GOST 12555.1-83
GOST 12555.1−83 Alloys, silver-platinum. Method for the determination of silver (with Change No. 1)
GOST 12555.1−83
Group B59
INTERSTATE STANDARD
ALLOYS OF SILVER AND PLATINUM
Method for the determination of silver
Silver-platinum alloys. Method for the determination of silver
AXTU 1709
Date of introduction 1984−07−01
INFORMATION DATA
1. DEVELOPED AND INTRODUCED by the Ministry of nonferrous metallurgy of the USSR
DEVELOPERS
A. A. Kuranov, G. S. HAK, N. With. Stepanova, N. D. Sergienko, I. G., Sazhin, T. I. Belyaeva
2. APPROVED AND put INTO EFFECT by Decision of the USSR State Committee for standards from
3. REPLACE GOST 12555−67 in part of sec. 2
4. REFERENCE NORMATIVE AND TECHNICAL DOCUMENTS
The designation of the reference document referenced |
Item number |
GOST 1770−74 |
Sec. 2 |
GOST 4217−77 |
Sec. 2 |
GOST 4233−77 |
Sec. 2 |
GOST 4461−77 |
Sec. 2 |
GOST 6836−80 |
Sec. 2 |
GOST 22864−83 |
1.1 |
GOST 24104−88 |
Sec. 2 |
GOST 25336−82 |
Sec. 2 |
GOST 29251−91 |
Sec. 2 |
5. Limitation of actions taken by Protocol No. 3−93 Interstate Council for standardization, Metrology and certification (ICS 5−6-93)
6. The re-release (Feb 1999) with amendment No. 1, approved in September 1988 (IUS 1−89)
This standard sets the potentiometric method for the determination of silver (at a weight ratio of 30.0 to 97,0%) in the silver-platinum alloys.
The method is based on potentiometric titration of silver ion with a sodium chloride solution up to a predetermined value the potential difference with the use of automatic titration unit. The indicator electrode is a silver wire. As the reference electrode used silver chloride electrode, filled with saturated solution of potassium nitrate.
1. GENERAL REQUIREMENTS
1.1. General requirements for method of analysis according to GOST 22864.
1.2. The numerical value of the result of the analysis must end with the digit the same category, and permissible differences.
(Added, Rev. N 1).
2. APPARATUS, REAGENTS AND SOLUTIONS
Laboratory scales for General purpose model GOST 24104*.
______________
* On the territory of the Russian Federation GOST 24104−2001. — Note the manufacturer’s database.
pH meter laboratory type millivoltmeter pH-121.
The block automatic titration lab BAT-15.
Electrode flat — wire silver SR 999,9 according to GOST 6836*.
________________
* On the territory of the Russian Federation GOST 6836−2002. Here and further. — Note the manufacturer’s database.
The reference electrode AVL-1M3.
Volumetric flasks according to GOST 1770, with a capacity of 1000 cm.
Beakers, glass, laboratory for GOST 25336, with a capacity of 150 cm.
Burette with automatic zero adjustment according to GOST 29251, with a capacity of 50 cm.
Silver brand 999,9 according to GOST 6836.
Nitric acid according to GOST 4461, diluted 1:1.
Potassium nitrate according to GOST 4217, saturated solution.
Sodium chloride according to GOST 4233, solution of concentration 0.1 mol/DM; prepare fiksanal 0.1 g·EQ/DMor 5,85 g of sodium chloride dissolved in water and the volume was adjusted to 1000 cm.
Determination of the mass concentration of the solution of concentration 0.1 mol/DMsodium chloride on silver:
a portion of silver with a mass of 0.40−0.45 g (take three parallel sample), weighed with an accuracy of more than 0.0001 g, placed in a beaker with a capacity of 150 cmand dissolved by heating in 10 cmof nitric acid (1:1). The solution is heated to remove oxides of nitrogen and diluted with distilled water to about 50 cm. After cooling, the solution of silver titrated with a solution of concentration 0.1 mol/DMsodium chloride as specified in sec. 4.
Mass concentration of sodium chloride solution to silver (), expressed in g/cm, is calculated by the formula
,
where is the mass of the silver sample, g;
— the amount of sodium chloride consumed for titration, sm.
Mass concentration of sodium chloride solution is determined before the analysis. Shelf life of sodium chloride solution 2−3 months.
(Changed edition, Rev. N 1).
3. PREPARATION FOR ASSAY
A sample of alloy weighing 0.5 g were placed in a glass with a capacity of 150 cmand dissolved by heating in 10 cmof nitric acid (1:1) for 30 min. after dissolving, the solution is heated to remove oxides of nitrogen and diluted with distilled water to about 50 cm.
4. ANALYSIS
Include to power supply devices rn-121 and BAHT 15. After warming up for 30 minutes set the switches of the devices in position:
pH-121 |
|||
Swipe |
from minus 1 to plus 14 | ||
«Line of work» | +mV |
BAT-15 |
|||
«Target point" |
The 3.0 and 3.4 | ||
«Excerpt" |
10 | ||
«Zone" |
1 | ||
«Up and down» | down |
Not filtering out the precipitate of platinum into the solution is dipped a stirring rod, electrodes and a metering tube, which should be located close to the indicator electrode, in order to avoid perelitsovyvat solution.
The solution is diluted with distilled water to a volume in which the working parts of the electrodes would be immersed in the solution.
Include the stirrer and begin the titration with a solution of sodium chloride is pressed on the block automatic titration of the keys «start» and «On». The beginning of the process of titration is accompanied by a fire warning light and «Process». The titration was carried out until a predetermined point in the 3.0 to 3.4, which is determined by the curve of potentiometric titration of a solution of silver nitrate solution of concentration 0.1 mol/DMsodium chloride. At the end of the titration the indicator light «End» and stops flow through the metering tube of a sodium chloride solution. Then press the keys «start» and «On»; turn off the magnetic stirrer, remove from the glass electrodes and a stirring rod, and wash them with distilled water. Record the volume of solution consumed for titration (accuracy 0.1 cm).
(Changed edition, Rev. N 1).
5. PROCESSING OF THE RESULTS
5.1. Mass fraction of silver () in percent is calculated by the formula
,
where is the mass of the sample analyzed alloy, g;
— the amount of sodium chloride consumed for titration, cm;
the titer of a solution of sodium chloride of silver, g/cm.
5.2. The difference between the highest and lowest results of parallel measurements at a confidence probability of 0.95 does not exceed the absolute value of the admitted discrepancies of 0.25%.
The difference between two results of analysis of the same sample obtained in different laboratories, should not exceed the absolute value of the admitted differences of 0.35%.
(Changed edition, Rev. N 1).
5.3. Control the accuracy of the results definition of the mass fraction of silver is playing its mass fraction in the artificial mixtures the chemical composition close to the composition of the analyzed alloy, drawn through the entire course of the analysis.
The sample analysis results are considered accurate if the absolute difference between the largest and smallest values of the mass fraction of silver in the artificial mixture does not exceed 0,20%.
(Added, Rev. N 1).