing agents can be used in gaseous, liquid and red-hot states;
Further, tantalum halide is also subjected to the reaction in gaseous or liquid form.

The reduction reaction occurs at a temperature of 250° C. or higher, and is carried out in an atmosphere of an inert gas such as Ar in order to suppress the formation of oxides. Further, a reducing gas may be mixed with an inert gas.

Tantalum, Nb, Fe, Mn, which are the starting materials in the present invention
, Ti, Sn, Sb, Wl, Ni, Co, Cu, K, N
a, N H4, Zn, Mo, Si, AZ, Ca, V
An aqueous solution in which one or more types of metal impurity ions such as , Li, and Th coexist is prepared as follows.

-m, tanlite, columbite, struberite,
By dissolving tantalum-containing raw materials such as pyrochlore, tin slag, and TaNbFe alloys, or electronic material waste such as tantalum capacitor scraps and defective products, with hydrofluoric acid alone or mixed acids such as hydrofluoric acid and sulfuric acid or hydrofluoric acid and nitric acid. can be built.

The organic solvent (A>) used in the present invention is selected from the following group:

■ Ketone group: R・>c=.

(In the formula, R and R' represent an alkyl group or an aryl group, and those having 3 to 18 carbon atoms are used.) Ketones, methyl isobutyl ketone, cyclohexanone, methyl propyl ketone and similar Ketones.

(2) Neutral phosphoric acid ester: (wherein, R represents an alkyl group having 4 to 18 carbon atoms).

■ Alkylamine group: Primary to primary represented by RNH-1R2NH- and R,NH- (in the formula, R represents an alkyl group, and those having 4 to 24 carbon atoms are used). Tertiary amine.

■Amide group: (In the formula, R represents an alkyl group and has 4 to 2 carbon atoms.
5 are used).

The diluent for the organic solvent (A) used in the method of the present invention is a petroleum hydrocarbon, and both aromatic and aliphatic diluents can be used. Of course, mixtures of these can also be used. The organic solvent (A), that is, the extractant, is selected from the above groups, and may be used alone or in combination of two or more, but the mixing ratio of these depends on the properties of the target aqueous solution and the types of impurities. It can be determined by the proportion of their coexistence.

The same applies to the extractant concentration, which can be adjusted to -m from 2 to 100% (volume ratio).

The organic solvent (B) used in the present invention is selected from the following group.

■ Ketone group: R・>c=.

Ketone, methyl isobutyl ketone, cyclohexanone, methyl propyl ketone, methyl cyclohexanone (wherein R and R' represent an alkyl group or an aryl group, and those having 2 to 18 carbon atoms are used) and similar ketones.

■Amide group: (In the formula, R represents an alkyl group and has 2 to 18 carbon atoms.
).

■Ester group: Can be selected from phosphate esters and acetate esters.

■Ether group: Can be selected from aliphatic single ether, aliphatic mixed ether, aliphatic unsaturated ether and aromatic ether, diisoamyl ether, diethyl ether, diisopropyl ether, dichloroethyl ether and these It contains ether in a similar form.

■Alcohol group: Various types with 4 to 22 carbon atoms (normal, secondary, tertiary)
Alcohol can be used.

Examples of the solvent for washing the solid by-product ammonium halide used in the present invention include the following.

■For petroleum hydrocarbons, the boiling point of petroleum ether, petroleum benzene, hexon, etc. is below 100℃, and the surface tension is 20℃.
Includes 30 dynes/C ring or less at °C.

■For aromatic hydrocarbons, benzene etc. are used.

The desiccant used in the present invention is used to remove and dry H2O extracted together with the water and tantalum halogenated complex physically mixed in the organic solvent (B). Molecular sieves such as anhydrous calcium chloride, anhydrous magnesium sulfate, anhydrous magnesium chloride, anhydrous potassium chloride, activated alumina, magnesium perchlorate, phosphorus pentoxide, anhydrous potassium carbonate, barium oxide, and synthetic zeolites can be used.

The drying step, which is an optional step of the present invention, removes the water physically mixed in the organic solvent (B) and H2O extracted together with the tantalum halide complex to form the final product tantalum halide. It is a process for reducing the oxygen content of However, some organic solvents (
The water present in B) can also be removed by heating and evaporation at normal pressure or reduced pressure, or by a heating and distillation process.

In addition, since this drying process brings the organic solvent (B) into contact with the above-mentioned substances, some impurities may be mixed into the organic solvent (B) instead of removing water. The treatment can be carried out as necessary depending on the desired oxygen content, impurity content, etc. in the tantalum halide product.

The inert gas used in the present invention is N2 gas or Ar gas, and is used to prevent oxidation of the organic solvent (B) during heating and evaporation or heat distillation of the organic solvent (B), and to prevent the halogen of tantalum produced. It can be used to prevent chemical substances from deteriorating.

Furthermore, when producing tantalum metal by bringing tantalum halide into contact with the metals Na, Mg, Ca, Zn, and Pb and/or alloys mainly composed of these metals at a high temperature of 250°C or higher, Ar gas can also be used to drive out gaseous reducing agent or gaseous tantalum halide to the reactor.

In order to prevent air from entering the reduction equipment,
It is also possible to introduce R gas alone or a mixed gas of Ar gas and hydrogen gas.

The method of the present invention will be explained below based on the accompanying drawings, but it should be understood that the present invention is not limited thereto.

The flow sheet in FIG. 1 is a diagram showing the basic type of operation of the present invention, in which hydrofluoric acid alone or hydrofluoric acid and sulfuric acid containing mainly Ta and Nb and one or more metal impurity ions are used. The mixture is led to the tantalum extraction step (A) and brought into contact with the organic solvent (A) to extract the tantalum in the hydrofluoric acid or mixture as a fluoride complex.

In the organic solvent (A) that extracts and contains tantalum, Nb
and one or more metal impurities such as Fe, Mn,
Ti, Sn, Sb, W, Ni, Co, Cu, K, Na
, N H4, Zn, Mo, Si, AI, Ca, V,
Trace amounts of metal ions such as Li and Th are also extracted, and if these extraction amounts are unacceptable, a cleaning step (B) is conducted to selectively clean these metal impurities, and water or N Hs is introduced.
The impurity metal ions are transferred from the organic phase to the aqueous phase by contacting with the mixture (a) of
Aqueous solution containing 3 and HF or ni+ and KF (b)
The first step of the method of the present invention is to transfer the tantalum fluoride complex from the organic phase to the aqueous phase by contacting with Become.

In the second step of the method of the present invention, the tantalum transferred into the aqueous phase is led to the neutralization/sifting step (D), and NH, gas and NH,
By adding ○H or KOH and KF (c), a precipitate containing tantalum, NH, + and HF is obtained.

Next, the strip extract containing the tantalum fluoride complex obtained in the first step and the NH3 and I-
Dissolution/H+ ion concentration adjustment step (E) of dissolving the tantalum precipitate containing IF and adjusting the H+ ion concentration
In, H, SO,, HBr, HI, HCI and HF
In the extraction step (F) of extracting the tantalum halogenated complex after adding one or more a(d) selected from the following, an ether group, a ketone group, an amide group, an ester By bringing the tantalum halogenated complex in the solution into contact with an organic solvent (B) consisting of one or more extractants selected from the group consisting of ) is extracted and contained in

Next, the organic solvent is heated and evaporated or heated and distilled (G
) and heat/evaporate or heat/evaporate under normal pressure or reduced pressure by introducing N2, Ar gas (e), etc. as necessary.
The method of the present invention comprises zero or more steps in which the organic solvent (B) can be regenerated by distillation and tantalum halides (H) such as tantalum chloride complexes and tantalum fluoride complexes can be produced quickly. This is the third step.

The fourth step of the present invention is to manufacture tantalum metal using the tantalum halide (H) produced in the third step of the present invention as a raw material.

In the reduction reaction step (K) of tantalum halide (H), metal N is added in the presence of an inert gas (g) if necessary.
Metal tantalum (L) is produced by contacting it with a reducing agent that is a simple substance of a, Mg, Ca, Zn, and Pb or an alloy mainly composed of these.

The flow sheet in Figure 2 is the same as the flow sheet in Figure 1 as a method for producing tantalum metal, but in the third step, an extraction step (
Organic solvent (B) that extracts and contains the tantalum released from F)
) is brought into contact with a desiccant (H).
J) is incorporated.

[Example] The present invention will be further explained with reference to Examples below.

The Ta-containing liquid used in the following tests was obtained by mixing tankite and columbite and dissolving the mixture in a mixed acid of HF and H2SO.

The composition of the obtained Ta-containing liquid is listed in Table 1 below.

Second knee large (unit g/1) Ta205 49.6N bzo
s 80 , 1Fe
8.4Mn
6.1Ti
1.8Sn 0.6S
b O,IW
0.04Si
4.1A1
1. lH2SO4152, O HF 120.8 Using the Ta-containing liquid mentioned above, using the same extraction conditions of 0/A = 1/1 and shaking time of 5 minutes, use the four types of extractants shown in Table 2. The extraction distribution ratio was calculated when The results obtained are listed in Table 2 below.

The extraction distribution ratio (DME) is calculated by the following formula.

Note that as the concentration of H2SO decreases, the extraction and distribution ratio of Nb2O5 decreases. Furthermore, as the TazOs concentration decreases, the extraction and distribution ratio of N b 20 s increases.

A cleaning test was conducted in which Nb2O was selectively removed by contacting the organic solvent containing the extracted metal with water or a solution containing 0.3 mol/ρNH4F as shown in Table 2. . The results are shown in Table 3.

In the actual device, since the cleaning operation is carried out in multiple stages of self-flow contact, impurities such as Nb2O5, Fe, Mn, and Ti, which have a small extraction/distribution ratio, are transferred to the aqueous phase, and only T a 20 s remains in the organic phase.

Ta ・ Bi ゛ ・ ・Next, 2.
A test was conducted in which Ta205 from the organic phase was back-extracted by contacting a 0 mol/INH,F aqueous solution with the organic phase. The results are shown in Table 4.

The obtained precipitate was dried and analyzed, and the obtained results are shown in Table 5 below. If the analysis results in Table 5 do not satisfy the desired product purity, redissolve the product. The purity of Ta can be improved by repeating the operations shown in Tables 2 and 3 one or more times.

1-5-1 Todoroki (unit: % double weight) Next, H2SO4 was added to the Ta back extract, and [-(C1 and H, SO,
A solution having the composition shown in the table was prepared and used as a raw material for the tantalum chloride and fluoride production test in the third step.

1-People (g/l)? B For W extraction, 1
00% dibutyl ether and 100% methyl isobutyl ketone were used, 2O/A=115, and shaking time was 5 minutes. The extraction results are shown in Table 7.

[-min (g/l) Organic solvent used: methyl isobutyl ketone TaJs
NbaOs IIF HCl1lzSO-Organic phase 84 <0.001 43.5 <0.1
<0.1 aqueous phase 103 0.06 92.3 --
91.7 Organic solvent used Nidibutyl ether Taxes NbtOs +lF flci'
H2SO4 organic phase 80.7 <0.001 1.
6 57.8 <0.1 Water phase 137.6 0.00
4 9.8156.2110.4Fe, Mn, Ti%S
n, Sb, W, Si, A1. The extracted amounts of Ni and Zn ions are both O,001g/I! It was below. In the unlikely event that
If a large amount of these impurities are extracted, a washing step is required.

In the above extraction test, all impurity metal ion concentrations other than TJL were O,0O1y/j! If impurity ions other than Ta ions are extracted due to a mistake, although the amount shown below is small, contact them with water and a solution containing NH4+ and HF in the same way as in the first cleaning step (B). Therefore, it is necessary to perform an operation in which impurity metal ions other than Ta are selectively transferred to the aqueous phase, and only Ta ions remain in the organic solvent.

DttL・ or ＾・ After putting Ar gas into the experimental vessel and expelling the atmosphere, heating/evaporation or heating/distillation tests were performed. The results obtained are shown in Table 8.

Summary 1 A reduction test was conducted using the tantalum halide prepared as described above. The results obtained are listed in Table 9.

[Effects of the invention: If tantalum metal is produced by the method of the present invention, the process will be simplified compared to conventional methods, there will be no restrictions on raw materials, and high-quality tantalum metal can be produced using an energy-saving manufacturing method. .

[Brief explanation of drawings]

FIG. 1 is a flow sheet showing a basic type of operation of the present invention, and FIG. 2 is a flow sheet showing an operation in which a drying step is added to the basic type operation described in FIG. In the figure: A...Extraction process; B...Washing process; C...Reverse extraction process; D...Neutralization/p-filtration process; E...Dissolution/H+ ion concentration adjustment process; F. ...Extraction process; G...Heating/evaporation or heating/distillation process; H...Tantalum halide; J...Drying process; K...Reduction reaction process; L...Metal tantalum; ( (b) Water or a mixed solution of NH3 and HF; (b) Water or an aqueous solution containing NH, and HF or Ni2 and KF; (c) NHs gas and NH, OH or KOH and HF; (d) IPl or two or more acids selected from H2SO4, HBr, HI, HCl and HF; (
e) N2. Ar gas; (f) Reducing agent; (G) Inert gas; (H) Drying agent.

Claims (1)

[Claims] 1. A method for producing tantalum metal from hydrofluoric acid or a mixture of hydrofluoric acid and sulfuric acid containing mainly tantalum and niobium and in which one or more metal impurity ions coexist, comprising: (a ) one or more organic solvents selected from the group of ketones, the group of neutral phosphoric acid esters, the group of alkyl amines, and the group of amides, in the hydrofluoric acid or the mixture of hydrofluoric acid and sulfuric acid; Organic solvent diluted with petroleum hydrocarbon (
A) to preferentially extract tantalum in the hydrofluoric acid or a mixture of hydrofluoric acid and sulfuric acid, and then contact with an organic solvent (A
) with water or an aqueous solution containing NH_3 and HF or K^+ and HF.
) A first step of back-extracting the tantalum extracted into the water or aqueous solution side and regenerating the organic solvent (A); (b
) NH to the aqueous solution containing the back-extracted tantalum ions.
Add _3 and NH_4OH or KOH and KF,
A second step of producing a precipitate containing tantalum, fluorine and NH_4^+ or tantalum, fluorine and K^+; (c) a tantalum-containing extract obtained in the first step or a precipitate produced in the second step; , H_2SO_4, HCl
, HI, HBr, and HF are added to dissolve the precipitate to form a solution.
After adjusting the ion concentration, the above-mentioned The tantalum ions in the solution are extracted as metal halide complexes into an organic solvent (B), and then the organic solvent (B) is heated and evaporated or heated and distilled at normal pressure or reduced pressure to form an organic solvent (B). ) a third step of regenerating tantalum halide and producing a tantalum halide; and (d) a tantalum halide obtained in the third step,
A method for producing tantalum metal, comprising a fourth step of producing tantalum metal by contacting with elemental metals Na, Mg, Ca, Zn, and Pb and/or an alloy mainly composed of these metals. 2. Add hydrofluoric acid and/or sulfuric acid to the tantalum-containing back extract obtained in the first step or the precipitate produced in the second step to dissolve the precipitate and adjust the concentration of H^+ ions. 2. The manufacturing method according to claim 1, wherein the purity of the tantalum halide obtained is improved by repeating the operations of the first step and the second step one or more times. 3. Extract the tantalum halide complex obtained in the third step and bring the organic solvent (B) containing it into contact with a drying agent to extract the physically contained water and the extracted and contained H_2O The manufacturing method according to claim 1, which comprises removing and drying. 4. Depending on the concentration of Nb ions or one or more metal impurity ions, the organic solvent (A) from which tantalum was extracted is brought into contact with water or an aqueous solution containing NH_3 and HF to form an organic solvent (A). The manufacturing method according to claim 1, wherein the one or more metal impurity ions co-extracted in A) are selectively transferred from the organic phase to the aqueous phase, and then back-extracted. 5. Depending on the concentration of Nb ions or one or more metal impurity ions, the organic solvent (B) from which tantalum was extracted is brought into contact with water or an aqueous solution containing NH_3 and HF to extract the organic solvent (B). B) The one or more metal impurity ions co-extracted in B) are selectively transferred from the organic phase to the aqueous phase, and then heated and evaporated or heated and distilled. Manufacturing method described.