GOST 23189-78

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  ГОСТ 23189-78

GOST 23189−78 Aluminium primary. Spectral method for the determination of arsenic and lead (Change No. 1)

GOST 23189−78

Group B59

INTERSTATE STANDARD

ALUMINIUM PRIMARY

Spectral method for the determination of arsenic and lead

Primary aluminium. Spectrochemical method for the determination of arsenic and lead

ISS 77.120.10
AXTU 1709

Date of introduction 1980−01−01

The decision of the State Committee of standards of Ministerial Council of the USSR of 26 June 1978 N 1671 date of introduction is established 01.01.80

The expiration time limit is removed by the Resolution of Gosstandart of the USSR from 03.06.91 N 773

EDITION with Change No. 1, approved in June 1989 (IUS 9−89)


This standard specifies the method of spectral determination of arsenic (in mass fraction from 0.001 to 0.015%) and lead (at a mass proportion of from 0.01 to 0.15%) in primary aluminum.

(Changed edition, Rev. N 1).

1. GENERAL REQUIREMENTS

1.1. The content of arsenic and lead in aluminum is determined by calibration graphs constructed for each element by the method of «three standards». The spectrum can be photographic and photoelectric.

The analysis of the photographic method of calibration graphs constructed in the coordinates: (if 0,50),

where is the difference of pochernenija lines of the designated element and an element of comparison;

 — concentration of the analyzed element in the standard samples;

 — the intensity of the line of the element minus the intensity of the nearby background;

 — relative strength line of the designated item and line comparison.

If line comparison is the background close to the analytical line, the coordinates are:

where .

The analysis of the PV method, the calibration graphs constructed in the coordinates: ; ,

where is the concentration of the analyzed element in the standard samples;

 — the readings of the output of the measuring device, is proportional to the logarithm of the relative intensity of the lines defined by item and line comparison.

(Changed edition, Rev. N 1).

1.2. For quantometer in which the readings of the output of the device proportional to the relative intensity of spectral lines, calibration curve constructed in the coordinates: or .

1.3. For evaporation of the sample and the excitation spectrum using arc generators.

1.4. When conducting analysis using state, industry standard samples or standard samples of the enterprise. To control the correctness of the results of analysis using GSO.

(Changed edition, Rev. N 1).

2. SAMPLING

2.1. The selection and preparation of samples for analysis is carried out according to GOST 3221−85 with the following additions: the surface of the end electrode with a diameter of 8−10 mm after sharpening on the plane of the handle rough with a file (to obtain a rough surface). When re-analysis cut off not less than 2−3 mm along the length of the electrode and re-treated with a coarse file. The roughness with this method of sharpening control not be.

The analyzed sample is the lower electrode. The upper electrode is a spectral-pure carbon electrode with a diameter of 6 mm. the Upper electrode is confined to a hemisphere with a radius of 3−6 mm, cone angle 120° or truncated cone with ground diameter of 1−2 mm with a sharpening angle of 40−60°. Allowed sampling in the form of a cylinder for analysis using quantometer.

After analyzing 8−10 electrodes, the electrode holders rubbing alcohol to clean off the aluminum oxide.

(Changed edition, Rev. N 1).

3. SPECTROGRAPHIC METHOD

3.1. The essence of the method

The method is based on the excitation spectrum of the arc discharge with subsequent registration on the photographic plate by a spectrograph.

3.2. Apparatus, materials and reagents

Spectrograph with quartz optics type ISP-30 or STE-1.

Generator type IVS-23, IVS-28, UGE-4. Allowed to use other sources of excitation spectrum, providing the desired mode of operation when conducting analysis.

Microphotometer type IPV-460, MF-2 or S-2.

Spectral-pure coals brand C2 in the form of bars with a diameter of 6 mm on the other 16583−240−74.

Photographic plates of the spectral types S, OFS, «Micro», 3−130 sensitivity units in GOST 10691.0−84-GOST 10691.4−84 or similar.

The lathe, bench type ТВ16.

The machine tool for sharpening of electrodes of the type КП35.

Vise.

Files.

Air-conditioned room type 1CS-12A, CT-2 or similar.

Reliever nine-platinum.

The technical rectified ethyl alcohol GOST 18300−87 (flow rate 1 ml per 2 electrode).

Photoreactive for processing of photographic plates by GOST 3221−85.

Absorbent cotton wool GOST 5556−81.

Permitted to use other equipment and materials, ensuring accuracy of analysis results is not worse than the regulated by this method.

(Changed edition, Rev. N 1).

3.3. Analysis

The conditions of analysis with photographic method are given in table.1.

Table 1

Notes:

1. The parameters selected in the range of specified values.

2. The exposure time is selected depending on the sensitivity of photographic plates, roughly 100−120 C.


When working according to the method of «three standards» perform the following operations:

a) choose at least five standard samples;

b) photographing the spectra of the standard and analyzed samples at least four times on two different photographic plates (for 2 spectra of standard and test sample on the plate);

C) manifest and process the photographic plates by GOST 3221−85 with the following additions: when using the photographic plates of the type UFS futurestory preparing for instruction to these photoplates;

g) measure the blackening of analytical lines and the background in the vicinity of these lines;

d) calculate the magnitude of the difference pucherani () for lines of lead and aluminum and the arithmetic average of 2−3 spectra;

e) at the characteristic curve (carefully constructed for neoteric for 9-step platinum attenuator) and the corresponding design adaptations translate blackening line of arsenic and the background intensity . Compute the logarithm of relative intensity,

and

2−3 spectra;

g) build the calibration graphs in the coordinate to determine the content of lead and coordinates for the determination of arsenic. These charts are suitable for the analysis of those samples whose spectra photographed together with the spectra of standard samples on a single photographic plate;

h) determine the content of element in aluminum on the relevant calibration chart.

Note. In the analysis of in-plant production assessment of arsenic and lead in aluminum is allowed to produce one standard sample of the enterprise. In this sample, the mass fraction of arsenic should be about 0,006%, and lead is 0.05% (no more). In this case, it is allowed to certify aluminium as «less than 0.01%" for arsenic and «less than 0,1%" for lead, if the intensity of the analytical lines in the sample will be less than the intensity of corresponding lines in the standard sample (standard testing conditions).

If the intensity of the lines of arsenic or lead in the samples more than the standard sample (reference sample), the analysis is repeated with a full set of standard samples.

3.2, 3.3. (Changed edition, Rev. N 1).

3.4. Processing of the results

3.4.1. The results of electrophoretic spectra of samples find and . Further, according to the relevant calibration chart find the mass fraction of lead and arsenic in the samples in percent. Repeat all the operations for the second photographic plates. For each item, therefore, have two values: and .

3.4.2. For the results analysis be the arithmetic mean of parallel definitions ().

,

where ,  — unit results determine the mass fraction of the component obtained in the first and second photographic plate in one shift.

The discrepancy between two single results of analysis (the measure of convergence), obtained using a single excitation source spectra should not exceed at a confidence probability of 0.95 the values of permissible differences given in table.2.

.

The discrepancy between two single results of analysis (the measure of reproducibility) obtained in different shifts should not exceed the values of permissible differences given in table.2.

The variance of a single result (a) determine the mass fraction of impurity in the standard samples used to control the accuracy of the analysis, which simultaneously photographed the spectra with the spectra of the analyzed samples and the certified values of mass fractions of impurities should not exceed the values given in table.2.

.

3.4.3. When the divergence of individual analysis results , and more than the value , the analysis should be repeated (including two made definitions) by setting the required number of parallel measurements by the formula

,

where is the divergence of individual results of determinations obtained in the analysis.

 — established values of acceptable differences (tab.2).

The final result is taken the arithmetic average of the individual denitions in the confidence interval, the corresponding confidence interval of the arithmetic mean that would be obtained in accordance to the standards table.2.

Table 2

3.4.4. Control the reproducibility of the analysis results fulfil at least 1 time per quarter.

If the discrepancy between the results of primary and repeated tests exceeds the values given in table.2, no more than 5% of cases, the reproducibility of the spectral method is considered satisfactory.

For re-definitions of the necessary amounts of control samples set at OST 48−292−86.

3.4.5. Control of the correctness of the results of the analysis performed at the state standard samples (GSO), guiding him through the entire course of the analysis in accordance with clause 3.3.

Control the correctness of the results of the analyses must be undertaken after a long break in work, repair of equipment.

The correctness of the analysis except with the use of GSO, is also checked by chemical method according to GOST 12697.11−77 and GOST 12697.12−77.

The coincidence of the two methods can be considered satisfactory if the condition

,

where and  — mass fraction of component a defined spectral and chemical methods, respectively, %;

,  — indicators of convergence for spectral and chemical methods given in the relevant standards, %.

Allowed the use of other methods according to certified methods with the metrological characteristics are not inferior to this standard.

3.4.2−3.4.5. (Added, Rev. N 1).

4. PHOTOELECTRIC METHOD OF ANALYSIS

4.1. The essence of the method

The method is based on the evaporation of the sample and the excitation spectrum of the arc discharge with subsequent registration with the photovoltaic installation.

4.2. Apparatus, materials and reagents according to claim 3.2 with the following additions:

the installation of a photovoltaic type MFS-4, MFS-6, MFS-8;

generator type geu-1, UGE-4, IVS-28, IVS-23.

Allowed to use other equipment, equipment, materials and reagents, subject to obtaining the metrological characteristics are not worse than specified in this standard. The equipment must be certified in accordance with GOST 8.326−89* and documentation of departmental metrological service.
_______________
* On the territory of the Russian Federation are PR 50.2.009−94**.
** In the territory of the Russian Federation to apply the Procedure of testing standard specimens or measurement facilities for the purposes of type approval, the Procedure for approval of type of standard samples or type of measuring instruments, the Procedure for issuing certificates on approval of type of standard samples or type of measuring instruments, establishment and changing of the validity period of these certificates and the interval between verifications of measuring instruments, Requirements to the signs of type approval for standard samples or type of measuring instruments and their application, approved by order of Minpromtorg of Russia of 30 November 2009 # 1081. — Note the manufacturer’s database.

(Changed edition, Rev. N 1).

4.3. Analysis

By the photoelectric method of analysis used the method of «three standards» and «reference standard».

The width of the entrance slit of polychromator 0.02 mm, the width of the output slit of 0.04−0.10 mm (depending on model quantometer).

It is desirable to set the slit with a minimal width.

The remaining terms of the analysis of the PV method are given in table.3.

Table 3

Note. The parameters selected in the range of specified values.

4.4. Processing of the results

4.4.1. Processing of the results performed according to claim 3.4. Mass fraction of the element in the analyzed sample determined by the calibration schedule, constructed in the coordinates or .

For the results analysis be the arithmetic mean of parallel definitions ()

,

where and  — unit results determine the mass fraction of a component made in one shift.

Permissible differences that characterize the repeatability and reproducibility of the results, given in table.2.

When determining the mass fraction of arsenic near the border brand of aluminium GOST 11069−2001, the amount of parallel measurements is calculated by GOST 3221−85.

(Changed edition, Rev. N 1).

4.4.2. (Deleted, Rev. N 1).