JPH02144101A - Distillatory refining method - Google Patents

Abstract

PURPOSE:To obtain a high-purity reagent free of metallic impurities such as nitric acid, hydrochloric acid, and hydrofluoric acid by refining after previously adding one or both of sulfuric acid and phosphoric acid to a soln. material. CONSTITUTION:The injection part 6 and discharge part 7 for a soln. material 2 are connected to the side wall of a closed vessel 1 contg. the soln. material 2 in the vicinity of its bottom. A means 3 for heating the material 2 in the vessel 1 and a cooling vessel 8 with the lower part tapered are also furnished. In addition, a collecting duct 13 with the upper end arranged close to the bottom of the cooling vessel 8 and the lower end piercing the bottom of the vessel 1 and extending downward and a container 15 for collecting the liq. distillate into which the lower end of the duct 13 is inserted are provided. Filter plates 21a and 21b are arranged in the vessel 1 positioned above the liq. surface of the material 2, and shielding plates 22 and 23 are provided respectively at the lower part of the cooling vessel 8, the inner surface part of the vessel 1 positioned at the liq. surface of the material 2, and the outer surface part of the duct 13. One or both of sulfuric acid and phosphoric acid are previously added to the material 2.

Description

Detailed Description of the Invention [Object of the Invention] (Industrial Application Field) The present invention relates to a distillation purification method for purifying a solution-like reagent such as an acid.

(Prior Art) With the progress of the electronics industry, the atomic industry, and various materials industries, the demand for highly purified materials is increasing.

Furthermore, in material evaluation technology, there is a desire to improve ultratrace component analysis technology. The recent rapid development of analytical equipment has made it possible to analyze ultratrace components in wet chemical analysis, but due to the problem of so-called contamination, in which target components are mixed in with the reagents used for analysis, blank values for analysis are In some cases, it was not always possible to analyze ultra-quantity components with high accuracy. Currently, high-purity reagents for use in the electronics industry or for measuring hazardous metals are commercially available, but they are not of sufficient purity for use in ultratrace component analysis, and require further purification depending on the intended use.

For this reason, a distillation apparatus (Japanese Unexamined Patent Application Publication No. 80-183002) for preparing high-purity reagents has been known. This distillation apparatus includes a Buddhist tank containing a liquid substance to be made into Buddha, a heater disposed at the bottom of the Buddha tank, and a cooling tank with a sloped bottom disposed at the top of the Buddha tank. , and a conduit inserted through the top and bottom of the bath to guide the liquid condensed and dripped in the cooling tank to a collection bottle. However, in such a distillation apparatus, when the solution material contained in the distillation tank is heated to boiling with a heater, a mist containing metal impurities is generated, and the mist also adheres to the cooling tank and together with the condensate of the vapor of the solution material. Since the liquid is introduced into the collection bottle through a conduit, there was a problem in that it was not possible to purify the liquid to a high degree of purity.

(Problems to be Solved and Attempted by the Invention) The present invention has been made in order to solve the above-mentioned conventional problems, and provides a purification method capable of purifying high-purity reagents etc. without contamination with metal impurities. This is what I am trying to do.

[Structure of the Invention] (Means for Solving the Problems) The present invention provides a closed container in which a solution substance is stored near the bottom, an injection part and a discharge part for the solution substance connected to the side wall of the closed container, a heating means for heating the solution substance in the sealed container; a cooling tank inserted in the upper part of the sealed container and having a tapered lower part; a collecting conduit having a lower end extending downwardly through the bottom of the container; a collection container for liquid liquid into which the lower end of the collecting conduit is inserted; a shielding plate provided on an inner surface portion of the sealed container and an outer surface portion of the collection conduit located between the lower part of the cooling tank and the liquid surface of the solution substance; This is a method for purifying a solution substance using a distillation apparatus equipped with the above method, characterized in that one or both of sulfuric acid and phosphoric acid is added to the solution substance in advance.

Examples of the solution substance include hydrochloric acid, nitric acid, hydrofluoric acid, and water.

The ratio of addition of one or both of sulfuric acid and phosphoric acid to the above solution material should be 0.L weight or more from the viewpoint of suppressing the generation of mist containing metal impurities in the solution material. desirable. However, regarding the upper limit of addition of sulfuric acid, etc., if it is added too much, there is a risk that a large amount of sulfuric acid, etc. will be mixed into the purified solution material, so it is practically desirable to set the upper limit to 5% by weight.

In addition, from the viewpoint of further reducing the generation of mist containing ferromagnetic metal impurities, it is desirable that the above-mentioned distillation apparatus used for purification be equipped with a magnetic field generating means for applying a magnetic field to the solution substance in the closed container.

(Function) According to the present invention, when a solution substance in a closed container is heated and vaporized by purification using a distillation apparatus in which a filter plate is arranged in a closed container located above the liquid level of the solution substance. The generation of mist due to bumping can be suppressed, and by providing shielding plates on the inner surface of the sealed container and the outer surface of the collection conduit located between the lower part of the cooling tank and the liquid surface of the solution material, the heating means can be used to seal the container. When the solution substance in the container is heated and vaporized, the above-mentioned shielding plates can prevent the solution substance from rising along the inner surface of the sealed container or the outer surface of the collection conduit, and the solution substance itself can be prevented from rising inside the conduit from the upper end. It can prevent the inflow. (Option 7) By adding one or both of sulfuric acid and phosphoric acid to the solution material, it reacts with metal impurity ions such as U, Th, and Fe in the solution material to form a high boiling point sulfuric acid compound or phosphoric acid. Since the compound is generated, the evaporation of metal impurities can be reduced, and the generation of mist containing these impurities can be suppressed.

Therefore, by condensing only the high-purity vapor of the solution substance in a cooling tank and guiding it as droplets through a collection conduit to a collection container, it is possible to obtain a high-purity liquid with very little metal impurities. .

(Example) Hereinafter, an example of the present invention will be described in detail with reference to FIG.

Example] 1 in the figure shows a solution material 2 for purifying Buddha nature near the bottom.
For example, it is a closed container with a space volume of about 1500 Oct+l. A heater 3 for heating the solution substance 2 is disposed on the bottom of the closed container 1. On the bottom of the heater 3, there is a magnetic field generating member 4 made of a permanent magnet coated with polytetrafluoroethylene and having a diameter of 25 cm and a thickness of 0.5 cm and a g K Gauss.
is installed. These heaters 3 and magnetic field generating members 4
A closed container l, in which the following are sequentially arranged on the bottom surface, is placed on a support stand 5.

An injection part 6 for the solution substance is connected to the lower side wall of the closed container (2), and a discharge part 7 for the solution substance bent up and down is connected to the lower side wall of the closed container 1 facing the injection part 6. ing.

Further, a cooling tank 8 is inserted in the upper part of the +T;2 sealed container I. The cooling tank 8 includes an outer cylinder 9 whose lower part is tapered and sealed vertically, an inner cylinder 10 inserted from the upper part of the outer cylinder 9, and an upper side wall of the outer cylinder 9. It consists of an open cooling water inlet 1.1 and a cooling water outlet 12 formed at the upper end of the zero weight inner cylinder.

In such a cooling tank 8, by introducing cooling water from a cooling water population 1.1, the cooling water is distributed between the outer cylinder body 9 and the inner cylinder body lO.
The cooling water moves downward through the annular space between them to cool the outer cylinder body 9, after which it flows into the inner cylinder body 10 and is discharged from the cooling water outlet 12.

Inside the hermetic container 1, a collection conduit 13 is arranged with its upper end close to the tapered lower part of the cooling tank 8, and the lower end of the collection conduit 13 is connected to the bottom surface of the hermetic container l, the heater 3, It passes through the magnetic field generating member 4 and the support base 5 and extends downward. A funnel-shaped collection portion 14 is formed at the upper end of the collection conduit 13 close to the tapered lower portion of the cooling tank 8 . The lower end of the collection conduit 13 is inserted into the mouth of the collection container 15.

This collection container 15 is arranged within a cooling container 17, and the cooling container 17 is filled with cooling water 18.

A cooling water introduction part 19 is provided on the lower side wall of the cooling container 17, and a cooling water I8 is provided on a part of the side wall of the cooling container 17.
An overflow portion 20 is provided.

Further, a filter plate 21a is provided in the portion of the closed container 1 where the solution substance 2 is accommodated and above the liquid level of the solution substance 2.
, 21b are provided, respectively. These filter plates 2
1a and 21b are in the shape of a disk with a large number of holes, and have a hole in the center through which the collection conduit 13 passes, and specifically have a diameter of 24 mm and a thickness of 0.
．． It is made of a polytetrafluoroethylene plate with approximately 5,000 2 cm holes punched out. Note that even if each of the filters 21a and 21b is formed of one piece,
It may also be formed by stacking several sheets at a predetermined interval.

A plurality of first shielding plates 22 parallel to each other and tilted downward are provided on the inner surface of the closed container l located between the lower part of the cooling Vj8 and the solution substance 2, respectively. Furthermore, a plurality of second shielding plates 23 are provided at four parts of the collection conduit 13 located between the upper part of the cooling fl 8 and the liquid surface of the solution substance 2, respectively, so as to be inclined downward. There is. An intake/exhaust pipe 24 is connected to the side wall of the closed container 1, and a valve 25 is interposed in the intake/exhaust pipe 24. The closed container 1, the collection conduit 13, the collection container 15, and the shielding plates 22 and 23, with which the solution substance 2, its evaporated substance, and liquid come into contact, are each made of high-purity quartz.

Next, a method for purifying nitric acid will be explained using the above-described apparatus shown in FIG.

First, a solution substance 2 obtained by adding 50 - of phosphoric acid to 100 - of nitric acid is injected into the closed container 1 from the injection part 6, and then
A quantity of solution substance 2 was stored in the container 1 by discharging it from the container. Subsequently, 8 K is applied from the magnetic field generating member 4 to the solution substance 2.
A Gaussian magnetic field is applied, and cooling water is supplied from the cooling water port 11 of the cooling tank 8 and discharged from the cooling water outlet 12 17
The outer cylinder 9 of the cooling tank 8 was cooled, and the solution substance 2 in the closed container I was further heated to 119° C. by the heater 3. By heating with the heater 3, the solution substance 2 in the closed container 1 is boiled and vaporized. In this case, mist is generated on the surface of the solution material 2, but since the filter plates 21a and 21b are arranged in and above the solution material 2, the mist is generated in the closed container 1 together with the vapor 26 of the solution material. It is restrained from rising to the top. In addition, due to the effect of the magnetic field from the magnetic field generating member 4, Fe5C is added to the mist.
It is possible to prevent ferromagnetic metal impurities such as O and N1 from being mixed in. Furthermore, since phosphoric acid is added to the solution material 2 in advance, metal impurity ions such as UlTh and Fe in nitric acid react with the phosphoric acid to produce a high boiling point phosphoric acid compound. Evaporation is reduced, and the generation of mist containing metal impurities is suppressed. Moreover, solution substance 2
When the solution substance 2 is heated and vaporized, it rises along the inner surface of the closed container 1 and the outer surface of the collection conduit 13, which is called creeping. The plates 22,23 prevent the solution substance 2 itself from flowing into its interior from the collecting section 14 at the upper end of the collecting conduit 13.

The vapor 2B of the solution substance, which is vaporized by the heating of the heater 3 and whose contamination with mist etc. is suppressed, rises inside the closed container 1, contacts the outer surface of the cooling tank 8 disposed above it, and condenses. do. The liquid droplets 27 of the solution material thus condensed in the cooling tank 8 gather at the bottom along the tapered part of the cooling tank 8 and fall.

The fallen liquid droplets 27 are introduced into the collection conduit 13 through the collection section 14 arranged close to the lower part of the cooling tank 8 . The liquid droplets 27 falling through the collection conduit I3 fall from the lower end of the conduit 13 into the collection container 15, which has been cooled in advance with the cooling water 18 in the cooling container 17, and collect the liquid 2 of nitric acid.
Collected as 8.

Comparative Example 1 Nitric acid was distilled in the same manner as in Example 1, except that a solution material in which phosphoric acid was not added to nitric acid was used.

Therefore, U and Th in the nitric acid solution obtained in Example 1 and Comparative Example 1 were analyzed using an inductively coupled plasma mass spectrometer, and Fc and Ca were analyzed using a flameless atomic absorption spectrometer. The results are shown in Table 1 below. In Table 1, the analytical values of nitric acid (undiluted solution) before distillation are also listed.

Shown in Table 1 and Table 2. Furthermore, in Table 2, hydrochloric acid (
The analytical values of the stock solution) are also listed.

Table 2 Example 2 Except that 50% of sulfuric acid was added to 10,000% of hydrochloric acid as the solution material, and the distillation temperature was 107°C.
Hydrochloric acid was distilled in the same manner as in Example 1.

Comparative Example 2 Hydrochloric acid was distilled in the same manner as in Example 2, except that a solution material in which sulfuric acid was not added to the hydrochloric acid was used.

Therefore, U and Th in the hydrochloric acid solution obtained in Example 2 and Comparative Example 2 were analyzed using an inductively coupled plasma mass spectrometer, and Fe and Ca were analyzed using a flameless atomic absorption spectrometer. The results are shown below in Example 3. In the apparatus shown in FIG.
, except that the collection container 15 and the shielding plates 22 and 23 were made of polytetrofluoroethylene, the solution material was hydrofluoric acid to which 50% of sulfuric acid had been added, and the distillation temperature was 110°C. , Hydrofluoric acid was distilled in the same manner as in Example 1.

Comparative Example 3 Except for using a solution material in which sulfuric acid was not added to hydrofluoric acid,
Hydrofluoric acid was distilled in the same manner as in Example 3 above.

Therefore, U and Th in the hydrofluoric acid solution obtained in Example 3 and Comparative Example 3 were transferred to the inductively coupled plasma ff.
Fc and Ca were analyzed using a frameless atomic absorption spectrometer. The results are shown in Table 3 below.

Additionally, Table 3 also shows the analytical values of hydrofluoric acid (undiluted solution) before distillation.

Table 3 As is clear from Tables 1 to 3 above, the distillation purification method of this example distilled nitric acid, hydrochloric acid, and hydrofluoric acid with extremely high purity compared to Comparative Examples 1 to 3. It turns out that it can be purified.

In addition, in the distillation apparatus used in the above example, the collection conduit 1
Although a straight pipe was used as No. 3, a collection pipe with a coiled part in the middle may be used to improve the collection effect of the droplets.

In the distillation apparatus used in the above embodiment, not only the filter 21b is disposed above the solution substance 2, but also the filter 21b is disposed above the solution substance 2.
A filter 21a is also arranged inside, but the filter 21a
may be omitted.

[Effects of the Invention] As detailed above, according to the present invention, it is possible to provide a distillation purification method capable of purifying highly pure reagents such as nitric acid, hydrochloric acid, and hydrofluoric acid without contamination with metal impurities.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing one form of a distillation apparatus used in an example of the present invention. l... Airtight container, 2... Solution substance, 3... Heater, 4... Magnetic field generating member, 8... Cooling tank, 13...
Collection conduit, 15... Collection container, 17... Cooling container,
21a, 21b... Filter, 22. 23... Shielding plate, 26... Steam, 27... Buddhist droplet, 28...
・French sexual fluid. Applicant's agent Patent attorney Takehiko Suzue

Claims (1)

[Claims] a closed container containing a solution substance near the bottom; an injection part and a discharge part for the solution substance connected to a side wall of the closed container; a heating means for heating the solution substance in the closed container; A cooling tank is inserted into the upper part of the container and has a tapered lower part, and the upper end is arranged close to the lower part of the cooling tank in the closed container, and the lower end extends downward through the bottom of the container. a collection conduit, a distillate collection container into which the lower end of the collection conduit is inserted, a filter plate disposed in the closed container located above the liquid level of the solution substance, and a lower part of the cooling tank. In a method for distilling and purifying a solution substance using a distillation apparatus equipped with a shielding plate provided on an inner surface of the closed container and an outer surface of the collection conduit located between the liquid surface of the solution substance, the solution substance is purified by distillation. A distillation purification method characterized by adding in advance one or both of sulfuric acid and phosphoric acid.