GOST 9717.3-82

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  ГОСТ 9717.3-82

GOST 9717.3−82 Copper. Method of spectral analysis of oxide standard specimens (with Amendments No. 1, 2)

GOST 9717.3−82

Group B59

STATE STANDARD OF THE USSR

COPPER

Method of spectral analysis of oxide standard specimens

Copper. Method of spectral analysis of oxide standart specimens

AXTU 1709

Date of introduction 1983−07−01

INFORMATION DATA

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

DEVELOPERS

A. M. Rytikov, A. A. Nemodruk, M. V. Taubkin, M. P., Burmistrov, I. A. Vorobyev

2. APPROVED AND put INTO EFFECT by Decision of the USSR State Committee for standards from 24.03.82 G. N 1199

3. REPLACE GOST 9717.3−75

4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS

5. The expiration time limit is removed by the Resolution of Gosstandard dated 30.11.92 N 1481

6. The re-release (may 1997) with Amendments No. 1, 2 approved in December 1987 and November 1992 (ICS 2−88, 2−93)


This standard sets the method of spectral analysis on the oxide samples with photographic and photoelectric registration of spectrum copper according to GOST 859*.
_______________
* On the territory of the Russian Federation the document is not valid. Valid GOST 859−2001, here and hereafter. — Note the manufacturer’s database.

Samples or subjected to preliminary oxidation of the melt at the cathode of the DC arc in an oxygen atmosphere. Allowed the conversion of the sample to oxides, dissolution in nitric acid, by evaporation and calcining.

The oxidized sample is placed on a graphite stand between him and the dummy electrode of pure copper or coal excite the arc of DC and subsequent photographic or photoelectric registration of spectrum.

The method provides the possibility to analyze samples in any form.

The method allows to determine the copper content of impurities in the range of mass fraction:

In the analysis of the copper grades Mook and Moab also determine cadmium, cobalt, selenium, tellurium in the range of a mass fraction of from 3·10to 1·10%.

The methods are characterized by a relative standard deviation of single measurement is given in table.1.

Table 1

(Changed edition, Rev. N 2).

1. GENERAL REQUIREMENTS

1.1. General requirements for method of analysis according to GOST and GOST 25086 9717.1*.
________________
* On the territory of the Russian Federation the document is not valid. Standards 31382−2009. — Note the manufacturer’s database.

2. APPARATUS, REAGENTS AND SOLUTIONS

Spectrograph with quartz optics or diffraction medium or coarser. Allowed the use of spectral apparatus with photoelectric registration of spectrum, for example, a photovoltaic installation MFS-8 or similar type if it achieves the convergence of the results of the analysis indicated in table.1.

A constant current source to power the arc, providing a voltage of 200−400 V and currents up to 10 A.

Device for high-frequency ignition of the DC arc from the generator of any system (PS-39, DG, IG).

Microphotometer designed for measuring optical densities of spectral lines and background.

Press oil, hydraulic, or any other, providing the durable pressed pellets of oxides or metal shavings with a diameter of 6−7 mm and a weight of (0,50±0,05) g.

Muffle furnace of any type with a thermostat that allows you to obtain and maintain temperatures up to 800 °C.

Cup platinum, porcelain or quartz varicellae for dissolution and evaporation of samples (dissolution, you can also use flasks or in the glasses heat resistant glass).

Electrodes-graphite stand of coal of high purity, type — crystal; brand, for example, EOS-M, or AUS-P GOST 17022 with a diameter of 6−10 mm. To place the briquettes or oxidized in oxygen tablets on the electrodes, the holders drill recesses with a diameter of 6 mm and a depth of 1.5−2 mm (see drawing).

and is the location of the electrodes and of the briquette before the exposure; b — shot in the anode mode; in shooting in the cathode mode; 1 — graphite stand; 2 — briquette; 3 — dummy electrode; 4 — melt

Electrodes of copper grade M00 or other brands with copper content not less than 99.97% of or coal of high purity S-2, S-3 in the form of bars with diameter 6−7 mm, sharpened to a hemisphere or a truncated cone with ground diameter of 1.5−1.7 mm.

A device for grinding coal or copper electrodes, for example, the machine model CP-35.

Oxygen chamber for oxidation of co and samples.

Oxygen cylinder fitted with reducer.

Spectrographic plates.

Drying oven laboratory.

Hot plate or sand bath.

Analytical scale 200 g with weights of type ADV-200.

Mortar agate or from glass. Allowed the use of a porcelain mortar.

Boxy storage oxidized briquettes or tablets.

Forceps for grasping of tablets or briquettes.

Caps, glass or plastic to protect from dust sharpened electrodes.

Magnet type MVM-63.

Stopwatch at the NTD or the time relay.

Nitric acid of high purity according to GOST 11125, or nitric acid according to GOST 4461 (distilled), diluted 1:1 and 1:10.

The technical rectified ethyl alcohol according to GOST 18300. Consumption of alcohol per one definition in ' 10

Metol (para-metilaminofenazon) according to GOST 25664.

Hydroquinone (paradoxians) according to GOST 19627.

Sanitarily anhydrous sodium GOST 195.

Sodium carbonate according to GOST 83.

Potassium bromide according to GOST 4160.

The sodium (thiosulfate) crystal according to GOST 244.

Acetic acid according to GOST 61.

Developer for plates the spectral type 1, 2 and «Micro» is prepared by mixing equal volumes of solutions 1 and 2 before use.

Solution 1: 2.5 g of metol 12 g of hydroquinone and 100 g of sodium semitecolo dissolved in 500−700 cmof water and add water to 1 DM.

Solution 2: 100 g of sodium carbonate and 7 g of potassium bromide dissolved in 500−700 cmand adjusted with water to 1 DM.

You can also use other high contrast developers.

Fixing solution: 300 g sodium thiosulfate, 25 g of sodium semitecolo and 8 cmof acetic acid are dissolved in 1 DMdistilled water.

Allowed to use other equipment, equipment and materials, provided that the metrological characteristics of analysis and lower limits defined by the mass fraction of elements.

Crucibles or bowls quartz GOST 19908.

Absorbent cotton wool GOST 5556.

Standard samples for composition of copper or copper oxide, or synthetic blends.

(Changed edition, Rev. N 1, 2).

3. PREPARATION FOR ASSAY

3.1. Sample and in tablet mass (0,5±0,05) g with a diameter of 6 mm and height 2 mm made in any metal cutting equipment, or manually from any of pieces of arbitrary shape.

Samples WITH the required mass can be cut (sawn) from rods or pressed from shavings. Chips pre-atminciai. Then chips and a pill is cleaned from surface contamination — etching in nitric acid (1:10). Chips and tablets WITH washed in distilled water, alcohol and dried. During the pressing of tablets from the chip matrix and the punch is carefully cleaned from the remnants of previously molded samples (washed with water and rubbing alcohol). Prepare at least two tablets of each sample and composition.

3.2. Carry out oxidation of co and of samples in an oxygen chamber: all the details of the hyperbaric chamber and graphite supports for samples and cleaned of copper oxides. The rotary table is strengthened in the lower elektrodvigateli camera. To avoid cross contamination of samples on the graphite stand of the rotary table is placed the tablets of the same composition.

In the upper holder reinforcing dummy electrode of copper or coal with a diameter of 6−7 mm, working end of which is sharpened to a truncated cone with an apex angle of 45° and a platform with a diameter of 1.5−1.7 mm. in the Interelectrode gap set to 1.5−2 mm. the Tablet serves as a cathode of the DC arc, the amperage set 6 A. air from the chamber being squeezed, compressed oxygen flowing through the chamber for 30 s. the oxidation of pills the oxygen pressure in the chamber is supported slightly above atmospheric. Tablet under the action of arc for 20−30 with melts and turns into a drop of melted oxides. The current is turned off, and is supplied to the dummy electrode next pill.

3.3. For analysis of the oxide samples average samples are taken for two sample weight of 5−10 g. Sample is placed in varicellae Cup, pour nitric acid, diluted 1:1, at the rate of 10 cmper 1 g of copper was dissolved with heating and evaporated to dry salts. Then the Cup is placed in a muffle furnace and calcined at a temperature of (400±50) °C for 30 min before the termination of allocation of oxides of nitrogen. The resulting powder is ground in an agate (or other) mortar. Mortar and pestle pre-wipe with alcohol. The powder fills the craters of carbon electrodes or compressed into tablets (at least two). The weight of the portion of the sample and must be the same (0,3−0,6±0,05) g.

3.1−3.3. (Changed edition, Rev. N 2).

3.4. Preparation of synthetic mixtures is given in Appendix 2.

(Added, Rev. N 2).

4. ANALYSIS

4.1. The end portion of the electrodes for removal of surface contaminants calcined in an arc of DC current for 20 s at 6−10 And including the electrode-stand as the anode of the arc. Prepared samples and calcined is placed on a graphite holder.

As a front electrode is applied the embers of the brand or high purity copper rods.

The shape and size of the electrodes and their location during the exposure shown in Fig.

4.2. For the determination of arsenic, antimony, lead, tin, bismuth, zinc and phosphorus, cadmium, selenium and tellurium graphite stand is placed on a breakout or use as the anode of the arc. When the current is switched on to melt the sample arc lights between the dummy electrode and the stand and after melting of the anode spot of the arc moves onto the formed melt of oxides. This transition is accelerating because after a few seconds of arc current is turned off and again turn it on until the melt has not yet had time to cool down. Getting exposure is considered after the transition of the anode spot of the arc on the sample. During the whole time of the exhibition it is necessary to adjust the initially established arc gap around the magnified image of the arc on the screen of the objective lens of the lighting system or with a special short throw projection lens.

Shooting conditions the spectrogram: the width of the slit of a spectrograph of 0.010−0.015 mm, the illumination of a slit by using a three-lens Achromat condenser; arc gap is 3 mm; rated current 6 to 8 A; the exposure time of 20−40 s. When using a spectral apparatus with photoelectric registration of spectrum, for example, MFS-8, the registration of spectra is carried out at the entrance slit width of 0.035 mm, the coverage of the raster-condenser, the discharge gap of 3.0 mm, the strength of the arc current is alternating or direct current of 6−10 A, the exposure time of 20−40 s.

4.3. For the determination of cobalt, magnesium, manganese, Nickel, silicon and iron formed kinglet (p.4.2) was placed on a graphite svezhezakachannyh stand and carry out the roasting for 10−15 s, using a graphite stand as the cathode.

Allowed to carry out the second stage without removing the bead from the base at the end of the first stage by changing the polarity of the electrode with the sample, and the amperage of the arc. When using a spectral apparatus with photoelectric registration of spectrum, for example, MFS-8, the registration of spectra is carried out at a discharge gap of 3.0 mm with the application of arc either AC or DC power 5−8 And in the first phase and 8−10 in the second stage, exposure time 30−60 s in absolute or relative modes.

Getting exposure counts after the transition of the cathode spot of the arc on the molten portion of the bead.

Shooting conditions the spectrogram: the width of the slit of a spectrograph — 0,010−0,015 mm; illumination of the slit by using a three-lens Achromat condenser; arc gap is 3 mm; rated current 6 to 8 A; the exposure time is 30−40.

4.4. To determine the silver content of the graphite stand is placed on a breakout or prepared for the analysis according to clause 3, include as the cathode of the arc.

Trial or pre-anneal for 1 min at 5−6 A. the Beginning of the firing counts after the transition of the cathode spot of the arc on the molten portion of the bead. Then, not including the arc, reduce a current of 1−2 A, open the shutter of the spectrograph and to photograph the spectrum of the sample for 20−30 C.

Shooting conditions the spectrogram: the width of the slit of a spectrograph of 0.010−0.015 mm, the illumination of a slit by using a three-lens Achromat condenser, the arc gap is 3 mm.

4.2−4.4. (Changed edition, Rev. N 2).

4.5. In cases where the shooting conditions of the spectra are different from rekomenduemyj (for example, the slit is illuminated by means of single-lens condenser, used a different power current, the other plate sensitivity, etc.), you should choose the conditions to select optimal interval the optical densities of the lines.

The exposure time is adjusted depending on the sensitivity of the used photographic plates, ensuring the normal optical density of the background of the continuous spectrum; otherwise, you have to build the characteristic curve. An increase in the density of the background due to the veils, lighting, etc. is not allowed.

4.6. Photographic plates show depending on their type in the corresponding developer. After washing the plates in tap water they are fixed in fixing solution, washed in running water and dried.

(Changed edition, Rev. N 2).

5. PROCESSING OF THE RESULTS

5.1. In the spectra of the samples and measure the intensity of the analytical lines and lines of comparison or background.

The wavelength of the analytical lines and lines of comparison, as well as ranges of mass fractions of elements for the spectrograph ISP-3 are given in table.2, for a diffraction spectrograph of STE-1 — in table.3. For PV plants ISF — in table.4.

Table 2

Note. Background 1. the optical density of weak molecular lines 235,08 nm, which in the calculations is taken for the optical density of the background.

Background 2 — the minimum value of optical density of the background measured near the line on the side of longer waves.

Background 3 background 259,715 nm. A maximum distance of 0.09 mm from the line of antimony 259,806 nm to shorter wavelengths.

Background 4 — the minimum value of the optical density of the background to the line of copper 287,71 nm from the shorter wavelength.

Background 5 is the maximum value of the optical density of the background, measured at a distance of 0.13 mm from the lead line 283,307 nm in the direction of long waves.

Background 6 means the minimum value of the optical density of the background, measured between lines of copper 288,29 and 288,53 nm.

Background 7 is the optical density of weak lines 283,8 nm, which in the calculations is taken for the optical density of the background.

Background 8 — the minimum value of the optical density of the background, izmerenie next to the line from the shorter wavelength.

Background 9 — 289,60 nm. The second implicitly defined maximum to shorter wavelengths from the line of bismuth 289,797 nm.

Table 3

Note. Background 1 — the minimum value of the optical density of the background measured near the line on the side of shorter waves.

Background 2 — the minimum value of optical density of the background measured near the line on the side of longer waves.

Table 4

Allowed the use of other analytical lines and comparisons provided that they provide the metrological characteristics of analysis and lower limits of this standard.

The calibration graphs are built in coordinates

.

The basic method for graphing is a method of «three standards». Allowed to use other types of graphing, for example, the method of solid calibration curve, the method of control of the Etalon and equation of this graph when processing on a computer.

Mass fraction of the designated contents of elements find the calibration schedule for the value found in the table of Appendix 1 , calculated at three (two) spectrograms, or values of output readings of a measurement instrument , or the values of pucherani spectral lines .

(Changed edition, Rev. N 2).

5.2. The analysis result should be the arithmetic mean of two parallel definitions, if the difference between them at a confidence probability of 0.95 does not exceed the value calculated by the formula

,

where is the arithmetic mean of two parallel definitions %;

 — relative standard deviation.

If exceeded , repeat analysis of new batches of the same sample. In the case of repeated discrepancies analyze a new sample.

5.3. The reproducibility of the results of primary and repeated tests are considered satisfactory if the difference between the results of the two tests does not exceed the value calculated by the formula

.

5.4. Control of accuracy of analysis results — GOST 25086 standard samples of composition of copper or copper oxide, or synthetic mixtures, or by the method of additions at least once a quarter.

5.5. The method used in the dispute in the assessment of quality copper.

5.2−5.5. (Added, Rev. N 2).

ANNEX 1 (mandatory)

ANNEX 1
Mandatory

Table of values corresponding to the measured values , serves for transmission of measured value in magnitude .

The table contains the results of the calculation .

We denote the total intensity of the line together with the background , the intensity of the background under the high line in the absence of the line . Since , the ratio of the intensity to the background intensity is determined by the expression

. (a)

If the conditions of photographing the spectrum chosen so that the optical density of the line background and the background in the absence of the line are in the normal range,

, (b)

where ;

 — contrast ratio.

Hence, using the expression (a), we obtain

.

The table covers the most important to the practice of analytical work values from 0.05 to 1.9.

Consider the expression (0,050,99).

The value printed in bold: 0,05; 0,06 etc. up to 0.99.

In the head of the table the numbers 0, 1, 2 etc. to denote third 9 after the decimal sign magnitude and printed in bold.

Having a certain value , for example, 0,537, find the line of 0.53 corresponding to the first two decimals and in column 7, we get the corresponding value 0,388.

Similarly, for 0,143 0,14 in the line in graph 3 we get the corresponding value .

Part of the table, covering values from 1.0 to 1.99, built in a similar way with the difference that in the first left column the value is shown only with one decimal and the numbers 0, 1, 2 etc to 9 at the head of the table denote the second after the decimal point, the sign of the value .

So, having a value of 1.36, in line 1 3 in column 6 resulting 1,341.

For values smaller than had 0.301, the characteristic is negative, which is denoted by a minus sign over the characteristic (, …).

Since , this table can be used to find values corresponding to values , however they were not measured.

In routine analytical work it is permissible to omit the measurement taking 1. This is a simplification of several curves calibration curve, if different from unity, but does not lead to significant errors in the analysis, since the same effect on the values obtained for WITH and samples.

Values corresponding to measured values

APPENDIX 2 (recommended). PREPARATION OF SYNTHETIC MIXTURES

ANNEX 2
Recommended

Synthetic mixes are a powder of copper oxide obtained by dissolving the pure base in nitric acid, the introduction of the dosed additives of solutions of impurities and a subsequent evaporation and thermal decomposition of mixtures of nitrates.

1. Equipment, reagents, solutions

Analytical scale any type of 2nd class of accuracy.

The furnace chamber of any type with thermostat.

The agate mortar.

Bowl quartz GOST 19908.

Banks, polyethylene, PTFE, with screw-on lids or boxy according to GOST 25336.

Carbonyl iron is particularly clean.

The brand Vi00 bismuth GOST 10928.

Copper grade M00k GOST 859.

Tin is not below grade 01 according to GOST 860.

Cadmium brand Кд0 according to GOST 1467.

The brand Н1у Nickel GOST 849*.
_______________
* On the territory of the Russian Federation the document is not valid. Standards 849−2008. — Note the manufacturer’s database.

Silver GOST 6836*.
_______________
* On the territory of the Russian Federation the document is not valid. Standards 6836−2002. — Note the manufacturer’s database.

Cobalt grade K0 GOST 123*.
_______________
* On the territory of the Russian Federation the document is not valid. Valid GOST 123−2008. — Note the manufacturer’s database.

Chrome brand H99N1 according to GOST 5905*.
_______________
* On the territory of the Russian Federation the document is not valid. Standards 5905−2004. — Note the manufacturer’s database.

Manganese brand Мр00 according to GOST 6008.

Lead brands S0 GOST 3778*.
________________
* On the territory of the Russian Federation the document is not valid. Valid GOST 3778−98. — Note the manufacturer’s database.

Phosphorus GOST 8655.

Tellurium GOST 17614.

Selenium GOST 10298.

Zinc brand of C0 according to GOST 3640.

Antimony brand Su00 according to GOST 1089.

Arsenic metal.

Sodium meta-silicate 9-water or tetraethoxysilane.

Lead (II) nitrate according to GOST 4236.

Nitric acid according to GOST 4461 (distilled in quartz apparatus) or nitric acid high purity according to GOST 11125 and diluted 2:1, 1:1.

Hydrochloric acid according to GOST 3118.

Tartaric acid according to GOST 5817.

Oxalic acid according to GOST 22180.

Sodium hydroxide according to GOST 4328, solution 100 g/DM.

The technical rectified ethyl alcohol according to GOST 18300.

Silver nitrate according to GOST 1277, a solution of 20 g/DM.

Deionized water obtained by passing distilled water through an ion exchange column with cation exchange resin, or water bidistilled.

2. Preparation of solutions of impurities

2.1. Each hanging mass 0,6250 g of Nickel, cobalt, iron, zinc, lead, bismuth, cadmium, arsenic, phosphorus, silver, selenium, tellurium dissolved in 25 cmof nitric acid in separate beakers with a capacity of 250 cm, the solutions were transferred to volumetric flasks with a capacity of 250 cm, and topped to the mark with nitric acid, diluted 1:1.

1 cmof each solution contains 2.5 mg of each of the above impurities.

2.2. A sample of chromium weighing 0,6250 g dissolved in 20−30 cmof hydrochloric acid in a boiling water bath. Then the solution is evaporated to dry salts. Add 5−10 cmof nitric acid and evaporated to moist salts. The processing operation of the salts of nitric acid is carried out three times. Then pour 100 cmof nitric acid, diluted 1:1, put the resulting solution in a volumetric flask with a capacity of 250 cm, and topped to the mark with nitric acid (1:1).

From the resulting solution sampled 10−20 cmand placed in a beaker with a capacity of 50 cmto test for the presence of chlorine-ion with a solution of nitrate of silver. When the solution revealed the presence of chlorine-ion, the operation of the treatment with nitric acid is repeated.

1 cmof solution contains 2.5 mg of chromium.

2.3. The weight of tin weight of 0,6250 g were placed in a glass with a capacity of 250 cm, add 5 g of oxalic acid and 20 cmof nitric acid, diluted 2:1, incubated without heating to dissolve the sample. Transfer the solution into a measuring flask with a capacity of 250 cm, and topped to the mark with nitric acid (2:1).

1 cmof solution contains 2.5 mg of tin.

2.4. A portion of the antimony by weight 0,6250 g placed in a beaker with a capacity of 250 cm, add 4 g of tartaric acid and then dissolved in excess of hot nitric acid when boiled. The solution was transferred to a volumetric flask with a capacity of 250 cm, and topped to the mark with nitric acid, diluted 1:1.

1 cmof solution contains 2.5 mg of antimony.

2.5. A portion of silicate of sodium with a mass 1,0117 g is placed in a volumetric flask with a capacity of 100 cm, dissolved in 5−7 cmof water and topped up to the mark with nitric acid, diluted 1:2, or a portion of tetraethoxysilane weight 0,7418 g is placed in a volumetric flask with a capacity of 100 cm, was dissolved in ethanol and topped up to the mark with alcohol.

1 cmof the solution contains 1 mg of silicon.

2.6. A portion of the arsenic, pre-cleaned from oxide films by mass 0,6250 g were placed in a glass with a capacity of 250 cm, 100−150 cm pourboiling nitric acid and dissolved by heating. After cooling, the solution is transferred to a volumetric flask with a capacity of 250 cm, and topped to the mark with nitric acid, diluted 1:1.

1 cmof solution contains 2.5 mg of arsenic.

2.7. A portion of nitric acid lead weight 0,9988 g is placed in a volumetric flask with a capacity of 250 cm, dissolved in 10−15 cmof water and topped up to the mark with nitric acid, diluted 1:1.

1 cmof solution contains 2.5 mg of lead.

3. Preparation of synthetic mixtures

3.1. Preparation of solutions of impurities

Solution 1: in a volumetric flask with a capacity of 250 cmis placed 10 cm innitric acid solutions of tin, cobalt, manganese, bismuth, cadmium, arsenic, tellurium, chromium and topped to the mark with nitric acid, diluted 1:1.

1 cmof the solution 1 contains 0.1 mg of these impurities.

Solution 2: in a volumetric flask with a capacity of 250 cmis placed 10 cm innitric acid solutions of lead, Nickel, antimony, zinc, selenium and topped to the mark with nitric acid, diluted 1:1.

1 cm2 of solution contains 0.1 mg of these impurities.

Solution 3: in a volumetric flask with a capacity of 100 cmis placed 20 cm innitric acid solutions phosphorus, iron, silver and topped to the mark with nitric acid, diluted 1:1.

1 cm3 of solution contains 0.5 mg of these impurities.

A solution of 4 to 10 cmof a solution of silicate of sodium is placed in a volumetric flask with a capacity of 100 cmand then filled to the mark with nitric acid, diluted 1:1, or 10 cmalcohol solution of tetraethoxysilane was placed in a volumetric flask with a capacity of 100 cmand then filled to the mark with alcohol.

1 cmof the solution 4 contains 0.1 mg of silicon.

3.2. Preparation of solutions of copper

In a number of beakers (depending on the number of mixtures) with a capacity of 2000 cmis placed on 200 g of copper, pour nitric acid, diluted 1:1 rate of 7−8 cm/ 1 g of copper, and dissolved by heating.

3.3. In the resulting solutions of copper enter the calculated volumes (depending on the contents of the determined elements) solutions 1−4, evaporated to dry salts, transferred to a quartz Cup and calcined at a temperature of 600−650 °C until the complete decomposition of nitrates, removal of nitrogen oxides.

The oxide mixture ground in a mortar or crushed in any way, prevent pollution of material defined by the items. Estimated mass fraction of elements in synthetic mixtures is given in the table.

Mixture and copper oxide without impurities stored in buksh or jars with screw caps. The method of storage needs to eliminate the possibility of contamination and moisture mixtures. Under these conditions the shelf life of the mixtures of 5 years.

Change the mass of the batches of copper and impurities, depending on the needs in mixtures and the mass fraction of elements, the composition of the analyzed samples with the appropriate conversion.

The use of mixtures allowed after their certification in the prescribed manner.

APPENDIX 2. (Added, Rev. N 2).