GOST 22518.4-77
GOST 22518.4−77 Lead of high purity. Spectral method for determination of mercury (with Amendments No. 1, 2, 3)
GOST 22518.4−77
Group B59
STATE STANDARD OF THE USSR
LEAD OF HIGH PURITY
Spectral method for determination of mercury
Lead of high purity. Spectral method for the determination of mercury
AXTU 1709
Date of introduction 1978−01−01
INFORMATION DATA
1. DEVELOPED AND INTRODUCED by the Ministry of nonferrous metallurgy of the USSR
DEVELOPERS
HP Garcin, L. K. Larina
2. APPROVED AND promulgated by the Decree of the State Committee of standards of Ministerial Council of the USSR from
3. INTRODUCED FOR THE FIRST TIME
4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS
The designation of the reference document referenced |
The number of the paragraph, subparagraph |
GOST 4658−73 |
Sec. 2 |
GOST 22518.1−77 |
1a.1 |
GOST 22861−93 |
Sec. 2 |
GOST 23683−89 |
Sec. 2 |
5. The expiration TIME LIMIT is removed by the Resolution of Gosstandart from 08.04.92 377
6. The re-release (Dec 1996) Amendments No. 1, 2, 3, approved in January 1983, June 1987, April 1992 (IUS 5−83, 9−87, 7−92)
This standard sets the spectrographic method for the determination of mass fraction of mercury in lead of high purity grades S0000, S000 and S00 from 1·10to 1·10%.
The method is based on the method of the three standards with the evaporation of mercury from the crater of the carbon electrode in the arc DC.
1. GENERAL REQUIREMENTS
1.1. General requirements for method of analysis according to GOST 22518.1.
(Changed edition, Rev. N 2).
1a. SAFETY REQUIREMENTS
1a.1. Safety requirements — according to GOST 22518.1.
Sec. 1A. (Added, Rev. N 1).
2. APPARATUS, MATERIALS AND REAGENTS
The quartz spectrograph medium dispersion type of ISP-28 or ISP-30 (complete set).
Generator DC arc providing a voltage of 200−400 V and the current intensity of 30 A.
Microphotometer of any type, allowing to measure the density of the blackening of analytical lines.
Grinding machine carbon electrodes.
A vertical tube furnace at 300 watts.
Analytical scale with a weighing error of no more than 0.0002 g and a torsion scales with a weighing error of no more than 0.001 g.
Chrome-plated tweezers with tips made of PTFE.
Spatulas made of organic glass.
Scalpel medical.
Carbon electrodes with a diameter of 6 mm, prepared from coals stamps-2 or S-3, form «glass» (head height 27 mm, depth of the crater 15 mm, diameter 4.5 mm, neck length of 4 mm, neck diameter 2 mm) and contradicted 50 mm length, sharpened at one end to the truncated cone.
Spectrographic plates of the type I.
Paraffin according to GOST 23683.
Mercury GOST 4658.
Lead according to GOST 22861.
Crucibles of iron.
Developer metagitnionom.
Fixer is acidic.
Samples comparison.
Note. Allowed the use of devices with photoelectric registration of spectrum and other spectral instruments, other reagents, materials, photographic plates, generating accuracy metrics that are regulated by this standard.
(Changed edition, Rev. N 1, 2, 3).
3. PREPARATION FOR ASSAY
3.1. The basis for the preparation of comparison samples is metallic lead with a mass fraction of mercury is less than 5·10%. The parent sample containing 1% of mercury, prepared as follows: a portion of mercury wrapped in a lead foil and dipped in molten lead. The temperature of the melt to approximately 350 °C. To reduce oxidation of the molten lead melt is carried out under a layer of paraffin. The melt is stirred quartz or graphite stick for 10 min and poured into a porcelain Cup.
A series of working samples comparison with a mass fraction of mercury 1·10, 3·10, 1·10, 5·10% prepared by successive dilution of the base by fusing.
(Changed edition, Rev. N 1, 3).
4. ANALYSIS
4.1. A portion of the sample or samples comparison of mass 1 g in the form of small pieces is placed in a hole of the electrode «glass». The prepared electrode was heated in a vertical tubular furnace for 20 to 30 C until the melt of metal in the electrode. The furnace has a temperature of 350−380 °C.
4.2. Three range of samples comparisons and six spectra of the sample photograph on a photographic plate. Illumination system slit — two -. Normalisierung condenser 75 installed on the light source at a distance of 100 mm from the slit — 316 mm. exposure Time 20 s. DC-Arc force 15 A. On the same plate photographed through a nine-reliever facilities iron to build the characteristic curve.
4.1, 4.2. (Changed edition, Rev. N 3).
5. PROCESSING OF THE RESULTS
5.1. The resulting spectrograms using microphotometry measure the blackening of analytical lines of mercury Hg 253,6 nm and minimum darkening of the background to the right and left of it. The average of the two measurements of the background accept as true darkening of the background. On the measured values and using the characteristic curve, determine the logarithms of the intensity of the line and background and the logarithm of the background intensity . Find . Build graphics in the coordinates , where — mass fraction of mercury in the samples comparison. The samples of the comparison find the mass percent of mercury in the sample.
The analysis result should be the arithmetic mean of two parallel definitions for the three spectrograms, each received on one photoplastic
E.
5.2. Discrepancies in the results of two parallel measurements () and the results of two tests () at a confidence probability of 0.95, should not exceed the permissible differences given in table.
Mass fraction of mercury, % |
The discrepancy between the results of parallel measurements , % |
The discrepancy between the results of two tests , % |
1·10 |
0,3·10 |
0,4·10 |
2·10 |
0,6·10 |
0,8·10 |
4·10 |
1·10 |
2·10 |
8·10 |
2·10 |
3·10 |
1·10 |
0,3·10 |
0,4·10 |
Permitted discrepancies for the intermediate mass fraction of mercury is calculated by the formula
;,
where is the arithmetic mean of the results of parallel measurements;
— the average of the two results of the analysis.