GOST 16274.9-77
GOST 16274.9−77 Bismuth. Chemical-spectral method of determination of gold (with Amendments No. 1, 2, 3)
GOST 16274.9−77
Group B59
STATE STANDARD OF THE USSR
BISMUTH
Chemical-spectral method of determination of gold
Bismuth. Spectrochemical method for determination
of gold content
AXTU 1709
Date of introduction 1978−01−01
INFORMATION DATA
1. DEVELOPED AND INTRODUCED by the Ministry of nonferrous metallurgy of the USSR
DEVELOPERS
PS Poklonsky, F. M. Manji, G. V. Khabarova
2. APPROVED AND promulgated by the Decree of the State Committee of standards of Ministerial Council of the USSR from
3. The frequency of inspection 5 years
4. INTRODUCED FOR THE FIRST TIME
5. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS
| The designation of the reference document referenced |
Paragraph number section |
| GOST 3118−77 |
Sec. 2 |
| GOST 11125−84 |
Sec. 2 |
| GOST 16274.0−77 |
1.1 |
| GOST 16274.1−77 |
4.1 |
| GOST 16274.8−77 |
Sec. 2 |
| GOST 19908−90 |
Sec. 2 |
| GOST 23463−79 |
Sec. 2 |
6. Resolution of the state standard from
7. REPRINT (July 1997) with Amendments No. 1, 2, 3, approved in January 1983, June 1987, July 1992 (IUS 5−83, 11−87, 10−92)
This standard applies to bismuth brands Ви0000, Ви000 and installs chemical-spectral method of determination of gold in gold content from 1·10to 1·10
%.
The method is based on the chemical enrichment of gold by the extraction of its diethyl ether from hydrochloric acid solution with a molar concentration of 6 mol/DMand subsequent spectral analysis of the concentrate using the three benchmarks.
(Changed edition, Rev. N 1, 2).
1. GENERAL REQUIREMENTS
1.1. General requirements for method of analysis according to GOST 16274.0.
2. APPARATUS, MATERIALS AND REAGENTS
The quartz type spectrograph ISP-30 (complete set).
A constant current source to power the arc, providing a voltage of 200−400 V and a current of 20 A. the Enrichment of lead from two parallel batches.
The lathe with a set of shaped cutters for sharpening carbon electrodes.
Electrodes, carbon, grades S-2 and S-3.
Microphotometer designed to measure pucherani spectral lines (complete set).
Spectrographic plates of type III.
Cup quartz GOST 19908.
Electric muffle furnace to regulate the temperature to 700 °C.
Tile electrical heating with a closed spiral.
Pad for electrodes.
Hydrochloric acid according to GOST 3118 and a solution with a molar concentration of 6 mol/DM.
Nitric acid of high purity according to GOST 11125 and diluted 1:1.
Bismuth oxide spectral-pure; prepared as described in GOST 16274.8.
Ethyl ether (diethyl).
Funnel separating.
Torsione type scales W, the weighing limit up to 1000 mg.
Graphite powder of high purity according to GOST 23463 or obtained from carbon electrodes.
Samples of comparison for the determination of gold, prepared according to the Annex to GOST 16274.1
Note. Allowed the use of devices with photovoltaic spectra and other spectral instruments, other reagents, materials and photographic plates, generating accuracy metrics defined in this standard.
(Changed edition, Rev. N 1, 2, 3).
3. PREPARATION FOR ASSAY
3.1. The concentration of gold
A sample of bismuth with a mass of 5 g was placed in a quartz glass with a capacity of 300 cmand dissolve in low heat 15−20 cm
Aqua Regia. The solutions were evaporated to obtain a wet salts, pour 3 cm
of hydrochloric acid and again evaporated to moist salts. The residue is dissolved in 40 cm
of a hydrochloric acid solution and transferred to a separatory funnel, then add 60 cm
of ether, and the funnel vigorously shaken for 2 min. Then repeat the extraction twice, adding each time a new portion of ether at 60 cm
.
The ether extracts are combined in a Cup for evaporation and evaporated to a volume of 8−10 cm. To the residue was added 50 mg of spectral pure oxide of bismuth, are added 5 cm.
of nitric acid diluted 1:1, and evaporated to dryness. The precipitate is then twice treated with 2−3 cm
of nitric acid, evaporating to dryness each time. The resulting precipitate was calcined on a hot stove, and then in a muffle at a temperature of 500−550 °C for 15 min and weighed. Enrichment of lead from the four parallel batches.
Through all stages of the analysis carried out in the control sample. As the basis for the sample using the spectral-pure oxide of bismuth in an amount equal to the mass of the enriched sample.
The coefficient () is calculated by the formula
where is the mass of the original sample of bismuth, g;
— the mass of the enriched sample, g;
0,897 — the ratio of bismuth oxide to bismuth.
Enriched sample and a sample control transfer experience for spectral analysis.
(Changed edition, Rev. N 2).
4. ANALYSIS
4.1. Spectral determination of gold in extract.
Carbon electrodes are pre-fired in an arc, the DC power of 12 And for 15 S.
The concentrate of gold of the sample, the control sample and the reference sample is mixed with graphite powder in a ratio of 5:1 and 27 mg is placed in the channels of the graphite electrodes. The spectra are photographed on the spectrograph ISP-30 in the arc of a DC power 12−13 A. the exposure Time was 50 s. the slit Width of the spectrograph 0.01 mm.
Quartz condenser with a focal length set 75 mm from the light source at a distance of 100 mm from the slit 316 mm.
The image of the electrodes projecting on the intermediate aperture 5 mm in from the slit of 100 mm. Range photographed on a photographic plate of the type III.
For the determination of gold using the analytical line 267,6 nm. The blackening of the lines and the background next to the line on the spectrogram measured on microphotometer.
(Changed edition, Rev. N 1, 2, 3).
5. PROCESSING OF THE RESULTS
5.1. The calculation of the analysis results produced by the method given in GOST 16274.8 (p.2.4.5). For the results analysis be the arithmetic mean of results of four parallel measurements obtained on two photographic plates (for two definitions on each plate, each definition of the two spectrograms). The analysis result should be the arithmetic mean of two parallel definitions (each definition of the two spectrograms) obtained on the same photographic plate.
(Changed edition, Rev. N 1, 2, 3).
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 values given in the table.
| Mass fraction of gold, % |
The discrepancy between the results of two parallel definitions % | The discrepancy between the results of two tests, % |
1·10 |
0,8·10 |
1·10 |
3·10 |
2·10 |
3·10 |
1·10 |
0,8·10 |
1·10 |
3·10 |
2·10 |
3·10 |
1·10 |
0,8·10 |
1·10 |
Permitted discrepancies for the intermediate mass fraction calculated using linear interpolation or according to the formulas:
where is the arithmetic mean of the results of parallel measurements;
— the arithmetic mean of the results of the two tests.
(Changed edition, Rev. N 3).
