GOST 11930.12-79
GOST 11930.12−79 Materials surfacing. Method for the determination of antimony (with Amendments No. 1, 2)
GOST 11930.12−79
Group B09
INTERSTATE STANDARD
MATERIALS SURFACING
Method for the determination of antimony
Hard-facing materials. Method of antimony determination
ISS 25.160.20
AXTU 1709
Date of introduction 1980−07−01
The decision of the State Committee USSR on standards on March 21, 1979 N 982 date of introduction is established 01.07.80
Limitation of actions taken by Protocol No. 4−93 of the Interstate Council for standardization, Metrology and certification (ICS 4−94)
EDITION (August 2011) with Amendments No. 1, 2 approved in December 1984, December 1989 (IUS 3−85, 3−90)
This standard establishes photocolorimetric method for the determination of antimony (in mass fraction of antimony from 0.01 to 0.2%) in rods for surfacing.
The method is based on formation of colored complex compounds of pentavalent antimony with methyl violet and the last extraction with toluene.
(Changed edition, Rev. N 2).
1. GENERAL REQUIREMENTS
1.1. General requirements for method of analysis according to GOST 11930.0−79.
2. APPARATUS, REAGENTS AND SOLUTIONS
Brands photoelectrocolorimeter FEK-56M and FEK-56 or any type.
Sulfuric acid GOST 4204−77, diluted 1:4.
Nitric acid GOST 4461−77.
Hydrochloric acid by the GOST 3118−77, diluted 1:1.
Sodium atomistically according to GOST 4168−79, a solution with a mass fraction of 10%.
Urea according to GOST 6691−77; prepared as follows: 100 g dissolved in 100 cmof hot water.
Methyl violet is prepared as follows: 0.2 g dissolved in 100 cmof hot water and filtered.
Toluene according to GOST 5789−78.
Antimony GOST 1089−82.
Solution antimony standard; prepared as follows: 0.05 g of metallic antimony is dissolved in 25 cmof concentrated sulfuric acid. The solution is poured into a measuring flask with a capacity of 500 cm
, add 25 cm
of concentrated sulfuric acid, then topped up to the mark with water and mix.
For preparation of working solution, a standard solution of antimony is diluted 10 times.
1 cmof the solution contains 0,00001 g of antimony.
3. ANALYSIS
3.1. The weight of the portion, the capacity of volumetric flasks and aliquota part of the solution, depending on the mass fraction of antimony should match the table.1.
Table 1
| Mass fraction of SB, % | The mass of charge, g | Capacity volumetric flasks, cm |
The volume aliquote part, see |
| 0,01−0,02 | 0,3 | - | - |
| 0,03−0,07 | 0,1 | - | - |
| 0,08−0,2 | 0,2 | 50 | 10 |
The sample is placed in a beaker with a capacity of 100 cmand dissolved in 20 cm
of sulphuric acid, diluted 1:4, followed by the addition of 1 cm
of nitric acid. The solution was evaporated twice to fumes of sulphuric anhydride. In a glass pour 10 cm
of hydrochloric acid diluted 1:1, transfer the contents of the Cup with a separating funnel, rinse the beaker with a little water so that the volume of the solution in separating funnel was not more than 25 cm
. Then injected 1 cm
of a solution of sodium attestatio, shake the solution for 2 min and leave it for 3 minutes at most for the oxidation of antimony.
In a separatory funnel pour 0.5 cmof the urea solution, shake well (without tube) the solution is not more than 30 seconds, quickly add 40 cm
of water, 0.25 cm
of methyl violet, rapidly stirred (closed tube) three times and immediately pour 25 cm
of toluene, and again thoroughly shaken for 2 min.
After separation of layers the aqueous layer drained and discarded, and the colored extract was transferred in cuvette with thickness of the absorbing layer 30 mm. Layer of toluene to give even stand for 5 min for final separation of water droplets and measure the optical density of colored solution on photocolorimeter with green filter (540 nm).
All operations after perelivania sodium nitrite must be performed quickly.
3.2. Construction of calibration curve
In the separatory funnel is placed a standard solution of antimony in an amount of from 2 to 8 cmwith an interval of 1 cm
, 10 cm
of hydrochloric acid diluted 1:1, then pour 1 cm
of a solution of sodium attestatio and further analysis are as indicated in claim 3.1.
4. PROCESSING OF THE RESULTS
4.1. Mass fraction of antimony () in percent is calculated by the formula
where is the mass of antimony, was found in the calibration schedule g;
— the mass of sample, g;
— the volume of the analyzed solution, cm
;
— aliquota part of the analyzed solution, cm
.
4.2. The difference between the largest and smallest results of the three parallel measurements, and the two results of the analysis at a confidence level of 0.95, should not exceed the values of permissible differences given in table.2.
Table 2
| Mass fraction of SB, % | The allowable divergence of the three parallel definitions % |
Permissible discrepancies in the results of the analysis % | ||||
| From | 0,010 | to | 0,100 | incl. | 0,002 | 0,004 |
| SV. | 0,100 | « | 0,200 | « | 0,005 | 0,010 |
(Changed edition, Rev. N 2).
