GOST 20580.8-80
GOST 20580.8−80 (ST SEV 913−78) Lead. Method for determination of iron (with Change No. 1)
GOST 20580.8−80
(ST CMEA 913−78)
Group B59
STATE STANDARD OF THE USSR
LEAD
Method for determination of iron
Lead. Method for the determination of iron
AXTU 1709*
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* Introduced advanced Edit. N 1.
Date of introduction 1980−12−01
Resolution of the USSR State Committee for standards, dated April 29, 1980, N 1976 the period of validity set with 01.12.80
Proven in 1983 by the Decree of Gosstandart from
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* Expiration removed by Protocol No. 7−95 Interstate Council for standardization, Metrology and certification. (IUS N 11, 1995). — Note the manufacturer’s database.
REPLACE GOST 20580.8−75
REPRINTING. December 1984
The Change N 1, approved and put into effect by the Decree of the USSR State Committee on management of quality and standards from
Change No. 1 made by the manufacturer of the database in the text IUS N 11, 1990
This standard sets the photometric method for determination of iron from 0.0005 to 0.015% lead (99,992−99,5%).
The method is based on the formation of complex compounds -fenantrolina with ions of bivalent iron at a pH of 2−9 and fotomaterialy obtained orange-red solution at a wavelength of 508 nm.
The standard fully complies ST SEV 913−78.
1. GENERAL REQUIREMENTS
1.1 General requirements to the method of analysis and security requirements — according to GOST 20580.0−80.
(Changed edition, Rev. N 1).
2. APPARATUS, REAGENTS AND SOLUTIONS
Spectrophotometer or photoelectrocolorimeter of any kind for measurements in the visible region of the spectrum.
Nitric acid GOST 4461−77 and diluted 1:1, 1:2 and 1:9.
Hydroxylamine hydrochloric acid according to GOST 5456−79, a solution with a mass concentration of 100 g/DM, freshly prepared.
Sodium acetate according to GOST 199−78, a solution with a mass concentration of 250 g/DM.
-phenanthrolin hydrochloride dnovotny, a solution with a mass concentration of 5 g/DM, freshly prepared.
Iron powder restored brand MLB-1 according to GOST 9849−86 or iron (III) oxide on the other 6−09−5346−87*.
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* The one mentioned here, are not given. For additional information, please refer to the link. — Note the manufacturer’s database.
Standard solutions of iron.
Solution a: 0,100 g of iron or 0,143 g of iron (III) oxide is dissolved in 5 cmof nitric acid (1:1), add 25 cmof water and heated to boiling. The solution was cooled, transferred to a measuring flask with volume capacity of 1000 cm, flow 10 cmof nitric acid, dilute to the mark with water and mix.
1 cmof solution A contains 0.1 mg of iron.
Solution B: 10 cmof solution A diluted with water in a volumetric flask with a capacity of 100 cmand mixed.
1 cmof a solution contains 0.01 mg of iron.
(Changed edition, Rev. N 1).
3. ANALYSIS
3.1 Shavings of lead is treated with a magnet to remove particles of iron that fall when grinding metal.
Depending on the expected mass fraction of iron you take charge, the mass of which are listed in table.1.
Table 1
Mass fraction of iron, % |
The mass of charge, g | |||
From |
0,0005 | to | 0,001 | 2,000 |
SV. |
0,001 | « | 0,005 | 1,000 |
« | 0,005 |
« | 0,008 | 0,500 |
« | 0,008 |
« | 0,015 | 0,250 |
A portion of the lead dissolved in 15 cmof nitric acid (1:2), evaporated to dryness, the dry residue dissolved in 10 cmof nitric acid (1:9). Add about 10 cmof a solution of sodium acetate to obtain pH 3.5. Transfer the solution into a measuring flask with a capacity of 25 cm. Then add 1 cmof a solution of hydrochloric acid hydroxylamine, 2 cmof mortar -phenantroline and topped to the mark with water. After addition of each reagent the solution was stirred. After 30 min measure the optical density of colored solution at a wavelength of 508 nm. Solution comparison is the solution of the reference experiment.
The amount of iron in kalorimetricheskim volume set calibration schedule.
(Changed edition, Rev. N 1).
3.2 To build a calibration curve in five out of six volumetric flasks with a capacity of 25 cmis placed 1,0; 2,0; 3,0; 4,0 and 5,0 cmstandard solution B. the Sixth flask is used for the reference experiment. All six volumetric flasks poured 10 cmof nitric acid (1:9) and then received, as indicated in paragraph 3.1.
According to the obtained values of optical density of solutions and their corresponding weight fractions of iron to build the calibration graph.
4. PROCESSING OF THE RESULTS
4.1 Mass fraction of iron () in percent is calculated by the formula
,
where is the mass of iron was found in the calibration schedule g;
— its weight of lead,
4.2. Allowable absolute discrepancies in the results of parallel measurements and the results of the analysis shall not exceed the values given in table.2.
Table 2
Mass fraction of iron, % | The allowable divergence of the parallel definitions % |
Permissible discrepancies in the results of the analysis % |
To from 0,0005 0,0010 incl. | 0,0003 |
0,0004 |
SV. 0,0010 «0,0030 « | 0,0005 |
About 0.0006 |
«0,0030» 0,0050 « | About 0.0006 |
0,0008 |
«0,0050» 0,0100 « | 0,0010 |
0,0013 |
«Of 0.010» to 0.015 « | 0,001 |
0,002 |
(Changed edition, Rev. N 1).
The electronic text of the document
prepared by JSC «Code» and checked by:
the official publication of the
Lead. Methods of chemical analysis.
GOST 20580.0−80 — GOST 20580.12−80: a Collection of Standards. -
M.: Publishing house of standards, 1985