GOST 12225-80

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  ГОСТ 12225-80

GOST 12225−80 Palladium. Methods of analysis (modified N 1−7)

GOST 12225−80

Group B59

INTERSTATE STANDARD

PALLADIUM

Methods of analysis

Palladium. Methods of analysis

AXTU 1709

Date of introduction 1981−07−01

INFORMATION DATA

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

DEVELOPERS

V. A. Korneev, V. E. Avramov, M. A. Gavrilov, G. N. Verkhoturov, A. K., Dementieva, I., Karshakevich

2. APPROVED AND put INTO EFFECT by Decision of the USSR State Committee for standards from 18.03.80 N 1201

Change No. 7 adopted by the Interstate Council for standardization, Metrology and certification (Protocol No. 10 dated 04.10.96)

Date of introduction 1997−09−01

Was the Technical Secretariat of MGS N 2250

The adoption voted:

3. The frequency of inspection 5 years

4. REPLACE GOST 12225−66

5. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

6. Resolution of the state standard from 24.02.92 N 175 removed the limitation of the validity period

7. REVISED (December 1998), with Changes N 1, 2, 3, 4, 5, 6, 7, approved in may 1982, June 1984, July 1985, February 1989, December 1990, February 1992, February 1997 (IUS 8−82, 10−84, 10−85, 5−89, 4−91, 6−92, 5−97)


This standard establishes spectrometry and spectrographic methods for the determination of platinum, rhodium, ruthenium, iridium, lead, gold, silver, Nickel, copper, iron, aluminum, silicon, tin, magnesium, zinc, antimony, and gravimetric method for the determination of volatile impurities, x-ray spectral fluorescent method for the determination of zinc.

The spectrometric method is based on spark excitation radiation between the sample of palladium and contradictator or translation of the sample of palladium in the globule, the evaporation of the elements of the impurities in the arc of DC with subsequent photoelectric measurement of intensity of analytical lines of impurities.

Determine impurities: platinum, iridium, ruthenium, antimony, zinc and lead — from 0.003 to 0.1% each; rhodium, gold, iron and Nickel, from 0.001 to 0.1% each; silver, silicon, aluminum, copper, magnesium, from 0.001 to 0.02% each; and tin from 0.0005 to 0.02%.

Spectrographic method is based on the translation of the samples of palladium in the globule, the evaporation of the elements of the impurities in the arc of DC and photographic registration of the spectra.

Determine impurities: platinum, rhodium, iridium, ruthenium is from 0.002 to 0.1% each; Nickel, copper, silver, magnesium 0.001 to 0.01% each; aluminum, silicon, lead from 0.001 to 0.02% each; iron from 0.002 to 0.05%; the gold is from 0.001 to 0.05%; tin, zinc from 0.0005 to 0.02%.

Gravimetric method is based on determining the mass fraction of loss on ignition by the mass difference of sample before and after calcination.

X-ray spectral fluorescent method is based on the excitation of secondary radiation from palladium polychromatic radiation x-ray tube with subsequent ionization measuring the intensity of the analytical line of zinc. Determine the zinc, from 0.001 to 0.02%.

(Changed edition, Rev. N 1, 2, 4, 5, 7).

1. GENERAL REQUIREMENTS

1.1. General requirements for method of analysis according to GOST 22864.

(Changed edition, Rev. N 5).

1.2. (Deleted, Rev. N 5).

1.3. Mass fraction of impurities gravimetric and spectrographic methods to determine no less than four parallel batches, spectrometric — no less than four places in one pill.

1.4, 1.5. (Deleted, Rev. N 5).

2. SPECTROMETRIC METHOD

2.1. Apparatus, reagents and solutions

Quantometer emission ARL 31000 or other equal precision instrument.

The generator of the unipolar low-voltage spark.

Press the str-60.

Steel mold with a matrix of an inner diameter of 40 mm.

A machine for sharpening metal bars.

Analytical scale.

Palladium rods with a diameter of 6 mm, length 150 mm (mass fraction of palladium is not less than 99,98%), sharpened on a cone at an angle of 90°.

The calibration samples.

Rectified ethyl alcohol according to GOST 5962*.
________________
* On the territory of the Russian Federation GOST R 51652−2000. Here and further. — Note the manufacturer’s database.

Hydrochloric acid of high purity according to GOST 14261, diluted 1:1.

Distilled water.

Standard sample of palladium to verify the correctness of analysis results.

The spectral graphite electrodes net.

(Changed edition, Rev. N, 5, 7).

2.2. Preparation for assay

To remove surface dirt palladium is boiled in hydrochloric acid for 2 min, washed with water and dried.

A sample weighing 20 g was placed in a mold and pressed with a force 490000 N.

The tablet sample is placed on a stand water-cooled air tripod spectrometer.

Contradictator is palladium rod.

Analytical gap 3±0.02 mm is installed by the template.

Tablet and palladium rod electrodes are unipolar low-voltage spark.

If you come to the analysis of samples in the form of cast rods with a diameter of 6−8 mm, length 20−25 mm, the ends of the rods processed on the machine on a flat smooth surface, after which the surface of palladium purified as described above.

The analysis in the arc of a DC sample of palladium weighing 100 mg were placed in the crater of the graphite electrode with a diameter of 6 mm (depth of crater, 1.5−2.0 mm, diameter 3.5−4.0 mm). Contradictator serve graphite rods with a length of 30−50 mm, sharpened to a truncated cone and a platform with a diameter of 2.5 mm.

2.3. Analysis

The palladium alloy is an anode (+) and contradicted — cathode (-).

Preparation of equipment for operation is carried out according to the operating instructions of the instruments.

Sample obygryvaet at least four times. After each sparking for a given analytical program automatically prints the result of measurement for each item.

Contradicted replaced with a new one before burning a new sample.

2.2, 2.3. (Changed edition, Rev. N 7).

2.4. Processing of the results

The results of measurements using a DC line built for the calibration specimens, determine the mass percent of impurities.

When equipped with quantometer computer (PC) according to the given analytical program to automatically conduct the calculation the mass fraction and printing.

The final result of the analysis be the arithmetic mean of four measurements (obygryvanii), the maximum difference between them does not exceed the permissible discrepancy at a confidence probability of 0.95.

If carried out calibration of measuring channels of the spectrometer for the calibration samples, the mass fraction of elements, impurities obtained by multiplying the registered value of the readings of the digital voltmeter to a scale which for each element is determined during calibration.

Analytical lines for analysis are presented in table.1.

Table 1

(Changed edition, Rev. N 6).

2.4.1. The preparation of calibration samples (see section 3.4.3).

2.4.2. Allowable absolute differences of the results of the parallel definitions should not exceed the values given in table.3.

3. SPECTROGRAPHIC METHOD

3.1. Apparatus, reagents and solutions

A diffraction spectrograph with a grating of 600 lines/mm or a quartz spectrograph medium dispersion. Three-step attenuator with transmittance degrees 100,40% and 10%.

Arc generator of AC or DC power up to 15 A.

Geregistreerde microphotometer.

Steel mold with a matrix of an inner diameter of 4 mm.

Grinding machine graphite electrodes.

The spectral graphite electrodes-pure grades of high purity 7−3, high purity 7−4, b-3, with a diameter of 6 mm.

The calibration samples.

Photographic plates of the spectral type of ES sensitivity of 5−10 units or type 2 sensitivity 16 units

Rectified ethyl alcohol according to GOST 5962.

Hydrochloric acid of high purity according to GOST 14261, diluted 1:1.

Developer and fixer according to GOST 10691.0, GOST 10691.1. Allowed to use other contrast working developer.

Standard sample of palladium to verify the correctness of analysis results.

(Changed edition, Rev. N 5).

3.2. Preparation for assay

To remove surface dirt palladium is boiled in hydrochloric acid for 2 min, washed with water and dried.

A portion weighing 100 mg was placed in the crater of the graphite electrode (crater depth is 1.5−2 mm, diameter 4 mm). In the case of the analysis of spongy palladium hinges, metal pressed force N 500−10000. Contradictator serve graphite rods with a length of 30−50 mm, sharpened to a truncated cone with ground diameter of 2.5 mm.

3.3. Analysis

The spectra of the calibration samples are photographed and analyzed on the spectrograph: the slit width of 0.015 mm, the light slit being a condenser, the current is 10−12 A, exposition 60 s. the test sample is the anode.

Analytical gap 2.5 mm adjust in the process of exhibiting spectra in the image on the intermediate diaphragm. Photographic plates showing for 5 min at developer temperature of 20 °C.

Shown photographic plates rinsed in water, fixed, washed in running water, dried and photometric.

3.4. Processing of the results

3.4.1. For all elements of internal standard are the lines of palladium. Determination of mass fraction of impurities is carried out by the method of «three standards». The final result of the analysis be the arithmetic mean of four parallel measurements, the maximum difference between them does not exceed the permissible discrepancy at a confidence probability of 0.95. Analytical lines for analysis are presented in table.2.

Table 2

(Changed edition, Rev. N 1, 5).

3.4.2. Using microphotometry measure the amount of blackening of analytical lines and the internal standard.

Using the characteristic curve, which is constructed for each spectrogram, determine the logarithm of the ratio of the intensity of analytical lines of impurities and the internal standard.

The calibration graphs are built in coordinates , x — axis is the (logarithm of the mass fraction of the calibration samples); on the y — axis (the logarithm of the ratio of the intensity of the impurity line to the line of the internal standard).

In the region of high mass fraction allowed the construction of calibration graphs in the coordinate , where is the difference of pochernenija analytical lines and the internal standard.

For the calibration chart to find the mass fraction of impurities in the analyzed samples.

The final result of the analysis be the arithmetic mean of four parallel measurements, the maximum difference between them does not exceed the permissible discrepancy at a confidence probability of 0.95.

3.4.3. The preparation of calibration samples

Calibration samples for spectral analysis were prepared by direct introduction of the calculated quantity of powders of impurities (grade hç) in the spectral pure palladium (mass fraction of palladium is not less than 99,98%).

Sample impurities with a small amount of palladium is compressed into the tablet (to avoid loss of impurities), then a pill and a balance of palladium is placed in a graphite crucible and melted in a heating furnace of the type IST-016 at 1700 °C for 20 min.

After melting the ingots are purified from mechanical inclusions, washed in hydrochloric acid and rasstraivaet chips of size 1 mm. Chips boil in hydrochloric acid, washed with distilled water and dried.

The purity of palladium to determine the melting spectrographic method under the same conditions under which to conduct analysis. Contaminants that can find in palladium, determined by the method of additives, and found the mass fraction take into account when producing the calibration samples.

Prepare a series of six calibration samples in the range of a mass fraction of from 0.0005 to 0.1%.

Allowed the preparation of calibration samples by another method ensuring the specified accuracy of the analysis.

3.4.4. The difference between the results of parallel measurements and the results of the analysis shall not exceed the values of permissible differences given in table.3.

Table 3

3.4.2−3.4.4. (Changed edition, Rev. N 5).

4. GRAVIMETRIC METHOD FOR THE DETERMINATION OF THE MASS FRACTION OF LOSS ON IGNITION

4.1. Equipment

Furnace for calcination at 900−1100 °C.

Platinum crucibles N 100−4 according to GOST 6563.

From Kipp apparatus for generating hydrogen.

Crucibles porcelain N 3 according to GOST 9147.

Analytical scale.

Desiccator, according to GOST 25336.

(Changed edition, Rev. N 4, 6).

4.2. Analysis

Clean platinum crucible with a constant specific mass is placed in a porcelain crucible and calcined in a furnace for 10−15 minutes at a temperature of 800−1000 °C. after calcination porcelain crucible with platinum are removed from the oven, recover platinum crucible flame of hydrogen to obtain the gray surface of the crucible, cool in a desiccator to a temperature of (20±5) °C and determine the mass of the platinum crucible. After that it is weighed 5.0 g of the analyzed metal.

The crucible with metal and placed in a porcelain crucible and calcined in an oven for 40−45 minutes at a temperature of 900−1000 °C, remove from the oven porcelain crucible platinum crucible, restore the analyzed metal hydrogen flames for 2−3 minutes, cool in a desiccator to a temperature of (20±5) °C.

A platinum crucible is weighed, placed in a porcelain crucible and calcined under the same conditions for 10 to 15 minutes, then the crucibles are removed from the oven, reduced the analyzed metal in the crucible flame of hydrogen for 2−3 minutes, cool in a desiccator to a temperature of (20±5) °C and re-weighed.

This operation is repeated until obtaining constant weight of the platinum crucible with metal.

The difference between the mass of the crucible with the metal before and after calcination and reconstruction gives the mass loss during annealing in the sample.

(Changed edition, Rev. N 4, 6).

4.3. Processing of the results

Mass fraction loss during annealing (a) percentage calculated by the formula

,

where the difference in mass of the crucible with the metal before calcination and after calcination and recovery, g;

 — weight of metal,

For the results analysis be the arithmetic mean of four parallel measurements, the maximum difference between them does not exceed 0,005% at a mass fraction loss during annealing up to 0.02% and 0.01% when the mass fraction of loss on ignition of from 0,02% to 0,05% at a confidence probability of 0.95.

(Changed edition, Rev. N 6).

5. X-RAY SPECTRAL FLUORESCENT METHOD FOR THE DETERMINATION OF ZINC

5.1. Apparatus, reagents and solutions

Semi-automatic x-ray fluorescence spectrometer PW-1220 «Philips».

Desktop calculator 9100 programming A Hewlett-Packard.

The x-ray tube OEG-100, with the mirror material of the anode made of gold, with a capacity of 2 kW.

Hydraulic press.

Standard steel spectrometric cuvette with an internal diameter of 3.2 cm

Steel mold consisting of a substrate and a rod with a diameter of 3.2 cm

Analytical scale.

Rectified ethyl alcohol according to GOST 5962.

Hydrochloric acid of high purity according to GOST 14261, diluted 1:1.

Palladium powder, spectrality (mass fraction of palladium is not less than 99,98%).

Distilled water according to GOST 6709.

Sieve to 0.074 mm.

Zinc granular brand h.d. a.

The calibration samples.

Agate mortar with pestle.

(Changed edition, Rev. N 4, 6).

5.2. Preparation for assay

5.2.1. Preparation of the calibration samples.

Calibration samples with a given mass fraction of zinc is prepared by planting the appropriate volume of standard zinc solution per 20 g sample of powdered palladium and grinding the mixture to dry in an agate mortar.*
________________
* The text matches the original. — Note the manufacturer’s database.

Prepare standard solutions of zinc:

A solution with a mass fraction of zinc, 1 g/DM; 1 g of zinc metal is transferred to the glass Cup, add 10 cmof dilute hydrochloric acid (1:1 ratio). After the dissolution of the zinc solution was transferred to volumetric flask with a capacity of 1 DMand adjusted to the mark with distilled water.

Solution B with a mass fraction of zinc of 0,1 g/DM; take 10 cmof solution A in a volumetric flask with a capacity of 100 cmand adjusted to the mark with distilled water.

Powdered palladium before preparation of calibration samples to remove the surface dirt is boiled in hydrochloric acid for 2 min, washed with distilled water and dried. Then the powder is sieved to 0.074 mm to zoom out* large fraction. Sample of the sifted powder of palladium with a mass of 20 g is used for preparation of calibration samples.
________________
* The text matches the original. — Note the manufacturer’s database.

Samples with a mass fraction of zinc 0,005; 0.01 and 0.02% are prepared by the introduction of respectively 1, 2 and 4 cmstandard solution And 20 g of palladium powder and stirring the mixtures until dry.

Samples with a mass fraction of zinc 0,001 and 0,003% prepared by the introduction of respectively 1 and 6 cmstandard solution B 20 g sample of palladium, and further mixing until completely dry. For a more uniform distribution of zinc throughout the volume of sample required re-grinding the samples with alcohol.

(Changed edition, Rev. N 5

).

5.2.2. Construction of calibration curve.

5.2.2.1. A portion of the calibration sample weighing 20 g was placed in a spectrometric cuvette mounted on the substrate of the mold and pressed with a force of 1.22·10GP (10 tons). Pressed on the cuvette with the calibration samples and the pure palladium is placed in the cassette probiodiesel spectrometer. Samples with a mass fraction of zinc 0.01%, and pure palladium are used as «external standard and background standard.» The mode of operation of the spectrometer is characterized by the following parameters: voltage x-ray tube was 70 kV; tube current — 25 mA; detector — a joint operation of proportional and scintillation counters. The collimator is rude. The crystal — analyzer LiF (200) in the first order reflection. Registration of the intensities is performed while rotating the sample in a vacuum not lower than 6·10mm Hg. article the Rate of gas flow mixture (90% argon and 10% methane) — 7 DM/min, exposure — 40 C.

5.2.2.2. The mode of operation of the pulse-height analyzer — differential with automatic selection of the window position (ext).

5.2.2.3. The calibration samples irradiated radiation x-ray tube and record the intensity of fluorescent radiation ZnK, line (0,1437 nm) in the first order reflection at least three times. After each measurement result is automatically printed. Then evaluate the dispersion of results. If the differences exceed the statistical error of the 3where  — the arithmetic mean of the number of dialed pulses, the series of measurements repeated. The number of dialed pulses proportional to the intensity of the analytical line of zinc from the sample.

5.2.2.4. A similar series of measurements performed sequentially for each sample, and for «external standard» and «background standard» this series is repeated in two of the calibration sample and the results of the measurements of each series average. When building a calibration curve carried out at least three measurement series. The relative intensity of analytical line of zinc is calculated by the formula

, (1)

where , and  — the average value of the number of impulses dialed for the exposure time, respectively, of the calibration sample, the «background» and «external standards».

Found thus the relative intensities of the calibration samples and the mass fractions of zinc in them to build a calibration curve, the ordinate of which is deposited mass fraction of zinc and x — axis is the relative intensity. In the presence of the programming table of the calculator calibration curve approximiert a linear function

, (2)

where  — the actual mass fraction of zinc in the sample;

 — relative intensity of analytical line of zinc.

and regression coefficients, determined experimentally using the method of least squares.

The position of the calibration curve (or the values of calibration coefficients) is controlled after the repair, configuration or change of the spectrometer.

(Changed edition, Rev. N 5).

5.3. Analysis

The analyzed samples of palladium for the removal of surface contamination is boiled in hydrochloric acid for 2 min, washed with water and dried. Sample samples weighing 20 g are pressed into spectrometric cuvettes. In probiodiesel the cassette spectrometer with the cuvette placed «outside» and «background standard» and two samples. Conducted a series of measurements of the intensities of three times from «outside» and «background» standards and two samples during the modes given in section 5.2.2.

A measurement series is repeated four times.

5.4. Processing of the results

5.4.1. The results of the measurements for each series of average and find relative intensity according to the formula (1). The relative intensities determine the mass percent zinc in the sample using the calibration curve or calculated by the formula (2).

5.4.2. If the maximum estimated variance of the parallel measurements does not exceed the permissible discrepancy at a confidence probability of 0.95, the final result of the analysis taking the arithmetic mean value of the mass fraction of all series of measurements equal to

, (3)

where the value of the mass fraction of zinc in the sample corresponding to the series of measurements;

 — number of measurement series.

Values (see table.1) calculated using values of errors of the experiment and a confidence factor according to Pearson by the formula

. (4)

5.4.3. Allowable absolute discrepancies in the results of parallel measurements at a confidence probability of 0.95 does not exceed the value specified in table.4.

Table 4

If the difference is extreme results of the analysis exceeds the value , the assessment stands out sharply deviations is performed using a test.

To calculate the experimental value according to the formula

, (5)

where

, (6)

 — the standard deviation of a single measurement result.

The result, for which the value exceeds in absolute value the value  — distribution for the significance level of 0.05 with the number of degrees of freedom;

(see table.5), is discarded as erroneous.

Values  — a criterion for the significance level of 0.05 (two-sided tests) are given in table.5.

Table 5

If among all the results two too high and too low, first check one of them, for example, the maximum. If this result is discarded, the count and , for the remaining results and evaluate the minimum value.

The final result of the analysis should be the arithmetic mean of the remaining results.

An example of the calculation of the mass fraction of zinc in palladium is given in the Appendix.

5.4.1−5.4.3. (Changed edition, Rev. N 5).

APPLICATION (recommended). AN EXAMPLE OF THE CALCULATION OF THE MASS FRACTION OF ZINC IN PALLADIUM

APP
Recommended

1. The results of measuring the intensity of analytical lines of zinc are given in table.1.

Table 1

2. Calculation of relative intensity of analytical lines of zinc are given in table.2

,

where  — number of a series of measurements,

1, 2, 3, 4.

Table 2

3. The calculation of the mass fraction of zinc in palladium is given in table.3.

,

where 0,0101; 0,0004.

Table 3

4. Evaluation of the results and calculate the average.

Because the maximum divergence of parallel equally for the final result of the analysis should be the arithmetic mean of all measurements.

%.

(Changed edition, Rev. N 1, 5).