JPH02212318A - Separation of niobium and tantalum from each other - Google Patents

Abstract

PURPOSE:To preferentially separate and elute Nb and to easily separate Nb and Ta from each other with good efficiency by using a mixture solution of sulfuric acid and fluoric acid as a separating liquid in an ion exchange method by use of fiber ion-exchanger. CONSTITUTION:A column is packed, for example, with fibers produced from PVA by dry spinning and treated to have ion-exchange function, such as anion- exchange fiber and preferably strong anion exchange fiber (IEF-SA). A weak acidity mixture solution of Nb and Ta is introduced into the column to make the mixture material of Nb and Ta adsorbed onto the IEF-SA. Then a mixture solution of sulfuric acid and fluoric acid as a separating liquid is introduced into the IEF-SA to preferentially elute Nb. Then the IEF-SA after eluting Nb is treated, for example, burnt at high temp. to obtain Ta. By this method, the rate of ion exchange reaction and the flowing rate of liquids can be raised.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for separating niobium (Nb) and tantalum (Ta). More specifically, after adsorbing a mixed raw material of Nb and T& on a strong anion-exchanging fiber (hereinafter abbreviated as IEF-8^), Nb can be preferentially separated and obtained by using a specific separation liquid. The present invention relates to a method for mutually separating Nb and Ta.

[Conventional technology]

Nb and Ta have recently become metals that occupy important positions in many fields of application. The metal is heat resistant.

Due to its high chemical resistance, it is attracting attention as a raw material for producing materials such as metals, superconducting materials, electronic equipment materials, engineering materials, and medical materials.

However, in most cases, Nb and Ta coexist in raw ores, etc., and the two metals have extremely similar chemical properties, so until now, much effort has been devoted to separating the two metals. However, at present, no easy and effective means of separation has been found.

The main method for mutual separation of Nb and Ta is solvent extraction method 1.
A fractional crystallization method, a partial ion exchange method, etc. are known. However, the solvent extraction method requires complicated processing steps and
The use of organic solvents poses major problems in terms of safety, economy, etc., while fractional crystallization requires the complexity of repeated fractionation operations based on solubility differences and is difficult to obtain high-purity products. There are drawbacks that I don't like. Furthermore, in the ion exchange method using ion exchange resins, the separation efficiency is low in the case of macroporous resins (it is impossible to separate Nb and Ta), and in the case of fine particle resins, the separation efficiency is low on an analytical scale. However, there were serious problems in industrial implementation, such as a large pressure loss during liquid passage, and therefore, a high productivity could not be obtained because the liquid passage rate could not be increased.

In recent years, due to the progress of research on fibrous ion exchangers,
Various types of separation and purification techniques using ion exchange methods have made great progress, and the mutual separation of metals, which was previously considered difficult, can now be carried out relatively easily.

[Problem that the invention seeks to solve]

In view of the current situation, the present invention was arrived at as a result of autopsy research on a method for easily and efficiently separating Nb and Taf from each other using a high-performance fibrous ion exchanger.

[Means and effects for solving the problems] The present invention provides a fibrous ion exchanger having anion exchange groups with Nb and Ta.
After adsorbing the mixed raw materials, JNb and Ta are absorbed by the separated liquid.
This is a method for separating Nb and Ta, which is characterized in that a mixed solution of sulfuric acid and hydrofluoric acid is used as a separation liquid to preferentially separate and elute Nbt.

The present invention will be explained in detail below.

As the fibrous ion exchanger used in the present invention, it is preferable to use a fiber made from polyvinyl alcohol (hereinafter abbreviated as PVA) by dry spinning and imparted with ion exchange ability. The reason is that compared to known resinous ion exchangers, fibrous ion exchangers (hereinafter referred to as IEF)
) has a large surface area, the ion exchange reaction rate is extremely fast, and the pressure loss during liquid passage is small, making it possible to increase the flow rate extremely high.

The type of functional group that imparts important properties to the ion exchange reaction must be an anion, and preferably a strong anion. This is because when Nb and Ta are dissociated and ionized in an aqueous solution, they do not form simple cations but form complex anions, so it is necessary to adsorb these metal complex anions onto the carrier through an ion exchange reaction. be.

As the anionic group 11, any known one may be used.

Among the types of strong anion groups, so-called 1m and type II amines in alkali are exemplified, and strong anion/exchange fibers (hereinafter abbreviated as IEF-8A) can be easily produced from PVA fibers and the like.

IEF-8A is long fibrous! It can be used in any desired form, such as a woven fabric, a non-woven fabric, or a cut thread after cutting as appropriate.

When the LEF-8A is used to separate Nb and Ta, it can be used in the force 2A type, PA, Te type, and other methods.
It may be selected as appropriate depending on the purpose of use.

When a mixed raw material of Nb and Ta is adsorbed onto IEF-8A, the mixed raw material is made into a low acid aqueous solution by using a mineral acid such as hydrochloric acid. Nb and Ta in a low acidic aqueous solution do not become cations but dissolve in the form of complex anions.

When using raw materials containing metals other than Nb and Ta, most of the alkali metals or alkaline earth metals are dissolved in an acidic aqueous solution and have no adsorption ability for IEP-8A K, so it is easy to do so. It can be separated into However, the prize JJ! For those forming complex anions with Group 4 and some metals, it is preferable to remove mixed impurities in advance by appropriate means such as alkali-melted 9-fraction crystallization, solvent extraction, etc.

In the adsorption operation, IEF-
A patch method is performed by dipping 8A, a column method is performed by flowing an acidic aqueous solution containing KNb and Ta into a column filled with Ia:F-8A, or other methods. are mixed and adsorbed. Next, in the case of a patch type, Nb is removed by filtration after adsorption treatment.
By introducing IEP-8A mixed and adsorbed with Ta into the separation liquid, or in the case of a column type, by subsequently flowing the separation liquid, it is possible to selectively elute and separate only Nb.

Effect 1 of the present invention! - In order to maximize its effectiveness, it is a good idea to adopt the five Kara type, and the flow rate of separated liquid during adsorption operation and separation acquisition can be set to a high flow rate of -20tx/by or less. It is. This is not possible with the currently commercially available ion exchange 4M in terms of separation efficiency, pressure loss, etc. Furthermore, the advantage of the 2A force type is that only the hoof force is required, which is different from the chromatographic separation method, which requires a WrgJ separation force of 2M, and is of no industrial significance. It is something.

There are many inorganic acids such as salt modified, sulfuric acid, nitric tR, and hydrofluoric acid as separation liquids that randomly leached out the excitation and Ta adsorbed on IEF-8A, but in order to elute and separate Nbt preferentially, A mixed solution of sulfuric acid and hydrofluoric acid is suitable as the separation liquid. The processing options at this time are not particularly limited.

Although it is not clear why a mixed solution of sulfuric acid and hydrofluoric acid selectively releases only Nb into the separated bath, the knowledge from experimental results suggests that in addition to the metal elution effect of sulfuric acid, hydrofluoric acid also has TaO#j
l! Since a blocking effect is observed, when looking at the relationship between Nb and the mixed solution or Ta and the mixed solution in IEF-8A, it is possible that the interaction of the former is p larger than that of the latter. Probably.

The higher the concentration of sulfuric acid, the greater the metal elution effect, but from the point of view of the acid resistance of IEF-8A, the upper limit is 5 moss, sy
/l.

Further, the lower limit is 0.01 mol/l, preferably 3 to 0.05 mol/l, from the viewpoint of metal elution effect. On the other hand, the upper limit of acid is 1 mol/j from the viewpoint of corrosivity, operability, and acid resistance of IEIP-8 people, and the lower limit is a001% #/j-e acid from the viewpoint of Ta bath tii inhibiting effect. , preferably in the range of 0.5 to 0.01 mol/j.

Thus, only Ta remains in IEF-8A after Nb is eluted and separated. To obtain the residual Ta, there are a method of incinerating the IEF-8A at a high temperature to produce tantalum oxide, a method of using a second separated liquid, and the like.

According to the latter, Ta f: can be easily obtained by elution from IEF-8A by using hydrochloric acid or a mixed solution of hydrochloric acid and citric acid, and IEF-8A can be used repeatedly. It is also economically advantageous.

〔effect〕

Conventionally, it has been difficult to separate N11i, Nb and Ta.
An easy and efficient method is to use IKF-8A f:(l!
This became possible by preferentially dissolving and separating Nb using a specific separation liquid. This has great industrial significance and contributes to improved fineness and cost reduction in the production of raw materials for high-temperature heat-resistant materials, superconducting materials, acid-resistant materials - medical materials, electronic nine-dimensional materials, etc. .

EXAMPLES The effects of the present invention will be explained in more detail with reference to Examples below.

Fruitful example 1: PVA mixed with 30% of high polymerization degree polyethyleneimine
From the stock solution, long fibers of 100R Neal 30 filament were obtained by dry spinning, and after being bundled, the fibers were cut into a length of L7. This material was cross-linked with ethylene glycol noglycinol ether and then formalized. Next, a quaternization treatment was performed with 3-cool-2-hydroxypropyltrimethylammonium chloride to obtain L5 Director's IEF-8.
A was created. The neutral salt S capacity of this IIF-8A is
It was 1.9 (per millimeter/!i fiber).

Net EF-+3A, 5Ji' and 1A5mm
(inner diameter) of glass force 5K 9.5 tag height.

0.143!1ONb2O5, or 0.122 l O
Ta205 was weighed according to its t-form, and after heating and melting with each 51io potassium hydrogen sulfate at 700°C in a Lutsu manufactured by Km, 3
--Shi.

Nb or T is dissolved by heating in an ammonium oxalate solution.
This was used as a single dissolved stock solution of a.

Mixed metal solution stock solution for adsorption is Nb:T.
a-1:1 (molar ratio), packed into a column, weighed out in an amount equivalent to 90% of the total neutral salt decomposition capacity of IEF-19A, and then diluted with hydrochloric acid to pH 1-2. It was made in v4.

! 1I4I prepared mixed stock solution was passed through a column packed with IEF-8A at room temperature at a linear velocity of 10.5 m/hr,
The entire amount of Nb and Th was adsorbed and washed with water.

Next, as the first separated liquid, 0.1 mol sulfuric acid and α
A mixed solution of 0.01 molar hydrofluoric acid at room temperature, -rate lα5m/
The eluate was collected into a 40 m 72 comb tube. The fractionated eluate was collected 1011117, and the test solution was 1011,30% of 20% sub-WtfIR soda.
*O via g a -A, 7t10 with 3rd no.
Place in an ON beaker and adjust the pH to a range of 6.5 to 7.5.

If Nb is present, the test solution will turn yellow. After carrying out such an operation and confirming that the test solution did not develop color, the passage of the 1st IllI solution was stopped (the number of fractions was 58) and the test solution was washed with water.

Subsequently, as a second separated liquid, 3 molar hydrochloric acid and 0.
5 molar oxalic acid mixed solution at room temperature, linear speed 10.5 m/
The eluate was fractionated into a 4031/flux tube. Collect 101j of the fractionated good port liquid, and test the sample solution with 0.5% citric acid, 30% pyrogallol, IQm, and 30% pyrogallol.
pH 1.8~
Set it to λO. If Ta is present, a yellow color develops. After carrying out these operations and confirming that the test solution did not develop color, the passage of the second separation solution was stopped (the number of 72 pumps was 66).

For each fractionated solution, Nb is determined according to JIS-G1237 @ (1
981) and Ta were analyzed according to the JIS-G1236 method (1981), and the results obtained are shown in FIG.

As is clear from Fig. 1, neither Ta mixed into the Nb region nor Nb mixed into the Ta region was observed, and Nb and T
It can be seen that a is beautifully separated.

Example 2 A long fiber of 2007'=-80 filament was obtained from a PVA stock solution by a dry spinning method. The entire mixture was converted into bromoacetal with promacetaldehyde noethyl acetal, and then treated with ethylene cyanogen.

After a long time, quaternization treatment was performed with trimethylamine to obtain I
EF-8A was produced. The neutral salt decomposition valley violet of this IEF-SA was 1.8 (f/I fiber per millimeter).

The IEF-SA with Net, 5p was weighed into an Erlenmeyer flask as a small raceme.

Using the single crude solution of Nb and Ta prepared in Example 1, they were mixed in a Nb:Ta=1:1 (molar ratio),
IJi: F'-8A was weighed to give a solution equivalent to 50% of the total neutral salt decomposition yield, the bath ratio was adjusted to 1:100, and further adjusted to -(-2) with hydrochloric acid. The mixture was poured into an Erlenmeyer flask containing 8A.

After 4 hours of treatment at room temperature with occasional stirring, the Nb
and IEF-8A adsorbed on Ta 1 were washed with water. At this time, no Nb or TaId was detected in the filtrate, and fc
6 Next, IEF-8A which adsorbs a mixture of Nb and Ta
In the Erlenmeyer flask, add 0.5 mol sulfuric acid and α1
Add a mixed bath solution containing morphine (bath ratio: 100),
After treatment at room temperature for 4 hours with occasional stirring, filter and separate.

When the Nb content was measured for the filtrate, the amount of adsorption was 9.
A5% was shown and Ta was not detected.

Next, a mixed solution of 4 molar hydrochloric acid and 0.75 molar water was added to the Erlenmeyer flask containing I'EF-8A in which Nb had been separated and removed (bath ratio 1:100), and the mixture was heated at room temperature.
After treatment for 4 hours with occasional stirring, the mixture was filtered.

When the filtrate was measured in a Ta-containing tube, the amount of adsorption was 9.
It was 7.8%.

Comparative Example 1 The procedure was carried out in exactly the same manner as in Example 1, except that commercially available strong anionic/exchanged soybean fat (particle size 200-400 mm) was used in place of IEF-8A. .

As a result, the contamination of Ta into Nb@ltl and the Ta
Contamination of Nb into the brewed slag region was observed, and it was not possible to selectively separate and obtain only Nb.

Comparative Example 2 The same procedure as in Example 2 was carried out except that a strong anion exchange resin (the same as that used in Comparative Example 1) was used instead of ZEF-5A.

As a result, Nb and Ta were adsorbed on the strong anion crosslinking resin, but it was difficult to selectively separate and obtain only Nb.
S%.

Figure 1 shows that after IEF-8A is packed into a column, a mixed raw material of Nb and T1 is deposited on the column as the first separated liquid.
After eluting and separating Nb by passing a mixed solution of 0.1 mol sulfuric acid, 0.01 mol sulfuric acid, and 0.01 mol sulfuric acid in l, as a second separated liquid,
A bath release curve showing the results when T1 was eluted by passing a mixed solution of 3 molar hydrochloric acid and 0.5 molar oxalic acid through the bath.

No. Haruma C-ma Clear weather (hr)

Claims (3)

[Claims] (1) A method in which a mixed raw material of niobium and tantalum is adsorbed onto a fibrous ion exchanger having an anion exchange group, and then niobium and tantalum are separated from each other using a separation liquid, in which a mixed solution of sulfuric acid and hydrofluoric acid is used as the separation liquid. A method for mutually separating niobium and tantalum, characterized in that niobium is preferentially separated and eluted using the niobium. (2) The method for mutually separating niobium and tantalum according to claim 1, wherein the anion exchange group is a strong anion group. (3) The method for mutually separating niobium and tantalum according to claim 1, wherein the separation liquid is a mixed solution of 5 to 0.01 moles of sulfuric acid and 1 to 0.001 moles of hydrofluoric acid per liter.