GOST 18904.6-89

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  ГОСТ 18904.6-89

GOST 18904.6−89 Tantalum and its oxide. Spectral method of determination of aluminum, vanadium, iron, calcium, silicon, magnesium, manganese, copper, Nickel, niobium, tin, titanium, chromium and zirconium

GOST 18904.6−89

Group B59

STATE STANDARD OF THE USSR

TANTALUM AND ITS OXIDE

Spectral method of determination of aluminum, vanadium, iron, calcium,
silicon, magnesium, manganese, copper, Nickel, niobium, tin, titanium, chromium and zirconium

Tantalum and its oxide. Spectral method for determination of aluminium,
vanadium, iron, calcium, silicon, magnesium, manganese, copper,
nickel, niobium, tin, titanium, chromium and zirconium

AXTU 1709

Valid from 01.01.90
to 01.01.95*
_________________________________
* Expiration removed
Protocol N 4−93 inter-state Council
for standardization, Metrology and certification
(IUS N 4, 1994). — Note the manufacturer’s database.

INFORMATION DATA

1. DEVELOPED AND INTRODUCED by the Ministry of nonferrous metallurgy of the USSR

PERFORMERS

L. N. Filimonov, V. M. Vladimirov, N. Arakelian, B. M. Dobkin, R. F. Makarov, A. S. Terekhov

2. APPROVED AND put INTO EFFECT by Decision of the USSR State Committee for standards from 20.03.89 N 563

3. INSTEAD 18904.6 GOST-73

4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

This standard establishes a spectral method for the determination of impurities of aluminum, vanadium, iron, calcium, silicon, magnesium, manganese, copper, Nickel, niobium, tin, titanium, chromium and zirconium in tantalum (previously translated into oxide) and their oxides.

The method is based on excitation and registration (photographic or photoelectric) arc emission spectra of analyzed samples and sample comparison.

Intervals determined by a mass fraction of impurities:

1. GENERAL REQUIREMENTS

1.1. General requirements for method of analysis and security requirements — according to GOST 18904.0 with the addition of: analysis result should be the arithmetic mean of two parallel definitions, each of which perform a separate sample.

2. APPARATUS, REAGENTS AND MATERIALS

The diffraction type spectrograph DFS-13 with the grating 600 gr/mm or similar.

Photovoltaic installation of DFS-DFS or 36 to 44.

Electronic computing machine «Iskra-1256» or «D-3−28» or similar type.

Generator UGE-4 or the rectifier 250 to 300 V, 20−30 A.

Microphotometer type MF-2 or similar.

Spectromancer PS-18 or similar.

Analytical scale.

Libra torsion.

Libra technical.

Shaker MEAS PRAHA TYP T22, 220 V, 50 Hz, 20 W, Czechoslovakia or other device for mixing and grinding samples.

Mortars and pestles of tantalum and organic glass.

Oven muffle.

Drying Cabinet.

Tile electric.

Grinding machine carbon electrodes.

Coals spectral high purity-7−3 or C-3, with a diameter of 6 mm.

The electrodes are machined from coals spectral:

type «glass»: the crater diameter — 4 mm, the depth of the crater — 3 mm, height of outer wall — 5 mm, pin height — 3 mm, leg diameter 2.5 mm; sharpened to a truncated cone with ground diameter of 2 mm.

Volumetric flasks with a capacity of 100 cm, 500 cm.

The quartz Cup.

Cups and crucibles of platinum.

Crucibles of glassy carbon.

A glass of vinyl plastic with a capacity of 2000 cm.

Funnel made of organic glass.

Flask Bunsen organic glass.

Medical forceps according to GOST 21241.

Polyacrylic fabric.

Aluminium metal according to GOST 13276.

Ammonia water according to GOST 3760 or obtained by saturating purified water with gaseous ammonia in a plastic container.

Ammonium fluoride according to GOST 4518, solution concentration 100 g/DM.

Barium carbonate according to GOST 4158.

Vanadium (V) oxide.

Iron (III) oxide.

Graphite powder OS.h. according to GOST 23463 or powder coal from coals of high purity-7−3 or C-3 followed by treatment with hydrochloric acid, hydrofluoric acid treatment and drying in a muffle furnace at 400 °C for 1−2 h. the Drying is carried out in a platinum Cup or crucible made of glassy carbon.

Potassium dichromate according to GOST 4220.

Calcium nitrate 4-water according to GOST 4142.

Nitric acid is the OS.h. according to GOST 11125 and diluted 1:1 or GOST 4461, double-distilled in quartz apparatus.

Sulfuric acid OS.h. according to GOST 14262, diluted 1:1.

Hydrochloric acid OS.h. according to GOST 14261, diluted 2:1, or according to GOST 3118, distilled in a quartz apparatus.

Hydrofluoric acid OS.h.

Silicon dioxide according to GOST 9428.

Magnesium nitrate according to GOST 11088.

Magnesium oxide according to GOST 4526.

Manganese (II) chloride 4-water according to GOST 612.

Copper nitrate.

Copper metal electrolytic grade M-0, M-1.

Sodium chloride according to GOST 4233.

Nickel sulfate 7-water according to GOST 4465.

Of niobium (V) oxide.

Tin (IV) oxide according to GOST 22516.

Rectified ethyl alcohol according to GOST 5962* or technical rectified ethyl alcohol according to GOST 18300.
_______________
* On the territory of the Russian Federation GOST R 51652−2000. — Note the manufacturer’s database.

Antimony (III) oxide.

The powdered tantalum of high purity or tantalum (V) oxide, pure for specific impurities.

Titanium (IV) oxide.

Tributyl cleaned.

Zirconium (IV) oxide.

Photographic plates of the spectral type I, type II, ES or equivalent, providing normal blackening photometrically lines and the background spectrum.

Developer contrast.

Fixer is acidic.

The standard solutions with mass concentration of 10 mg/cm:

a portion of metallic aluminium with a mass of 5 g is dissolved in 80 cmof hydrochloric acid, diluted 2:1, transferred into a volumetric flask with a capacity of 500 cm, was adjusted to the mark with water and mix;

a portion of calcium nitrate weight 5,8902 g dissolved in water, transferred to a volumetric flask of 100 cm, adjusted to the mark with water and mix;

a sample of magnesium nitrate with a mass of 6,0987 g dissolved in water, transferred to a volumetric flask with a capacity of 100 cm, adjusted to the mark with water and stirred; or the portion of magnesium oxide by weight 1,6583 g dissolved in 40 cmof hydrochloric acid diluted 1:1, transferred into a volumetric flask with a capacity of 100 cm, adjusted to the mark with water and mix.

A portion of chloride of manganese mass 3,603 g dissolved in water, transferred to a volumetric flask with a capacity of 100 cm, adjusted to the mark with water and mix.

A sample of copper nitrate by mass 3,8022 g dissolved in water, transferred to a volumetric flask with a capacity of 100 cm, adjusted to the mark with water and stirred; or 1 g of electrolytic copper is dissolved in a quartz Cup by heating in 25 cmof nitric acid, diluted 1:1, transferred into a volumetric flask with a capacity of 100 cm, adjusted to the mark with water and mix.

A portion of sulphate of Nickel with a weight of 4,785 g dissolved in water containing 1 cmof sulfuric acid, transferred into a volumetric flask with a capacity of 100 cm, adjusted to the mark with water and mix. The value of the mass of sample after precise definition of the basic substance in sulfuric acid Nickel.

A portion twice recrystallized potassium dichromate weight 2,828 g dissolved in water, transferred to a volumetric flask with a capacity of 100 cm, adjusted to the mark with water and mix.

3. PREPARATION FOR ASSAY

3.1. Preparation of the buffer mixture

20 g of graphite powder, 2.5 g of sodium chloride, 0.05 g of antimony trioxide and 1.0 g of barium carbonate is stirred in a mortar for 1 h on the shaker for 40−50 min.

3.2. Sample preparation comparison

References (OS) is prepared on the basis of oxides of tantalum, clean-defined impurities, these impurities not detected in the test given in sect.4 and 5 of this standard. They are allowed to cook the basics of tantalum powder of high purity according to claim 3.2.1.

3.2.1. Cooking basics

A portion of the tantalum powder mass 500 g is placed in a vinyl plastic beaker, moistened with water to form a thick slurry, portions (after stopping reaction) add 1100 cmhydrofluoric acid, then dropwise adding nitric acid until the termination of allocation of oxides of nitrogen. After cooling, the solution was filtered into a flask Bunsen organic glass using polyacrylic fabric. To the filtrate add water with the expectation that the concentration of tantalum in the solution was 100 g/DM. Tantalum is extracted with tributyl phosphate in three stages when the ratio of organic and aqueous phases 0,5:1,0; 0,3:1,0; 0,2:1,0. The aqueous phase is drained to waste, the organic combined and washed with sulfuric acid (1:1), when phase ratio of 1.0:0,2.

From the organic phase is carried out extraly tantalum with a solution of ammonium fluoride in three stages when the ratio of organic and aqueous phases 1:0,4; 1:0,2; 1:0,1. From the aqueous phase tantalum is precipitated with ammonia at pH 7−8, and the precipitate was filtered through filter «blue ribbon» under vacuum on the funnel of organic glass. The resulting hydroxide tantalum wash away in a glass of organic glass five times the volume of water and again filtered. Washing with water is repeated three times, then washed on the funnel with alcohol, placed in a platinum Cup, dried in a drying Cabinet for 5−6 h at 140−150 °C, and then calcined in a muffle furnace for 24 hours at 800−900 °C. the resulting framework analyzed in accordance with sec. 4, 5.

3.2.2. Sample preparation comparison

The head sample comparison (GOS) is prepared by mixing the basics with the standard solutions and pre-calcined oxides of the determined elements.

The platinum Cup was placed 20 g of bases, sequentially injected at 18 cmof each of the standard solutions at a concentration of 10 mg/cm. After the introduction of the solution mixture is dried on the tile. After the introduction of standard solutions of aluminium, calcium, magnesium, manganese, copper, Nickel and chromium, the dried mixture is calcined in a muffle furnace at a temperature of 750 °C for 1 h.

In tantalum mortar placed 0,3213 g of an oxide of vanadium (V), 0,3851 g of silicon oxide (IV); 0,2573 g of iron oxide (III); 25,7510 g of niobium oxide (V); 0,2285 g of tin oxide (IV); 0,3002 g of titanium oxide (IV) and 0,2431 g of zirconium oxide (V), mix, then add the contents of the platinum Cup and thoroughly mix the tantalum pestle for 3−3. 5 h then add 28,4267 g of base and stir thoroughly for 3 h on the shaker for about 40−50 mins Stirring in a mortar may be performed with the addition of alcohol to maintain the mixture in a pasty state, followed by drying. The received STATE is stored in a hermetic glass jar.

Other operating systems prepare serial dilution of GOS and subsequent OS basis. The mass fraction of the designated impurities in the percentage of the sum of the metals tantalum and impurities and added to the mixture sample diluted basis and OS are shown in table.1.

Table 1

Each reference sample mixed with the buffer mixture in the ratio 3:1 in a mortar made of Plexiglas for 2−3 hours or on the shaker for 1.5−2 h. Ready OS stored in tightly closed glass jars.

Allowed trade OS using other quantities of the mixed substances by storing values of the mass fraction specified in the standard.

4. ANALYSIS

4.1. Preparation of samples for analysis

A sample of the metal converted into oxide in a platinum crucible, previously rubbed with alcohol (0.5 cm) was placed in 0.9−1.0 g of sample is oxidized first at the edge of the preheated muffle furnace and then calcined at a temperature of 700−800 °C. complete oxidation set color: fully oxidized sample has a white or light yellow color. The resulting tantalum oxide is transferred to a mortar and triturated for 5 min.

The analyzed oxide is mixed with the buffer mixture in the ratio 3:1 by weight in a mortar or on a shaker (10−15 min).

When taking batches boats, spatulas and other tools rubbing alcohol (0.5 cmper sample).

When mixing mortars, pestles or part of vibrostanok washed with water and rubbing alcohol (2 cmper sample).

4.2. Excitation spectra

The analyzed samples and the OS mixed with the buffer mixture, tightly (without weighing) fill in craters of the carbon electrodes of the type «glass», which include in a circuit of a DC arc as the lower electrode of the anode. The cathode serve as the upper electrode, sharpened to a truncated cone. The power of the arc current is 20 A, the exposure time of 30 s, in the interelectrode gap of 2.5 mm.

In the determination of low content of niobium (3·10 — 3·10%): current And 22−24, firing time — 10 sec, exposure time — 40 C, other conditions are the same as in determining other impurities.

4.3. Check spectra

4.3.1. While photographic registration, the slit width of the spectrograph DFS-13 13−15 µm, lighting — being. On a photographic plate 3 photograph of the spectrum of each sample and of each OS. Photographing is repeated twice. Photographed region of the spectrum: 245−350 nm or 360−450 nm (in the determination of calcium). Take pictures of every portion of the prepared (mixed with the buffer mixture) from one sample to the original sample of oxide (or oxidized metal samples) on two photographic plates three times each.

After photographing the spectra show photographic plates, washed, fixed, washed in running water and dried.

4.3.2. With the photoelectric registration of the width of the entrance slit of a photovoltaic plant DFS-36 (DFS-44) of 0.15−0.20 microns, and lighting system — two -. Register two spectrum one portion is prepared (mixed with the buffer mixture) from one sample to the original sample of oxide (or oxidized samples of the metal).

5. PROCESSING OF THE RESULTS

5.1. Photographic plates photometrist on microphotometer. On each spectrogram to measure the blackening of analytical lines and lines of comparison, calculate the difference of pucheranii (), find the arithmetic average for the three spectrograms obtained from the same sample. The wavelengths of the analytical lines and lines of comparison are given in table.2.

Table 2

* Lines used in photoelectric registration.

5.2. At the output of the photovoltaic installation (display of digital voltmeter or tape tsifropechatayuschee device), get values (), which is proportional to the logarithm of the relative intensity of the analytical lines and comparison lines (tab.2).

5.3. For each user-defined impurities build a calibration curve: the abscissa shows the delay values , where  — mass fraction (%) determined by the impurities in the OS; on the vertical axis lay the average values of the analytical signal (or ) of the respective OS. The graphs and average values of the analytical signal obtained for the spectra of samples, find the values of the mass fraction of the designated impurities in the analyzed samples.

5.3.1. While photographic registration of the spectrum for one of the results of parallel determination of taking the average of the results obtained on two photographic plates, each of which is the average of the three spectrograms.

5.3.2. By the photoelectric registration of spectrum for the result of one of parallel measurements take average of the results of measurements of analytical signals of the two spectra.

5.4. Allowed to carry out the analytical signals with the help of computers «Iskra-1256», D-3−28 or similar type programme, approved in the prescribed manner.

5.5. The absolute value of the difference of the two results of parallel measurements (rate of convergence) and two test results (index of reproducibility), which is numerically equal, with a probability of 0.95, should not exceed the values of permissible differences given in table.3.

Table 3

Allowable differences for intermediate values of mass fraction are calculated by using linear interpolation.

5.6. Allowed the use of other techniques of analysis on metrological characteristics are not inferior to mentioned in the standard.