GOST R 51014-97
GOST R 51014−97 calcium Babbits. Method of atomic-absorption determination of zinc
GOST R 51014−97
Group B59
STATE STANDARD OF THE RUSSIAN FEDERATION
CALCIUM BABBITS
Method of atomic-absorption determination of zinc
Lead calcium bearing alloys.
Method of atomic absorption of zinc
OKS 77.040*
AXTU 77080
____________________
* In the index «National standards», 2008
OKS
Date of introduction 1997−07−01
Preface
1 DEVELOPED AND INTRODUCED by the Russian research Institute of railway transport (VNIIZHT) of the Ministry of communications of the Russian Federation
2 ADOPTED AND put INTO EFFECT by the Resolution of Gosstandart of Russia of 22 January 1997 No. 11
3 INTRODUCED FOR THE FIRST TIME
1 SCOPE
This standard establishes the method of atomic absorption determination of zinc in calcium babbits for rail transport in the range of from 0.1 to 1.0%.
The method is based on the change in absorption of the zinc atoms in the flame acetylene-air at a wavelength of 213,8 nm.
2 NORMATIVE REFERENCES
The present standard features references to the following standards:
GOST 1209−90 calcium Babbits. Specifications
GOST 3640−94 Zinc. Specifications
GOST 4461−77 nitric Acid. Specifications
GOST 25086−87 Nonferrous alloys. General requirements for methods of analysis
3 GENERAL REQUIREMENTS
3.1 Selection and preparation of samples for analysis of zinc is carried out according to GOST 1209.
3.2 requirements for the method of analysis of zinc set by GOST 25086 (for two parallel determinations).
The maximum discrepancy between the results of the analysis of the same samples obtained in two laboratories or in one laboratory, but in different conditions, should not exceed the permissible discrepancy of the two results of the analysis indicated in table 1.
Table 1
| Mass fraction of zinc, % |
The absolute allowable difference |
| 0,01−0,25 |
0,02 |
| 0,25−0,50 |
0,03 |
| 0,50−1,00 |
0,05 |
4 APPARATUS, REAGENTS AND SOLUTIONS USED IN THE PROCEDURE
Atomic absorption spectrophotometer.
Lamp with hollow cathode for measuring the radiation of zinc.
Nitric acid according to GOST 4461, 1:1.
Zinc metal according to GOST 3640 mass fraction of zinc not less than 99.9%.
Standard solutions of zinc:
Solution a: 1 g of zinc is dissolved in 20 cmof hydrochloric acid 1:1, cooled, transferred into a measuring flask with volume capacity of 1000 cm
and the volume was adjusted to the mark with water. 1 cm
of the solution contains 0.001 g of zinc.
Solution B: 10 cmsolution And transferred to a volumetric flask with a capacity of 100 cm
and the volume was adjusted to the mark with water. 1 cm
of a solution contains 0.0001 g of zinc.
5 ANALYSIS
A portion of calcium babbit weighing 1 g is placed in a beaker with a capacity of 250 cmand dissolved in 15 cm.
of nitric acid of 1:1 by heating the mixture. The contents of the beaker cooled to room temperature and transferred to a volumetric flask with a capacity of 100 cm
, the volume was adjusted to the mark with water and mix. Filtered a portion of solution from the precipitated tin through the dense filter filtrowanie weight of the dry glass with a capacity of 100 cm
. Take 20 cm
of filtered solution in the zinc content of from 0.1 to 0.5% or 10 cm
when the content of zinc of 0.5 to 1.0% in volumetric flask with a capacity of 100 cm
, the volume was adjusted to the mark with water and mix. Use these solutions for the absorption in the flame acetylene-air at a wavelength of 213,8 nm parallel to the calibration solutions. At the same time do control the experience on the reagents used in the analysis
.
5.1 Construction of calibration curve
For construction of calibration curve six volumetric flasks with a capacity of 100 cmeach placed 1, 2, 4, 8, 10, and 20 cm
of a standard solution of zinc B. the Solutions was adjusted to the mark with water, mix and measure the atomic absorption of zinc under the conditions described above. According to the obtained results build a calibration curve.
6 PROCESSING OF THE RESULTS OF THE ANALYSIS
6.1 Mass fraction of zinc , %, is calculated by the formula
where — concentration of zinc was found in the calibration schedule, g/cm
;
— the volume of the final sample solution subject to dilution, cm
;
— the weight of the portion of the babbit in the final volume of the solution,
6.2 Differences between results of two parallel measurements at a confidence level =0.95 does not exceed the values listed in table 1.
