GOST 17235-71
GOST 17235−71 Gold alloys. Spectral method of determination of bismuth, antimony, lead and iron (with Change No. 1)
GOST 17235−71*
Group B59
STATE STANDARD OF THE USSR
GOLD ALLOYS
Spectral method of determination of bismuth, antimony, lead and iron
Gold alloys. Spectral method for determination of bismuth, antimony, lead and iron content
AXTU 1709
Date of introduction 1973−01−01
The decision of the State standards Committee of the USSR Council of Ministers from October 25, 1971 N 1759 the introduction of set with 01.01.73
Proven in 1985 by the Resolution of Gosstandart from
REPLACE GOST 7980−56 in part of sec. VI-X
* REISSUE (January 1986) Change N 1, approved in February 1985 (I & C 5−85).
This standard applies to the gold-silver-copper, gold-copper and gold-silver alloys and establishes a spectral method for the determination of bismuth, antimony, lead (with a mass fraction of from 0.002 to 0.01% each) and iron (in mass fraction from 0.01 to 0.20%).
The method is based on measurement of the intensities of analytical lines of impurities in the arc spectrum. The relationship of intensity with concentration is established by calibration with standard samples of the system. The electrodes were applied to the rods of the analyzed alloy.
1. GENERAL REQUIREMENTS
1.1. General requirements for method of analysis according to GOST 22864−83.
2. APPARATUS, REAGENTS AND SOLUTIONS
Quartz spectrograph medium dispersion.
The generator is activated the arc AC.
Microphotometer.
Clips for electrodes with forced cooling.
Photographic plates of the spectral sensitivity of 10−15 conventional units .
Standard samples of the enterprise, made by the specialized organizations for the production of precious metals.
Hydrochloric acid by the GOST 3118−77.
Developer and fixer according to GOST 10691.0−73*, GOST 10691.4−73**.
________________
* On the territory of the Russian Federation the document is not valid. Valid GOST 10691.0−84;
** In the territory of the Russian Federation the document is not valid. Standards 10691.4−84. — Note the manufacturer’s database.
3. PREPARATION FOR ASSAY
Samples and standard samples are taken in the form of cast rods with a diameter of 6 mm, a length of 20−30 mm. Rods with both ends sharpened to a hemisphere or a truncated cone with ground diameter of 1.5−1.7 mm.
To remove surface contamination samples standards and samples were placed in a glass, pour diluted 1:1 hydrochloric acid, boiled for 3 min, then washed with water and dried.
(Changed edition, Rev. N 1).
4. ANALYSIS
Photographing spectra is produced when the width of the slit of a spectrograph 0.010 mm, the distance between the electrodes is 1.5 mm, the current strength of the arc And 5−7, the time of the preliminary firing 20 C exposure time 30−60 s. the Interelectrode gap is set by the template. Electrodes serve as cast members. The spectra are photographed on photographic plates of the spectral type II. Together with the samples on the same plate photographed spectra of standard samples analyzed grade alloy.
For each sample and the standard sample receive four parallel spectrogram.
Photographic plates showing within 3 min when the temperature of the developer is 18−20 °C. the Shown plate is rinsed in water, fixed, washed in running water and dried.
(Changed edition, Rev. N 1).
5. CALCULATION OF RESULTS OF ANALYSIS
5. PROCESSING OF THE RESULTS
Analytical lines are recommended for analysis, and identify intervals of the concentrations given in the table.
| The designated element |
Wavelength in nm |
Element comparison |
The range of detectable concentrations, % | |||
| Bismuth |
306,772 289,797 |
Background in the long wavelength side |
From |
0,001 | to | 0,01 |
| Lead |
266,316 261,418 |
The same |
« | 0,001 | « | 0,01 |
| Antimony |
259,806 |
« |
« | 0,001 | « | 0,01 |
| Iron |
259,940 |
« |
« | 0,01 | « | 0,05 |
| 258,588 |
« | « | 0,05 | « | 0,20 | |
For all impurities, the element of comparison is the background of the continuous spectrum. The background value should be in the region of normal pochernenija.
The concentration of impurities is determined using the three standards with the objective photoretrieval. Build calibration graphs for each element being measured. The ordinate of the delay values of the logarithm of the relative intensity of the impurity lines and the background, and the abscissa shows the value of the logarithm of concentration of standard samples. With the help of calibration curve by the known values of the logarithm of relative intensity find concentrations of impurities in the sample.
The convergence of the results of parallel measurements are characterized by a relative standard deviation not to exceed 0,15.
(Changed edition, Rev. N 1).
